---------------------------------------------------------- Pietenpol-List Digest Archive --- Total Messages Posted Tue 12/14/04: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:27 AM - gear legs (Douwe Blumberg) 2. 05:27 AM - Re: Landing Gear (FTLovley@aol.com) 3. 05:41 AM - Re: gear legs (FTLovley@aol.com) 4. 06:48 AM - Re: gear legs (Rick Holland) 5. 06:52 AM - Re: Fly Baby gear (Jim Markle) 6. 09:27 AM - aircraft repairman (Richard Navratil) 7. 10:46 AM - Re: aircraft repairman (Phillips, Jack) 8. 02:48 PM - Re: Re: Landing gear (Richard Navratil) 9. 05:03 PM - Re: Re: Landing gear (Gary Gower) 10. 10:33 PM - Re: Re: Landing gear (Galen Hutcheson) ________________________________ Message 1 _____________________________________ Time: 05:27:23 AM PST US From: "Douwe Blumberg" Subject: Pietenpol-List: gear legs One of the big reasons BHP changed to the split gear was it's superior performance on unprepared fields. I'm building the axle gear but it can really foul up with long grass, weeds or crops on a rough field, and can contribute significantly to a nose over whereas the split gear is much less likely to do this. Though Larry Williams airplane was actually saved from a nose over by his axle gear during his off field experience when he taxied into a hidden hold and the axle caught on the edge of the hole thereby stopping the wheel from going all the way in. He swears he would have gone over it it had been a split gear. The split gear is also lighter and less draggy. I don't think it is necessarily stronger however. I noticed an interesting thing on a friend's split gear recently. His cross fusalage straps run on the outside and have bowed our away from the fuselage about an eighth of an inch, he couldn't figure it out. But what's happening is this. With a split gear, during a hard landing, downloads are delivered through the lift struts to the lift strut/gear fitting in combination with a downward pull of the opposite bungee. So basically both side gear/strut fittings are being pushed down rather hard and there is nothing to counteract this. In a axle gear design, the X bracing and the legs themselves actually form an upside down "pylon" or truss which resists any upward or downward pull from the struts. In conclusion, I think the split gear is more efficient and clean and less likely to cause a nose over by picking up weeds, the straight axle is stiffer and contributes to the overall rigidity and strength of the airframe. .02 $ ________________________________ Message 2 _____________________________________ Time: 05:27:39 AM PST US From: FTLovley@aol.com Subject: Re: Pietenpol-List: Landing Gear --> Pietenpol-List message posted by: FTLovley@aol.com I think Bernard just changed the gear to the split axle type because it was easier to build, lighter, less drag, and most important, it was safer when you landed in tall hay. The straight axle tended to put airplanes on their back in tall grass. Just one of the reasons he called it the "Improved Aircamper". Forrest Lovley ________________________________ Message 3 _____________________________________ Time: 05:41:36 AM PST US From: FTLovley@aol.com Subject: Re: Pietenpol-List: gear legs --> Pietenpol-List message posted by: FTLovley@aol.com The explanation for the bowed cross strap on the bottom of the fuselage is much simpler than all the engineered down loads and cross loads etc...after the first few hard landings, the wooden fuselage simply compresses slightly and is slightly narrower than it was when the cross strap was welded to the gear/strut fitting. Since the strap doesn't compress like the fuselage, there is now excess length, hence the bow. On one of the original airplanes that I rebuilt, Bernard had bolted a steel ruler across the fuselage between the fittings as a cross strap, and it's still there today. Forrest Lovley ________________________________ Message 4 _____________________________________ Time: 06:48:27 AM PST US DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; b=N//Gqr1ayXVKCXXWMWJ3Rzr/9RY7TdxpsUY+7ig3BLpCMsoMabzVZWZh4PQzoHv3ociJwh4fhEfwrRJ4CMVgVwp4sFGzoqPPqY86ImYWscy0XosIovU7B66ZnZiDl6RqBuXQcZ6XkKiCantAobwx/Lh8ujR/hp7AGcUbxevBx6gMessage-ID: From: Rick Holland Subject: Re: Pietenpol-List: gear legs --> Pietenpol-List message posted by: Rick Holland The J3 split gear uses ridgid u-channel in place of thin metal cross straps. This provides tensile and compressive strength under the fuselage at the cost of a small amount of weight, no more buckling cross straps. Was thinking of using this on my Piet. > I noticed an interesting thing on a friend's split gear recently. His cross > fusalage straps run on the outside and have bowed our away from the fuselage > about an eighth of an inch, he couldn't figure it out. But what's happening > is this. With a split gear, during a hard landing, downloads are delivered > through the lift struts to the lift strut/gear fitting in combination with a > downward pull of the opposite bungee. So basically both side gear/strut > fittings are being pushed down rather hard and there is nothing to > counteract this. > > In a axle gear design, the X bracing and the legs themselves actually form > an upside down "pylon" or truss which resists any upward or downward pull > from the struts. > > In conclusion, I think the split gear is more efficient and clean and less > likely to cause a nose over by picking up weeds, the straight axle is > stiffer and contributes to the overall rigidity and strength of the > airframe. > > .02 $ > -- Rick Holland ________________________________ Message 5 _____________________________________ Time: 06:52:34 AM PST US From: "Jim Markle" Subject: Re: Pietenpol-List: Fly Baby gear --> Pietenpol-List message posted by: "Jim Markle" Yup Clif, agreed. I wasn't really thinking about isolating the cables and their structural properties when I typed that. As I see it, the cables are great for tension and helping keep all the compression elements lined up nice and straight....zero direct benefit themselves in tension..... Kinda reminds me of years ago when I worked at an engineering company that built offshore platforms...they used some cable (for tension) in combination with some heavy wall pipe (for compression) to come up with some strange looking but incredibly strong structures.....hey wait, I wonder if you could actually fly an Air Camper over open water?!?! Hmmm, oops, I digress..... Actually, this landing gear thingy has become one of the more interesting aspects of this project! And that's partly because of the opportunity to learn from concepts like those discussed in your links below. VERY interesting. I love this learning process! One other benefit....I love the way the straight axle landing gear looks!! Thanks for the clarification...... Jim in COLD Plano..... ----- Original Message ----- From: "Clif Dawson" Subject: Re: Pietenpol-List: Fly Baby gear > --> Pietenpol-List message posted by: Clif Dawson > > Sorry Jimmy but there's no compressive strength in cable. > It's only good for tension. Those cables hold the solid > members in proper position and relation to each other > along with the spreader bars. All in triangulation. It's called > tensegrity; > > http://www.synearth.net/TensegrityHtml/Tensegrity.html > > http://www.frontiernet.net/~imaging/tenseg1.html > > Clif > > > Subject: Re: Pietenpol-List: Fly Baby gear > > >> Well, I think the cables may actually provide only minimal compressive >> strength at landing. It does seem to me that the real benefit at landing > is >> in the compression of the spruce gear legs themselves. >> > >> Jim in Plano..... > > > ________________________________ Message 6 _____________________________________ Time: 09:27:10 AM PST US From: "Richard Navratil" Subject: Pietenpol-List: aircraft repairman I just returned from my FAA interview which went just fine. After the various comments on the list here which I very much appreciate, I realize there are big differences around the country in how inspectors handle many of their duties. One big reason for this might be the type of FAA office we deal with. The office that I went to for this certificate is located at the Minneapolis airport which is home base for Northwest Airlines. There was a steady stream of people coming in for airline related ratings. Technicians in avionics shops, propeller repairs or other specialty fields who arent an A&P need to be an Aircraft Repairman. Things in the larger FAA offices just need to be more formal. My airworthieness inspection was by the Aircraft Manufacturing office and this was by Flight Standards. I suspect anyone going to Atlanta, Dallas or other airline bases will run into the same. The interview was about 15 minutes while I filled out a second copy of the application and he went thru my builders log and operations manual and asked a few questioins about wing construction and dihedrial. He was impressed with my Harley wheels and asked about what areas I had help with. I got the impression that he just wanted to be sure that I didn't just buy a completed project and claim to have built it. It was a pleasant experience, I didn't have to write a check and I've got my certificate so I'm happy. Dick N. ________________________________ Message 7 _____________________________________ Time: 10:46:39 AM PST US Subject: RE: Pietenpol-List: aircraft repairman From: "Phillips, Jack" Good for you, Dick! I just got my permanent Repairmans Certificate in the mail yesterday. Gotta admit, after having a forced landing on a US highway 2 weeks ago, I was a bit fearful to open an envelope from the FAA. The FSDO has already closed out my "incident" though and said there will be no repercussions. After all the horror stories one hears about the FAA I was very pleasantly surprised by how nice and helpful they were. This was the Greensboro FSDO that I was dealing with (they handle all the USAir stuff out of Charlotte). Jack Phillips Finally starting to repair NX899JP -----Original Message----- I just returned from my FAA interview which went just fine. After the various comments on the list here which I very much appreciate, I realize there are big differences around the country in how inspectors handle many of their duties. One big reason for this might be the type of FAA office we deal with. The office that I went to for this certificate is located at the Minneapolis airport which is home base for Northwest Airlines. There was a steady stream of people coming in for airline related ratings. Technicians in avionics shops, propeller repairs or other specialty fields who arent an A&P need to be an Aircraft Repairman. Things in the larger FAA offices just need to be more formal. My airworthieness inspection was by the Aircraft Manufacturing office and this was by Flight Standards. I suspect anyone going to Atlanta, Dallas or other airline bases will run into the same. The interview was about 15 minutes while I filled out a second copy of the application and he went thru my builders log and operations manual and asked a few questioins about wing construction and dihedrial. He was impressed with my Harley wheels and asked about what areas I had help with. I got the impression that he just wanted to be sure that I didn't just buy a completed project and claim to have built it. It was a pleasant experience, I didn't have to write a check and I've got my certificate so I'm happy. Dick N. ________________________________ Message 8 _____________________________________ Time: 02:48:01 PM PST US From: "Richard Navratil" Subject: Re: Pietenpol-List: Re: Landing gear I say it only with respect. Why re-invent 2 great gear options? Stick to the plans. Dick N. ----- Original Message ----- From: ADonJr@aol.com To: pietenpol-list@matronics.com Sent: Monday, December 13, 2004 11:06 PM Subject: Pietenpol-List: Re: Landing gear Hello Group, I addressed this subject with the group a while ago, but got no response...I'd like to use the landing gear configuration used on the Sky Scout on my Aircamper. I've done some preliminary design for adapting the fittings and it looks feasable. Has anyone had any experience with this? It looks like the forward cabane fitting can be combined with the upper shock strut fitting without modifying the fuselage truss. Am I missing something here? Don Cooley ________________________________ Message 9 _____________________________________ Time: 05:03:26 PM PST US DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; b=sOoPliDNreGfigZDWO9m4aDlc0W1hZZDt8N9CxpbpE0w27PwVXqfqpdTon6CHEXwsOfooOLdRBZPbPA70NxLJrqNb8pJPtpvSvofweMn8Qk98OhMTtHAmdvrDX0SmsfzjiYvq0Z4WKr11AGXRx4SwPQMDBMUB41KJTJ5JAJC5Sc= ; From: Gary Gower Subject: Re: Pietenpol-List: Re: Landing gear I just got curious and went over to see the Glider Manuales.... It could be a good option, The Scout (construction) is very similar to the Aircamper, Just need to do your homework in modifying the structural area in the front part of the fuselage where the gears and the struts will join... maybe a lots of work, Remeber that even a little modification from the plans will add at least 100 hours (sometimes more) to any project. On the other side, the looks of that landing gear will be beautiful... As will be the wooden landing gear. Split is more common but a good and proven option. Just check also the position of the wheels in relation of the Center of Gravity, to be sure that the legs ar as straight as possible to prevent lateral (or front/back) forces not spected in the original design of the fuselage... Try it in paper first, if not satisfied or convinced, just make a paper ball and practice with the trash can... Search for similar LG in other airplanes (Curtis Robin, etc) to compare your drawings. Have Fun But be Safe. Saludos Gary Gower. Richard Navratil wrote: I say it only with respect. Why re-invent 2 great gear options? Stick to the plans. Dick N. ----- Original Message ----- From: ADonJr@aol.com Subject: Pietenpol-List: Re: Landing gear Hello Group, I addressed this subject with the group a while ago, but got no response...I'd like to use the landing gear configuration used on the Sky Scout on my Aircamper. I've done some preliminary design for adapting the fittings and it looks feasable. Has anyone had any experience with this? It looks like the forward cabane fitting can be combined with the upper shock strut fitting without modifying the fuselage truss. Am I missing something here? Don Cooley --------------------------------- ________________________________ Message 10 ____________________________________ Time: 10:33:01 PM PST US DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; b=diPCSTo/GFv/2tDTdXMPKticmqY1hanHyuFB/13obmrtcO9DnG7n4ycIh7KdIG7Es6kkKN28Sp9eycPP52HrON1PAL4JXgub+3UTvaiM7g2wCKB/ztxr30Hpp8zycNy/WvKfLRDCZZtOQQRLCIfwC5v/+TtCXf+xjBxfdE8MU0o= ; From: Galen Hutcheson Subject: Re: Pietenpol-List: Re: Landing gear --> Pietenpol-List message posted by: Galen Hutcheson In all due respect, to some people (to me especially), sticking to the plans is rather boring and lacluster. I for one, enjoy experimentation and discovery. If this gentleman wants to build a certain type of landing gear, I applaude him. My Waco KNF had an outrigger landing gear (the type he wants to build) and it did look great, not to mention the fact that it functioned very well on rough terrain. much better. I might add, than the more common landing gears. I don't think there is any hurdle he can't cross if he wishes to take on the challenge. This is all in the sprit of experimentation and one reason we all proudly afix the placard on our planes that says "EXPERIMENTAL." So Don, full steam ahead and if I can be of any help, just ask. Doc --- Gary Gower wrote: > I just got curious and went over to see the Glider > Manuales.... It could be a good option, > The Scout (construction) is very similar to the > Aircamper, Just need to do your homework in > modifying the structural area in the front part of > the fuselage where the gears and the struts will > join... maybe a lots of work, > Remeber that even a little modification from the > plans will add at least 100 hours (sometimes more) > to any project. > On the other side, the looks of that landing gear > will be beautiful... As will be the wooden landing > gear. Split is more common but a good and proven > option. > > Just check also the position of the wheels in > relation of the Center of Gravity, to be sure that > the legs ar as straight as possible to prevent > lateral (or front/back) forces not spected in the > original design of the fuselage... > > Try it in paper first, if not satisfied or > convinced, just make a paper ball and practice with > the trash can... Search for similar LG in other > airplanes (Curtis Robin, etc) to compare your > drawings. Have Fun But be Safe. > > > Saludos > Gary Gower. > > > Richard Navratil wrote: > I say it only with respect. Why re-invent 2 great > gear options? Stick to the plans. > Dick N. > ----- Original Message ----- > From: ADonJr@aol.com > To: pietenpol-list@matronics.com > Sent: Monday, December 13, 2004 11:06 PM > Subject: Pietenpol-List: Re: Landing gear > > > Hello Group, > I addressed this subject with the group a while > ago, but got no response...I'd like to use the > landing gear configuration used on the Sky Scout on > my Aircamper. I've done some preliminary design for > adapting the fittings and it looks feasable. Has > anyone had any experience with this? It looks like > the forward cabane fitting can be combined with the > upper shock strut fitting without modifying the > fuselage truss. Am I missing something here? > Don Cooley > > > --------------------------------- > search. Learn more.