Brodhead Pietenpol Association

Original Posted By: "ED GRENTZER"
Subject: Re: Pietenpol-List: ElevatorsIn any stable, conventionally configured, airplane (not a canard), there willbe a download on the tail in flight. This means that if the tail stalls, itwill rise and the nose will drop.To be stable, the CG is forward of a neutral point. If the tail drops when itstalls, the CG is aft of the neutral point and the airplane is longitudinallyunstable. If the tail were going to drop when it stalls, the pilot would haveto be moving the stick forward as the airplane slows.The problem described with Redeye's very heavy Piet (462 kg means over 1000lb... empty! ) sounds like the tailwheel is quite a bit lower than the mains ontouchdown and is probably making hard contact while the mains are still fairlyhigh.Putting a stop on elevator travel is a very good idea but excessive travel andelevator stall isn't causing the tail to drop unless the CG is too far aft,which Redeye's Weight and Balance test says isn't the case.Mike Hardaway________________________________________________________________________________

Original Posted By:> mike(at)hardaway.com
I Wonder if the main gear is not closer to the firewall on the pietdropping it's tail. Could be the gear are too far ahead of the CG, causingthe tail to drop when the mains touch down. Wayne Sippola, Winnipeg----------

Original Posted By:>> mike(at)hardaway.com
Subject: Re: Pietenpol-List: Elevators>> I Wonder if the main gear is not closer to the firewall on the piet>dropping it's tail. Could be the gear are too far ahead of the CG, causing>the tail to drop when the mains touch down.> Wayne Sippola, Winnipeg>>----------

Original Posted By: Wayne Sippola
The tail wheel drops onto the ground before the mains touchRedeye-----Original Message-----

Original Posted By: "Don Emch"
Hi everyone-hope everyone had a safe and Merry Christmas. I'm fitting togeather the elevators and am curious to know if I should start the taper on the end pieces from the main beam to the trailing edge from the main beam or should I start the taper at or just behind the center beam. Thanks. Steve Singleton________________________________________________________________________________Subject: Pietenpol-List: Re: Elevators

Original Posted By: "Steve Singleton"
I think I kept mine the same thickness until the last few inches and then triedto taper it down to nicely match the trailing edge piece. It probably doesn'tmatter much, but I guess I tried to err on the side of holding that thicknessfor rigidity. The elevators and rudders are fairly flexible when they are complete.In flight, however I'm sure there isn't much flexing. Don EmchNX899DEP.S. Definitely the time of year that I miss building!Read this topic online here:http://forums.matronics.com/viewtopic.p ... __________

Original Posted By: "Don Emch"
Thanks Don. I fitted one together tapering from the center beam but like the idea of holding the thickness until farther back. Another question-is there any structural difference between Birch plywood and mahogany. I had in mind to use mahogany but may go with birch if there is a big price difference. I know this must be an age old question but is there any where else other than Wicks or spruce to buy plywood? Thanks. Steve Singleton----- Original Message -----

Original Posted By: "Ed G."
Hello Steve,I really don't think there should be any difference in where you start the taper.I'll bet the plane won't know the difference! Birch plywood is slightly heavier,slightly stiffer, and I think slightly less expensive. I used mahoganythroughout with the exception of the wing rib gussets. No real reason to useone versus the other, I guess. I made the ribs first and afterwards realizedI liked the look of the mahogany for the rest of the airframe. Preference,I guess. There is other plywood out there but be careful and know what you'relooking for. I used all Wick's and Aircraft Spruce but only because I didn'tknow what to look for. Other guys on the list have used other materials withgreat success, just be careful and research it if you decide on that route. Don't know about others, but I get a good feeling in flying along and knowingthat the nuts, bolts, and chunks of wood are "aircraft quality". Passengers probablyappreciate it too!!Don EmchNX899DERead this topic online here:http://forums.matronics.com/viewtopic.p ... __________

Original Posted By: Don Emch
A lot of builders use marine grade mahogany plywoood which is less expensive than aircraft grade and depending on your location might be locally available. Just be sure to sand off the sealer coating before glueing, especially with the birch plywood. It helps let the glue penetrate the grain of the wood. I've heard that tests say it doesn't make any difference with T-88 but I find that hard to believe so I always sand it. Ed G. ----- Original Message -----

Original Posted By: "Dick Navratil"
ggower_99(at)yahoo.com wrote:> We do aluminum castings in our factory... > > Could be with "Aircamper" and another ones later with "FlyCorvair".....> As a Zodiac/Corvair builder (considering a Piet for a 2nd plane), this idea reallyappeals to me...- PatrickWRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________

Original Posted By: "Steve Singleton"
Steve Many of us have used Okume plywood, available from Wicks or ACS. Okume is much lighter and cheaper but not quite as strong as aircraft grade. ACS cataloug has a good description of the properties of plywoods.Dick N.----- Original Message -----

Original Posted By: Dave and Connie

Original Posted By: "Dave and Connie"
I'll look into the Okume and also see if I can find a Marine supply house. Worked most of today on the tail and have it all ready to glue togeather except the rudder and hopefully will get that done tomorrow. I know i'm just a beginer at this but it's sure neat to see all this layed out and ready to glue up. Steve S----- Original Message -----

Original Posted By: "Steve Singleton"
SteveWhen posting this type of thing, it would be helpful to include where you live. Somebody may well have a local source for you.Dick N.----- Original Message -----

Original Posted By:> "Steve Singleton"
----- Dick-I live near Hale MO. about two hr drive North east of KC MO. I'd sure like to hear from somebody that has used the marine plywood. If there is anybody within a 2 or 3 hour drive of me that has any sruce to sell to make the longerons i'd sure be interested in buying it. I believe i have enough for the rest of the fuseledge. If i have to make the 4 1/2 hour drive to Wicks fore my longeron material then I'l probable get the plywood there also.> >> Steve> When posting this type of thing, it would be helpful to include where you > live. Somebody may well have a local source for you.> Dick N.> ----- Original Message -----

Original Posted By:> Goff Electric
Keith,Hey, I'm right there with you! I got both elevators finished today, still have the cement on my fingers, as I'm typing. The verticals are done and I'm starting on horizontal stabilizer tomorrow.How do you eat an elephant, one bite at a time!Ray KrauseBuilding a Sky Scout.=46rom two day agoRay KrauseSent from my iPad> On Jan 19, 2015, at 7:03 PM, goffelectric(at)comcast.net wrote:> > Attached is a picture of one elevator covered on January 1st, still have to rib stitch and perimeter tape but we are moving forward. Ran my engine at corvair college in Barnwell. > > Keith goff> > ----- Forwarded Message -----

Original Posted By: "Wayne Sippola"
> > > In any stable, conventionally configured, airplane (not a canard), therewill> be a download on the tail in flight. This means that if the tail stalls,it> will rise and the nose will drop.> > To be stable, the CG is forward of a neutral point. If the tail dropswhen it> stalls, the CG is aft of the neutral point and the airplane islongitudinally> unstable. If the tail were going to drop when it stalls, the pilot wouldhave> to be moving the stick forward as the airplane slows.> > The problem described with Redeye's very heavy Piet (462 kg means over1000> lb... empty! ) sounds like the tailwheel is quite a bit lower than themains on> touchdown and is probably making hard contact while the mains are stillfairly> high.> > Putting a stop on elevator travel is a very good idea but excessivetravel and> elevator stall isn't causing the tail to drop unless the CG is too faraft,> which Redeye's Weight and Balance test says isn't the case.> > Mike Hardaway> > > > ________________________________________________________________________________

Original Posted By: "Richard Gillespie"
>>>>>> In any stable, conventionally configured, airplane (not a canard), there>will>> be a download on the tail in flight. This means that if the tail stalls,>it>> will rise and the nose will drop.>>>> To be stable, the CG is forward of a neutral point. If the tail drops>when it>> stalls, the CG is aft of the neutral point and the airplane is>longitudinally>> unstable. If the tail were going to drop when it stalls, the pilot would>have>> to be moving the stick forward as the airplane slows.>>>> The problem described with Redeye's very heavy Piet (462 kg means over>1000>> lb... empty! ) sounds like the tailwheel is quite a bit lower than the>mains on>> touchdown and is probably making hard contact while the mains are still>fairly>> high.>>>> Putting a stop on elevator travel is a very good idea but excessive>travel and>> elevator stall isn't causing the tail to drop unless the CG is too far>aft,>> which Redeye's Weight and Balance test says isn't the case.>>>> Mike Hardaway>>>>>>>>>>________________________________________________________________________________