Original Posted By: Patcoolnet(at)aol.com
Subject: Pietenpol-List: Re: Airfoils>Last time I wrote, I was looking at drawings of the Sky Scout, with ideas>about using an A75 for power. My spouse caught me studying those drawingsand>said something to the effect that "Wait a minute! There's only one seat!">End of consideration. Ergo, I'm working on my long delayed AirCamper, tobe>powered by the self-same A75. I've now glued up the rudder, and if I dosay>so myself, it don't look bad...at least for a first effort at aircraft>cabinetry..>>Now for the poser. Given that BP designed a good airfoil for theAirCamper,>there have been advances in aerodynamics, and I have to wonder about usinga>bit more modern airfoil...the 4412 comes easily to mind. Has anyone any>actual experience with this? Is there some great advantage to using the>modified Eiffel, or is there some great disadvantage to using the 4412. It>seems that I might get a little more lift and a tad more speed from the4412,>but I am not an engineer. While I appreciate the purist philosophy, and>intend to stick closely to plans, (BP 1933), I think it's appropriate to>explore some minor changes to make minor improvements in performance and or>utility. I'd sure appreciate input from the group. Thanx!>>________________________________________________________________________________
Pietenpol-List: Re: Airfoils
Pietenpol-List: Re: Airfoils
Original Posted By: oil can
Last time I wrote, I was looking at drawings of the Sky Scout, with ideasabout using an A75 for power. My spouse caught me studying those drawings andsaid something to the effect that "Wait a minute! There's only one seat!"End of consideration. Ergo, I'm working on my long delayed AirCamper, to bepowered by the self-same A75. I've now glued up the rudder, and if I do sayso myself, it don't look bad...at least for a first effort at aircraftcabinetry.. Now for the poser. Given that BP designed a good airfoil for the AirCamper,there have been advances in aerodynamics, and I have to wonder about using abit more modern airfoil...the 4412 comes easily to mind. Has anyone anyactual experience with this? Is there some great advantage to using themodified Eiffel, or is there some great disadvantage to using the 4412. Itseems that I might get a little more lift and a tad more speed from the 4412,but I am not an engineer. While I appreciate the purist philosophy, andintend to stick closely to plans, (BP 1933), I think it's appropriate toexplore some minor changes to make minor improvements in performance and orutility. I'd sure appreciate input from the group. Thanx! ________________________________________________________________________________
Last time I wrote, I was looking at drawings of the Sky Scout, with ideasabout using an A75 for power. My spouse caught me studying those drawings andsaid something to the effect that "Wait a minute! There's only one seat!"End of consideration. Ergo, I'm working on my long delayed AirCamper, to bepowered by the self-same A75. I've now glued up the rudder, and if I do sayso myself, it don't look bad...at least for a first effort at aircraftcabinetry.. Now for the poser. Given that BP designed a good airfoil for the AirCamper,there have been advances in aerodynamics, and I have to wonder about using abit more modern airfoil...the 4412 comes easily to mind. Has anyone anyactual experience with this? Is there some great advantage to using themodified Eiffel, or is there some great disadvantage to using the 4412. Itseems that I might get a little more lift and a tad more speed from the 4412,but I am not an engineer. While I appreciate the purist philosophy, andintend to stick closely to plans, (BP 1933), I think it's appropriate toexplore some minor changes to make minor improvements in performance and orutility. I'd sure appreciate input from the group. Thanx! ________________________________________________________________________________
Pietenpol-List: Re: Airfoils
Original Posted By: "David B. Schober"
I spoke with Harry Riblett at OshKosh this year at he says the airfoilon the Piet has a sharp stall characteristic. By this, he is meaningthat there is very little burble transistion from being attached airflow to the stalled un-attached air flow. He scared me a littleby stating he knew of one person who had stall-spun ina piet, survived unscathed, and proceded to do it a second time. Iassumed he survived since he said he did not indicate otherwise.He recommended to me an airfoil in his book, GA Aifoils, the numberof which I think was 30615 or 15630 or something like it (my notes areat home). When I plotted a 60 inch chord based on this airfoil, andcompared it to the Piet airfoil, the trailing edge top surface for thelast 12 inches or so is the same, the top surface for the leading edgefor the first 6 inches or so is the same, but the remaining portionis much different. The top surface is 2 inches higher and thelower surface is about 2 inches lower at the thickest portion (yes,the thickness is about 9 inches verses the Piet at 5 inches). A littleaggressive to making it a replacement. Center of lift, liftcoefficent, L/D ratio, etc... comparisons to Piet are a littledifficult without having the data for the Piet airfoil. I believethis project stems into new design. A test pilot I am not.His book is very infomative with insites to airfoil design, so thepurchase was not a waste. It runs about $17 for it from EAA.I spoke with Warren Wiggett who drove to Broadhead this year andhe had modified his Piet, which first flew in July I think, withadvise he received from Harry. His modification was to addthickness to the leading edge between the 3inch to 12 inch areaof about 1/4 inch and also to the lower edge in the 2inch to 5 incharea of about 1/8 inch. He did so with plywood sheeting andsays that the test pilot "felt" that there was some improvementin takeoff performance, and said his cruise was about 70mph.I believe there may be better knowledge of airfoils today, Harrybeing a very good, general aviation supporter who has suchexpertise, which could be applied to the Piet design."Modifications - The Bad And The Ugly" at OshKoshthis year (different aero-nut engineer guy) told me that anymodification has potential to change any and every othercharacteristic of the airplane, making it a fully un-tested,possible killing machine. He had very few examples, butnone the less scary enough to leave an impression.His basic premise was - if not broke, don't fix it.ADonJr(at)aol.com wrote:> Last time I wrote, I was looking at drawings of the Sky Scout, with ideas> about using an A75 for power. My spouse caught me studying those drawings and> said something to the effect that "Wait a minute! There's only one seat!"> End of consideration. Ergo, I'm working on my long delayed AirCamper, to be> powered by the self-same A75. I've now glued up the rudder, and if I do say> so myself, it don't look bad...at least for a first effort at aircraft> cabinetry..>> Now for the poser. Given that BP designed a good airfoil for the AirCamper,> there have been advances in aerodynamics, and I have to wonder about using a> bit more modern airfoil...the 4412 comes easily to mind. Has anyone any> actual experience with this? Is there some great advantage to using the> modified Eiffel, or is there some great disadvantage to using the 4412. It> seems that I might get a little more lift and a tad more speed from the 4412,> but I am not an engineer. While I appreciate the purist philosophy, and> intend to stick closely to plans, (BP 1933), I think it's appropriate to> explore some minor changes to make minor improvements in performance and or> utility. I'd sure appreciate input from the group. Thanx!>--/-------------------- |~~_____/~~__ ||scott(at)haulpak.com | o' ~~|~~~ |title: Design Engineertel;work: 309-672-7706tel;fax: 309-672-7753tel;home: not posted________________________________________________________________________________
I spoke with Harry Riblett at OshKosh this year at he says the airfoilon the Piet has a sharp stall characteristic. By this, he is meaningthat there is very little burble transistion from being attached airflow to the stalled un-attached air flow. He scared me a littleby stating he knew of one person who had stall-spun ina piet, survived unscathed, and proceded to do it a second time. Iassumed he survived since he said he did not indicate otherwise.He recommended to me an airfoil in his book, GA Aifoils, the numberof which I think was 30615 or 15630 or something like it (my notes areat home). When I plotted a 60 inch chord based on this airfoil, andcompared it to the Piet airfoil, the trailing edge top surface for thelast 12 inches or so is the same, the top surface for the leading edgefor the first 6 inches or so is the same, but the remaining portionis much different. The top surface is 2 inches higher and thelower surface is about 2 inches lower at the thickest portion (yes,the thickness is about 9 inches verses the Piet at 5 inches). A littleaggressive to making it a replacement. Center of lift, liftcoefficent, L/D ratio, etc... comparisons to Piet are a littledifficult without having the data for the Piet airfoil. I believethis project stems into new design. A test pilot I am not.His book is very infomative with insites to airfoil design, so thepurchase was not a waste. It runs about $17 for it from EAA.I spoke with Warren Wiggett who drove to Broadhead this year andhe had modified his Piet, which first flew in July I think, withadvise he received from Harry. His modification was to addthickness to the leading edge between the 3inch to 12 inch areaof about 1/4 inch and also to the lower edge in the 2inch to 5 incharea of about 1/8 inch. He did so with plywood sheeting andsays that the test pilot "felt" that there was some improvementin takeoff performance, and said his cruise was about 70mph.I believe there may be better knowledge of airfoils today, Harrybeing a very good, general aviation supporter who has suchexpertise, which could be applied to the Piet design."Modifications - The Bad And The Ugly" at OshKoshthis year (different aero-nut engineer guy) told me that anymodification has potential to change any and every othercharacteristic of the airplane, making it a fully un-tested,possible killing machine. He had very few examples, butnone the less scary enough to leave an impression.His basic premise was - if not broke, don't fix it.ADonJr(at)aol.com wrote:> Last time I wrote, I was looking at drawings of the Sky Scout, with ideas> about using an A75 for power. My spouse caught me studying those drawings and> said something to the effect that "Wait a minute! There's only one seat!"> End of consideration. Ergo, I'm working on my long delayed AirCamper, to be> powered by the self-same A75. I've now glued up the rudder, and if I do say> so myself, it don't look bad...at least for a first effort at aircraft> cabinetry..>> Now for the poser. Given that BP designed a good airfoil for the AirCamper,> there have been advances in aerodynamics, and I have to wonder about using a> bit more modern airfoil...the 4412 comes easily to mind. Has anyone any> actual experience with this? Is there some great advantage to using the> modified Eiffel, or is there some great disadvantage to using the 4412. It> seems that I might get a little more lift and a tad more speed from the 4412,> but I am not an engineer. While I appreciate the purist philosophy, and> intend to stick closely to plans, (BP 1933), I think it's appropriate to> explore some minor changes to make minor improvements in performance and or> utility. I'd sure appreciate input from the group. Thanx!>--/-------------------- |~~_____/~~__ ||scott(at)haulpak.com | o' ~~|~~~ |title: Design Engineertel;work: 309-672-7706tel;fax: 309-672-7753tel;home: not posted________________________________________________________________________________
Pietenpol-List: Re: Airfoils
Original Posted By: Michael D Cuy
Maybe A little wash out in each wing tip would help to keep the entire wingfrom stalling out at the same time ?>If you want to compare the Piet airtfoil to others you need to get data onthe Piet>airfoil. You can try to get Dr. Patrick Hanley to run the coordinates thruhis>Visual Airfoil program. He ran another airfoil (the one on my Howard DGA)and was>very helpful. His E-Mail is hanley(at)hanleyinnovations.com>>I've seen Piets with different airfoils and never saw any real improvement.Of all>the Piets I've flown (one "A", one corvair and one A-65) all had theoriginal>airfoil and none had bad stall charicteristics. All were a blast to fly!The "A" was>the best!>>David Scott wrote:>>> I spoke with Harry Riblett at OshKosh this year at he says the airfoil>> on the Piet has a sharp stall characteristic. By this, he is meaning>> that there is very little burble transistion from being attached air>> flow to the stalled un-attached air flow. He scared me a little>> by stating he knew of one person who had stall-spun in>> a piet, survived unscathed, and proceded to do it a second time. I>> assumed he survived since he said he did not indicate otherwise.>>>> He recommended to me an airfoil in his book, GA Aifoils, the number>> of which I think was 30615 or 15630 or something like it (my notes are>> at home). When I plotted a 60 inch chord based on this airfoil, and>> compared it to the Piet airfoil, the trailing edge top surface for the>> last 12 inches or so is the same, the top surface for the leading edge>> for the first 6 inches or so is the same, but the remaining portion>> is much different. The top surface is 2 inches higher and the>> lower surface is about 2 inches lower at the thickest portion (yes,>> the thickness is about 9 inches verses the Piet at 5 inches). A little>> aggressive to making it a replacement. Center of lift, lift>> coefficent, L/D ratio, etc... comparisons to Piet are a little>> difficult without having the data for the Piet airfoil. I believe>> this project stems into new design. A test pilot I am not.>>>> His book is very infomative with insites to airfoil design, so the>> purchase was not a waste. It runs about $17 for it from EAA.>>>> I spoke with Warren Wiggett who drove to Broadhead this year and>> he had modified his Piet, which first flew in July I think, with>> advise he received from Harry. His modification was to add>> thickness to the leading edge between the 3inch to 12 inch area>> of about 1/4 inch and also to the lower edge in the 2inch to 5 inch>> area of about 1/8 inch. He did so with plywood sheeting and>> says that the test pilot "felt" that there was some improvement>> in takeoff performance, and said his cruise was about 70mph.>>>> I believe there may be better knowledge of airfoils today, Harry>> being a very good, general aviation supporter who has such>> expertise, which could be applied to the Piet design.>>>> "Modifications - The Bad And The Ugly" at OshKosh>> this year (different aero-nut engineer guy) told me that any>> modification has potential to change any and every other>> characteristic of the airplane, making it a fully un-tested,>> possible killing machine. He had very few examples, but>> none the less scary enough to leave an impression.>>>> His basic premise was - if not broke, don't fix it.>>>> ADonJr(at)aol.com wrote:>>>> > Last time I wrote, I was looking at drawings of the Sky Scout, withideas>> > about using an A75 for power. My spouse caught me studying thosedrawings and>> > said something to the effect that "Wait a minute! There's only oneseat!">> > End of consideration. Ergo, I'm working on my long delayed AirCamper,to be>> > powered by the self-same A75. I've now glued up the rudder, and if Ido say>> > so myself, it don't look bad...at least for a first effort at aircraft>> > cabinetry..>> >>> > Now for the poser. Given that BP designed a good airfoil for theAirCamper,>> > there have been advances in aerodynamics, and I have to wonder aboutusing a>> > bit more modern airfoil...the 4412 comes easily to mind. Has anyoneany>> > actual experience with this? Is there some great advantage to usingthe>> > modified Eiffel, or is there some great disadvantage to using the 4412.It>> > seems that I might get a little more lift and a tad more speed from the4412,>> > but I am not an engineer. While I appreciate the purist philosophy,and>> > intend to stick closely to plans, (BP 1933), I think it's appropriateto>> > explore some minor changes to make minor improvements in performanceand or>> > utility. I'd sure appreciate input from the group. Thanx!>> >>> >ADonJr(at)AOL.com>>>> -->> /-------------------- |~~_____/~~__ |>> |scott(at)haulpak.com | o' ~~|~~~ |>>>> ------------------------------------------------------------------------>>>> David Scott >> Design Engineer>> Komatsu Mining Systems>>>> David Scott>> Design Engineer >> Komatsu Mining Systems>> 2300 NE Adams St Work: 309-672-7706>> U.S.A.>> Additional Information:>> Last Name Scott>> First Name David>> Version 2.1>>>-->**>David B.Schober, CPE>Instructor, Aviation Maintenance>Fairmont State College>National Aerospace Education Center>Rt. 3 Box 13>Bridgeport, WV 26330-9503>(304) 842-8300>>________________________________________________________________________________
Maybe A little wash out in each wing tip would help to keep the entire wingfrom stalling out at the same time ?>If you want to compare the Piet airtfoil to others you need to get data onthe Piet>airfoil. You can try to get Dr. Patrick Hanley to run the coordinates thruhis>Visual Airfoil program. He ran another airfoil (the one on my Howard DGA)and was>very helpful. His E-Mail is hanley(at)hanleyinnovations.com>>I've seen Piets with different airfoils and never saw any real improvement.Of all>the Piets I've flown (one "A", one corvair and one A-65) all had theoriginal>airfoil and none had bad stall charicteristics. All were a blast to fly!The "A" was>the best!>>David Scott wrote:>>> I spoke with Harry Riblett at OshKosh this year at he says the airfoil>> on the Piet has a sharp stall characteristic. By this, he is meaning>> that there is very little burble transistion from being attached air>> flow to the stalled un-attached air flow. He scared me a little>> by stating he knew of one person who had stall-spun in>> a piet, survived unscathed, and proceded to do it a second time. I>> assumed he survived since he said he did not indicate otherwise.>>>> He recommended to me an airfoil in his book, GA Aifoils, the number>> of which I think was 30615 or 15630 or something like it (my notes are>> at home). When I plotted a 60 inch chord based on this airfoil, and>> compared it to the Piet airfoil, the trailing edge top surface for the>> last 12 inches or so is the same, the top surface for the leading edge>> for the first 6 inches or so is the same, but the remaining portion>> is much different. The top surface is 2 inches higher and the>> lower surface is about 2 inches lower at the thickest portion (yes,>> the thickness is about 9 inches verses the Piet at 5 inches). A little>> aggressive to making it a replacement. Center of lift, lift>> coefficent, L/D ratio, etc... comparisons to Piet are a little>> difficult without having the data for the Piet airfoil. I believe>> this project stems into new design. A test pilot I am not.>>>> His book is very infomative with insites to airfoil design, so the>> purchase was not a waste. It runs about $17 for it from EAA.>>>> I spoke with Warren Wiggett who drove to Broadhead this year and>> he had modified his Piet, which first flew in July I think, with>> advise he received from Harry. His modification was to add>> thickness to the leading edge between the 3inch to 12 inch area>> of about 1/4 inch and also to the lower edge in the 2inch to 5 inch>> area of about 1/8 inch. He did so with plywood sheeting and>> says that the test pilot "felt" that there was some improvement>> in takeoff performance, and said his cruise was about 70mph.>>>> I believe there may be better knowledge of airfoils today, Harry>> being a very good, general aviation supporter who has such>> expertise, which could be applied to the Piet design.>>>> "Modifications - The Bad And The Ugly" at OshKosh>> this year (different aero-nut engineer guy) told me that any>> modification has potential to change any and every other>> characteristic of the airplane, making it a fully un-tested,>> possible killing machine. He had very few examples, but>> none the less scary enough to leave an impression.>>>> His basic premise was - if not broke, don't fix it.>>>> ADonJr(at)aol.com wrote:>>>> > Last time I wrote, I was looking at drawings of the Sky Scout, withideas>> > about using an A75 for power. My spouse caught me studying thosedrawings and>> > said something to the effect that "Wait a minute! There's only oneseat!">> > End of consideration. Ergo, I'm working on my long delayed AirCamper,to be>> > powered by the self-same A75. I've now glued up the rudder, and if Ido say>> > so myself, it don't look bad...at least for a first effort at aircraft>> > cabinetry..>> >>> > Now for the poser. Given that BP designed a good airfoil for theAirCamper,>> > there have been advances in aerodynamics, and I have to wonder aboutusing a>> > bit more modern airfoil...the 4412 comes easily to mind. Has anyoneany>> > actual experience with this? Is there some great advantage to usingthe>> > modified Eiffel, or is there some great disadvantage to using the 4412.It>> > seems that I might get a little more lift and a tad more speed from the4412,>> > but I am not an engineer. While I appreciate the purist philosophy,and>> > intend to stick closely to plans, (BP 1933), I think it's appropriateto>> > explore some minor changes to make minor improvements in performanceand or>> > utility. I'd sure appreciate input from the group. Thanx!>> >>> >ADonJr(at)AOL.com>>>> -->> /-------------------- |~~_____/~~__ |>> |scott(at)haulpak.com | o' ~~|~~~ |>>>> ------------------------------------------------------------------------>>>> David Scott >> Design Engineer>> Komatsu Mining Systems>>>> David Scott>> Design Engineer >> Komatsu Mining Systems>> 2300 NE Adams St Work: 309-672-7706>> U.S.A.>> Additional Information:>> Last Name Scott>> First Name David>> Version 2.1>>>-->**>David B.Schober, CPE>Instructor, Aviation Maintenance>Fairmont State College>National Aerospace Education Center>Rt. 3 Box 13>Bridgeport, WV 26330-9503>(304) 842-8300>>________________________________________________________________________________
Pietenpol-List: Re: Airfoils
Original Posted By: Ken Hannan
If you want to compare the Piet airtfoil to others you need to get data on thePietairfoil. You can try to get Dr. Patrick Hanley to run the coordinates thru hisVisual Airfoil program. He ran another airfoil (the one on my Howard DGA) and wasvery helpful. His E-Mail is hanley(at)hanleyinnovations.comI've seen Piets with different airfoils and never saw any real improvement. Ofallthe Piets I've flown (one "A", one corvair and one A-65) all had the originalairfoil and none had bad stall charicteristics. All were a blast to fly! The "A"wasthe best!David Scott wrote:> I spoke with Harry Riblett at OshKosh this year at he says the airfoil> on the Piet has a sharp stall characteristic. By this, he is meaning> that there is very little burble transistion from being attached air> flow to the stalled un-attached air flow. He scared me a little> by stating he knew of one person who had stall-spun in> a piet, survived unscathed, and proceded to do it a second time. I> assumed he survived since he said he did not indicate otherwise.>> He recommended to me an airfoil in his book, GA Aifoils, the number> of which I think was 30615 or 15630 or something like it (my notes are> at home). When I plotted a 60 inch chord based on this airfoil, and> compared it to the Piet airfoil, the trailing edge top surface for the> last 12 inches or so is the same, the top surface for the leading edge> for the first 6 inches or so is the same, but the remaining portion> is much different. The top surface is 2 inches higher and the> lower surface is about 2 inches lower at the thickest portion (yes,> the thickness is about 9 inches verses the Piet at 5 inches). A little> aggressive to making it a replacement. Center of lift, lift> coefficent, L/D ratio, etc... comparisons to Piet are a little> difficult without having the data for the Piet airfoil. I believe> this project stems into new design. A test pilot I am not.>> His book is very infomative with insites to airfoil design, so the> purchase was not a waste. It runs about $17 for it from EAA.>> I spoke with Warren Wiggett who drove to Broadhead this year and> he had modified his Piet, which first flew in July I think, with> advise he received from Harry. His modification was to add> thickness to the leading edge between the 3inch to 12 inch area> of about 1/4 inch and also to the lower edge in the 2inch to 5 inch> area of about 1/8 inch. He did so with plywood sheeting and> says that the test pilot "felt" that there was some improvement> in takeoff performance, and said his cruise was about 70mph.>> I believe there may be better knowledge of airfoils today, Harry> being a very good, general aviation supporter who has such> expertise, which could be applied to the Piet design.>> "Modifications - The Bad And The Ugly" at OshKosh> this year (different aero-nut engineer guy) told me that any> modification has potential to change any and every other> characteristic of the airplane, making it a fully un-tested,> possible killing machine. He had very few examples, but> none the less scary enough to leave an impression.>> His basic premise was - if not broke, don't fix it.>> ADonJr(at)aol.com wrote:>> > Last time I wrote, I was looking at drawings of the Sky Scout, with ideas> > about using an A75 for power. My spouse caught me studying those drawingsand> > said something to the effect that "Wait a minute! There's only one seat!"> > End of consideration. Ergo, I'm working on my long delayed AirCamper, to be> > powered by the self-same A75. I've now glued up the rudder, and if I do say> > so myself, it don't look bad...at least for a first effort at aircraft> > cabinetry..> >> > Now for the poser. Given that BP designed a good airfoil for the AirCamper,> > there have been advances in aerodynamics, and I have to wonder about usinga> > bit more modern airfoil...the 4412 comes easily to mind. Has anyone any> > actual experience with this? Is there some great advantage to using the> > modified Eiffel, or is there some great disadvantage to using the 4412. It> > seems that I might get a little more lift and a tad more speed from the 4412,> > but I am not an engineer. While I appreciate the purist philosophy, and> > intend to stick closely to plans, (BP 1933), I think it's appropriate to> > explore some minor changes to make minor improvements in performance and or> > utility. I'd sure appreciate input from the group. Thanx!> >>> --> /-------------------- |~~_____/~~__ |> |scott(at)haulpak.com | o' ~~|~~~ |>> ------------------------------------------------------------------------>> David Scott > Design Engineer> Komatsu Mining Systems>> David Scott> Design Engineer > Komatsu Mining Systems> 2300 NE Adams St Work: 309-672-7706> U.S.A.> Additional Information:> Last Name Scott> First Name David> Version 2.1--David B.Schober, CPEInstructor, Aviation MaintenanceFairmont State CollegeNational Aerospace Education CenterRt. 3 Box 13Bridgeport, WV 26330-9503(304) 842-8300________________________________________________________________________________
If you want to compare the Piet airtfoil to others you need to get data on thePietairfoil. You can try to get Dr. Patrick Hanley to run the coordinates thru hisVisual Airfoil program. He ran another airfoil (the one on my Howard DGA) and wasvery helpful. His E-Mail is hanley(at)hanleyinnovations.comI've seen Piets with different airfoils and never saw any real improvement. Ofallthe Piets I've flown (one "A", one corvair and one A-65) all had the originalairfoil and none had bad stall charicteristics. All were a blast to fly! The "A"wasthe best!David Scott wrote:> I spoke with Harry Riblett at OshKosh this year at he says the airfoil> on the Piet has a sharp stall characteristic. By this, he is meaning> that there is very little burble transistion from being attached air> flow to the stalled un-attached air flow. He scared me a little> by stating he knew of one person who had stall-spun in> a piet, survived unscathed, and proceded to do it a second time. I> assumed he survived since he said he did not indicate otherwise.>> He recommended to me an airfoil in his book, GA Aifoils, the number> of which I think was 30615 or 15630 or something like it (my notes are> at home). When I plotted a 60 inch chord based on this airfoil, and> compared it to the Piet airfoil, the trailing edge top surface for the> last 12 inches or so is the same, the top surface for the leading edge> for the first 6 inches or so is the same, but the remaining portion> is much different. The top surface is 2 inches higher and the> lower surface is about 2 inches lower at the thickest portion (yes,> the thickness is about 9 inches verses the Piet at 5 inches). A little> aggressive to making it a replacement. Center of lift, lift> coefficent, L/D ratio, etc... comparisons to Piet are a little> difficult without having the data for the Piet airfoil. I believe> this project stems into new design. A test pilot I am not.>> His book is very infomative with insites to airfoil design, so the> purchase was not a waste. It runs about $17 for it from EAA.>> I spoke with Warren Wiggett who drove to Broadhead this year and> he had modified his Piet, which first flew in July I think, with> advise he received from Harry. His modification was to add> thickness to the leading edge between the 3inch to 12 inch area> of about 1/4 inch and also to the lower edge in the 2inch to 5 inch> area of about 1/8 inch. He did so with plywood sheeting and> says that the test pilot "felt" that there was some improvement> in takeoff performance, and said his cruise was about 70mph.>> I believe there may be better knowledge of airfoils today, Harry> being a very good, general aviation supporter who has such> expertise, which could be applied to the Piet design.>> "Modifications - The Bad And The Ugly" at OshKosh> this year (different aero-nut engineer guy) told me that any> modification has potential to change any and every other> characteristic of the airplane, making it a fully un-tested,> possible killing machine. He had very few examples, but> none the less scary enough to leave an impression.>> His basic premise was - if not broke, don't fix it.>> ADonJr(at)aol.com wrote:>> > Last time I wrote, I was looking at drawings of the Sky Scout, with ideas> > about using an A75 for power. My spouse caught me studying those drawingsand> > said something to the effect that "Wait a minute! There's only one seat!"> > End of consideration. Ergo, I'm working on my long delayed AirCamper, to be> > powered by the self-same A75. I've now glued up the rudder, and if I do say> > so myself, it don't look bad...at least for a first effort at aircraft> > cabinetry..> >> > Now for the poser. Given that BP designed a good airfoil for the AirCamper,> > there have been advances in aerodynamics, and I have to wonder about usinga> > bit more modern airfoil...the 4412 comes easily to mind. Has anyone any> > actual experience with this? Is there some great advantage to using the> > modified Eiffel, or is there some great disadvantage to using the 4412. It> > seems that I might get a little more lift and a tad more speed from the 4412,> > but I am not an engineer. While I appreciate the purist philosophy, and> > intend to stick closely to plans, (BP 1933), I think it's appropriate to> > explore some minor changes to make minor improvements in performance and or> > utility. I'd sure appreciate input from the group. Thanx!> >>> --> /-------------------- |~~_____/~~__ |> |scott(at)haulpak.com | o' ~~|~~~ |>> ------------------------------------------------------------------------>> David Scott > Design Engineer> Komatsu Mining Systems>> David Scott> Design Engineer > Komatsu Mining Systems> 2300 NE Adams St Work: 309-672-7706> U.S.A.> Additional Information:> Last Name Scott> First Name David> Version 2.1--David B.Schober, CPEInstructor, Aviation MaintenanceFairmont State CollegeNational Aerospace Education CenterRt. 3 Box 13Bridgeport, WV 26330-9503(304) 842-8300________________________________________________________________________________
Pietenpol-List: Re: Airfoils
Original Posted By: ADonJr(at)aol.com
im speculating on this however wasn't one of the first wind tunnelsdesigned by a frenchman named Effiel, is this wherethe jenny got here airfoil that Mr. Pietenpol was so fond of,in the glider manual,s Mr. Pietenpol comments that he himselftried different airfoils such as the gotengen (excuse the spelling)but none would lift hen's feathers. so they used the effiel withan increase in ordinance! then she climbed like a home sickangel!!!-----Original Message-----
im speculating on this however wasn't one of the first wind tunnelsdesigned by a frenchman named Effiel, is this wherethe jenny got here airfoil that Mr. Pietenpol was so fond of,in the glider manual,s Mr. Pietenpol comments that he himselftried different airfoils such as the gotengen (excuse the spelling)but none would lift hen's feathers. so they used the effiel withan increase in ordinance! then she climbed like a home sickangel!!!-----Original Message-----
Pietenpol-List: Re: Airfoils
Original Posted By: David
David B. Schober wrote:> > If you want to compare the Piet airtfoil to others you need to get data on thePiet> airfoil. You can try to get Dr. Patrick Hanley to run the coordinates thru his> Visual Airfoil program. He ran another airfoil (the one on my Howard DGA) andwas> very helpful. His E-Mail is hanley(at)hanleyinnovations.com> > I've seen Piets with different airfoils and never saw any real improvement. Ofall> the Piets I've flown (one "A", one corvair and one A-65) all had the original> airfoil and none had bad stall charicteristics. All were a blast to fly! The"A" was> the best!> To the group - (I hope I don't regret this) I have VisualFoil and wouldbe willing to run a virtual test on airfoils for you, time permitting.All I ask is that you create the ordinate file, the format for whichI'll provide. I caution everyone that its Cm calculations aren't alwaysaccurate (I have NASA papers for wind tunnel tests of the UI-1720airfoil and the theoretical values are way off from the actual).Nevertheless, it's Cl figures do seem fairly accurate.Richard Melaun________________________________________________________________________________
David B. Schober wrote:> > If you want to compare the Piet airtfoil to others you need to get data on thePiet> airfoil. You can try to get Dr. Patrick Hanley to run the coordinates thru his> Visual Airfoil program. He ran another airfoil (the one on my Howard DGA) andwas> very helpful. His E-Mail is hanley(at)hanleyinnovations.com> > I've seen Piets with different airfoils and never saw any real improvement. Ofall> the Piets I've flown (one "A", one corvair and one A-65) all had the original> airfoil and none had bad stall charicteristics. All were a blast to fly! The"A" was> the best!> To the group - (I hope I don't regret this) I have VisualFoil and wouldbe willing to run a virtual test on airfoils for you, time permitting.All I ask is that you create the ordinate file, the format for whichI'll provide. I caution everyone that its Cm calculations aren't alwaysaccurate (I have NASA papers for wind tunnel tests of the UI-1720airfoil and the theoretical values are way off from the actual).Nevertheless, it's Cl figures do seem fairly accurate.Richard Melaun________________________________________________________________________________
Pietenpol-List: Re: Airfoils
Original Posted By: ADonJr(at)aol.com
I heard Vi Kapler state that a 3/8 inch washout would give a gentler stall. I also stated that a 1 inch dihedral looked nicer but didn't really effect perfomance.>Maybe A little wash out in each wing tip would help to keep the entire wing>from stalling out at the same time ?>>>>If you want to compare the Piet airtfoil to others you need to get data on>the Piet>>airfoil. You can try to get Dr. Patrick Hanley to run the coordinates thru>his>>Visual Airfoil program. He ran another airfoil (the one on my Howard DGA)>and was>>very helpful. His E-Mail is hanley(at)hanleyinnovations.com>>>>I've seen Piets with different airfoils and never saw any real improvement.>Of all>>the Piets I've flown (one "A", one corvair and one A-65) all had the>original>>airfoil and none had bad stall charicteristics. All were a blast to fly!>The "A" was>>the best!>>>>David Scott wrote:>>>>> I spoke with Harry Riblett at OshKosh this year at he says the airfoil>>> on the Piet has a sharp stall characteristic. By this, he is meaning>>> that there is very little burble transistion from being attached air>>> flow to the stalled un-attached air flow. He scared me a little>>> by stating he knew of one person who had stall-spun in>>> a piet, survived unscathed, and proceded to do it a second time. I>>> assumed he survived since he said he did not indicate otherwise.>>>>>> He recommended to me an airfoil in his book, GA Aifoils, the number>>> of which I think was 30615 or 15630 or something like it (my notes are>>> at home). When I plotted a 60 inch chord based on this airfoil, and>>> compared it to the Piet airfoil, the trailing edge top surface for the>>> last 12 inches or so is the same, the top surface for the leading edge>>> for the first 6 inches or so is the same, but the remaining portion>>> is much different. The top surface is 2 inches higher and the>>> lower surface is about 2 inches lower at the thickest portion (yes,>>> the thickness is about 9 inches verses the Piet at 5 inches). A little>>> aggressive to making it a replacement. Center of lift, lift>>> coefficent, L/D ratio, etc... comparisons to Piet are a little>>> difficult without having the data for the Piet airfoil. I believe>>> this project stems into new design. A test pilot I am not.>>>>>> His book is very infomative with insites to airfoil design, so the>>> purchase was not a waste. It runs about $17 for it from EAA.>>>>>> I spoke with Warren Wiggett who drove to Broadhead this year and>>> he had modified his Piet, which first flew in July I think, with>>> advise he received from Harry. His modification was to add>>> thickness to the leading edge between the 3inch to 12 inch area>>> of about 1/4 inch and also to the lower edge in the 2inch to 5 inch>>> area of about 1/8 inch. He did so with plywood sheeting and>>> says that the test pilot "felt" that there was some improvement>>> in takeoff performance, and said his cruise was about 70mph.>>>>>> I believe there may be better knowledge of airfoils today, Harry>>> being a very good, general aviation supporter who has such>>> expertise, which could be applied to the Piet design.>>>>>> "Modifications - The Bad And The Ugly" at OshKosh>>> this year (different aero-nut engineer guy) told me that any>>> modification has potential to change any and every other>>> characteristic of the airplane, making it a fully un-tested,>>> possible killing machine. He had very few examples, but>>> none the less scary enough to leave an impression.>>>>>> His basic premise was - if not broke, don't fix it.>>>>>> ADonJr(at)aol.com wrote:>>>>>> > Last time I wrote, I was looking at drawings of the Sky Scout, with>ideas>>> > about using an A75 for power. My spouse caught me studying those>drawings and>>> > said something to the effect that "Wait a minute! There's only one>seat!">>> > End of consideration. Ergo, I'm working on my long delayed AirCamper,>to be>>> > powered by the self-same A75. I've now glued up the rudder, and if I>do say>>> > so myself, it don't look bad...at least for a first effort at aircraft>>> > cabinetry..>>> >>>> > Now for the poser. Given that BP designed a good airfoil for the>AirCamper,>>> > there have been advances in aerodynamics, and I have to wonder about>using a>>> > bit more modern airfoil...the 4412 comes easily to mind. Has anyone>any>>> > actual experience with this? Is there some great advantage to using>the>>> > modified Eiffel, or is there some great disadvantage to using the 4412.>It>>> > seems that I might get a little more lift and a tad more speed from the>4412,>>> > but I am not an engineer. While I appreciate the purist philosophy,>and>>> > intend to stick closely to plans, (BP 1933), I think it's appropriate>to>>> > explore some minor changes to make minor improvements in performance>and or>>> > utility. I'd sure appreciate input from the group. Thanx!>>> >Cooley>>> >>ADonJr(at)AOL.com>>>>>> -->>> /-------------------- |~~_____/~~__ |>>> |scott(at)haulpak.com | o' ~~|~~~ |>>>>>> ----------------------------------------------------------------------->->>>>>> David Scott >>> Design Engineer>>> Komatsu Mining Systems>>>>>> David Scott>>> Design Engineer >>> Komatsu Mining Systems>>> 2300 NE Adams St Work: 309-672-7706>>> U.S.A.>>> Additional Information:>>> Last Name Scott>>> First Name David>>> Version 2.1>>>>>>>>-->>>**>>David B.Schober, CPE>>Instructor, Aviation Maintenance>>Fairmont State College>>National Aerospace Education Center>>Rt. 3 Box 13>>Bridgeport, WV 26330-9503>>(304) 842-8300>>>>>>>>>>>>________________________________________________________________________________
I heard Vi Kapler state that a 3/8 inch washout would give a gentler stall. I also stated that a 1 inch dihedral looked nicer but didn't really effect perfomance.>Maybe A little wash out in each wing tip would help to keep the entire wing>from stalling out at the same time ?>>>>If you want to compare the Piet airtfoil to others you need to get data on>the Piet>>airfoil. You can try to get Dr. Patrick Hanley to run the coordinates thru>his>>Visual Airfoil program. He ran another airfoil (the one on my Howard DGA)>and was>>very helpful. His E-Mail is hanley(at)hanleyinnovations.com>>>>I've seen Piets with different airfoils and never saw any real improvement.>Of all>>the Piets I've flown (one "A", one corvair and one A-65) all had the>original>>airfoil and none had bad stall charicteristics. All were a blast to fly!>The "A" was>>the best!>>>>David Scott wrote:>>>>> I spoke with Harry Riblett at OshKosh this year at he says the airfoil>>> on the Piet has a sharp stall characteristic. By this, he is meaning>>> that there is very little burble transistion from being attached air>>> flow to the stalled un-attached air flow. He scared me a little>>> by stating he knew of one person who had stall-spun in>>> a piet, survived unscathed, and proceded to do it a second time. I>>> assumed he survived since he said he did not indicate otherwise.>>>>>> He recommended to me an airfoil in his book, GA Aifoils, the number>>> of which I think was 30615 or 15630 or something like it (my notes are>>> at home). When I plotted a 60 inch chord based on this airfoil, and>>> compared it to the Piet airfoil, the trailing edge top surface for the>>> last 12 inches or so is the same, the top surface for the leading edge>>> for the first 6 inches or so is the same, but the remaining portion>>> is much different. The top surface is 2 inches higher and the>>> lower surface is about 2 inches lower at the thickest portion (yes,>>> the thickness is about 9 inches verses the Piet at 5 inches). A little>>> aggressive to making it a replacement. Center of lift, lift>>> coefficent, L/D ratio, etc... comparisons to Piet are a little>>> difficult without having the data for the Piet airfoil. I believe>>> this project stems into new design. A test pilot I am not.>>>>>> His book is very infomative with insites to airfoil design, so the>>> purchase was not a waste. It runs about $17 for it from EAA.>>>>>> I spoke with Warren Wiggett who drove to Broadhead this year and>>> he had modified his Piet, which first flew in July I think, with>>> advise he received from Harry. His modification was to add>>> thickness to the leading edge between the 3inch to 12 inch area>>> of about 1/4 inch and also to the lower edge in the 2inch to 5 inch>>> area of about 1/8 inch. He did so with plywood sheeting and>>> says that the test pilot "felt" that there was some improvement>>> in takeoff performance, and said his cruise was about 70mph.>>>>>> I believe there may be better knowledge of airfoils today, Harry>>> being a very good, general aviation supporter who has such>>> expertise, which could be applied to the Piet design.>>>>>> "Modifications - The Bad And The Ugly" at OshKosh>>> this year (different aero-nut engineer guy) told me that any>>> modification has potential to change any and every other>>> characteristic of the airplane, making it a fully un-tested,>>> possible killing machine. He had very few examples, but>>> none the less scary enough to leave an impression.>>>>>> His basic premise was - if not broke, don't fix it.>>>>>> ADonJr(at)aol.com wrote:>>>>>> > Last time I wrote, I was looking at drawings of the Sky Scout, with>ideas>>> > about using an A75 for power. My spouse caught me studying those>drawings and>>> > said something to the effect that "Wait a minute! There's only one>seat!">>> > End of consideration. Ergo, I'm working on my long delayed AirCamper,>to be>>> > powered by the self-same A75. I've now glued up the rudder, and if I>do say>>> > so myself, it don't look bad...at least for a first effort at aircraft>>> > cabinetry..>>> >>>> > Now for the poser. Given that BP designed a good airfoil for the>AirCamper,>>> > there have been advances in aerodynamics, and I have to wonder about>using a>>> > bit more modern airfoil...the 4412 comes easily to mind. Has anyone>any>>> > actual experience with this? Is there some great advantage to using>the>>> > modified Eiffel, or is there some great disadvantage to using the 4412.>It>>> > seems that I might get a little more lift and a tad more speed from the>4412,>>> > but I am not an engineer. While I appreciate the purist philosophy,>and>>> > intend to stick closely to plans, (BP 1933), I think it's appropriate>to>>> > explore some minor changes to make minor improvements in performance>and or>>> > utility. I'd sure appreciate input from the group. Thanx!>>> >Cooley>>> >>ADonJr(at)AOL.com>>>>>> -->>> /-------------------- |~~_____/~~__ |>>> |scott(at)haulpak.com | o' ~~|~~~ |>>>>>> ----------------------------------------------------------------------->->>>>>> David Scott >>> Design Engineer>>> Komatsu Mining Systems>>>>>> David Scott>>> Design Engineer >>> Komatsu Mining Systems>>> 2300 NE Adams St Work: 309-672-7706>>> U.S.A.>>> Additional Information:>>> Last Name Scott>>> First Name David>>> Version 2.1>>>>>>>>-->>>**>>David B.Schober, CPE>>Instructor, Aviation Maintenance>>Fairmont State College>>National Aerospace Education Center>>Rt. 3 Box 13>>Bridgeport, WV 26330-9503>>(304) 842-8300>>>>>>>>>>>>________________________________________________________________________________
Re: Pietenpol-List: Airfoils
Original Posted By: Ken Chambers
I originally wrote to Corky in La about doing a study on the Piet airfoil and recommendedkeeping it quiet until we had something to really say, but there seemsto be tremendous interest in this subject and quite a bit of passion too.There are at least two people on this list who are (or have been) with NASA andseveral Aero Engineers and students studying Aero Engineering. I would liketo suggest that those with a technical background get together and set up atest plan to include a section of wing for wind tunnel testing (I have seen thedata on BPs wing that is available and there doesn't appear to be any data atthe stall where it's needed)From there we all do some of the building and testing to find out just how goodan airfoil the edge of BPs shoe really made. I'm not saying everybody shouldgo out and change their wings, just that we ought to know what the current (andalternate) wings are really doing. The accident statistics do seem to be sayingthat there are some unusual features to flying a Piet. If that's true letsfind out what those features are and make sure the new guys thoroughly understandwhat their new birds are going to do. In the process, there will probablybe some new changes that will come out that SOME people will want to maketo the aerodynamics of their projects. That's why they call them "Experimental".Any students out there want a really off beat special project for their engineeringdegree? Any of the other engineers interested in doing some REALLY cheapengineering (trust me, there is NO MONEY in this kind of thing) and lastly I'llbet there are several out there that would like to see a section of the wingthey built in a real wind tunnel or would like to try their hand at being aREAL TEST PILOT to test out the real world differences with different airfoilson a Piet.Hank J ----- Original Message -----
I originally wrote to Corky in La about doing a study on the Piet airfoil and recommendedkeeping it quiet until we had something to really say, but there seemsto be tremendous interest in this subject and quite a bit of passion too.There are at least two people on this list who are (or have been) with NASA andseveral Aero Engineers and students studying Aero Engineering. I would liketo suggest that those with a technical background get together and set up atest plan to include a section of wing for wind tunnel testing (I have seen thedata on BPs wing that is available and there doesn't appear to be any data atthe stall where it's needed)From there we all do some of the building and testing to find out just how goodan airfoil the edge of BPs shoe really made. I'm not saying everybody shouldgo out and change their wings, just that we ought to know what the current (andalternate) wings are really doing. The accident statistics do seem to be sayingthat there are some unusual features to flying a Piet. If that's true letsfind out what those features are and make sure the new guys thoroughly understandwhat their new birds are going to do. In the process, there will probablybe some new changes that will come out that SOME people will want to maketo the aerodynamics of their projects. That's why they call them "Experimental".Any students out there want a really off beat special project for their engineeringdegree? Any of the other engineers interested in doing some REALLY cheapengineering (trust me, there is NO MONEY in this kind of thing) and lastly I'llbet there are several out there that would like to see a section of the wingthey built in a real wind tunnel or would like to try their hand at being aREAL TEST PILOT to test out the real world differences with different airfoilson a Piet.Hank J ----- Original Message -----
Re: Pietenpol-List: Airfoils
Original Posted By: hjarrett
Obtaining data near stall is a big problem. The CFD methods break down, they canbe used to explain what happens after you know what the answer is. Howeverthey are not of much use in predicting when it will stall. The trick is to knowwhen the airflow unattaches itself from the surface. Wind tunnel methodsare not much better as the behavior of an airfoil near stall very sensitive toreynolds number. You would pretty much have to test at full scale and full speed.One trick that the pros use when doing wind tunnel test is they attacha strip to the top surface of the wing to trip the air. That little trick helpsa great deal in obtaining repeatable data. It also hints that data withoutthat strip will not be easily repeatable, and thus not reliable. The pointis, don't look to either of the two big tools for reliable predictions aroundstall.If you want to arm chair engineer this one, use XFOIL to run the cases and simplynot run or look at any cases beyond the angle at which experience shows mostairfoils stall (somewhere between 11 and 14 degrees.) Keep in mind data obtainedfrom different methods is not as consistent as data obtained from the samemethod. XFOIL has a function that lets you quickly generate any NACA airfoil.Also, keep in mind that 3D results are usually slightly worse than the 2D(infinite wings) sections the NACA reports or XFOIL deals with. Not a big dealas long as you compare apples to apples, but expect to lose 5% when you translatefrom theorey to real life. Ignore any laminar airfoils; laminar flowsimply won't happen on a piet or for that matter most GA airplanes. When usingcharts, you want to use the 'standard roughness' numbers, yes they are lowerthan the others but you simply won't get the better results on anything lessthan an extreamly exact, smooth and polished wing; s o no sense dreaming about them. Also, make sure that you compare pitching moments.The GA(W)-1 that was developed for optimum lift to drag has an extreamlyhigh pitching moment, which when incorporated in a complete design requiresmore stabilizer, that in turn increases the airplanes drag and thus may not presentan optimum solution of maximum lift for the drag after all. If you selectan airplane with a greater pitching moment you will most likely discover thatyou do not have enough horizontal stabilizer area, and in such ways small designchanges spiral out of control. After you do all this, I think you will find the BHP airfoil is a pretty good choicefor an airplane of the size and that flies at the speeds of a Piet.Kevinwww.airminded.net----- Original Message -----
Obtaining data near stall is a big problem. The CFD methods break down, they canbe used to explain what happens after you know what the answer is. Howeverthey are not of much use in predicting when it will stall. The trick is to knowwhen the airflow unattaches itself from the surface. Wind tunnel methodsare not much better as the behavior of an airfoil near stall very sensitive toreynolds number. You would pretty much have to test at full scale and full speed.One trick that the pros use when doing wind tunnel test is they attacha strip to the top surface of the wing to trip the air. That little trick helpsa great deal in obtaining repeatable data. It also hints that data withoutthat strip will not be easily repeatable, and thus not reliable. The pointis, don't look to either of the two big tools for reliable predictions aroundstall.If you want to arm chair engineer this one, use XFOIL to run the cases and simplynot run or look at any cases beyond the angle at which experience shows mostairfoils stall (somewhere between 11 and 14 degrees.) Keep in mind data obtainedfrom different methods is not as consistent as data obtained from the samemethod. XFOIL has a function that lets you quickly generate any NACA airfoil.Also, keep in mind that 3D results are usually slightly worse than the 2D(infinite wings) sections the NACA reports or XFOIL deals with. Not a big dealas long as you compare apples to apples, but expect to lose 5% when you translatefrom theorey to real life. Ignore any laminar airfoils; laminar flowsimply won't happen on a piet or for that matter most GA airplanes. When usingcharts, you want to use the 'standard roughness' numbers, yes they are lowerthan the others but you simply won't get the better results on anything lessthan an extreamly exact, smooth and polished wing; s o no sense dreaming about them. Also, make sure that you compare pitching moments.The GA(W)-1 that was developed for optimum lift to drag has an extreamlyhigh pitching moment, which when incorporated in a complete design requiresmore stabilizer, that in turn increases the airplanes drag and thus may not presentan optimum solution of maximum lift for the drag after all. If you selectan airplane with a greater pitching moment you will most likely discover thatyou do not have enough horizontal stabilizer area, and in such ways small designchanges spiral out of control. After you do all this, I think you will find the BHP airfoil is a pretty good choicefor an airplane of the size and that flies at the speeds of a Piet.Kevinwww.airminded.net----- Original Message -----
Re: Pietenpol-List: Airfoils
Original Posted By: Kevin Holcomb
Testing a section at full chord size and actual Reynolds Number is exactly whatI had in mind. A Piet wing has a small enough size that one of the universitytunnels might be able to hold a section and it would make a GREAT student project.Then too, we might be able to get one of the NASA tunnels to make a runin conjunction with another test if there wasn't significant interference withtheir schedule. Glenn and Langley both have facilities that might be workedif there was a strong education connection and some good publicity. One ofthe Langley tunnels is managed by the local university but it is big enough fora WHOLE Piet!The problem with arm chair engineer using something like XFOIL is it lets you sizea wing and do some performance work but the problems hit right where the predictiveCFD tools break down. The shape of the hook at the top of the liftcurve slope is what makes the Piet fly (stall) like it does and CFD doesn't giveyou that.I also think you would be amazed at how much Natural Laminar Flow happens in nature(and on a Piet). It isn't that it's not there as much as I think we don'treally understand it that well (certainly not on wood and cloth wings!). Theheavy iron and even the major GA manufactures just don't care about aerodynamicsin the area we work in. Sounds like you may be one of the Engineer types that would be right for this partof a project. Do we have others? Mike C?Hank J ----- Original Message -----
Testing a section at full chord size and actual Reynolds Number is exactly whatI had in mind. A Piet wing has a small enough size that one of the universitytunnels might be able to hold a section and it would make a GREAT student project.Then too, we might be able to get one of the NASA tunnels to make a runin conjunction with another test if there wasn't significant interference withtheir schedule. Glenn and Langley both have facilities that might be workedif there was a strong education connection and some good publicity. One ofthe Langley tunnels is managed by the local university but it is big enough fora WHOLE Piet!The problem with arm chair engineer using something like XFOIL is it lets you sizea wing and do some performance work but the problems hit right where the predictiveCFD tools break down. The shape of the hook at the top of the liftcurve slope is what makes the Piet fly (stall) like it does and CFD doesn't giveyou that.I also think you would be amazed at how much Natural Laminar Flow happens in nature(and on a Piet). It isn't that it's not there as much as I think we don'treally understand it that well (certainly not on wood and cloth wings!). Theheavy iron and even the major GA manufactures just don't care about aerodynamicsin the area we work in. Sounds like you may be one of the Engineer types that would be right for this partof a project. Do we have others? Mike C?Hank J ----- Original Message -----
Re: Pietenpol-List: Airfoils
Original Posted By: Mike
Subject: Re: Pietenpol-List: Airfoils
Subject: Re: Pietenpol-List: Airfoils
Re: Pietenpol-List: Re: what medical
Original Posted By: "Janis Nielsen"
Regarding getting help on a medical. I know one person who contacted theirSenator and he sent some inquiries to FAA and some lady from Washington, DC,called and began getting the necessary machinery in motion. You havenothing to lose.----- Original Message -----
Regarding getting help on a medical. I know one person who contacted theirSenator and he sent some inquiries to FAA and some lady from Washington, DC,called and began getting the necessary machinery in motion. You havenothing to lose.----- Original Message -----
Re: Pietenpol-List: Re: what medical
Original Posted By: "John Dilatush"
Subject: Re: Pietenpol-List: Re: what medicalEAA maintains a list of MDs to which they refer as "Advocates"...Doctors who fly and have a broader understanding of the requirements and passions for flight. It might be that from that list, you could find the kind of help you need....Carl Vought________________________________________________________________________________
Subject: Re: Pietenpol-List: Re: what medicalEAA maintains a list of MDs to which they refer as "Advocates"...Doctors who fly and have a broader understanding of the requirements and passions for flight. It might be that from that list, you could find the kind of help you need....Carl Vought________________________________________________________________________________
Re: Pietenpol-List: Airfoils
Original Posted By: Mike
Re: Pietenpol-List: Airfoils ----- Original Message -----
Re: Pietenpol-List: Airfoils ----- Original Message -----
Re: Pietenpol-List: Airfoils
Original Posted By: hjarrett
I thought that if you double the density of the air in the tunnel, then you couldgo with half the chord and keep all other parameters the same like speed. This would keep the Reynolds Number the same and would allow for good data thatwould work in the real world. Is this not what Munk, Diehl, Weick and all theguys at NACA back in the twenties did to make up the charts we use today?Are these tunnels of increased density or is a smaller but high density tunnelmore available that would allow for a scaled wing section?I imagine that aspect ratio is very important. It almost sounds easiest to hangMike C.'s Piet in a full scale tunnel and work up the numbers.I am not an engineer by training but would love to contribute to this project.Working for the airline enables me to get around easy too.Chris Bobka ----- Original Message -----
I thought that if you double the density of the air in the tunnel, then you couldgo with half the chord and keep all other parameters the same like speed. This would keep the Reynolds Number the same and would allow for good data thatwould work in the real world. Is this not what Munk, Diehl, Weick and all theguys at NACA back in the twenties did to make up the charts we use today?Are these tunnels of increased density or is a smaller but high density tunnelmore available that would allow for a scaled wing section?I imagine that aspect ratio is very important. It almost sounds easiest to hangMike C.'s Piet in a full scale tunnel and work up the numbers.I am not an engineer by training but would love to contribute to this project.Working for the airline enables me to get around easy too.Chris Bobka ----- Original Message -----
Re: Pietenpol-List: Airfoils
Original Posted By: "hjarrett"
tests=FORGED_OUTLOOK_TAGS, MIME_QP_LONG_LINEMike Hardaway, you said exactly what needed to be said aboutthe venerable Pietenpol design. Now I'll add my 2 cents worth.Those who build the Pietenpol Aircamper pretty much as it wasdesigned will have built a Time Machine that will take themback to the early days when flying an airplane was more of an artthan a science---and, above all, fun.I made a few changes on mine, but nothing that affected the aero-dynamics or the overall appearance. It has been my "time machine"for over 33 years and, of all the airplanes I have owned over the last50 years, has given me the most satisfaction for pure sport flying.Sure, it is draggy and antiquated in appearance, but it is one of myall-time favorite sport airplanes. The only competition it has, in myexperience, is the DeHavilland DH 60 Gypsy Moth which I had theprivilege of flying back in 1952. These are rare as tooth decay in ahen and, accordingly, fetch a king's ransom should one ever be forsale. The D.H. has a pretty thin airfoil, too, and lots of them spun inover the years (I have the history of dozens of them in Canada duringthe 1920's and 30's).The bottom line is that many early designs require careful handlingin the air, particularly when heavily loaded. They lose speed easilyand quickly, and need a lot of altitude to regain it when there is nopower available. But in general they are a blast (literally) to fly!The late Peter Bowers wrote an article on the Pietenpol airplanesand it appeared in a magazine (some time in the 1970's, I think itwas), entitled "Pietenpol--The Pasture Pilot's Pride and Joy".Theessence of the article was this:If you want to experience flying as it was many years ago withgoggles, scarf, etc., the Pietenpol will take you there for a modestamount of money and some effort on your part. But if you must"modernize" it extensively, build or buy something else.Graham Hansen (Pietenpol CF-AUN)________________________________________________________________________________
tests=FORGED_OUTLOOK_TAGS, MIME_QP_LONG_LINEMike Hardaway, you said exactly what needed to be said aboutthe venerable Pietenpol design. Now I'll add my 2 cents worth.Those who build the Pietenpol Aircamper pretty much as it wasdesigned will have built a Time Machine that will take themback to the early days when flying an airplane was more of an artthan a science---and, above all, fun.I made a few changes on mine, but nothing that affected the aero-dynamics or the overall appearance. It has been my "time machine"for over 33 years and, of all the airplanes I have owned over the last50 years, has given me the most satisfaction for pure sport flying.Sure, it is draggy and antiquated in appearance, but it is one of myall-time favorite sport airplanes. The only competition it has, in myexperience, is the DeHavilland DH 60 Gypsy Moth which I had theprivilege of flying back in 1952. These are rare as tooth decay in ahen and, accordingly, fetch a king's ransom should one ever be forsale. The D.H. has a pretty thin airfoil, too, and lots of them spun inover the years (I have the history of dozens of them in Canada duringthe 1920's and 30's).The bottom line is that many early designs require careful handlingin the air, particularly when heavily loaded. They lose speed easilyand quickly, and need a lot of altitude to regain it when there is nopower available. But in general they are a blast (literally) to fly!The late Peter Bowers wrote an article on the Pietenpol airplanesand it appeared in a magazine (some time in the 1970's, I think itwas), entitled "Pietenpol--The Pasture Pilot's Pride and Joy".Theessence of the article was this:If you want to experience flying as it was many years ago withgoggles, scarf, etc., the Pietenpol will take you there for a modestamount of money and some effort on your part. But if you must"modernize" it extensively, build or buy something else.Graham Hansen (Pietenpol CF-AUN)________________________________________________________________________________
Re: Pietenpol-List: Airfoils
Original Posted By: Mike
Re: Pietenpol-List: AirfoilsI like the Piet for all the same reasons you listed,as is, with no changes. I'm also trained as an aeronautical (OK, aerospace)engineer which is why I want to know "why" it does what it does. If a studyshowed I could get the better handling and performance by just opening the leadingedge diameter 1/4" or adding a Phillips entry or dropping the undercamber10%, I would probably do it. Would I change the character of the design? NOWAY. I LIKE struts, tight cockpits (within reason) fabric over wood and thesing of flying wires on a warm spring day. Even if I never changed ANYTHING Iwould still want to know why it does what it does. It's just my nature. Noone would EVER be able to force any of us (OK, again, Uncle CAN force us) to makechanges to the design, but some of us would like to "tweak" it a little. That's what BP did and I think he would approve of us looking at how well he didit..Hank J ----- Original Message -----
Re: Pietenpol-List: AirfoilsI like the Piet for all the same reasons you listed,as is, with no changes. I'm also trained as an aeronautical (OK, aerospace)engineer which is why I want to know "why" it does what it does. If a studyshowed I could get the better handling and performance by just opening the leadingedge diameter 1/4" or adding a Phillips entry or dropping the undercamber10%, I would probably do it. Would I change the character of the design? NOWAY. I LIKE struts, tight cockpits (within reason) fabric over wood and thesing of flying wires on a warm spring day. Even if I never changed ANYTHING Iwould still want to know why it does what it does. It's just my nature. Noone would EVER be able to force any of us (OK, again, Uncle CAN force us) to makechanges to the design, but some of us would like to "tweak" it a little. That's what BP did and I think he would approve of us looking at how well he didit..Hank J ----- Original Message -----
Re: Pietenpol-List: Airfoils
Original Posted By: "Jim Markle"
Subject: Re: Pietenpol-List: AirfoilsIn a message dated 1/9/04 8:09:27 PM Central Standard Time, bike.mike(at)verizon.net writes:>Mike,Very well put !! It takes a while to get acquainted with flying your new ship, but once you do, and you know what to expect, her characteristics become engrained in your reflexes, and I promise you - you wouldn't have it any other way !! Whileyou're getting to know 'er, the robust design will allow you to drop 'er in, and cause no damage (although a close inspection would be in order). She's a 'Stick & Rudder' airplane. Her characteristics are not worse than newer aircraft....just different. All of your senses are used - Sight - view over thecowl during takeoff / landing & oh the beautiful landscape, Sound - wind noise& engine sound to indicate your speed, or the ground rumbling under the tires, Feel - seat of the pants, G force in conjunction with the sound of speed and buffet of the wing indicates your angle of attack & which side of your face youfeel the wind, so you know which rudder input to use without looking at the ball, or the feel of a brisk temperature indicating a better climb rate and visaversa, Smell - occasional exhaust, barbaques, road kill, spring flowers, Taste - summer air, bugs, and beer after sunset. As you eventually become one with your ship, it will offer you as much or more satisfaction flying 'er, as ithas building 'er, and showing 'er off on the ramp !! You just don't get thatin very many ships. I would encourage everyone to study and learn everything you can about aerodynamics - you will be a better pilot as a result, but please - Don't Changethe Pietenpol Airfoil !!!!Chuck GantzerNX770CG________________________________________________________________________________
Subject: Re: Pietenpol-List: AirfoilsIn a message dated 1/9/04 8:09:27 PM Central Standard Time, bike.mike(at)verizon.net writes:>Mike,Very well put !! It takes a while to get acquainted with flying your new ship, but once you do, and you know what to expect, her characteristics become engrained in your reflexes, and I promise you - you wouldn't have it any other way !! Whileyou're getting to know 'er, the robust design will allow you to drop 'er in, and cause no damage (although a close inspection would be in order). She's a 'Stick & Rudder' airplane. Her characteristics are not worse than newer aircraft....just different. All of your senses are used - Sight - view over thecowl during takeoff / landing & oh the beautiful landscape, Sound - wind noise& engine sound to indicate your speed, or the ground rumbling under the tires, Feel - seat of the pants, G force in conjunction with the sound of speed and buffet of the wing indicates your angle of attack & which side of your face youfeel the wind, so you know which rudder input to use without looking at the ball, or the feel of a brisk temperature indicating a better climb rate and visaversa, Smell - occasional exhaust, barbaques, road kill, spring flowers, Taste - summer air, bugs, and beer after sunset. As you eventually become one with your ship, it will offer you as much or more satisfaction flying 'er, as ithas building 'er, and showing 'er off on the ramp !! You just don't get thatin very many ships. I would encourage everyone to study and learn everything you can about aerodynamics - you will be a better pilot as a result, but please - Don't Changethe Pietenpol Airfoil !!!!Chuck GantzerNX770CG________________________________________________________________________________
Re: Pietenpol-List: Airfoils
Original Posted By:
Seems I hit a real nerve here with some of you guys. Maybe a little historyis in order. I am a retired engineer from NASA and was the manager of theAGATE (Advanced General Aviation Transportation Experiments) project. We(AGATE) are the guys that developed all the glass displays (primarily withAvroTec and AVIDYNE), SLPC & FADEC systems (with the Glenn Research Center),the composite manufacture methods used on the LANCAIR and Cirrus as well asthe parachute recovery system technologies, databuss systems so all the junkin new planes could talk to each other and more other stuff than I couldrecount in a message like this.None of that matters. I fly a 1945 Taylorcraft that I have been taking backto absolute original (heck, I even put back the non-sensitive altimeter). Ihave torn out the entire electrical system (that had been added over theyears by prior owners) and am putting back only what came from the factory.I even have the original wind generator working again. The entireinstrument panel was pulled and the original design hand hammered from aflat sheet and put back with all original instrument. I'm a true believerin keeping it original, WITHIN REASON.There are a few MINOR changes I am putting in even if they DO violate Mr.Taylors original design. The first is the fabric is a modern synthetic, notcotton. I tried my best but there just isn't any long twill cottonavailable like what was used originally. I have tested the new stuff (thatinsatiable curiosity coming through again) and none of it is as good as theancient scraps I had around from 30 or 40 years ago. I DID use a certifiedsystem that used DOPE for a finish and LOVE the process. If you areinterested call Jim and Dondie at Poly-Fiber, they are the greatest andcater to the whims of nut cases like us. The other items are metal to metalseat belt buckles (Uncle CAN force some changes), hard points for shoulderbelts (that can be hidden when not in use), a 12V jack for charging my handheld radio or GPS (OK I didn't give up ALL the fancy stuff) and I plan toput in one of the new type ELTs that transmit your GPS position in a crashwhen they come down a bit in price(remember in 41 there was no ELT of ANYkind). Do these changes make me a "violator of the original designersintent"? I doubt it. I haven't clipped the wings, put in a center stick,added an extra 100 HP, full electrical system or glass cockpit. I couldhave, but I'm with YOU guys. It wouldn't be a Taylorcraft any more. If theTaylorcraft had any really bad (dangerous) characteristics that could becorrected easily without violating what made me love the plane in the firstplace (like the extra hard points for shoulder the harness) I would put themin. No one is forcing (or even asking) anyone to change anything on theirplane.It's beyond me why some of you guys not only don't want to improve yourplanes (I can understand the pride of having an ORIGINAL) but seem to wantto attack those that DO want to look at what makes them fly like they do.If you don't want to change, no one will look down on you. Why the attackson those that have some intellectual curiosity? Do you think the testing ofthe Wright props, engine and airframe were some kind of insult to Orvilleand Wilbur?Hank J----- Original Message -----
Seems I hit a real nerve here with some of you guys. Maybe a little historyis in order. I am a retired engineer from NASA and was the manager of theAGATE (Advanced General Aviation Transportation Experiments) project. We(AGATE) are the guys that developed all the glass displays (primarily withAvroTec and AVIDYNE), SLPC & FADEC systems (with the Glenn Research Center),the composite manufacture methods used on the LANCAIR and Cirrus as well asthe parachute recovery system technologies, databuss systems so all the junkin new planes could talk to each other and more other stuff than I couldrecount in a message like this.None of that matters. I fly a 1945 Taylorcraft that I have been taking backto absolute original (heck, I even put back the non-sensitive altimeter). Ihave torn out the entire electrical system (that had been added over theyears by prior owners) and am putting back only what came from the factory.I even have the original wind generator working again. The entireinstrument panel was pulled and the original design hand hammered from aflat sheet and put back with all original instrument. I'm a true believerin keeping it original, WITHIN REASON.There are a few MINOR changes I am putting in even if they DO violate Mr.Taylors original design. The first is the fabric is a modern synthetic, notcotton. I tried my best but there just isn't any long twill cottonavailable like what was used originally. I have tested the new stuff (thatinsatiable curiosity coming through again) and none of it is as good as theancient scraps I had around from 30 or 40 years ago. I DID use a certifiedsystem that used DOPE for a finish and LOVE the process. If you areinterested call Jim and Dondie at Poly-Fiber, they are the greatest andcater to the whims of nut cases like us. The other items are metal to metalseat belt buckles (Uncle CAN force some changes), hard points for shoulderbelts (that can be hidden when not in use), a 12V jack for charging my handheld radio or GPS (OK I didn't give up ALL the fancy stuff) and I plan toput in one of the new type ELTs that transmit your GPS position in a crashwhen they come down a bit in price(remember in 41 there was no ELT of ANYkind). Do these changes make me a "violator of the original designersintent"? I doubt it. I haven't clipped the wings, put in a center stick,added an extra 100 HP, full electrical system or glass cockpit. I couldhave, but I'm with YOU guys. It wouldn't be a Taylorcraft any more. If theTaylorcraft had any really bad (dangerous) characteristics that could becorrected easily without violating what made me love the plane in the firstplace (like the extra hard points for shoulder the harness) I would put themin. No one is forcing (or even asking) anyone to change anything on theirplane.It's beyond me why some of you guys not only don't want to improve yourplanes (I can understand the pride of having an ORIGINAL) but seem to wantto attack those that DO want to look at what makes them fly like they do.If you don't want to change, no one will look down on you. Why the attackson those that have some intellectual curiosity? Do you think the testing ofthe Wright props, engine and airframe were some kind of insult to Orvilleand Wilbur?Hank J----- Original Message -----
Re: Pietenpol-List: Re: what medical
Original Posted By: Gary Gower
Subject: Re: Pietenpol-List: Re: what medicalI have been in the same boat for 28 years Bruce. Lost my medical in 75. The Sport Pilot thing should be done by April (hopefully). Piet easily qualifies, that is why I started on mine several months ago. I would keep building. Soundslike you already have enough flight hours for Sport Pilot, may only have to take a written and an FAA checkout.Rick HollandI have been following this group for a year now andfeel that I know some of you personally. The medicalthing has really hit home to me. I was going to starton my Piet this year and then the FAA yanked mymedical because I take Prozac. Anyone have any cluesas to how to get the guys in Oklahoma City toreinstate my medical so I can finish getting myPrivate license (only about 10 hours to go) or will Ihave to wait until the Sport Pilot issue getsresolved? I have put the Piet on hold until I find outif I will be able to fly the thing once it is built.________________________________________________________________________________Date: Sat, 10 Jan 2004 07:33:24 -0800 (PST)
Subject: Re: Pietenpol-List: Re: what medicalI have been in the same boat for 28 years Bruce. Lost my medical in 75. The Sport Pilot thing should be done by April (hopefully). Piet easily qualifies, that is why I started on mine several months ago. I would keep building. Soundslike you already have enough flight hours for Sport Pilot, may only have to take a written and an FAA checkout.Rick HollandI have been following this group for a year now andfeel that I know some of you personally. The medicalthing has really hit home to me. I was going to starton my Piet this year and then the FAA yanked mymedical because I take Prozac. Anyone have any cluesas to how to get the guys in Oklahoma City toreinstate my medical so I can finish getting myPrivate license (only about 10 hours to go) or will Ihave to wait until the Sport Pilot issue getsresolved? I have put the Piet on hold until I find outif I will be able to fly the thing once it is built.________________________________________________________________________________Date: Sat, 10 Jan 2004 07:33:24 -0800 (PST)
Re: Pietenpol-List: Airfoils
Original Posted By: "hjarrett"
Great comments Hank.Alex S.----- Original Message -----
Great comments Hank.Alex S.----- Original Message -----
Re: Pietenpol-List: Airfoils
Original Posted By: Mike
Re: Pietenpol-List: AirfoilsAmen, MikeTed BrousseauStill makin sawdust in FL ----- Original Message -----
Re: Pietenpol-List: AirfoilsAmen, MikeTed BrousseauStill makin sawdust in FL ----- Original Message -----
Pietenpol-List: Airfoils
Original Posted By: "DJ Vegh"
Subject: Pietenpol-List: AirfoilsPieters,Anyone know whether the GN is the same airfoil as the B H Pietenpol?Corky________________________________________________________________________________
Subject: Pietenpol-List: AirfoilsPieters,Anyone know whether the GN is the same airfoil as the B H Pietenpol?Corky________________________________________________________________________________
Re: Pietenpol-List: Airfoils
Original Posted By: Isablcorky(at)aol.com
it is with the exception of the radius of the leading edge. the GN1 has a largerradius for a more blunt leading edge. Other than that it's the same.also the spars are placed on 31" centers on the GN1.DJ ----- Original Message -----
it is with the exception of the radius of the leading edge. the GN1 has a largerradius for a more blunt leading edge. Other than that it's the same.also the spars are placed on 31" centers on the GN1.DJ ----- Original Message -----
Re: Pietenpol-List: Airfoils
Original Posted By: Rcaprd(at)aol.com
Subject: Re: Pietenpol-List: AirfoilsIn a message dated 2/21/05 12:18:52 PM Central Standard Time, djv(at)imagedv.com writes:>DJ is correct about the leading edge, and although I've never seen the GN1 and the Pietenpol 'FC 10' overlaid on each other, I'd be willing to bet there are other small differences. I do understand that a larger radius on the leading edge helps keep the wing flying at a higher 'Critical Angle of Attack'(AOA when the wing begins to stall). Have you ever noticed how large the radius ison aerobatic planes? It's Huge !! It allows them to fly at a higher angle of attack, and use the enormous amount of thrust to maintain altitude, when they are behind the power curve. The official name for behind the power curveis the 'Region of Reversed Command'. The drawback to a larger radius leading edge is in cruise flight, where drag is increased significantly...that's why the aerobatic planes don't make a very efficient cross country plane. Nothingis for Free in aircraft design !!Chuck G.Hey...I've been reading a book by Berry Schiff called '1001 Things You Though You Knew About Aviation'.Why was it decided in the 18th Century that the territorial limit of the United States (and other countries) should extend three miles beyond shore ?This was the maximum range of a shore based cannon.________________________________________________________________________________
Subject: Re: Pietenpol-List: AirfoilsIn a message dated 2/21/05 12:18:52 PM Central Standard Time, djv(at)imagedv.com writes:>DJ is correct about the leading edge, and although I've never seen the GN1 and the Pietenpol 'FC 10' overlaid on each other, I'd be willing to bet there are other small differences. I do understand that a larger radius on the leading edge helps keep the wing flying at a higher 'Critical Angle of Attack'(AOA when the wing begins to stall). Have you ever noticed how large the radius ison aerobatic planes? It's Huge !! It allows them to fly at a higher angle of attack, and use the enormous amount of thrust to maintain altitude, when they are behind the power curve. The official name for behind the power curveis the 'Region of Reversed Command'. The drawback to a larger radius leading edge is in cruise flight, where drag is increased significantly...that's why the aerobatic planes don't make a very efficient cross country plane. Nothingis for Free in aircraft design !!Chuck G.Hey...I've been reading a book by Berry Schiff called '1001 Things You Though You Knew About Aviation'.Why was it decided in the 18th Century that the territorial limit of the United States (and other countries) should extend three miles beyond shore ?This was the maximum range of a shore based cannon.________________________________________________________________________________
Re: Pietenpol-List: Weldable flange (fiberglass fuel tank)
Original Posted By: Michael D Cuy
Subject: Re: Pietenpol-List: Weldable flange (fiberglass fuel tank)In a message dated 2/21/05 8:20:19 AM Central Standard Time, Pilots4ETW(at)wmconnect.com writes:>Roy,I believe 3/8" is the chosen pipe thread for the small Continentals. That is what I used, however I did some rework to the finger strainer. The only finger strainer I could find had 3/8" male pipe threads, and reduced to 1/4" female threads, with a hex to tighten the finger strainer into the weldable fitting. I was afraid 1/4" is too small, and would restrict fuel flow. I reworkedthe finger strainer by using a die to cut the male threads of the finger strainer down to the point where it would go in the female threads of the weldablefitting enough to allow an AN822 ELBOW with 3/8" male pipe thread on one end, to go into the weldable fitting, and 3/8" Flair fitting on the other end ofthe elbow. I left the hex on the finger strainer till I got the threads cut down enough, then cut the hex off, and used a square easy out to install and seat the finger strainer down in the weldable fitting, then installed the elbowon top of it. I ruined the first finger strainer, by cutting too much threadsoff, and it just threaded right through the weldable fitting. I now have 3/8" plumbing all the way from the tank, through the gascolator, to the carb. Oh yeah, before glassing it in, I also cut the ridge down around the radius of the weldable fitting, so the fiberglass layers would lay right up aroundit.Chuck G.the word 'Aileron' is derived from a French word referring to a 'Small Wing'.(sheesh.......I feel like Cliff Claven from Cheers !! )________________________________________________________________________________Date: Tue, 22 Feb 2005 13:51:50 -0500
Subject: Re: Pietenpol-List: Weldable flange (fiberglass fuel tank)In a message dated 2/21/05 8:20:19 AM Central Standard Time, Pilots4ETW(at)wmconnect.com writes:>Roy,I believe 3/8" is the chosen pipe thread for the small Continentals. That is what I used, however I did some rework to the finger strainer. The only finger strainer I could find had 3/8" male pipe threads, and reduced to 1/4" female threads, with a hex to tighten the finger strainer into the weldable fitting. I was afraid 1/4" is too small, and would restrict fuel flow. I reworkedthe finger strainer by using a die to cut the male threads of the finger strainer down to the point where it would go in the female threads of the weldablefitting enough to allow an AN822 ELBOW with 3/8" male pipe thread on one end, to go into the weldable fitting, and 3/8" Flair fitting on the other end ofthe elbow. I left the hex on the finger strainer till I got the threads cut down enough, then cut the hex off, and used a square easy out to install and seat the finger strainer down in the weldable fitting, then installed the elbowon top of it. I ruined the first finger strainer, by cutting too much threadsoff, and it just threaded right through the weldable fitting. I now have 3/8" plumbing all the way from the tank, through the gascolator, to the carb. Oh yeah, before glassing it in, I also cut the ridge down around the radius of the weldable fitting, so the fiberglass layers would lay right up aroundit.Chuck G.the word 'Aileron' is derived from a French word referring to a 'Small Wing'.(sheesh.......I feel like Cliff Claven from Cheers !! )________________________________________________________________________________Date: Tue, 22 Feb 2005 13:51:50 -0500
Re: Pietenpol-List: GN-1 project on ebay
Original Posted By: "Michael D Cuy"
that's the same one that was for sale last year. Not sure why it's listed again cause I thought it sold last time.It does look nice though. I like the aluminum combing work.DJ----- Original Message -----
that's the same one that was for sale last year. Not sure why it's listed again cause I thought it sold last time.It does look nice though. I like the aluminum combing work.DJ----- Original Message -----
Pietenpol-List: Airfoils
Original Posted By: Jeff Boatright
RE: Pietenpol-List: Airfoils
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Good information Ameet. However I have to differ with the conclusion thatthe Pietenpol horizontal tail is providing a large amount of downforce. Ihave about about 1 of decalage in my Piet, with a 2 incidence on the wing,and still hold a bit of down elevator in flight. Look at a picture of justabout any Pietenpol in flight and you will notice they are holding some downelevator, generating uplift on the tail.Jack PhillipsNX899JP-----Original Message-----
Good information Ameet. However I have to differ with the conclusion thatthe Pietenpol horizontal tail is providing a large amount of downforce. Ihave about about 1 of decalage in my Piet, with a 2 incidence on the wing,and still hold a bit of down elevator in flight. Look at a picture of justabout any Pietenpol in flight and you will notice they are holding some downelevator, generating uplift on the tail.Jack PhillipsNX899JP-----Original Message-----
Pietenpol-List: Airfoils
Original Posted By: Ameet Savant
Pietenpol-List: Tapered shaft Dimensions?
Original Posted By: "mike"
Let me know if you didn't get the information you neededon the tapered shaft and a hub for it. I may have a leadon a tapered shaft hub that a guy has, and can probablyalso get the dimensions from the tech literature.There is an excellent step-by-step pictorial on workingwith the tapered shaft hub, on one of the Cub webpages. Itincludes how to make two simple tools that will helpwhen you're removing and installing your hub. I canfind that webpage again but even if not, I printed itout and have it at home too.Oscar ZunigaAir Camper NX41CCSan Antonio, TXmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net________________________________________________________________________________
Let me know if you didn't get the information you neededon the tapered shaft and a hub for it. I may have a leadon a tapered shaft hub that a guy has, and can probablyalso get the dimensions from the tech literature.There is an excellent step-by-step pictorial on workingwith the tapered shaft hub, on one of the Cub webpages. Itincludes how to make two simple tools that will helpwhen you're removing and installing your hub. I canfind that webpage again but even if not, I printed itout and have it at home too.Oscar ZunigaAir Camper NX41CCSan Antonio, TXmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net________________________________________________________________________________
RE: Pietenpol-List: Airfoils
Original Posted By: owner-pietenpol-list-server(at)matronics.com
I would like to add to Jack's discussion of Ameet's analysis. Ameet has done some good work in quantifying the FC-10. However, Ameet says that the FC-10 has a higher Cl in cruise conditions. Iftwo airplanes, one with an FC-10 and the other with a Riblett 612, weigh thesame, have the same wing area, and are flying at the same airspeed, theywill have the same Cl, by definition. They may have differing AoAs andtheir fuselage attitudes may differ, but the Cl has to be the same.If an airplane is statically stable, down-force is always required at thetail. (No talk here about Rutan's funny plastic airplanes from the '80sthat flew backwards or Jack Phillips' computer-controlled F-16.)The position of a Piet elevator in flight, slightly trailing edge down, maynot be to produce lift but to reduce down-force. If there is a large amountof wing downwash at the horizontal, the horizontal may be flying at arelatively large negative AoA. Nose-down elevator (TE down) may be what isrequired to prevent too much down-force (negative lift). I think we all understand that minimum drag was not what was on BHP's mindin building his airplanes. The trailing-edge-down position of elevator inflight, in addition to producing lift or reducing down-force, causes somedrag relative to an elevator aligned with the horizontal. Trying to balancean airplane so that the tail becomes a positively lifting surface producesstatic instability that is not desirable.Ameet also said that the FC-10 produces a lower stall speed. By Ameet'scomputer analysis, this is true. However, experience has shown that theFC-10 stalls out at a Cl of about 1.3 where the Ribletts get to about 1.6.Again, if wing area and weight are the same, the higher Cl allows a lowerairspeed. Thus the Riblett airfoils have a slower stall speed.In selecting an airfoil, keep in mind that all surfaces, barn doors andrough-sawn logs included, can produce lift. All airfoils have about the same slope of the Cl/AoA curve at Cls lower thanstall.The main differences in airfoils lie in the amount of drag that is producedfor a given amount of lift, the moment coefficients at various conditions,stalling characteristics and the ability to build strong enough for flight.(A sheet of paper makes a fine airfoil but isn't very strong.)Ameet said that the FC-10 is lighter because the spar height is smaller.That is counter-intuitive. A higher spar height means that, for the samestrength, a spar can be made lighter, making the Ribletts a better choicefor structural weight. However, Ameet's last two paragraphs say everything. There are indeedhundreds of beautifully flying Piets with FC-10 airfoils. Eighty years ofexperience is a great indicator of success. Or, as my professors used tosay: "Data trumps theory, every time."Mike Hardaway-----Original Message-----
I would like to add to Jack's discussion of Ameet's analysis. Ameet has done some good work in quantifying the FC-10. However, Ameet says that the FC-10 has a higher Cl in cruise conditions. Iftwo airplanes, one with an FC-10 and the other with a Riblett 612, weigh thesame, have the same wing area, and are flying at the same airspeed, theywill have the same Cl, by definition. They may have differing AoAs andtheir fuselage attitudes may differ, but the Cl has to be the same.If an airplane is statically stable, down-force is always required at thetail. (No talk here about Rutan's funny plastic airplanes from the '80sthat flew backwards or Jack Phillips' computer-controlled F-16.)The position of a Piet elevator in flight, slightly trailing edge down, maynot be to produce lift but to reduce down-force. If there is a large amountof wing downwash at the horizontal, the horizontal may be flying at arelatively large negative AoA. Nose-down elevator (TE down) may be what isrequired to prevent too much down-force (negative lift). I think we all understand that minimum drag was not what was on BHP's mindin building his airplanes. The trailing-edge-down position of elevator inflight, in addition to producing lift or reducing down-force, causes somedrag relative to an elevator aligned with the horizontal. Trying to balancean airplane so that the tail becomes a positively lifting surface producesstatic instability that is not desirable.Ameet also said that the FC-10 produces a lower stall speed. By Ameet'scomputer analysis, this is true. However, experience has shown that theFC-10 stalls out at a Cl of about 1.3 where the Ribletts get to about 1.6.Again, if wing area and weight are the same, the higher Cl allows a lowerairspeed. Thus the Riblett airfoils have a slower stall speed.In selecting an airfoil, keep in mind that all surfaces, barn doors andrough-sawn logs included, can produce lift. All airfoils have about the same slope of the Cl/AoA curve at Cls lower thanstall.The main differences in airfoils lie in the amount of drag that is producedfor a given amount of lift, the moment coefficients at various conditions,stalling characteristics and the ability to build strong enough for flight.(A sheet of paper makes a fine airfoil but isn't very strong.)Ameet said that the FC-10 is lighter because the spar height is smaller.That is counter-intuitive. A higher spar height means that, for the samestrength, a spar can be made lighter, making the Ribletts a better choicefor structural weight. However, Ameet's last two paragraphs say everything. There are indeedhundreds of beautifully flying Piets with FC-10 airfoils. Eighty years ofexperience is a great indicator of success. Or, as my professors used tosay: "Data trumps theory, every time."Mike Hardaway-----Original Message-----
> Pietenpol-List: Airfoils
Original Posted By: Jeff Boatright
Re: Pietenpol-List: Airfoils
Original Posted By: Ryan Mueller
Subject: Re: Pietenpol-List: Airfoils
Subject: Re: Pietenpol-List: Airfoils
RE: Pietenpol-List: Airfoils
Original Posted By: shad bell
RE: Pietenpol-List: Airfoils
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Now the T-craft has a sharp flare??!! Son, it floats forever and is the mostforgiving wing you could hope for! A stall is a stall and no plane will flythru it when it happens at 5' above the runway.Let's face it, every model of airplane has its own characteristics. A goodpilot will learn those and become second nature. Gary BootheCool, Ca.PietenpolWW Corvair ConversionTail done, Fuselage on gear(13 ribs down.)-----Original Message-----
Now the T-craft has a sharp flare??!! Son, it floats forever and is the mostforgiving wing you could hope for! A stall is a stall and no plane will flythru it when it happens at 5' above the runway.Let's face it, every model of airplane has its own characteristics. A goodpilot will learn those and become second nature. Gary BootheCool, Ca.PietenpolWW Corvair ConversionTail done, Fuselage on gear(13 ribs down.)-----Original Message-----
Re: Pietenpol-List: Airfoils
Original Posted By: "Oscar Zuniga"
Right on Oscar! Good post.Gene----- Original Message -----
Right on Oscar! Good post.Gene----- Original Message -----
Pietenpol-List: Airfoils
Original Posted By: airlion
Pietenpol-List: Re: Airfoils
Original Posted By: "Don Emch"
Gardiner,P F Beck has vortex generators on his Piet. If I recall correctly he saysthey help everything but top speed.Skip> > Hey guys, with all this discussion about different airfoils, has anybodytried vortex generetors? I have the BP wing and I don't want to spend thetime to build a new one. My piet is to the plans with a 3 ft.centersection. Not flying yet, but will be soon. Gardiner Mason>>________________________________________________________________________________Subject: Pietenpol-List: Re: Airfoils
Gardiner,P F Beck has vortex generators on his Piet. If I recall correctly he saysthey help everything but top speed.Skip> > Hey guys, with all this discussion about different airfoils, has anybodytried vortex generetors? I have the BP wing and I don't want to spend thetime to build a new one. My piet is to the plans with a 3 ft.centersection. Not flying yet, but will be soon. Gardiner Mason>>________________________________________________________________________________Subject: Pietenpol-List: Re: Airfoils
Original Posted By: Dan Yocum
Amen to that Oscar. That is probably the most "well put" explanation on the Piet'sflying qualities I've heard. It really is a sweet flying airplane.Don EmchNX899DERead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Fri, 21 Aug 2009 11:07:02 -0500
Amen to that Oscar. That is probably the most "well put" explanation on the Piet'sflying qualities I've heard. It really is a sweet flying airplane.Don EmchNX899DERead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Fri, 21 Aug 2009 11:07:02 -0500
Pietenpol-List: Airfoils
Original Posted By: Ray Krause
Subject: Pietenpol-List: AirfoilsPieters,So pleased to read Brodhead was as usual a big success. Now that it is behind us may I ask the list a few stupid questions and hopefully receive a few intelligent answers and/or suggestions.I am presently building Pietenpol wingribs. Before I build a set for my next I want the pro and cons of these Riblett airfoil wings. I would be hopeful that it might be after the roundout a little float as with a 7AC insteadof the Pietenpol brick.Corky________________________________________________________________________________
Subject: Pietenpol-List: AirfoilsPieters,So pleased to read Brodhead was as usual a big success. Now that it is behind us may I ask the list a few stupid questions and hopefully receive a few intelligent answers and/or suggestions.I am presently building Pietenpol wingribs. Before I build a set for my next I want the pro and cons of these Riblett airfoil wings. I would be hopeful that it might be after the roundout a little float as with a 7AC insteadof the Pietenpol brick.Corky________________________________________________________________________________
> RE: Pietenpol-List: Airfoils
Original Posted By: Oscar Zuniga
> --> Pietenpol-List message posted> by: "Jack Phillips" > > Good information Ameet. However I have to differ with> the conclusion that> the Pietenpol horizontal tail is providing a large amount> of downforce. I> have about about 1 of decalage in my Piet, with a 2> incidence on the wing,> and still hold a bit of down elevator in flight. Look> at a picture of just> about any Pietenpol in flight and you will notice they are> holding some down> elevator, generating uplift on the tail.> > Jack Phillips> NX899JP> ________________________________________________________________________________
> --> Pietenpol-List message posted> by: "Jack Phillips" > > Good information Ameet. However I have to differ with> the conclusion that> the Pietenpol horizontal tail is providing a large amount> of downforce. I> have about about 1 of decalage in my Piet, with a 2> incidence on the wing,> and still hold a bit of down elevator in flight. Look> at a picture of just> about any Pietenpol in flight and you will notice they are> holding some down> elevator, generating uplift on the tail.> > Jack Phillips> NX899JP> ________________________________________________________________________________
> RE: Pietenpol-List: Airfoils
Original Posted By: Tim Willis
> --> Pietenpol-List message posted> by: "Jack Phillips" > > Good information Ameet. However I have to differ with the conclusion > that the Pietenpol horizontal tail is providing a large amount of > downforce. I have about about 1 of decalage in my Piet, with a 2 > incidence on the wing, and still hold a bit of down elevator in > flight. Look at a picture of just about any Pietenpol in flight and > you will notice they are holding some down elevator, generating uplift > on the tail.> > Jack Phillips> NX899JP> ________________________________________________________________________________Date: Thu, 20 Aug 2009 11:15:36 -0400 (EDT)
> --> Pietenpol-List message posted> by: "Jack Phillips" > > Good information Ameet. However I have to differ with the conclusion > that the Pietenpol horizontal tail is providing a large amount of > downforce. I have about about 1 of decalage in my Piet, with a 2 > incidence on the wing, and still hold a bit of down elevator in > flight. Look at a picture of just about any Pietenpol in flight and > you will notice they are holding some down elevator, generating uplift > on the tail.> > Jack Phillips> NX899JP> ________________________________________________________________________________Date: Thu, 20 Aug 2009 11:15:36 -0400 (EDT)