Original Posted By: Oscar Zuniga
Just a suggestion but, has anyone considered the design that Steve Eldredge useson his caps as a patch design? Its been around awhile representing the fraternityand I would think Steve would allow it and maybe even produce them sincehe has an embroidery outfit already selected. Just a thought.Larry Williams if youre looking for Chris Egsgaard or Billy Pobah, Id try themachine shop!________________________________________________________________________________
Pietenpol-List: Patch design
Pietenpol-List: Alternate Airfoils Riblett 612 and 613.5
Original Posted By: Oscar Zuniga
Ryan;You could ask Riblett but If I remember correctly, Doc Mosher's narrativeand analysis ondetermining CG range for the Piet pretty much covered most conventionalairfoils at least as a starting point. Here's Doc's commentary, fromOct. of 2002:======================Recently there have been some questions concerning establishing practical CG limits on homebuilt Pietenpols. Perhaps by going back to the Piet era (1930s) we can gain an insight about how the CG limits were established in those days ("That's how Bernie did it.")Years ago, the CAA published a manual that all the A&E mechanics (Aircraft & Engine mechanics in those days) used as a standard for airworthy repairs and alterations. It was called the "Department of Commerce, Civil Aeronautics Administration Manual 18." The title was "Maintenance, Repair, and Alteration of Certificated Aircraft, Aircraft Engines, Propellers, and Instruments." Manual 18 had a bunch of changes over the years, so don't use a Manual 18 printed later than 1941 or it may not have these 1930s tips about weight and balance limits.Back in the early 1930s, the Type Certificate Data Sheets that were issued by the CAA for each model of certificated airplane were quite brief - 10 or 12 lines of print. Today, those same TCDSs for those antique airplanes still appear in that brief, sweet, naive condition. Compare that with today's TCDS of the popular Aeronca Champion - 32 pages!So if the C.G. limits are not set by the FAA in a TCDS (and of course, on your homebuilt experimental Pietenpol there is no TCDS), how can you know where the limits should be? If you can find an old pre-WWII Manual 18 (my reference is "As amended June 1, 1941), you will find a couple of interesting rules of thumb about Center of Gravity locations.For instance, on page II-5, under "E. APPROVED CENTER OF GRAVITY LIMITS"1. Current Models - stated on the pertinent aircraft specification in percent of the MAC or in inches aft of a given datum. This information may be obtained from the local Civil Aeronautics Inspector.2. Older Models - In the case of those models for which approved limits are not given on the specification or listing, it will usually be acceptable to assume the limits to be at 18% and 30% of the MAC for low and mid wing monoplanes and 22% and 34% of the MAC for high wing monoplanes and biplanes.Inasmuch as several models are known to have satisfactory flight characteristics with the C.G. beyond such arbitrary positions, these should not be considered hard and fast limits. In such cases, approval will depend largely upon the recommendations of the examining inspector. The major consideration governing approval of such cases will be the relative change in the empty weight C.G. due to the alterations, rather than the absolute C.G. extremes.If the approved forward limit thus determined is exceeded, it may be considered satisfactory provided that it is demonstrated to the local Civil Aeronautics Inspector that the aircraft can be landed in the three-point position when landed in the extreme forward condition.Page II-6 of old CAA Manual 18 goes on to say:G. DETERMINATION OF LOADED CENTER OF GRAVITY EXTREMES (The most forward and most rearward C.G. positions obtainable as equipped and with the most critical distribution of useful load.) The loaded extremes may be determined either, (1) by weighing the two loaded conditions or, (2) by computation. Both procedures have a common objective; namely, to demonstrate that, under the most adverse loading conditions (forward and aft), the C.G. positions will not exceed the approved limits (Part E) which have been determined by flight test as the most extreme positions at which the model will satisfactorily comply with the Civil Air Regulations.A note on page II-17 states:When the necessary information is not included in the pertinent specifications (as for older models), it will be necessary to obtain such data by computation and actual measurement.OK, when you start your establishment of loaded C.G. limits on your Pietenpol, lets use these old CAA limits (22% of the MAC for forward limit and 34% of the MAC for the rearward limit on your high wing monoplane). A forward C.G. may make it so you cannot land the airplane in a three-point position (put another way, the engine is just too heavy for the too-small elevators at slow speed to overcome). A rearward C.G. starts to get into problems with stability and spin recovery. Vaughan Askue in his book Flight Testing Homebuilt Aircraft says "C.G. provides the most direct method the pilot has for controlling pitch stability. Moving the C.G. forward increases the effectiveness of the horizontal tail and improves both static and dynamic stability. The primary objective of a stability test program is to prove that the airplane has acceptable stability characteristics at a limiting C.G. This C.G. then becomes the aft C.G. limit called out in the airplane's limitations. If moving the C.G. limit forward gives acceptable stability without hurting the utility of the airplane, then this is the simplest fix for a stability problem.What does all this mean in your Piet? If you establish the fore and aft loaded C.G. limits at something like 22% and 34% of the Mean Aerodynamic Chord and try to stay away from the rear limit as much as possible (that's the one where instability starts to take over), you will probably be OK.Historically, most Piets come out of the jig being tail heavy because they don't have that heavy Ford A engine on the front end of the teeter-totter. If you increase the arm of the engine weight of a 220# Corvair engine, for example, (move it 4 or 5 inches forward of where the Ford used to be) your Piet will probably not be chronically tail heavy. Then, if you want, you can tweak it by moving the wing fore or aft - usually aft - to really set the loaded CG between your goal numbers of 22/34%That's how Bernie did it. It still works. A pound is a pound the world around.Oscar ZunigaSan Antonio, TXmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net________________________________________________________________________________
Ryan;You could ask Riblett but If I remember correctly, Doc Mosher's narrativeand analysis ondetermining CG range for the Piet pretty much covered most conventionalairfoils at least as a starting point. Here's Doc's commentary, fromOct. of 2002:======================Recently there have been some questions concerning establishing practical CG limits on homebuilt Pietenpols. Perhaps by going back to the Piet era (1930s) we can gain an insight about how the CG limits were established in those days ("That's how Bernie did it.")Years ago, the CAA published a manual that all the A&E mechanics (Aircraft & Engine mechanics in those days) used as a standard for airworthy repairs and alterations. It was called the "Department of Commerce, Civil Aeronautics Administration Manual 18." The title was "Maintenance, Repair, and Alteration of Certificated Aircraft, Aircraft Engines, Propellers, and Instruments." Manual 18 had a bunch of changes over the years, so don't use a Manual 18 printed later than 1941 or it may not have these 1930s tips about weight and balance limits.Back in the early 1930s, the Type Certificate Data Sheets that were issued by the CAA for each model of certificated airplane were quite brief - 10 or 12 lines of print. Today, those same TCDSs for those antique airplanes still appear in that brief, sweet, naive condition. Compare that with today's TCDS of the popular Aeronca Champion - 32 pages!So if the C.G. limits are not set by the FAA in a TCDS (and of course, on your homebuilt experimental Pietenpol there is no TCDS), how can you know where the limits should be? If you can find an old pre-WWII Manual 18 (my reference is "As amended June 1, 1941), you will find a couple of interesting rules of thumb about Center of Gravity locations.For instance, on page II-5, under "E. APPROVED CENTER OF GRAVITY LIMITS"1. Current Models - stated on the pertinent aircraft specification in percent of the MAC or in inches aft of a given datum. This information may be obtained from the local Civil Aeronautics Inspector.2. Older Models - In the case of those models for which approved limits are not given on the specification or listing, it will usually be acceptable to assume the limits to be at 18% and 30% of the MAC for low and mid wing monoplanes and 22% and 34% of the MAC for high wing monoplanes and biplanes.Inasmuch as several models are known to have satisfactory flight characteristics with the C.G. beyond such arbitrary positions, these should not be considered hard and fast limits. In such cases, approval will depend largely upon the recommendations of the examining inspector. The major consideration governing approval of such cases will be the relative change in the empty weight C.G. due to the alterations, rather than the absolute C.G. extremes.If the approved forward limit thus determined is exceeded, it may be considered satisfactory provided that it is demonstrated to the local Civil Aeronautics Inspector that the aircraft can be landed in the three-point position when landed in the extreme forward condition.Page II-6 of old CAA Manual 18 goes on to say:G. DETERMINATION OF LOADED CENTER OF GRAVITY EXTREMES (The most forward and most rearward C.G. positions obtainable as equipped and with the most critical distribution of useful load.) The loaded extremes may be determined either, (1) by weighing the two loaded conditions or, (2) by computation. Both procedures have a common objective; namely, to demonstrate that, under the most adverse loading conditions (forward and aft), the C.G. positions will not exceed the approved limits (Part E) which have been determined by flight test as the most extreme positions at which the model will satisfactorily comply with the Civil Air Regulations.A note on page II-17 states:When the necessary information is not included in the pertinent specifications (as for older models), it will be necessary to obtain such data by computation and actual measurement.OK, when you start your establishment of loaded C.G. limits on your Pietenpol, lets use these old CAA limits (22% of the MAC for forward limit and 34% of the MAC for the rearward limit on your high wing monoplane). A forward C.G. may make it so you cannot land the airplane in a three-point position (put another way, the engine is just too heavy for the too-small elevators at slow speed to overcome). A rearward C.G. starts to get into problems with stability and spin recovery. Vaughan Askue in his book Flight Testing Homebuilt Aircraft says "C.G. provides the most direct method the pilot has for controlling pitch stability. Moving the C.G. forward increases the effectiveness of the horizontal tail and improves both static and dynamic stability. The primary objective of a stability test program is to prove that the airplane has acceptable stability characteristics at a limiting C.G. This C.G. then becomes the aft C.G. limit called out in the airplane's limitations. If moving the C.G. limit forward gives acceptable stability without hurting the utility of the airplane, then this is the simplest fix for a stability problem.What does all this mean in your Piet? If you establish the fore and aft loaded C.G. limits at something like 22% and 34% of the Mean Aerodynamic Chord and try to stay away from the rear limit as much as possible (that's the one where instability starts to take over), you will probably be OK.Historically, most Piets come out of the jig being tail heavy because they don't have that heavy Ford A engine on the front end of the teeter-totter. If you increase the arm of the engine weight of a 220# Corvair engine, for example, (move it 4 or 5 inches forward of where the Ford used to be) your Piet will probably not be chronically tail heavy. Then, if you want, you can tweak it by moving the wing fore or aft - usually aft - to really set the loaded CG between your goal numbers of 22/34%That's how Bernie did it. It still works. A pound is a pound the world around.Oscar ZunigaSan Antonio, TXmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net________________________________________________________________________________
RE: Pietenpol-List: Patch design
Original Posted By: owner-pietenpol-list-server(at)matronics.com [mailto:owner-pietenpol-list-server(at)matronics.com] On Behalf Of BYD(at)att.net
Subject: RE: Pietenpol-List: Patch designGood thought. I've already planned on making hats for the 80th, like I did forthe 70th and 75th. Patches and embroidered t-shirts are in the works too.If you like it you can buy it. If you want to make your own, you can do that too.Steve E.-----Original Message-----
Subject: RE: Pietenpol-List: Patch designGood thought. I've already planned on making hats for the 80th, like I did forthe 70th and 75th. Patches and embroidered t-shirts are in the works too.If you like it you can buy it. If you want to make your own, you can do that too.Steve E.-----Original Message-----
Re: Pietenpol-List: Patch design
Original Posted By: amsafetyc(at)aol.com
Ryan asks->how do you determine the correct angle of incidence for a>non Piet wing?Well, you could go through a bunch of analysis and probablyfigure out a good starting point that way, but I'd say aneven easier way would be to start by setting the angle ofincidence of a non-Piet wing the same as for a Piet wing.It's probably going to require some tweaking no matter what,unless you use a wing and geometry that someone has alreadyused and flown and can tell you what angle works.In order to change the incidence later, you'll have to changethe length of either the front cabanes or the rear ones, aswell as adjusting the front or rear lift struts to keep thesame washout when the incidence is adjusted. One way toallow for adjustment of the cabane lengths is to useadjustable connections for either the front or the rearcabanes (I think I'd do the rear ones unless that adds morecomplexity, such as if your fuel line runs down one of thecabanes from a center-section fuel tank). That could be doneby attaching the top ends to the wing with fork ends orsomething similar instead of fixed mounts.Oscar ZunigaAir Camper NX41CCSan Antonio, TXmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net________________________________________________________________________________Subject: Re: Pietenpol-List: Patch design
Ryan asks->how do you determine the correct angle of incidence for a>non Piet wing?Well, you could go through a bunch of analysis and probablyfigure out a good starting point that way, but I'd say aneven easier way would be to start by setting the angle ofincidence of a non-Piet wing the same as for a Piet wing.It's probably going to require some tweaking no matter what,unless you use a wing and geometry that someone has alreadyused and flown and can tell you what angle works.In order to change the incidence later, you'll have to changethe length of either the front cabanes or the rear ones, aswell as adjusting the front or rear lift struts to keep thesame washout when the incidence is adjusted. One way toallow for adjustment of the cabane lengths is to useadjustable connections for either the front or the rearcabanes (I think I'd do the rear ones unless that adds morecomplexity, such as if your fuel line runs down one of thecabanes from a center-section fuel tank). That could be doneby attaching the top ends to the wing with fork ends orsomething similar instead of fixed mounts.Oscar ZunigaAir Camper NX41CCSan Antonio, TXmailto: taildrags(at)hotmail.comwebsite at http://www.flysquirrel.net________________________________________________________________________________Subject: Re: Pietenpol-List: Patch design
Pietenpol-List: Patch design
Original Posted By: Jeff Boatright
Re: Pietenpol-List: Plane sitting: need list advice on elevator control
Original Posted By: Jeff Boatright
Hey JeffSounds like you got her fixed up without any ancillary issues to deal with. Now about that paycheck bet, I met your wife a really nice person. I doubt shewould be all that nice having found out you bet her paycheck!Glad to hear you'll be back in action tomorrowFly safeJohnSent from my Verizon Wireless BlackBerry-----Original Message-----
Hey JeffSounds like you got her fixed up without any ancillary issues to deal with. Now about that paycheck bet, I met your wife a really nice person. I doubt shewould be all that nice having found out you bet her paycheck!Glad to hear you'll be back in action tomorrowFly safeJohnSent from my Verizon Wireless BlackBerry-----Original Message-----
FW: Pietenpol-List: Patch design
Original Posted By: owner-pietenpol-list-server(at)matronics.com [mailto:owner-pietenpol-list-server(at)matronics.com] On Behalf Of amsafetyc(at)aol.com
Subject: FW: Pietenpol-List: Patch designSure! This is my starting point. http://share.shutterfly.com/action/welc ... VqyYvkghas two pictures...I can change thread colors and backgrounds easily, so send in your suggestions,I like the one that has only the "75 years" above the Camper, but want onlythe 75 years in a different color. The hats are the same as before, with the words 'LOW AND SLOW FOR 80 YEARS' or'CHERRY GROVE - 80 - BRODHEAD' over the back adjustment. I have had several customdone with N-numbers which I may offer again.The patch version will have the 80 years inside the patch similar to the 75th.Comments welcome...If there is interest, I can start making them available now, instead of waitingtill summer.Like the 70th year (1999) and the 75th year, I plan on bringing a supply of patchesand hats and t-shirts, and maybe a few sweatshirts.Andrew (in the piet) and I in the Stinson, plan on making the trip together. I'veinvited all 4 of my brothers to make the trip. 3 of us are pilots...I'm already looking forward to the gathering!!Best regards,Steve E.-----Original Message-----
Subject: FW: Pietenpol-List: Patch designSure! This is my starting point. http://share.shutterfly.com/action/welc ... VqyYvkghas two pictures...I can change thread colors and backgrounds easily, so send in your suggestions,I like the one that has only the "75 years" above the Camper, but want onlythe 75 years in a different color. The hats are the same as before, with the words 'LOW AND SLOW FOR 80 YEARS' or'CHERRY GROVE - 80 - BRODHEAD' over the back adjustment. I have had several customdone with N-numbers which I may offer again.The patch version will have the 80 years inside the patch similar to the 75th.Comments welcome...If there is interest, I can start making them available now, instead of waitingtill summer.Like the 70th year (1999) and the 75th year, I plan on bringing a supply of patchesand hats and t-shirts, and maybe a few sweatshirts.Andrew (in the piet) and I in the Stinson, plan on making the trip together. I'veinvited all 4 of my brothers to make the trip. 3 of us are pilots...I'm already looking forward to the gathering!!Best regards,Steve E.-----Original Message-----