---------------------------------------------------------- Pietenpol-List Digest Archive --- Total Messages Posted Thu 03/27/14: 30 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:23 AM - Re: Red Baron video (Michael Perez) 2. 04:06 AM - Re: Re: Speaking of outdated stuff? Center section fuel tanks vs. n (Michael Perez) 3. 04:11 AM - Re: Red Baron video (womenfly2) 4. 04:24 AM - Yes indeed... (tkreiner) 5. 04:49 AM - Re: Re: Red Baron video (Michael Perez) 6. 04:53 AM - Re: It's FINALLY a hangar... (Jack Phillips) 7. 05:23 AM - Re: Speaking of outdated stuff? Center section fuel tanks vs. n (tkreiner) 8. 05:24 AM - Re: It's FINALLY a hangar... (jarheadpilot82) 9. 05:25 AM - Re: Speaking of outdated stuff? Center section fuel tanks vs. n (tkreiner) 10. 05:30 AM - Re: Speaking of outdated stuff? Center section fuel tanks vs. n (tkreiner) 11. 05:48 AM - Re: Speaking of outdated stuff? Center section fuel tanks vs. n (jarheadpilot82) 12. 05:54 AM - Re: Yes indeed... (jarheadpilot82) 13. 06:03 AM - Re: It's FINALLY a hangar... (tools) 14. 06:15 AM - Re: Re: Speaking of outdated stuff? Center section fuel tanks vs. n (Jack Phillips) 15. 06:26 AM - Re: Speaking of outdated stuff? Center section fuel tanks vs. n (curtdm(at)gmail.com) 16. 06:38 AM - Re: Re: Speaking of outdated stuff? Center section fuel tanks vs. n (Brian Kenney) 17. 06:45 AM - Re: Re: Speaking of outdated stuff? Center section fuel tanks vs. n (Brian Kenney) 18. 07:02 AM - Re: Re: Speaking of outdated stuff? Center section fuel tanks vs. n (Gary Boothe) 19. 07:38 AM - Re: Speaking of outdated stuff? Center section fuel tanks vs. n (tkreiner) 20. 07:41 AM - Re: Re: Speaking of outdated stuff? Center section fuel tanks vs. n (Jack Phillips) 21. 08:49 AM - Re: Re: Weight & Balance Spreadsheet (Steven Dortch) 22. 09:47 AM - Re: fuel tanks (macz@peak.org) 23. 09:47 AM - Re: fuel tanks (macz@peak.org) 24. 05:29 PM - Elevator droop (danhelsper@aol.com) 25. 06:35 PM - Re: Elevator droop (Brian Kenney) 26. 06:42 PM - Re: Elevator droop (Gary Boothe) 27. 07:08 PM - Re: Elevator droop...zoom in (M. Zeke Zechini) 28. 07:19 PM - Re: [Shaw Suspected Junk Email] Re: Re: Speaking of outdated stuff? Center section fuel tanks vs. n (Clif Dawson) 29. 07:23 PM - Re: Elevator droop (Clif Dawson) 30. 07:35 PM - Re: Elevator droop (Brian Kenney) ________________________________ Message 1 _____________________________________ Time: 03:23:07 AM PST US From: Michael Perez Subject: Re: Pietenpol-List: Red Baron video Thanks Oscar. Have you seen/heard of the History Channel series Dog Fights? They are mostly computer generated animated documentaries depicting- air combat scenarios form WWI through Desert Storm.- They look fantastic! Ve ry well done. You may be interested in taking a look. =0A=0A=0AIf God is yo ur co-pilot...switch seats.=0AMike Perez=0AKaretakerAero=0ASTILL Building.. .=0A ________________________________ Message 2 _____________________________________ Time: 04:06:54 AM PST US From: Michael Perez Subject: Re: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n Neither was I. Like you said, Just trying to nudge the collective grey matt er... =0A=0A=0AIf God is your co-pilot...switch seats.=0AMike Perez=0AKaret aker Aero=0ASTILL Building...=0A=0A=0A=0ASomething else, I thought about, which may or my not matter:=0A--- A wing mounted tank does have an ar m of sorts, along the longitudinal axis. In a roll, the wing tank has an arm greater than the nose tank. It is a weight, being swung around the lon gitudinal axis. Does this matter, does it effect stability? What, if anythi ng, changes as fuel burns? ________________________________ Message 3 _____________________________________ Time: 04:11:30 AM PST US Subject: Pietenpol-List: Re: Red Baron video From: "womenfly2" Its from a WW! flight sim called: Rise of Flight. Its not factual its fictitious. There are factual accounts better then the sim video posted on MvR death. The video is good just for the enjoyment of watching. The sim RoF is free to download and play, the cravat is you have to purchase more airplanes. {url}http://riseofflight.com/en[/ur]l Enjoy, WF2 -------- Read this topic online here: http://forums.matronics.com/viewtopic.php?p=421118#421118 ________________________________ Message 4 _____________________________________ Time: 04:24:34 AM PST US Subject: Pietenpol-List: Yes indeed... From: "tkreiner" It's truly a great book, but I didn't know there was a second edition... I have the first, along with the companion book, Aircraft Engines, by the same authors. Once I started reading them, I was sure I'd be able to acquire or develop the skills needed to build a Piet. I'd recommend them to anyone wanting to know the old school way of doing things. As some other threads have mentioned lately, old school isn't always what we might do today... but there's value in knowing how things were originally done in the aircraft world, compared to some more modern techniques. Along with you, I think a lot of folks here will either learn something from this book, or at least derive some pleasure reading it. -------- Tom Kreiner Read this topic online here: http://forums.matronics.com/viewtopic.php?p=421119#421119 ________________________________ Message 5 _____________________________________ Time: 04:49:30 AM PST US From: Michael Perez Subject: Re: Pietenpol-List: Re: Red Baron video I own RoF ICE. (Iron Cross Edition) Not sure if that is a free download or not, but I paid for mine at the time.- Very impressive sim. for sure...al ong the lines of IL2 HSFX6. =0A=0AIf God is your co-pilot...switch seats. =0AMike Perez=0AKaretakerAero=0ASTILL Building...=0A ________________________________ Message 6 _____________________________________ Time: 04:53:58 AM PST US From: "Jack Phillips" Subject: RE: Pietenpol-List: It's FINALLY a hangar... It'll be good to see that Pietenpol back in the air! Jack Phillips NX899JP Smith Mountain Lake, Virginia -----Original Message----- From: owner-pietenpol-list-server@matronics.com [mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of tools Sent: Wednesday, March 26, 2014 10:31 PM Subject: Pietenpol-List: It's FINALLY a hangar... N2RN got her tailwheel, horiz and vert stabs, elevators and rudder, WING, and an aileron reinstalled today. FINALLY... For the first time, a big structure is holding an airplane, so it's technically a hangar I guess. Tomorrow is lots of adjusting wires, controls, cotter keying and safety wiring turnbuckles. Hopefully get the motor running. Early next week should be in annual and ready for flight. The runway finally seems hard enough to fly upon. Been a long haul on this one. [img]https://us-mg4.mail.yahoo.com/ya/download?mid=2_0_0_1_1096192_ACINiWIAA BLeUzOKpwAAAJxxXlE&pid=2&fid=Inbox&inline=1[/img] Read this topic online here: http://forums.matronics.com/viewtopic.php?p=421104#421104 ________________________________ Message 7 _____________________________________ Time: 05:23:00 AM PST US Subject: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n From: "tkreiner" Cliff, You ask, "Doesn't everything below it act like a pendulum? The short answer is NO, however that requires some explanation... In a most properly designed and built airplane - the designer sets CG so the plane is slightly nose heavy, which requires an equal and opposite tail down force in flight. Now on the surface this may appear to be a pendulum, but in fact, its quite different. The purpose of nose heavy, coupled with tail down force is what gives us pitch stability. In other words, the plane will tend to stabilize itself in flight when you take your hands off the stick -assuming, of course, that you've trimmed the plane for whatever pitch attitude you need. What is somewhat bothersome is that many on the list have indicated that the elevator on a Piet "droops" during flight, when in fact, the elevator should be slightly up, in which case it's providing the tail down force. Perhaps the horizontal stabilizer on the Piet is - HERESY COMING - improperly designed, but satisfactory. If the angle of incidence of the stab were changed somewhat, this condition would be corrected... Personally, I'd like for Jack Phillips and a few of the others to comment on the drooping issue, as I'd like to make sure the plane I build is flying "correctly." I KNOW, I KNOW, I KNOW, BUILD IT PER THE PLANS, AND IT WILL FLY.... that still doesn't satisfy the Mechanical Engineer I am.... just sayin. -------- Tom Kreiner Read this topic online here: http://forums.matronics.com/viewtopic.php?p=421123#421123 ________________________________ Message 8 _____________________________________ Time: 05:24:24 AM PST US Subject: Pietenpol-List: Re: It's FINALLY a hangar... From: "jarheadpilot82" Tools, Share with everybody how > expensive that big hangar is, and how you did it. I think that it would encourage people with maybe ideas of their own. P.S. She looks like you gave her a bath from when I was at Toolstock. It IS good to have Scott around! -------- Semper Fi, Terry Hand Athens, GA USMC, USMCR, ATP BVD DVD PDQ BBQ Read this topic online here: http://forums.matronics.com/viewtopic.php?p=421124#421124 ________________________________ Message 9 _____________________________________ Time: 05:25:52 AM PST US Subject: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n From: "tkreiner" Cliff, You ask, "Doesn't everything below it act like a pendulum? The short answer is NO, however that requires some explanation... In a most properly designed and built airplane - the designer sets CG so the plane is slightly nose heavy, which requires an equal and opposite tail down force in flight. Now on the surface this may appear to be a pendulum, but in fact, its quite different. The purpose of nose heavy, coupled with tail down force is what gives us pitch stability. In other words, the plane will tend to stabilize itself in flight when you take your hands off the stick -assuming, of course, that you've trimmed the plane for whatever pitch attitude you need. What is somewhat bothersome is that many on the list have indicated that the elevator on a Piet "droops" during flight, when in fact, the elevator should be slightly up, in which case it's providing the tail down force. Perhaps the horizontal stabilizer on the Piet is - HERESY COMING - improperly designed, but satisfactory. If the angle of incidence of the stab were changed somewhat, this condition would be corrected... Personally, I'd like for Jack Phillips and a few of the others to comment on the drooping issue, as I'd like to make sure the plane I build is flying "correctly." I KNOW, I KNOW, I KNOW, BUILD IT PER THE PLANS, AND IT WILL FLY.... that still doesn't satisfy the Mechanical Engineer I am.... just sayin. -------- Tom Kreiner Read this topic online here: http://forums.matronics.com/viewtopic.php?p=421125#421125 ________________________________ Message 10 ____________________________________ Time: 05:30:40 AM PST US Subject: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n From: "tkreiner" Cliff, In response to your question, "Doesn't everything below it act like a pendulum? The short answer is NO, that said, some explanation is required... In a properly designed and built airplane - the designer sets the CG so that the plane is slightly nose heavy, which, in flight, requires an equal and opposite tail down force. Now on the surface this may appear to be a pendulum, but in fact, its quite different. The purpose of nose heavy, coupled with tail down force is what gives us pitch stability. In other words, the plane will tend to stabilize itself in flight when you take your hands off the stick - and return to whatever pitch it's trimmed for, assuming, of course, that you've trimmed the plane for a given pitch attitude, i.e., climb, cruise, descent. What is somewhat bothersome is that many on the list have indicated that the elevator on a Piet "droops" during cruise flight, when in fact, the elevator should be slightly up, in order to provide the tail down force. Perhaps the horizontal stabilizer on the Piet is - HERESY COMING - improperly designed, but satisfactory. If the angle of incidence of the stab were changed somewhat, this condition might be corrected... Personally, I'd like for Jack Phillips and a few of the others to comment on the drooping issue, as I'd like to make sure the plane I build is flying "correctly." I KNOW, I KNOW, I KNOW, BUILD IT PER THE PLANS, AND IT WILL FLY.... that still doesn't satisfy the Mechanical Engineer I am.... just sayin. -------- Tom Kreiner Read this topic online here: http://forums.matronics.com/viewtopic.php?p=421126#421126 ________________________________ Message 11 ____________________________________ Time: 05:48:18 AM PST US Subject: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n From: "jarheadpilot82" Mike, I just reread your post where you asked- > A wing mounted tank does have an arm of sorts, along the longitudinal axis. In a roll, the wing tank has an arm greater than the nose tank. It is a weight, being swung around the longitudinal axis. Does this matter, does it effect stability? What, if anything, changes as fuel burns? so, are you asking about lateral cg? If building to plans the wing tank is not appreciably wider than a nose tank, I would guess. Unless you either builder a wider center section(i.e. a Bill Rewey center section), or you put the fuel in true wing tanks, which I have not heard of anyone doing. So, I don't think there is an appreciable difference between either tank in terms of the longituinal axis, or in terms of a lateral cg. However, I did not sleep in a Holiday Inn Express last night, and I am not an aeronautical engineer. But I have flown aircraft that lateral CG was a very big deal - helicopters with rescue hoists sticking out the side of the aircraft with people on the hoist. -------- Semper Fi, Terry Hand Athens, GA USMC, USMCR, ATP BVD DVD PDQ BBQ Read this topic online here: http://forums.matronics.com/viewtopic.php?p=421128#421128 ________________________________ Message 12 ____________________________________ Time: 05:54:11 AM PST US Subject: Pietenpol-List: Re: Yes indeed... From: "jarheadpilot82" Tom, I actually saw a 4th edition (I think) published around 1960. It was listed on eBay. It had a picture of a Pan Am Boeing 707 tail in the front pages, so I thought it was too "modern" for my needs. [Wink] -------- Semper Fi, Terry Hand Athens, GA USMC, USMCR, ATP BVD DVD PDQ BBQ Read this topic online here: http://forums.matronics.com/viewtopic.php?p=421129#421129 ________________________________ Message 13 ____________________________________ Time: 06:03:21 AM PST US Subject: Pietenpol-List: Re: It's FINALLY a hangar... From: "tools" Like everything, there's a thousand ways... and Scott and I climbed a really steep curve! The one constant is that, unfortunately, the chicken industry is going through quite an upheaval. Like lots of things, all the chicken houses built in the 80's aren't economically feasible to update. Most of them are either 36' or 40' wide and clear spanned. You can get the trusses and tin for nickels on the dollar, or free. And seem to be available about everywhere. I've got maybe two grand in it as it stands, 40 x 85 but not yet sided and no big front door. It's really tall so that we can get the motorhome in it from the side (at the back) so it wouldn't block things in, or get blocked in. Lots of hangars have built in living areas, well, the motorhome is going to serve that purpose in this one. Gotta go work on a plane! Read this topic online here: http://forums.matronics.com/viewtopic.php?p=421130#421130 ________________________________ Message 14 ____________________________________ Time: 06:15:22 AM PST US From: "Jack Phillips" Subject: RE: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n OK Tom, You asked for it... I think the drooping elevator is largely a myth. From many angles, the elevator looks like it droops in flight because the reference that the eye has is the horizontal stabilizer. But the edge of the stabilizer is at an angle to the edge of the elevator, hence the appearance of a droop. Here are a few pictures from my files of Pietenpols in cruise flight: This shows the difference in angles I was talking about. See the angle of the edge of the horizontal stabilizer, compared to the edge of the elevator, which is straight? This is what creates the illusion of tail droop. Your eye tries to make the two edges line up. This one is a picture of Gene Rambo flying his son, Will, in my airplane. In this picture the horizontal tail is just about edge on, so the side of the stabilizer doesn't give the impression that the elevator is drooping. Looks pretty straight to me Here's another picture of my plane in flight: Here the angle is different and the side of the stabilizer does make it look like the elevator is slightly down, but I assure you it's not. Here's Mike Cuy's airplane, photo taken from mine. Note his tail - no droop. Here's Randy Bush's airplane, photo taken from Ryan Mueller's (now John Hofmann's) N502R. Notice the tail. Where's the supposed droop? Lastly, this picture shows Kevin Purtee on the left, Shad Bell in the center, and me on the right (photo taken by Bill Church during Brodhead 2011). You will note that my tail is slightly drooped with respect to the other two. The reason for this is that I was having to push my little Continental A65 for all it was worth to keep up with those two Corvair powered Pietenpols, and I had to hold the nose down to maintain my position in the formation and keep it from climbing at that speed. There may be a slight droop due to downwash from the wing, but other than that, I don't think the dreaded tail droop exists at all. Build it to the plans, and build it straight and it should fly just fine. Jack Phillips NX899JP Smith Mountain Lake, Virginia -----Original Message----- From: owner-pietenpol-list-server@matronics.com [mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of tkreiner Sent: Thursday, March 27, 2014 8:20 AM Subject: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n Cliff, You ask, "Doesn't everything below it act like a pendulum? The short answer is NO, however that requires some explanation... In a most properly designed and built airplane - the designer sets CG so the plane is slightly nose heavy, which requires an equal and opposite tail down force in flight. Now on the surface this may appear to be a pendulum, but in fact, its quite different. The purpose of nose heavy, coupled with tail down force is what gives us pitch stability. In other words, the plane will tend to stabilize itself in flight when you take your hands off the stick -assuming, of course, that you've trimmed the plane for whatever pitch attitude you need. What is somewhat bothersome is that many on the list have indicated that the elevator on a Piet "droops" during flight, when in fact, the elevator should be slightly up, in which case it's providing the tail down force. Perhaps the horizontal stabilizer on the Piet is - HERESY COMING - improperly designed, but satisfactory. If the angle of incidence of the stab were changed somewhat, this condition would be corrected... Personally, I'd like for Jack Phillips and a few of the others to comment on the drooping issue, as I'd like to make sure the plane I build is flying "correctly." I KNOW, I KNOW, I KNOW, BUILD IT PER THE PLANS, AND IT WILL FLY.... that still doesn't satisfy the Mechanical Engineer I am.... just sayin. -------- Tom Kreiner Read this topic online here: http://forums.matronics.com/viewtopic.php?p=421123#421123 ________________________________ Message 15 ____________________________________ Time: 06:26:50 AM PST US Subject: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n From: "curtdm(at)gmail.com" My theory of the elevator droop is it could be an optical illusion. The outboard line from the elevator and horizontal stabilizer is bent because of the leading edge of the horizontal stabilizer not having the same span as the rest of the tail. I had this discussion and wanted to do some testing at Brodhead last year, but because of lack of time I was unable. I propose those who could, prior to Brodhead, set, their elevators in a faired (neutral) position and and somehow temporarily make a mark on their torque tube and the cable just above. Then go fly and compare in cruise flight if the marks are aligned yet. If not, make another mark to show the difference. Also while the tail is faired neutral on the ground, sit in the cockpit and look over your shoulder and look or take a picture of the tail and let us know what it looks like. Take pictures in slightly up and down elevator position. This is a great exercise not only to prove my theory right/wrong, but also like Tom said, the tail should always be creating downforce while flying and if elevators are drooping, the horizontal stab might need some shimming and re-rigging. My planes not flying and I'm definitely not an Opthamolagist, he'll I don't even think I can spell. -------- Curt Merdan Flower Mound, TX Read this topic online here: http://forums.matronics.com/viewtopic.php?p=421132#421132 Attachments: http://forums.matronics.com//files/image_545.jpg ________________________________ Message 16 ____________________________________ Time: 06:38:55 AM PST US From: Brian Kenney Subject: RE: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n Tom being similarly educated I have thought about this too. Yes you could conclude that the horizontal stabilizer is not at the correct angle however here is some more to think about I think in reality the more correct assumption is that angle of incident of the wing is incorrect - this is important - wait for it - because these ai rcraft are flying too fast. The Air Camper was designed for an engine that produced less power than mo st of the ones flying. If you reduce the power the trim changes and the ele vator position changes and this slightly down elevator position changes fro m slightly down to level and if you are slow enough to up. When I first bui lt my aircraft it had an engine problem and it was producing an estimated 4 0 to 45 horsepower. I needed a fixed trim to give the elevators an up posit ion to adjust the nose down trim. While this a true observation it creates another mystery? Why does flying faster not do the opposite? Asymmetrical airfoils have a negative pitching coefficient. What this means is that the air coming off the tailing edge is at a downward angle and this is behind both the center of pressure and c enter of gravity so there is a torque created that wants to rotate the wing nose down. If you have every thrown a model wing without a tail you will o bserve that the wing just dives. The amount of this torque increases the fa ster you fly. In many aircraft the tail or elevator trim has to be adjusted to increase the negative tail lift or to say it another way to increase th e down force on the tail. So flying faster should mean the opposite to what is observed in reality wi th an Air Camper. Here is why I think the Air Camper is different. The wing is higher than th e tail. As the wing downwash exits the trailing edge it hits the horizontal tail and automatically compensates for the increasing negative pitching mo ment. This is not a feature of just the Pietenpol but many high wing aircra ft. The faster I fly the more I have to push the elevator down (stick forward)- totally counter intuitive. The correction to this problem is if you are going to fly faster you need t o reduce the lift on the wing at the higher speed and that means you need t o reduce ever so slightly the wing incidence. Here is another way to look at it and it demonstrates why this is the fix i f you want to fly faster. If you use more power the angle of the wing to the horizon changes. This is because the lift is increasing with speed. You can get this wing "up on th e step"=2C as some people call it=2C so far the bottom of the wing is on a negative angle to the horizon. That means the by that point the fuselage i s pointing down quite significantly. So at that speed the wing is lifting and the fuselage is diving. So you are really starting to increase the drag and aerodynamically the airplane tryi ng to separate the wing from the fuselage. So decreasing the angle of incid ence would reduce the negative angle at that speed and reduce the drag for that speed and allow the aircraft to fly even faster. In reality everything is just fine if the elevator is pointing down slightl y and the aircraft is completely stable and safe. The mystery of the Air Camper continues - why is it so good? > Subject: Pietenpol-List: Re: Speaking of outdated stuff? Center section f uel tanks vs. n > From: tkreiner@gmail.com > Date: Thu=2C 27 Mar 2014 05:30:26 -0700 > To: pietenpol-list@matronics.com > > > Cliff=2C > > In response to your question=2C "Doesn't everything below it act like a > pendulum? > > The short answer is NO=2C that said=2C some explanation is required... > > In a properly designed and built airplane - the designer sets the CG so t hat the plane is slightly nose heavy=2C which=2C in flight=2C requires an e qual and opposite tail down force. Now on the surface this may appear to b e a pendulum=2C but in fact=2C its quite different. > > The purpose of nose heavy=2C coupled with tail down force is what gives u s pitch stability. In other words=2C the plane will tend to stabilize itse lf in flight when you take your hands off the stick - and return to whateve r pitch it's trimmed for=2C assuming=2C of course=2C that you've trimmed th e plane for a given pitch attitude=2C i.e.=2C climb=2C cruise=2C descent. > > What is somewhat bothersome is that many on the list have indicated that the elevator on a Piet "droops" during cruise flight=2C when in fact=2C the elevator should be slightly up=2C in order to provide the tail down force. > > Perhaps the horizontal stabilizer on the Piet is - HERESY COMING - improp erly designed=2C but satisfactory. If the angle of incidence of the stab w ere changed somewhat=2C this condition might be corrected... > > Personally=2C I'd like for Jack Phillips and a few of the others to comme nt on the drooping issue=2C as I'd like to make sure the plane I build is f lying "correctly." > > I KNOW=2C I KNOW=2C I KNOW=2C BUILD IT PER THE PLANS=2C AND IT WILL FLY.. .. that still doesn't satisfy the Mechanical Engineer I am.... just sayin. > > -------- > Tom Kreiner > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=421126#421126 > > > > > > > =========== =========== =========== =========== > > > ________________________________ Message 17 ____________________________________ Time: 06:45:17 AM PST US From: Brian Kenney Subject: RE: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n It is not an illusion but it requires two things to be happening for it to happen and to be obvious The aircraft need to be lightly loaded and the airplane needs to be flying fairly fast. If the CG is forward it is less likely to happen as well. > Subject: Pietenpol-List: Re: Speaking of outdated stuff? Center section f uel tanks vs. n > From: curtdm@gmail.com > Date: Thu=2C 27 Mar 2014 06:26:20 -0700 > To: pietenpol-list@matronics.com > .com> > > My theory of the elevator droop is it could be an optical illusion. The outboard line from the elevator and horizontal stabilizer is bent because o f the leading edge of the horizontal stabilizer not having the same span as the rest of the tail. > > I had this discussion and wanted to do some testing at Brodhead last year =2C but because of lack of time I was unable. > > I propose those who could=2C prior to Brodhead=2C set=2C their elevators in a faired (neutral) position and and somehow temporarily make a mark on their torque tube and the cable just above. > Then go fly and compare in cruise flight if the marks are aligned yet. I f not=2C make another mark to show the difference. > > Also while the tail is faired neutral on the ground=2C sit in the cockpit and look over your shoulder and look or take a picture of the tail and let us know what it looks like. Take pictures in slightly up and down elevato r position. > > This is a great exercise not only to prove my theory right/wrong=2C but a lso like Tom said=2C the tail should always be creating downforce while fly ing and if elevators are drooping=2C the horizontal stab might need some sh imming and re-rigging. > > My planes not flying and I'm definitely not an Opthamolagist=2C he'll I d on't even think I can spell. > > -------- > Curt Merdan > Flower Mound=2C TX > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=421132#421132 > > > > > Attachments: > > http://forums.matronics.com//files/image_545.jpg > > > > =========== =========== =========== =========== > > > ________________________________ Message 18 ____________________________________ Time: 07:02:29 AM PST US From: "Gary Boothe" Subject: RE: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n In this picture, Lee Graybill, a retired AA pilot and longtime PT-22 flyer, pulled up alongside. He later told me, without being asked, that he had eyeballed my rigging and noted no elevator deflection, nor any aileron deflection (and was impressed with the 'look' of the plane!). Admittedly, I was pushing the airspeed a bit to the high 70's, as his Baby Ace is much faster. I believe it is Dick Navratil who gives a lecture at Brodhead about tweaking the horizontal stab to correct tail-low conditions. I believe that may be useful on some airplanes depending on weight and preferred flying speed. Gary Boothe NX308MB From: owner-pietenpol-list-server@matronics.com [mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of Jack Phillips Sent: Thursday, March 27, 2014 6:15 AM Subject: RE: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n OK Tom, You asked for it... I think the drooping elevator is largely a myth. From many angles, the elevator looks like it droops in flight because the reference that the eye has is the horizontal stabilizer. But the edge of the stabilizer is at an angle to the edge of the elevator, hence the appearance of a droop. Here are a few pictures from my files of Pietenpols in cruise flight: This shows the difference in angles I was talking about. See the angle of the edge of the horizontal stabilizer, compared to the edge of the elevator, which is straight? This is what creates the illusion of tail droop. Your eye tries to make the two edges line up. This one is a picture of Gene Rambo flying his son, Will, in my airplane. In this picture the horizontal tail is just about edge on, so the side of the stabilizer doesn't give the impression that the elevator is drooping. Looks pretty straight to me Here's another picture of my plane in flight: Here the angle is different and the side of the stabilizer does make it look like the elevator is slightly down, but I assure you it's not. Here's Mike Cuy's airplane, photo taken from mine. Note his tail - no droop. Here's Randy Bush's airplane, photo taken from Ryan Mueller's (now John Hofmann's) N502R. Notice the tail. Where's the supposed droop? Lastly, this picture shows Kevin Purtee on the left, Shad Bell in the center, and me on the right (photo taken by Bill Church during Brodhead 2011). You will note that my tail is slightly drooped with respect to the other two. The reason for this is that I was having to push my little Continental A65 for all it was worth to keep up with those two Corvair powered Pietenpols, and I had to hold the nose down to maintain my position in the formation and keep it from climbing at that speed. There may be a slight droop due to downwash from the wing, but other than that, I don't think the dreaded tail droop exists at all. Build it to the plans, and build it straight and it should fly just fine. Jack Phillips NX899JP Smith Mountain Lake, Virginia -----Original Message----- From: owner-pietenpol-list-server@matronics.com [mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of tkreiner Sent: Thursday, March 27, 2014 8:20 AM Subject: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n Cliff, You ask, "Doesn't everything below it act like a pendulum? The short answer is NO, however that requires some explanation... In a most properly designed and built airplane - the designer sets CG so the plane is slightly nose heavy, which requires an equal and opposite tail down force in flight. Now on the surface this may appear to be a pendulum, but in fact, its quite different. The purpose of nose heavy, coupled with tail down force is what gives us pitch stability. In other words, the plane will tend to stabilize itself in flight when you take your hands off the stick -assuming, of course, that you've trimmed the plane for whatever pitch attitude you need. What is somewhat bothersome is that many on the list have indicated that the elevator on a Piet "droops" during flight, when in fact, the elevator should be slightly up, in which case it's providing the tail down force. Perhaps the horizontal stabilizer on the Piet is - HERESY COMING - improperly designed, but satisfactory. If the angle of incidence of the stab were changed somewhat, this condition would be corrected... Personally, I'd like for Jack Phillips and a few of the others to comment on the drooping issue, as I'd like to make sure the plane I build is flying "correctly." I KNOW, I KNOW, I KNOW, BUILD IT PER THE PLANS, AND IT WILL FLY.... that still doesn't satisfy the Mechanical Engineer I am.... just sayin. -------- Tom Kreiner Read this topic online here: http://forums.matronics.com/viewtopic.php?p=421123#421123 ________________________________ Message 19 ____________________________________ Time: 07:38:22 AM PST US Subject: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n From: "tkreiner" Jack, I concur, it appears to be an optical illusion... But if that's the case, why does Dick N give a spiel on drooping at Brodhead? -------- Tom Kreiner Read this topic online here: http://forums.matronics.com/viewtopic.php?p=421139#421139 ________________________________ Message 20 ____________________________________ Time: 07:41:58 AM PST US From: "Jack Phillips" Subject: RE: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n Maybe he needs the money. Those forums pay incredibly well. Jack Phillips NX899JP Smith Mountain Lake, Virginia -----Original Message----- From: owner-pietenpol-list-server@matronics.com [mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of tkreiner Sent: Thursday, March 27, 2014 10:38 AM Subject: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n Jack, I concur, it appears to be an optical illusion... But if that's the case, why does Dick N give a spiel on drooping at Brodhead? -------- Tom Kreiner Read this topic online here: http://forums.matronics.com/viewtopic.php?p=421139#421139 ________________________________ Message 21 ____________________________________ Time: 08:49:39 AM PST US Subject: Re: Pietenpol-List: Re: Weight & Balance Spreadsheet From: Steven Dortch But it shouldn't moving the axle forward help prevent noseovers? A La Cessna 120/140s? Blue Skies, Steve D On Sun, Mar 23, 2014 at 9:04 PM, Gary Boothe wrote: > > Moving the axel only changes the weight on the tail while on the > ground...not in the air. > > Gary > NX308MB > > Sent from my iPhone > > > On Mar 23, 2014, at 6:59 PM, "dgaldrich" > wrote: > > > dgaldrich@embarqmail.com> > > > > Waaiiit a minute. Moving the location of the wheels should have very > little, if any, effect on CG. What DOES change, from a CG perspective, > when you move the wheels forward is the weight on the tail wheel. A couple > of pounds increase makes a large difference since the arm is so long and > moving the wheels forward increases it. Using Jack's spreadsheet, I added > just 5 pounds to the tailwheel weight and it moved the CG aft by 1 inch. > That's 20% of the total allowable range. A Scott 2000 tailwheel from a > Piper Cub is about five pounds heavier than an original BHP tail skid. As > Jack, and others, have said, accurate measurement is important. Bathroom > scales are for my fat ass, not aircraft. > > > > You have correctly noticed that moving the wing also has almost a 1 for > 1 relationship to CG. Moving the wing aft 1 inch moves the CG almost 1 > inch forward and is by far the most effective way of achieving a correctly > balanced airplane. That's one of the advantages of this design is that > it's relatively easy to do since the cabanes are equal length and parallel, > more or less. > > > > Dave > > > > > > > > > > Read this topic online here: > > > > http://forums.matronics.com/viewtopic.php?p=420910#420910 > > > > > > > > > > > > > > > > > > > > > > -- Blue Skies, Steve D ________________________________ Message 22 ____________________________________ Time: 09:47:36 AM PST US Subject: Re: Pietenpol-List: fuel tanks From: macz@peak.org Douwe-- I agree with you on the value of the head the wing tank provides--it was put there for Ford engines which don't have (and don't need complication of) a fuel pump. --Mac in Oregon > Both fuel tank locations have worked fine. Here's why I went with a wing > tank and like it. > > > 1. The fuel is farther from the hot engine and electrics in most > "unplanned attitudes" such as upside down or on it's nose, or in case of > an > engine fire. > 2. I have heard of too low fuel head pressure/fuel starvation issues > with fuselage tanks, but not with wing tanks. If you're building a big > fuse > tank, it can be tricky to design it so you get the head pressure you need. > It can certainly be done, just watch it in all attitudes. > 3. Fuel overhead or fuel in my lap can both be bad situations, but it's > all dependent on the incident and there's probably no way to foresee. > 4. zero CG shift from full to empty. > 5. I like the storage area up front. > > > In view of WW's accident and the very real potential for forward wing > displacement during a sudden stop, I strongly recommend flexible fuel > lines > to the tank. When 799B went over, the wing DID move forward about three > inches and my hard lines held fine, but when I rebuilt her, I was sure to > use flexible lines. > > > There are certainly pros for fuselage tanks too, but these are the reasons > I > went with a wing tank. > > > Douwe > > ________________________________ Message 23 ____________________________________ Time: 09:47:37 AM PST US Subject: Re: Pietenpol-List: fuel tanks From: macz@peak.org Douwe-- I agree with you on the value of the head the wing tank provides--it was put there for Ford engines which don't have (and don't need complication of) a fuel pump. --Mac in Oregon > Both fuel tank locations have worked fine. Here's why I went with a wing > tank and like it. > > > 1. The fuel is farther from the hot engine and electrics in most > "unplanned attitudes" such as upside down or on it's nose, or in case of > an > engine fire. > 2. I have heard of too low fuel head pressure/fuel starvation issues > with fuselage tanks, but not with wing tanks. If you're building a big > fuse > tank, it can be tricky to design it so you get the head pressure you need. > It can certainly be done, just watch it in all attitudes. > 3. Fuel overhead or fuel in my lap can both be bad situations, but it's > all dependent on the incident and there's probably no way to foresee. > 4. zero CG shift from full to empty. > 5. I like the storage area up front. > > > In view of WW's accident and the very real potential for forward wing > displacement during a sudden stop, I strongly recommend flexible fuel > lines > to the tank. When 799B went over, the wing DID move forward about three > inches and my hard lines held fine, but when I rebuilt her, I was sure to > use flexible lines. > > > There are certainly pros for fuselage tanks too, but these are the reasons > I > went with a wing tank. > > > Douwe > > ________________________________ Message 24 ____________________________________ Time: 05:29:06 PM PST US Subject: Pietenpol-List: Elevator droop From: danhelsper@aol.com Uh Oh........here are some photos of a to-the-plans, properly-built (and po wered) Pietenpol in flight. If I am not mistaken, I detect some elevator dr oop in all of them.You know, there are consequences, to making changes to t he original genuine BHP-authored plans. Just say'n. And by the way, what is all this talk of "improper" angle of incidence? ... .and "wrongly-designed" mounting-angle of the elevator? There is a lot of d issention on this list. Disturbing. Dan Helsper Puryear, TN ________________________________ Message 25 ____________________________________ Time: 06:35:05 PM PST US From: Brian Kenney Subject: RE: Pietenpol-List: Elevator droop That's surprising -to me it is a bunch of people sharing ideas and concept s to better understand how things work. Sorry if that disturbs you. Subject: Pietenpol-List: Elevator droop From: danhelsper@aol.com =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A Uh Oh........here are some photos of a to-the-plans=2C properly-built (and powered) Pietenpol in flight. If I am not mistaken=2C I detect some elevato r droop in all of them.=0A You know=2C there are consequences=2C to making changes to the original gen uine BHP-authored plans. Just say'n.=0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A And by the way=2C what is all this talk of "improper" angle of incidence? . ...and "wrongly-designed" mounting-angle of the elevator? There is a lot of dissention on this list. Disturbing.=0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A Dan Helsper=0A =0A =0A =0A =0A =0A =0A =0A Puryear=2C TN=0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A =0A ________________________________ Message 26 ____________________________________ Time: 06:42:32 PM PST US Subject: Re: Pietenpol-List: Elevator droop From: Gary Boothe Brian, You do understand there's a lot of tongue-in-cheek stuff that goes on here, r ight? Gary NX308MB Sent from my iPhone > On Mar 27, 2014, at 6:34 PM, Brian Kenney wrote: > > That's surprising -to me it is a bunch of people sharing ideas and concep ts to better understand how things work. Sorry if that disturbs you. > > To: pietenpol-list@matronics.com > Subject: Pietenpol-List: Elevator droop > From: danhelsper@aol.com > Date: Thu, 27 Mar 2014 20:27:51 -0400 > > > > Uh Oh........here are some photos of a to-the-plans, properly-built (and p owered) Pietenpol in flight. If I am not mistaken, I detect some elevator dr oop in all of them. You know, there are consequences, to making changes to t he original genuine BHP-authored plans. Just say'n. > > And by the way, what is all this talk of "improper" angle of incidence? .. ..and "wrongly-designed" mounting-angle of the elevator? There is a lot of d issention on this list. Disturbing. > > Dan Helsper > Puryear, TN > > > 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > ________________________________ Message 27 ____________________________________ Time: 07:08:41 PM PST US Subject: Re: Pietenpol-List: Elevator droop...zoom in From: "M. Zeke Zechini" ________________________________ Message 28 ____________________________________ Time: 07:19:01 PM PST US From: "Clif Dawson" Subject: Re: [Shaw Suspected Junk Email] Re: Pietenpol-List: Re: Speaking of outdated stuff? Center section fuel tanks vs. n We're so bad! :-) Neither was I. Like you said, Just trying to nudge the collective grey matter... If God is your co-pilot...switch seats. Mike Perez Karetaker Aero STILL Building... ________________________________ Message 29 ____________________________________ Time: 07:23:53 PM PST US From: "Clif Dawson" Subject: Re: Pietenpol-List: Elevator droop We're ALL so bad! :-) One really good thing is that without this discussion we wouldn't have been privy to some really great pics! Clif Not a shred of evidence exists in favor of the idea that life is serious. -Brendan Gill Brian, You do understand there's a lot of tongue-in-cheek stuff that goes on here, right? Gary NX308MB ________________________________ Message 30 ____________________________________ Time: 07:35:42 PM PST US Subject: Re: Pietenpol-List: Elevator droop From: Brian Kenney No I thought my family invented it. That's why I left home. Sent from my iPad > On Mar 27, 2014, at 9:44 PM, "Gary Boothe" wrote: > > Brian, > > You do understand there's a lot of tongue-in-cheek stuff that goes on here , right? > > Gary > NX308MB > > Sent from my iPhone > >> On Mar 27, 2014, at 6:34 PM, Brian Kenney wrote: >> >> That's surprising -to me it is a bunch of people sharing ideas and conce pts to better understand how things work. Sorry if that disturbs you. >> >> To: pietenpol-list@matronics.com >> Subject: Pietenpol-List: Elevator droop >> From: danhelsper@aol.com >> Date: Thu, 27 Mar 2014 20:27:51 -0400 >> >> >> >> Uh Oh........here are some photos of a to-the-plans, properly-built (and p owered) Pietenpol in flight. If I am not mistaken, I detect some elevator dr oop in all of them. You know, there are consequences, to making changes to t he original genuine BHP-authored plans. Just say'n. >> >> And by the way, what is all this talk of "improper" angle of incidence? . ...and "wrongly-designed" mounting-angle of the elevator? There is a lot of d issention on this list. Disturbing. >> >> Dan Helsper >> Puryear, TN > > 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3 D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message pietenpol-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Pietenpol-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/pietenpol-list Browse Digests http://www.matronics.com/digest/pietenpol-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.