Original Posted By: dave rowe
Pietenpol-List: Another change of subject. . .
Re: Pietenpol-List: From the keyboard of a hill billy
Original Posted By: "John Ford"
Pietenpol-List: Another change of subject. . .
Original Posted By: Clif Dawson
I have used the HIPEC system on my Pietenpol. 2.7oz.fabric, and brushed on theGrey coat (Hipec sun barrer).This is the same material that is used to gluethe fabric to the ribs. When I made a sample test jig, the adhesion was strongenough to rip apart the capstrips on the test jig. Whats reallyneatabout thestuffis its incredible flexibility. You can take a piece of HSB treated fabric,roll it up in to a ball. The spread it out andtry shining a light threw it.The coating isn't damaged. On the tail I finished the colour coat with the HIPEC Top Coat. This is thetwo part cyanate based polyurethane that requires air supply while spraying. WhenI recovered the wing this spring I used HIPEC again with 2.7oz. fabric,butsprayed it with latex forthe colour topcoat. Mainly because I didn't want tospray that poison again. The latex though is heavier and no way as nice as thefinish of the HIPEC Top Coat that was used on the tail. On my other homebuilt, the original builder used HIPEC HSB then used Centaurias a top coat. Centauri is a premium automotive finish. The Centauri seems tohave lost alot of its elasticity, and is cracking and peeling in places. Butwith close inspection, the HIPEC underneath is in great shape. No cracking orsign of any deterioration at all. Repairs are also simple with the HIPEC, and no ribstitching or tapes at theribs. The extra work for getting the HIPEC to glue the fabric to the bottom ofthe undercambered wing was a pain. I had to weight the fabric down so it wasresting on the ribs with over a hundred margarine tubs filled with sand & gravel. Just to give you a p[erspective on how well the HSB glues. When I was removingthe masking tape from the fuel filler on the wing tank. I didn't run a knifearound first, and the HSB glued the masking tape to the edge of the fabric sowell that I ripped the fabric pulling off the tape. Good thing its easy to patchwith HIPEC.Shawn WolkC-FRAZ Pietenpol AircamperC-GZOT Skyhopper 2________________________________________________________________________________Date: Sat, 07 Feb 2004 00:23:31 -0800
I have used the HIPEC system on my Pietenpol. 2.7oz.fabric, and brushed on theGrey coat (Hipec sun barrer).This is the same material that is used to gluethe fabric to the ribs. When I made a sample test jig, the adhesion was strongenough to rip apart the capstrips on the test jig. Whats reallyneatabout thestuffis its incredible flexibility. You can take a piece of HSB treated fabric,roll it up in to a ball. The spread it out andtry shining a light threw it.The coating isn't damaged. On the tail I finished the colour coat with the HIPEC Top Coat. This is thetwo part cyanate based polyurethane that requires air supply while spraying. WhenI recovered the wing this spring I used HIPEC again with 2.7oz. fabric,butsprayed it with latex forthe colour topcoat. Mainly because I didn't want tospray that poison again. The latex though is heavier and no way as nice as thefinish of the HIPEC Top Coat that was used on the tail. On my other homebuilt, the original builder used HIPEC HSB then used Centaurias a top coat. Centauri is a premium automotive finish. The Centauri seems tohave lost alot of its elasticity, and is cracking and peeling in places. Butwith close inspection, the HIPEC underneath is in great shape. No cracking orsign of any deterioration at all. Repairs are also simple with the HIPEC, and no ribstitching or tapes at theribs. The extra work for getting the HIPEC to glue the fabric to the bottom ofthe undercambered wing was a pain. I had to weight the fabric down so it wasresting on the ribs with over a hundred margarine tubs filled with sand & gravel. Just to give you a p[erspective on how well the HSB glues. When I was removingthe masking tape from the fuel filler on the wing tank. I didn't run a knifearound first, and the HSB glued the masking tape to the edge of the fabric sowell that I ripped the fabric pulling off the tape. Good thing its easy to patchwith HIPEC.Shawn WolkC-FRAZ Pietenpol AircamperC-GZOT Skyhopper 2________________________________________________________________________________Date: Sat, 07 Feb 2004 00:23:31 -0800
Re: Pietenpol-List: Another change of subject. . .
Original Posted By: dave rowe
RE: Pietenpol-List: Another change of subject. . .
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Shawn,For a Piet, or any aircraft with truss type ribs, rib stitching is importantand needed for more than just holding the fabric to the rib. The truss isvery strong in compression, but not as strong in tension. The stitchinghelps hold the top and bottom of the wing together.Now, the Piet rib may be over designed enough that this is not a concernbut, for the one or two days it takes to stitch-up the wing, it is not worththe risk to me.Skip-----Original Message-----
Shawn,For a Piet, or any aircraft with truss type ribs, rib stitching is importantand needed for more than just holding the fabric to the rib. The truss isvery strong in compression, but not as strong in tension. The stitchinghelps hold the top and bottom of the wing together.Now, the Piet rib may be over designed enough that this is not a concernbut, for the one or two days it takes to stitch-up the wing, it is not worththe risk to me.Skip-----Original Message-----
Pietenpol-List: RE: Another change of subject. . .
Original Posted By: "Cy Galley"
Yes Skip, I kind of agree with you. But with with the incredibly low wing loadings. (mineis 1180# gross and 31' span...works out to 7.6lbs. per square ft.) That isa very small load in tension. If someone feels that ribstitching is a must.It can still be done using HIPEC. A guy on our field did that on a Christavia4 seater. I personally was convinced after I made my own destructive test. Shawn Wolk C-FRAZ Pietenpol Aircamper C-GZOT Skyhopper 2 'Finally took to the air for its first two hours of flightyesterday' So I couldn't fly my Pietenpol.________________________________________________________________________________
Yes Skip, I kind of agree with you. But with with the incredibly low wing loadings. (mineis 1180# gross and 31' span...works out to 7.6lbs. per square ft.) That isa very small load in tension. If someone feels that ribstitching is a must.It can still be done using HIPEC. A guy on our field did that on a Christavia4 seater. I personally was convinced after I made my own destructive test. Shawn Wolk C-FRAZ Pietenpol Aircamper C-GZOT Skyhopper 2 'Finally took to the air for its first two hours of flightyesterday' So I couldn't fly my Pietenpol.________________________________________________________________________________
Re: Pietenpol-List: RE: Another change of subject. . .
Original Posted By: Shawn Wolk
Think about the G-loading. 5 Gs would multiply the 7.6 by 5 38. before you dismissrib stitching, talk to an old timer; one that flew with grade A. Someonethat had the fabric rip off.Cy Galley, TC - Chair, Emergency Aircraft Repair, OshkoshEditor, EAA Safety Programscgalley(at)qcbc.org or experimenter(at)eaa.orgAlways looking for articles for the Experimenter soon to be Sport Pilot ----- Original Message -----
Think about the G-loading. 5 Gs would multiply the 7.6 by 5 38. before you dismissrib stitching, talk to an old timer; one that flew with grade A. Someonethat had the fabric rip off.Cy Galley, TC - Chair, Emergency Aircraft Repair, OshkoshEditor, EAA Safety Programscgalley(at)qcbc.org or experimenter(at)eaa.orgAlways looking for articles for the Experimenter soon to be Sport Pilot ----- Original Message -----
Re: Pietenpol-List: RE: Another change of subject. . .
Original Posted By: Clif Dawson
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Re: Pietenpol-List: Another change of subject. . .
Original Posted By: KRSBtv(at)aol.com
Subject: Re: Pietenpol-List: Another change of subject. . .In a message dated 2/7/04 1:49:11 AM Central Standard Time, shawnwolk(at)sprint.ca writes:>Shawn,Ribstitching is certainly still necessary.Chuck G.________________________________________________________________________________
Subject: Re: Pietenpol-List: Another change of subject. . .In a message dated 2/7/04 1:49:11 AM Central Standard Time, shawnwolk(at)sprint.ca writes:>Shawn,Ribstitching is certainly still necessary.Chuck G.________________________________________________________________________________
Re: Pietenpol-List: RE: Another change of subject. . .
Original Posted By: TomTravis(at)aol.com
Subject: Re: Pietenpol-List: RE: Another change of subject. . .Avids and the Kitfox are wing fabrics are generally glued, not rib-stitched and I'm not aware of a single one having fabric separation on a wing. In fact,Jim Metzger, former General Manager of Avid did fairly extensive spins, loops,snap rolls in the Avid Speedwing over the course of several years and never had a problem. This was a Ceconite process. The capstrips on the Avid are about3/4 inch wide if memory serves me correct. The above mentioned ribs are/were diecut from spruce plywood and in the Avid, the rib was glued to the front spar using a 2-part epoxy glue for the Speedwing and heavy-hauler wings. In the case of the Speedwing Avid, the planeeasily cruised better than 100 mph.I'm not advocating that people avoid rib stitching, but the glue on process worked well on the Avids.________________________________________________________________________________
Subject: Re: Pietenpol-List: RE: Another change of subject. . .Avids and the Kitfox are wing fabrics are generally glued, not rib-stitched and I'm not aware of a single one having fabric separation on a wing. In fact,Jim Metzger, former General Manager of Avid did fairly extensive spins, loops,snap rolls in the Avid Speedwing over the course of several years and never had a problem. This was a Ceconite process. The capstrips on the Avid are about3/4 inch wide if memory serves me correct. The above mentioned ribs are/were diecut from spruce plywood and in the Avid, the rib was glued to the front spar using a 2-part epoxy glue for the Speedwing and heavy-hauler wings. In the case of the Speedwing Avid, the planeeasily cruised better than 100 mph.I'm not advocating that people avoid rib stitching, but the glue on process worked well on the Avids.________________________________________________________________________________
Re: Pietenpol-List: RE: Another change of subject. . .
Original Posted By: "Jack Phillips"
Subject: Re: Pietenpol-List: RE: Another change of subject. . .I'm sure the new glues are fine but as one who has heard the sickening sound of fabric ripping off in flight, I plan to rib stitch. That's all that saved me the first time.________________________________________________________________________________
Subject: Re: Pietenpol-List: RE: Another change of subject. . .I'm sure the new glues are fine but as one who has heard the sickening sound of fabric ripping off in flight, I plan to rib stitch. That's all that saved me the first time.________________________________________________________________________________
RE: Pietenpol-List: RE: Another change of subject. . .
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Rib stitching is fun, and it's a skill uncommon in today's modern world.Why risk death just to avoid acquiring a unique skill? I would hate to bethinking to myself as i plunged to my death - "Damn! I sure wish I'drib-stitched it!"Another fact that I'm sure doesn't figure into the Avid or Kitfox is theundercamber in the Pietenpol's wing. If you just glue it and don'tribstitch before fully tautening the fabric, it may pull away from the ribson the bottom of the wing.Jack-----Original Message-----
Rib stitching is fun, and it's a skill uncommon in today's modern world.Why risk death just to avoid acquiring a unique skill? I would hate to bethinking to myself as i plunged to my death - "Damn! I sure wish I'drib-stitched it!"Another fact that I'm sure doesn't figure into the Avid or Kitfox is theundercamber in the Pietenpol's wing. If you just glue it and don'tribstitch before fully tautening the fabric, it may pull away from the ribson the bottom of the wing.Jack-----Original Message-----
> Re: Pietenpol-List: thinking about airfoils
Original Posted By: "Jim Markle"
Mike-I'd love to see your test data. Mainly just to stisfy my curiosity.Best regards,Robert HollyNew list member contemplating a Piet.>From: "Mike Whaley" >Reply-To: pietenpol-list(at)matronics.com>To: "Pietenpol List" >Subject: Re: Pietenpol-List: thinking about airfoils>Date: Sun, 8 Feb 2004 23:54:51 -0500>>> > not having access to a wind tunnel isn't really a limitation if someone> > wants to test the FC-10, since automobile highway speeds are a pretty> > good match for Pietenpol airspeeds. If you had the proper test rig, you> > could mount an airfoil section in, say, the bed of a pickup truck,> > poking up well above the cab to get it into clean air, and collect data> > at night on a smooth section of rural highway.>>I've done the truck-testing bit, a friend and I wanted to know the real>forces put onto the servo actuating an R/C Pattern plane's rudder, with and>without balance tabs (the difference was dramatic). Back in high school, I>also did some real wind-tunnel testing in a Florida Tech's low-speed tunnel>(at the time, it was one of the best in the country) for a science fair>project with variable-camber airfoild (took first place at state, so I >guess>I wasn't complete clueless back then.) My guess is that the truck method>could give you some OK data, but if you're serious about getting really >good>data, then you really would need to do a bit more and go for the tunnel. >The>problem is that the fine differences between two airfoils (or to get a good>baseline on the FC-10) would need to be measured with very smooth, laminar>airflow and sensitive instruments, you need to know not only the airspeed>but precise AOA, pressure, and forces acting on teh wing section. More>importantly, the conditions need to be identical between the control test>with the old airfoild, and the experimental test with the new one. As we>discovered with the rudder test, you have very strong boundary layer and>other effects generated by the vehicle itself that will destroy your >ability>to get really good data. In our case, we figured this out and built a>boundary layer diverter (similar to that found on the intake of an F-15 or>similar jet) but we still had some effects of the vehicle. You could put a>test section on a long truss way out in front of the truck to get better>results, but then every bump will be magnified and really screw up the >force>balance or whatever you're using to measure the forces. Plus, turbulence>from other vehicles, wind, fog, etc. will all affect things too.>>Here's what I would do (and no, I'm not volunteering as my plate is too >full>already...) I would get in touch with a college with an aeronautical >program>and a wind tunnel. You want to figure out the typical Reynolds number that>the Piet flies at (low and high speeds) and then find a tunnel that can do>that. Then try to find a sympathetic prof to work with you and connect you>with a group of students so that they can learn, while generating useful>data. Dr. Michael Selig has done a lot of work at UIUC (I think) so that>might be one place to start. I think the guy I was working with went to>Purdue. (BTW, for those who don't know, the Reynold's number basically just>takes into account the size of an airfoil, the air density, speed,>viscosity, etc. and adjusts it for scale effects, thus allowing you to>compare airfoils of different sizes. With some exceptions and >modifications,>you will get very close to the same performance as the full-size aircraft>has by adjusting the speed and density of the air passing over a >small-scale>test model such that it has the same Reynold's number as the real one does>in flight. That's how they can test planes like the C-5 and 747 in a >regular>tunnel.) As the test section's chord is a factor in the Reynold's number,>and it's impractical to build a test section at too small a scale, you'd>need to figure all this out to get teh right combination to be both>rpactical to build as well as what will suit the tunnel that's available. I>don't think it would be too hard to find someplace that could test a half->or third- scale test section properly.>>Bear in mind that a wind-tunnel test is typically going to produce 2-D test>data, which is invaluable, but not the whole story. The Piet, like all>planes, has a lot of 3-D effects going on... not only at the wingtips, but >a>lot of interesting stuff may be happening between the wing and fuselage,>especially for a plane with a radiator there. There may well be a>significant difference between having a cut-out and a wing flap too. You'll>even get different wing sections where the covering sags between the ribs,>which could be significantly better or worse than the section on a rib. So>don't expect any single test to yield all-encompassing results. But it will>allow you to validly compare to other airfoils.>>If anyone is interested in the full story of the truck testing I took part>in, let me know privately and I will send it to you (the list server >doesn't>like ZIP file attachments.) It contains a writeup with our test results and>description of how we did it, as well as the test data. At highway speeds,>several times, the airflow on the standard rudder section was stronger than>I was... I pity those poor little servos trying to move the typical pattern>plane rudder!>>Just some thoughts,>Mike>>Mike Whaley merlin@ov-10bronco.net>Webmaster, OV-10 Bronco Association>http://www.ov-10bronco.net/>>overload! http://click.atdmt.com/AVE/go/onm002003 ... __________
Mike-I'd love to see your test data. Mainly just to stisfy my curiosity.Best regards,Robert HollyNew list member contemplating a Piet.>From: "Mike Whaley" >Reply-To: pietenpol-list(at)matronics.com>To: "Pietenpol List" >Subject: Re: Pietenpol-List: thinking about airfoils>Date: Sun, 8 Feb 2004 23:54:51 -0500>>> > not having access to a wind tunnel isn't really a limitation if someone> > wants to test the FC-10, since automobile highway speeds are a pretty> > good match for Pietenpol airspeeds. If you had the proper test rig, you> > could mount an airfoil section in, say, the bed of a pickup truck,> > poking up well above the cab to get it into clean air, and collect data> > at night on a smooth section of rural highway.>>I've done the truck-testing bit, a friend and I wanted to know the real>forces put onto the servo actuating an R/C Pattern plane's rudder, with and>without balance tabs (the difference was dramatic). Back in high school, I>also did some real wind-tunnel testing in a Florida Tech's low-speed tunnel>(at the time, it was one of the best in the country) for a science fair>project with variable-camber airfoild (took first place at state, so I >guess>I wasn't complete clueless back then.) My guess is that the truck method>could give you some OK data, but if you're serious about getting really >good>data, then you really would need to do a bit more and go for the tunnel. >The>problem is that the fine differences between two airfoils (or to get a good>baseline on the FC-10) would need to be measured with very smooth, laminar>airflow and sensitive instruments, you need to know not only the airspeed>but precise AOA, pressure, and forces acting on teh wing section. More>importantly, the conditions need to be identical between the control test>with the old airfoild, and the experimental test with the new one. As we>discovered with the rudder test, you have very strong boundary layer and>other effects generated by the vehicle itself that will destroy your >ability>to get really good data. In our case, we figured this out and built a>boundary layer diverter (similar to that found on the intake of an F-15 or>similar jet) but we still had some effects of the vehicle. You could put a>test section on a long truss way out in front of the truck to get better>results, but then every bump will be magnified and really screw up the >force>balance or whatever you're using to measure the forces. Plus, turbulence>from other vehicles, wind, fog, etc. will all affect things too.>>Here's what I would do (and no, I'm not volunteering as my plate is too >full>already...) I would get in touch with a college with an aeronautical >program>and a wind tunnel. You want to figure out the typical Reynolds number that>the Piet flies at (low and high speeds) and then find a tunnel that can do>that. Then try to find a sympathetic prof to work with you and connect you>with a group of students so that they can learn, while generating useful>data. Dr. Michael Selig has done a lot of work at UIUC (I think) so that>might be one place to start. I think the guy I was working with went to>Purdue. (BTW, for those who don't know, the Reynold's number basically just>takes into account the size of an airfoil, the air density, speed,>viscosity, etc. and adjusts it for scale effects, thus allowing you to>compare airfoils of different sizes. With some exceptions and >modifications,>you will get very close to the same performance as the full-size aircraft>has by adjusting the speed and density of the air passing over a >small-scale>test model such that it has the same Reynold's number as the real one does>in flight. That's how they can test planes like the C-5 and 747 in a >regular>tunnel.) As the test section's chord is a factor in the Reynold's number,>and it's impractical to build a test section at too small a scale, you'd>need to figure all this out to get teh right combination to be both>rpactical to build as well as what will suit the tunnel that's available. I>don't think it would be too hard to find someplace that could test a half->or third- scale test section properly.>>Bear in mind that a wind-tunnel test is typically going to produce 2-D test>data, which is invaluable, but not the whole story. The Piet, like all>planes, has a lot of 3-D effects going on... not only at the wingtips, but >a>lot of interesting stuff may be happening between the wing and fuselage,>especially for a plane with a radiator there. There may well be a>significant difference between having a cut-out and a wing flap too. You'll>even get different wing sections where the covering sags between the ribs,>which could be significantly better or worse than the section on a rib. So>don't expect any single test to yield all-encompassing results. But it will>allow you to validly compare to other airfoils.>>If anyone is interested in the full story of the truck testing I took part>in, let me know privately and I will send it to you (the list server >doesn't>like ZIP file attachments.) It contains a writeup with our test results and>description of how we did it, as well as the test data. At highway speeds,>several times, the airflow on the standard rudder section was stronger than>I was... I pity those poor little servos trying to move the typical pattern>plane rudder!>>Just some thoughts,>Mike>>Mike Whaley merlin@ov-10bronco.net>Webmaster, OV-10 Bronco Association>http://www.ov-10bronco.net/>>overload! http://click.atdmt.com/AVE/go/onm002003 ... __________
Re: Pietenpol-List: RE: Another change of subject. . .
Original Posted By: dave rowe
Re: Pietenpol-List: RE: Another change of subject. . .
Original Posted By: Michael D Cuy
Re: Pietenpol-List: RE: Another change of subject. . .
Original Posted By: "dave rowe"
Man. you really don't want to ribstitch do you?Carl----- Original Message -----
Man. you really don't want to ribstitch do you?Carl----- Original Message -----
> Re: Pietenpol-List: RE: Another change of subject. . .
Original Posted By: dave rowe