Original Posted By: Dan Yocum
I think the intent for the longer fuselage was really to gain some leg room andpossibly add some pitch stability. A lot of the length is added from the rearcabane back to the tail. So the making it longer for lighter engines idea doesn'treally make sense. I kinda like the looks of the earlier short version,but I went ahead and used the longer version on mine because I'm kinda longmyself (about 6' 3" actually). I moved my wing back 4" and am really happy withthe balance. As far as the C.G. is concerned we really aren't moving the wingback, we really are moving the fuselage forward because the C.G. is determinedbased on the chord of the wing. Which makes sense to do rather than lengtheningthe engine mount. I think this is true because in lengthening the enginemount by 4" you are only setting that much weight out there 4" more. By movingthe entire fuselage forward (or moving the wing back) 4" you are movingall of the weight (fuselage structure, landing gear, fuel tank if in the fuselage,etc.) of the fuselage ahead of the C.G. forward. If I confused you don'tworry because I confuse myself all the time!As far as the 33% of chord for aft C.G. goes, I think it is very important. However,I do think the fantastic Pietenpol wing is fairly tolerant of aft C.G.I watched my airplane fly with a 37% of chord C.G. Kind of a long story buta test pilot friend wanted to show me that it would fly fine with that far aftof a C.G. and I guess it did. He said he definitely wouldn't spin it like thatbut otherwise it flew fine. Myself, I wouldn't ever spin my Piet, but I guessothers do. Enough rambling!Hoping to see some of the list guys at Brodhead!Don EmchNX899DENXRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Thu, 02 Jul 2009 16:07:13 -0500
Pietenpol-List: Keeping the C.G. from getting to far aft
Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Original Posted By: "Will42"
conceptmodels(at)tds.net wrote:> Doesn't moving the wing back move the CG forward relative to the > leading edge?> Moving the wing back creates a longer nose moment.> On Jul 1, 2009, at 5:09 PM, Jack Phillips wrote:> > > --I don't know about the "relative to the leading edge" bit, but if you look at aweight and balance work sheet, you will see that any weight aft of the datumline is a + and any weight forward is a -; likewise, any weight moved aft addsto the + and any weight moved forward adds to the -; assuming that the wing hasweight, and surely it does, then it stands to reason that moving the weightof the wing aft moves the CG aft by a relative amount. Moving the wing aft willlighten the tail in flight no doubt, but CG is figured on the ground and level.Moving the wing back does not necessarily lengthen the nose moment; it dependson where the datum line is.WillRead this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
conceptmodels(at)tds.net wrote:> Doesn't moving the wing back move the CG forward relative to the > leading edge?> Moving the wing back creates a longer nose moment.> On Jul 1, 2009, at 5:09 PM, Jack Phillips wrote:> > > --I don't know about the "relative to the leading edge" bit, but if you look at aweight and balance work sheet, you will see that any weight aft of the datumline is a + and any weight forward is a -; likewise, any weight moved aft addsto the + and any weight moved forward adds to the -; assuming that the wing hasweight, and surely it does, then it stands to reason that moving the weightof the wing aft moves the CG aft by a relative amount. Moving the wing aft willlighten the tail in flight no doubt, but CG is figured on the ground and level.Moving the wing back does not necessarily lengthen the nose moment; it dependson where the datum line is.WillRead this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Original Posted By: "Gene Rambo"
I don't know who did the weight and balance sheet on your Piet, but if you willtake a look at it, no where on it does it refer to the length of the wing cord,in fact it does not mention the wing. Weight and balance is determined by weighingthe main gear and nose or tail wheel; using those weights and arms todetermine moments, then adding fuel, oil, pilot, passenger and baggage/freightweights and arms to determine their moments and then enter all info on the weightand balance work sheet to determine the CG.The wing has a center of lift ( typically about 33% of cord) that works with theCG to produce safe loading conditions but neither the wing nor the wing corddetermines the CG. WillRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________
I don't know who did the weight and balance sheet on your Piet, but if you willtake a look at it, no where on it does it refer to the length of the wing cord,in fact it does not mention the wing. Weight and balance is determined by weighingthe main gear and nose or tail wheel; using those weights and arms todetermine moments, then adding fuel, oil, pilot, passenger and baggage/freightweights and arms to determine their moments and then enter all info on the weightand balance work sheet to determine the CG.The wing has a center of lift ( typically about 33% of cord) that works with theCG to produce safe loading conditions but neither the wing nor the wing corddetermines the CG. WillRead this topic online here:http://forums.matronics.com/viewtopic.p ... __________
Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Original Posted By: "Don Emch"
Subject: Pietenpol-List: W&BI hadn't done a weight and balance since getting my private ticket back in 1981when I finished my Pietenpol and didn't ask a single questionor ask for help. I went to the TONY BINGELIS books and he explained it all in simple terms and gaveyou several ways to do it and to see if your numbers were any good. I used the tip of the prop as my datum---all the numbers are positive then makingthe math simple. I could not believe how EASY it was. There is nothingmysterious or magical about CG or doing a W&B. Jack's teeter-totter example wasa good one. At one Brodhead back in the mid 90's they had a hangar all setup to weigh any Pietsthat were there and then measured things like long fuse, short fuse, engine type, overall weight, and published it in the then Grant MacLaren newsletter. Was pretty interesting to see all the various configurationsand results. Nice thing is that no matter what engine/fuselage/pilot weight you've got going----there'ssomeone out there who has been there, done that and cantell you how their CG worked out and what they would have (if anything) done differentlyto make it come out better. Mike C. ________________________________________________________________________________Subject: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Subject: Pietenpol-List: W&BI hadn't done a weight and balance since getting my private ticket back in 1981when I finished my Pietenpol and didn't ask a single questionor ask for help. I went to the TONY BINGELIS books and he explained it all in simple terms and gaveyou several ways to do it and to see if your numbers were any good. I used the tip of the prop as my datum---all the numbers are positive then makingthe math simple. I could not believe how EASY it was. There is nothingmysterious or magical about CG or doing a W&B. Jack's teeter-totter example wasa good one. At one Brodhead back in the mid 90's they had a hangar all setup to weigh any Pietsthat were there and then measured things like long fuse, short fuse, engine type, overall weight, and published it in the then Grant MacLaren newsletter. Was pretty interesting to see all the various configurationsand results. Nice thing is that no matter what engine/fuselage/pilot weight you've got going----there'ssomeone out there who has been there, done that and cantell you how their CG worked out and what they would have (if anything) done differentlyto make it come out better. Mike C. ________________________________________________________________________________Subject: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Original Posted By: "Don Emch"
You seem to have a fairly good understanding of the weight and balance issue andI agree with you on everything you said except one.........." we can't justfigure where the C.G. is according to the fuselage and gear or weighing points."This is, in fact, the ONLY accepted way ( according to FAA publication, EA-AC65-9A, chapter 3), one can determine the actual CG.Will [/quote]Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
You seem to have a fairly good understanding of the weight and balance issue andI agree with you on everything you said except one.........." we can't justfigure where the C.G. is according to the fuselage and gear or weighing points."This is, in fact, the ONLY accepted way ( according to FAA publication, EA-AC65-9A, chapter 3), one can determine the actual CG.Will [/quote]Read this topic online here:http://forums.matronics.com/viewtopic.p ... ___Subject: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Original Posted By: Lawrence Williams
Will,That's right, weighing the airplane at certain points while it is level is theonly accepted method of finding the C.G. Using the arms for the gear, findinga datum point, etc., are all required to do this. And as far as I know it isthe only way. But we need to know exactly where the wing is because that determinesour C.G. range. We really don't care where it falls on the fuselage aslong as it falls within the % of chord that we need it to fall into.I really didn't mean to ruffle feathers and get something started, I just wantedto try to share some information. Hopefully our discussions helped someoneunderstand this a little better. Does anyone know when it will stop raining in NE Ohio? I was planning on flyingthis morning!Don EmchNX899DERead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Fri, 3 Jul 2009 06:18:28 -0700 (PDT)
Will,That's right, weighing the airplane at certain points while it is level is theonly accepted method of finding the C.G. Using the arms for the gear, findinga datum point, etc., are all required to do this. And as far as I know it isthe only way. But we need to know exactly where the wing is because that determinesour C.G. range. We really don't care where it falls on the fuselage aslong as it falls within the % of chord that we need it to fall into.I really didn't mean to ruffle feathers and get something started, I just wantedto try to share some information. Hopefully our discussions helped someoneunderstand this a little better. Does anyone know when it will stop raining in NE Ohio? I was planning on flyingthis morning!Don EmchNX899DERead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Fri, 3 Jul 2009 06:18:28 -0700 (PDT)
Re: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Original Posted By: Rick Holland
Don; you now have it exactly right. And you didn't ruffle any feathers here.WillRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Fri, 3 Jul 2009 09:21:07 -0600Subject: Re: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Don; you now have it exactly right. And you didn't ruffle any feathers here.WillRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Fri, 3 Jul 2009 09:21:07 -0600Subject: Re: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
RE: Pietenpol-List: Wt/Bal
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Hi Larry,You are exactly right. When I first built my Piet, I did the weighing andfound my CG. Weight on the tailwheel (empty, in 3-pt position) was a nicelight 20 lbs. But the CG was too far aft with respect to the wing cord andI moved the wing another 2-1/2" aft, putting the CG well within theacceptable range as a percentage of wing cord, but now the weight on thetailwheel in the 3 pt position was nearly 30 lbs. With the top longeronslevel, the plane will nearly balance. Weight on the tailwheel (empty) withthe longerons level is only a couple of pounds.Not that this means anything, since with my 200 lb bulk on board, the weighton the tailwheel is substantial. The extra 5-10 lbs that moving the wingaft put on the tailwheel is not noticeable compared to the punishment my fatbutt gives it.Jack PhillipsNX899JPAnxiously awaiting passage of the next 19 days so we can get to Brodhead _____
Hi Larry,You are exactly right. When I first built my Piet, I did the weighing andfound my CG. Weight on the tailwheel (empty, in 3-pt position) was a nicelight 20 lbs. But the CG was too far aft with respect to the wing cord andI moved the wing another 2-1/2" aft, putting the CG well within theacceptable range as a percentage of wing cord, but now the weight on thetailwheel in the 3 pt position was nearly 30 lbs. With the top longeronslevel, the plane will nearly balance. Weight on the tailwheel (empty) withthe longerons level is only a couple of pounds.Not that this means anything, since with my 200 lb bulk on board, the weighton the tailwheel is substantial. The extra 5-10 lbs that moving the wingaft put on the tailwheel is not noticeable compared to the punishment my fatbutt gives it.Jack PhillipsNX899JPAnxiously awaiting passage of the next 19 days so we can get to Brodhead _____
Re: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Original Posted By: Mark Roberts
Subject: Pietenpol-List: ALittle HelpPieters,I'm not very sharp, Pietering or computering. What I need is a bit of help to get to the archive or somewhere to find as much info on the Riblet airfoil. As an old Louisiana politician used to ask while running for governor," won't ya hep me".Corky in real hot Louisiana but the tomatoes are abundant and delicious.**************A Good Credit Score is 700 or Above. See yours in just 2 easy steps! JulystepsfooterNO62)________________________________________________________________________________Date: Fri, 3 Jul 2009 09:36:02 -0700Subject: Re: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Subject: Pietenpol-List: ALittle HelpPieters,I'm not very sharp, Pietering or computering. What I need is a bit of help to get to the archive or somewhere to find as much info on the Riblet airfoil. As an old Louisiana politician used to ask while running for governor," won't ya hep me".Corky in real hot Louisiana but the tomatoes are abundant and delicious.**************A Good Credit Score is 700 or Above. See yours in just 2 easy steps! JulystepsfooterNO62)________________________________________________________________________________Date: Fri, 3 Jul 2009 09:36:02 -0700Subject: Re: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Re: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Original Posted By: Mark Roberts
Mark , I understand Bill does not have website. His phone is 608-833-5839. Address is 3339 Mound view Rd., Verona Wisc. 53593--Jim Lagowski ----- Original Message -----
Mark , I understand Bill does not have website. His phone is 608-833-5839. Address is 3339 Mound view Rd., Verona Wisc. 53593--Jim Lagowski ----- Original Message -----
Re: Pietenpol-List: Wt/Bal
Original Posted By: Lloyd Smith
Larry and Jack,I think my tail weighs somewhere around 8-10 lbs. with the plane level with a fulltank. If I lift the tail about a foot higher I need to hang on tight becauseit will keep on going till the nose hits the ground if I would let go. Anyway,I've often wondered if I would have made the cabanes straight and lengthenedthe engine mount instead of moving the wing back if it would actually betoo light on the tail and want to tip forward. Anyway, I'm glad I didn't messwith that stuff and moved the wing.I'm counting the days too!DonRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Fri, 3 Jul 2009 15:46:10 -0400Subject: Re: Pietenpol-List: Wt/Bal
Larry and Jack,I think my tail weighs somewhere around 8-10 lbs. with the plane level with a fulltank. If I lift the tail about a foot higher I need to hang on tight becauseit will keep on going till the nose hits the ground if I would let go. Anyway,I've often wondered if I would have made the cabanes straight and lengthenedthe engine mount instead of moving the wing back if it would actually betoo light on the tail and want to tip forward. Anyway, I'm glad I didn't messwith that stuff and moved the wing.I'm counting the days too!DonRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Fri, 3 Jul 2009 15:46:10 -0400Subject: Re: Pietenpol-List: Wt/Bal
> ** Pietenpol-List: Wt/Bal
Original Posted By: shad bell
Re: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Original Posted By: Mark Roberts
The weight and balance is concerning me as I know I have very light tail rightnow with the wings off and the engine on.the modified GN-1 I picked up. DJ didsome size changes for his height and I fit pretty good with my long legs.I guessif I were to build one from scratch I might look into moving the main gearforward but after completion I'll finally know if it is necessary.I would guessthe main thing if the CG is OK will be to really be careful hitting the brakes.mighteven need to do something like the Cessna 140's had moving the wheelsforward but I'm not sure that would be practical with the Cub gear.but I couldprobably build new main legs with a forward angle.but that would move wheelweight forward as well as helping it to be less likely to nose over. maybe it'llbe perfect-I sure hope so.I would rather put the battery under the back seator even behind it than angle the cabanes forward or back either one.RaymondRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Fri, 3 Jul 2009 16:38:21 -0700Subject: Re: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
The weight and balance is concerning me as I know I have very light tail rightnow with the wings off and the engine on.the modified GN-1 I picked up. DJ didsome size changes for his height and I fit pretty good with my long legs.I guessif I were to build one from scratch I might look into moving the main gearforward but after completion I'll finally know if it is necessary.I would guessthe main thing if the CG is OK will be to really be careful hitting the brakes.mighteven need to do something like the Cessna 140's had moving the wheelsforward but I'm not sure that would be practical with the Cub gear.but I couldprobably build new main legs with a forward angle.but that would move wheelweight forward as well as helping it to be less likely to nose over. maybe it'llbe perfect-I sure hope so.I would rather put the battery under the back seator even behind it than angle the cabanes forward or back either one.RaymondRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Fri, 3 Jul 2009 16:38:21 -0700Subject: Re: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Re: Pietenpol-List: Re: Wt/Bal
Original Posted By: Lloyd Smith
Thanks for the tip-that's what I was hoping for-some real experience numbers. I'mnot too worried. I think the 37 lb. was not running too fast.maybe a thousand-oilwas fairly warm and my probe is in the oil filter housing so most likelynot getting as much heat as it would in the engine.thanks.I haven't changedit yet but I'm guessing it might be 10/40 or 15/40 weight.no real way of knowing.Ihaven't heard from DJ lately.not sure he still has the same E-mail address.butI'm pressing forward with it.RaymondRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Fri, 3 Jul 2009 22:09:17 -0400Subject: Re: Pietenpol-List: Re: Wt/Bal
Thanks for the tip-that's what I was hoping for-some real experience numbers. I'mnot too worried. I think the 37 lb. was not running too fast.maybe a thousand-oilwas fairly warm and my probe is in the oil filter housing so most likelynot getting as much heat as it would in the engine.thanks.I haven't changedit yet but I'm guessing it might be 10/40 or 15/40 weight.no real way of knowing.Ihaven't heard from DJ lately.not sure he still has the same E-mail address.butI'm pressing forward with it.RaymondRead this topic online here:http://forums.matronics.com/viewtopic.p ... ______Date: Fri, 3 Jul 2009 22:09:17 -0400Subject: Re: Pietenpol-List: Re: Wt/Bal
Re: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Original Posted By: "skellytown flyer"
Well if you do have to move the gear it should not be to difficult. The wayDJ set that one up with the cradle that holds the gear on the fuse you couldmove the whole thing forward if you needed to.http://www.imagedv.com/aircamper/log/im ... chael----- Original Message -----
Well if you do have to move the gear it should not be to difficult. The wayDJ set that one up with the cradle that holds the gear on the fuse you couldmove the whole thing forward if you needed to.http://www.imagedv.com/aircamper/log/im ... chael----- Original Message -----
Re: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Original Posted By: Ryan Mueller
> Subject: Pietenpol-List: ALittle Help> To: pietenpol-list(at)matronics.com>> Pieters,>> I'm not very sharp, Pietering or computering. What I need is a bit of help> to get to the archive or somewhere to find as much info on the Riblet> airfoil. As an old Louisiana politician used to ask while running for> governor, " won't ya hep me".>> Corky in real hot Louisiana but the tomatoes are abundant and delicious.>> ------------------------------> *A Good Credit Score is 70001462804/aol?redir> http://www.freecreditreport.com/pm/defa ... erNO62>See> yours in just 2 easy steps!*>> *>> st">http://www.matronics.com/Navigator?Piet ... ntribution> *>>> ------------------------------> Hotmail=AE has ever-growing storage! Don=92t worry about storage limits. Check> it out.>> *>===========w.matronics.com/Navigator?Pietenpol-List======================com/contribution===========> *>>________________________________________________________________________________Date: Fri, 3 Jul 2009 13:55:32 -0500Subject: Re: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
> Subject: Pietenpol-List: ALittle Help> To: pietenpol-list(at)matronics.com>> Pieters,>> I'm not very sharp, Pietering or computering. What I need is a bit of help> to get to the archive or somewhere to find as much info on the Riblet> airfoil. As an old Louisiana politician used to ask while running for> governor, " won't ya hep me".>> Corky in real hot Louisiana but the tomatoes are abundant and delicious.>> ------------------------------> *A Good Credit Score is 70001462804/aol?redir> http://www.freecreditreport.com/pm/defa ... erNO62>See> yours in just 2 easy steps!*>> *>> st">http://www.matronics.com/Navigator?Piet ... ntribution> *>>> ------------------------------> Hotmail=AE has ever-growing storage! Don=92t worry about storage limits. Check> it out.>> *>===========w.matronics.com/Navigator?Pietenpol-List======================com/contribution===========> *>>________________________________________________________________________________Date: Fri, 3 Jul 2009 13:55:32 -0500Subject: Re: Pietenpol-List: Re: Keeping the C.G. from getting to far aft
Pietenpol-List: Re: Wt/Bal
Original Posted By: "Don Emch"
>> *>> *>>________________________________________________________________________________Subject: Pietenpol-List: Re: Wt/Bal
>> *>> *>>________________________________________________________________________________Subject: Pietenpol-List: Re: Wt/Bal
Pietenpol-List: Re: it's alive!
Original Posted By: "skellytown flyer"
>>>> *>>>> " target="_blank"> http://www.matronics.com/Navigator?Pietenpol-List>> a> http://forums.matronics.com>> _blank"> http://www.matronics.com/contribution>> *>>>>> *>>> *>>________________________________________________________________________________Subject: Pietenpol-List: Re: it's alive!
>>>> *>>>> " target="_blank"> http://www.matronics.com/Navigator?Pietenpol-List>> a> http://forums.matronics.com>> _blank"> http://www.matronics.com/contribution>> *>>>>> *>>> *>>________________________________________________________________________________Subject: Pietenpol-List: Re: it's alive!