---------------------------------------------------------- Pietenpol-List Digest Archive --- Total Messages Posted Sun 02/08/04: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 01:17 AM - Re: Changing the subject (Clif Dawson) 2. 07:20 PM - The Flying & Glider Manuals - EAA vs. Originals (Mike Whaley) 3. 07:58 PM - Re: blood, sweat & tears (Mike Whaley) 4. 08:31 PM - Re: The Flying & Glider Manuals - EAA vs. Originals (Kevin Holcomb) 5. 08:50 PM - Re: thinking about airfoils (Mike Whaley) ________________________________ Message 1 _____________________________________ Time: 01:17:35 AM PST US From: Clif Dawson Subject: Re: Pietenpol-List: Changing the subject Even if you don't use any strip the fabric should cover the ply to give protection to it and a more water and oil proof finish. The bare wood, just painted, will inevitably crack in little splits. My plan is to have a full width panel from the ply back to the first cross brace under the bell crank, no strips and fabric over the ply. But now that it's been mentioned, a full length panel would be a neater looking installation, only one seam across the belly. How do you plan on sealing the edges? I finally found the time to visit my local 4130 supplier and get what I need to make up that vast array of fittings. Clif ----- Original Message ----- From: BARNSTMR@aol.com To: pietenpol-list@matronics.com Sent: Saturday, February 07, 2004 7:55 AM Subject: Re: Pietenpol-List: Changing the subject Also, I might add that I plan to use a center fairing strip and cover the belly with fabric from the firewall to the tail, with only a small access panel (maybe one bay) for access to the belcrank area. Fabric on the belly is desireable for cleaning off the oil spatters and fuel drips that are inevitable, no matter which engine you use. I'd prefer to clean off of fabric, rather than allow those intrusive fluids to soak into the belly plywood. Terry Bowden ph (254) 715-4773 fax (254) 853-3805 ________________________________ Message 2 _____________________________________ Time: 07:20:15 PM PST US From: "Mike Whaley" Subject: Pietenpol-List: The Flying & Glider Manuals - EAA vs. Originals --> Pietenpol-List message posted by: "Mike Whaley" Hi listers, Can someone tell me the differences between the original Flying and Glider manuals and the EAA reprints? I own the set of EAA reprints, but haven't yet been able to find an original set of manuals for what seemed like a reasonable price. I know the EAA ones are "distilled" and don't have the advertisements, original covers, etc. as the real ones. But are there any relevant illustrations or text that were deleted from the EAA reprints? I'd love to have the originals but we're on a really tight budget and don't want to spend money needlessly. -Mike Mike Whaley merlin@ov-10bronco.net Webmaster, OV-10 Bronco Association http://www.ov-10bronco.net/ ________________________________ Message 3 _____________________________________ Time: 07:58:34 PM PST US From: "Mike Whaley" Subject: Re: Pietenpol-List: blood, sweat & tears --> Pietenpol-List message posted by: "Mike Whaley" About a year ago, I was sawing a piece of thin plywood for a model using an a hand saw." And sure 'nuff, within 5 seconds, I did just that! Nothing major but man did it look bad, because you could look at all the parallel cuts and quickly figure out that I was in fact stupid enough to saw through myself with a hand saw. Never get complacent! You ever notice the "Ohnosecond"? That's that split-second when you say to yourself, "Oh, no..." and then whatever it is that you were thinking "oh no" about actually happens. Mike Whaley merlin@ov-10bronco.net Webmaster, OV-10 Bronco Association http://www.ov-10bronco.net/ http://www.ov-10bronco.net/users/merlin/ ________________________________ Message 4 _____________________________________ Time: 08:31:00 PM PST US From: "Kevin Holcomb" Subject: RE: Pietenpol-List: The Flying & Glider Manuals - EAA vs. Originals --> Pietenpol-List message posted by: "Kevin Holcomb" The biggest difference that I can think of is in the 1933 Manual. The original has a large section on the Corben Baby Ace, including plans for both a parasol and a cabin version. That section does not appear in the EAA reprint. Best Regards, Kevin Holcomb www.airminded.net > [Original Message] > From: Mike Whaley > To: Pietenpol List > Date: 2/8/2004 10:19:46 PM > Subject: Pietenpol-List: The Flying & Glider Manuals - EAA vs. Originals > > --> Pietenpol-List message posted by: "Mike Whaley" > > Hi listers, > > Can someone tell me the differences between the original Flying and Glider > manuals and the EAA reprints? I own the set of EAA reprints, but haven't yet > been able to find an original set of manuals for what seemed like a > reasonable price. I know the EAA ones are "distilled" and don't have the > advertisements, original covers, etc. as the real ones. But are there any > relevant illustrations or text that were deleted from the EAA reprints? I'd > love to have the originals but we're on a really tight budget and don't want > to spend money needlessly. > > -Mike > > Mike Whaley merlin@ov-10bronco.net > Webmaster, OV-10 Bronco Association > http://www.ov-10bronco.net/ > > > > > > > > > ________________________________ Message 5 _____________________________________ Time: 08:50:39 PM PST US From: "Mike Whaley" Subject: Re: Pietenpol-List: thinking about airfoils --> Pietenpol-List message posted by: "Mike Whaley" > 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/