X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 06 Oct 2013 19:32:47 -0400 Message-ID: X-Original-Return-Path: Received: from nm17-vm7.bullet.mail.gq1.yahoo.com ([98.137.177.231] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTPS id 6504450 for lml@lancaironline.net; Sun, 06 Oct 2013 11:57:26 -0400 Received-SPF: none receiver=logan.com; client-ip=98.137.177.231; envelope-from=chris_zavatson@yahoo.com Received: from [98.137.12.174] by nm17.bullet.mail.gq1.yahoo.com with NNFMP; 06 Oct 2013 15:56:50 -0000 Received: from [98.137.12.201] by tm13.bullet.mail.gq1.yahoo.com with NNFMP; 06 Oct 2013 15:56:50 -0000 Received: from [127.0.0.1] by omp1009.mail.gq1.yahoo.com with NNFMP; 06 Oct 2013 15:56:50 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 495616.15562.bm@omp1009.mail.gq1.yahoo.com Received: (qmail 67876 invoked by uid 60001); 6 Oct 2013 15:56:49 -0000 DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=X-YMail-OSG:Received:X-Rocket-MIMEInfo:X-Mailer:References:Message-ID:Date:From:Reply-To:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=C5YDVhRrnIMp3gPofNV8PCm8/g+BmZp/Gd3srTYvGhZPYiwRhWfT6FShB4uX3CcSs3bZI+8s/0DpWSsz/T36xJ8cZEP25gqsWLqjHUxnTk507AG/At6y+H0FYB/f/K/CeuvnZN0RlysP6QYOfVftSm6hDXTRI/f3DWl2QaIfgcw=; X-YMail-OSG: VT28q6oVM1meY5.PtmZFZwvMvZxuj4Xq7PmkoYTAig0Um0A rQC_5nhUi7Z3xKD.EBlHu_4RozanO7DpdPvD_8P8rTiQYyvw_N9hA.2tv7Gt fFQatyJwtNGcHik94LDxmjxiH7qtF6cVVmIe_XTDmIMllEvSWQmFfgfrH3Om Kl.Tq8yvmTUo0XbEZeF3mmIAF0Dhg7aEwkDvtn2VCDItY3GuoUvcO8O8LUbN 8pM1Se2rUQ7xBhanbFlD53HxBEgK_mI_ls.sdePqmQTJO3SS2n25vZPH6jrc lUOvin9L1fBDk2oWFmDSn85WBZAwJGAxVsnenEQymNtJZ3d0deFYP8TH7mOG yZ.pjS43wmOCvT3517merfog01E5HYb8qHtrTLoTnrQk6.CmXiOMlYXfQV5R Y2XRKOdkVGm7IygMiPothv5KT5zGhrTPg7j1irwthPGB0ftQz_t0ryvzwbV6 uOX0N2EPVKew82XNIPAlLXzVFwrSm.8oqU1xL0B6ggUGu8MGCW2vNM8Asc1v 9nTi_l5JpTFTnmS50jExooz6ItCs9A9h7fA5sRGJjXbQcJa_BZM0Jaym2yvz LtS4nSFPNt3mR2JxmdocjyOvZ6yaSEC4zut3F0iJlDg3TRCnSNdnGhgHtIdM 2c2FsBriDQ88QBUkbhy_QSzsvCIFSxvaYzlTeUaS6eJvPkMShSXTZWdc5VcF A91ZiysIxurekzjBrbR3Oe0Mrf1onoZGXjJfDIs4KiipseBSxlEhZKRZC5F9 v0g-- Received: from [172.14.16.72] by web121605.mail.ne1.yahoo.com via HTTP; Sun, 06 Oct 2013 08:56:49 PDT X-Rocket-MIMEInfo: 002.001,QmlsbCwKSSB0dWZ0ZWQgYW5kIHZpZGVvIHRhcGVkIHRoaXMgcmVnaW9uIG9mIHRoZSB3aW5nLsKgIFRoZXJlIHdhcyBuZXZlciBhbnkgc2lnbiBvZiBmbG93IHNlcGFyYXRpb24gYW5kIHRoZXJlZm9yZSBubyBiZW5lZml0IHRvIHZvcnRleCBnZW5lcmF0b3JzLsKgIFRoZSB3aW5kIHR1bm5lbCBkYXRhIHNob3dzIHRoZSBzYW1lLCBhbHRob3VnaCB0aGUgd2luZCB0dW5uZWwgbW9kZWwgd2lsbCBnZW5lcmFsbHkgaGF2ZSBhIGNsZWFuZXIgdHJhbnNpdGlvbiBmcm9tIHdpbmcgdG8gZmxhcCAtIG5vIGdhcHMsIGgBMAEBAQE- X-Mailer: YahooMailWebService/0.8.160.587 References: X-Original-Message-ID: <1381075009.60374.YahooMailNeo@web121605.mail.ne1.yahoo.com> X-Original-Date: Sun, 6 Oct 2013 08:56:49 -0700 (PDT) From: Chris Zavatson Reply-To: Chris Zavatson Subject: Re: [LML] 320/360 performance and stability X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="2053635335-1718330688-1381075009=:60374" --2053635335-1718330688-1381075009=:60374 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Bill,=0AI tufted and video taped this region of the wing.=A0 There was neve= r any sign of flow separation and therefore no benefit to vortex generators= .=A0 The wind tunnel data shows the same, although the wind tunnel model wi= ll generally have a cleaner transition from wing to flap - no gaps, hinges,= etc.=A0 Avoiding separation in this area is difficult on a laminar section= and is looked at closer when developing the section.=A0 Inaccuracies durin= g construction could lead to a different result. Flying at much lower than = the design lift coefficient could change the result also. I checked down to= about 0.17=0A=A0=0AChris Zavatson=0AN91CZ=0A360std=0Ahttp://www.n91cz.net/= =0A =0A=0A________________________________=0A From: Bill Hannahan =0ATo: lml@lancaironline.net =0ASent: Sunday, October 6, 2013 = 5:44 AM=0ASubject: [LML] 320/360 performance and stability=0A =0A=0A=0A=0A= =0A=A0=0A=A0Tom, thanks for sharing your work.=0A=0AJust=0A wondering if yo= u, or anyone else, tried vortex generators in the =0Aconcave wing/fuselage = intersection behind the spar. The idea being to =0Areduce drag by maintaini= ng attached airflow in that region without the big mod.=0A=0A=0ARegards, = =0ABill Hannahan =0A=0Awfhannahan@yahoo.com=0A =0A=0A______________________= __________=0A From: "dudewanarace@yahoo.com" =0ATo:= lml@lancaironline.net =0ASent: Wednesday, October 2, 2013 5:49 AM=0ASubjec= t: [LML] 320/360 performance and stability=0A =0A=0A=0AReaders,=0AI have b= een watching this conversation with interest. =A0I have some odd experience= s with stability in my small tail 360 that was improperly built (not by me)= . =A0Geez, that is going to hurt resale.. haha=0A=0AAnyway, I have been wai= ting to comment as it will just fog the data that has been presented given = my totally odd arrangement and lack of any real data. =A0All of my 'data' i= s seat of the pants, thus not worth mentioning. =A0But, figured I could exp= and on an envelope probably few have visited just for interesting reading.= =0A=0AThis is my elevator angle with the airplane in a forward C.G. conditi= on (header fuel only, single pilot), flaps in reflex and, well, going as fa= st as an RV-7 will go in formation. :)=0Ahttp://www.n54sg.com/images/tuft_t= est_08.jpg=0A=0A=0ASo, this problem poses a few issues.=0AFirst, this is ob= viously drag, probably a measurable amount thus for me the driving force be= hind correcting it one day. =A0Second is the available elevator travel. =A0= If you read the manual, I have the correct amount of up / down elevator tra= vel. =A0But, if the photo is my starting point, it means I have much less u= p, and way too much down available to use. =A0The important part being the = elevator up while in the flare. =A0Given a forward C.G. and a huge amount o= f flaps, this can be an issue. (ask me how I know...)=0A=0ANext I would lik= e to mention that not all small tails trim the same. =A0Some use a spring s= ystem to bias the entire elevator. =A0Others use trim tabs. =A0I have a tab= that due to its placement and odd elevator deflection has a limited functi= onal envelope. =A0Another driving force to change incidence.=0A=0ANow the o= ften obvious question people ask is why haven't I fixed it yet. =A0Well, be= cause the job of fixing it is going to totally suck, and I wanted it to be = the last thing I do as my other aerodynamic changes may affect the angle of= incidence. =A0This brings me to the next subject, what I have changed.=0A= =0ASo I have this airplane going faster than most and figured why stop now.= . I made a rather drastic change that some call the beluga belly. =A0It has= been done to a few Legacys that race with varied applications of the same = idea. =A0Those familiar with the 320/360 fuselage will notice it in this pi= cture:=0Ahttp://www.n54sg.com/images/tuft_test_04.jpg=0A=0AI'm working on a= write up for my website detailing the project and its purpose and will hav= e that posted sometime soon. =A0But, I will report that this did change the= downwash on my horiztonal and did change my required angle of incidence. H= ence, I'm glad I waited to change that. =A0It actually requires less up ele= vator than it did before so less negative incidence. =A0The general theory = is I have corrected some flow around the fuselage thus making the entire ho= rizontal a bit more effective. =A0Some modified Legacys experienced somethi= ng similar. =A0I only wish it would have corrected it more! =A0I now know m= ore about this mod and maybe would have applied it differently. =A0Just not= sure I'm willing to do the work again for unknown gains.=0A=0AThe other ae= rodynamic change I made (that relates to the original stability post) is I = removed the cusp from the bottom surface of my flaps as suggested in a book= about GA airfoils by Harry Riblett. =A0Below is a simplified version of hi= s drawing. =A0(Not accurate, just for explanation purposes) =A0The solid bl= ack is the modification.=0Ahttp://www.n54sg.com/images/Flap_Drawing.jpg=0A= =0ASo, what I have done to the camber of the wing is a bit odd I suppose, b= ut it was odd to start with. =A0Keep in mind, the 320 / 360 ailerons alread= y have this modification. =A0I didn't get the 10 kts I thought I would. =A0= (Aren't all mods worth 10 kts? haha) =A0But, it is a different airfoil. =A0= Stall was no different, but the pitch force did increase with flaps extende= d. =A0Not a bad thing in my opinion. =A0Overall it is hard to explain, it i= s a different wing, just can't pinpoint how.=A0=0A=0AIn the end I think I h= ave made the airplane aerodynamically better, but I have moved the problem.= =A0It seems with just a little bit cleaner airplane I ran in to the limit = of the propeller. =A0Previously more rpm always netted more speed. =A0Now t= he top 250ish rpm doesn't do much at all. =A0Total bummer! =A0Having to lea= rn a lot more about propellers than I ever thought I would now...=0A=0AResu= lts of my airplane at Reno this year:=0AQualifying: 268.272 mph=0ASport Med= allion: 1st 261.906 mph (only 2600 rpm!)=0AHeat 1C: 3rd 268.300 mph=0AHeat = 2C: 2nd 265.030 mph=0AHeat 3C: 2nd 266.717 mph=0ABronze Race: 2nd 266..944 = mph=0A=0A=0AI have some really cool video from my helmet/dash cameras, just= trying to get it all edited. =A0Hear is a teaser of some VERY close racing= with Dave Morss in his Legacy: http://youtu.be/iegd6ylVHI4=0ABest to watch= in full screen in HD. =A0Keep in mind, objects in a wide angle lens are cl= oser than they appear! haha=0A=0ATom McNerney=0Awww.N54SG.com=A0 --2053635335-1718330688-1381075009=:60374 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
Bill,
I tufted and video taped this region of the wing.  There was n= ever any sign of flow separation and therefore no benefit to vortex generat= ors.  The wind tunnel data shows the same, although the wind tunnel mo= del will generally have a cleaner transition from wing to flap - no gaps, h= inges, etc.  Avoiding separation in this area is difficult on a lamina= r section and is looked at closer when developing the section.  Inaccu= racies during construction could lead to a different result. Flying at much= lower than the design lift coefficient could change the result also. I che= cked down to about 0.17
 
Chris Zavatson
N91CZ
360std=
=
From: Bill Hannahan <wfhannahan@yahoo.com>
= To: lml@lancaironline.net Sent: Sunday, October 6,= 2013 5:44 AM
Subject:= [LML] 320/360 performance and stability


 

 Tom, thanks for sharing your work.

Just=0A wondering if you, or anyone else, tried vorte= x generators in the =0Aconcave wing/fuselage intersection behind the spar. = The idea being to =0Areduce drag by maintaining attached airflow in that re= gion without the big mod.

Regards,
=
Bill Hannahan

From: "dudewanarace@y= ahoo.com" <dudewanarace@yahoo.com>
To: lml@lancaironline.net
Sent: Wednesday, October 2, 2013 5:49 AM
Subject:<= /b> [LML] 320/360 performance and stability

Readers,
I have b= een watching this conversation with interest.  I have some odd experie= nces with stability in my small tail 360 that was improperly built (not by = me).  Geez, that is going to hurt resale.. haha

Anyway, I = have been waiting to comment as it will just fog the data that has been presented gi= ven my totally odd arrangement and lack of any real data.  All of my '= data' is seat of the pants, thus not worth mentioning.  But, figured I= =0A could expand on an envelope probably few have visited just for interest= ing reading.

This is my elevator angle with the airplane in a forw= ard C.G. condition (header fuel only, single pilot), flaps in reflex and, w= ell, going as fast as an RV-7 will go in formation. :)
= http://www.n54sg.com/images/tuft_test_08.jpg

So, th= is problem poses a few issues.
First, this is obviously drag, probably a measurable amount thus f= or me the driving force behind correcting it one day.  Second is the a= vailable elevator travel.  If you read the manual, I have the correct = amount of up / down elevator travel.  But, if the photo is my starting= point, it means I have much less up, and way too much down available to us= e.  The important part being the elevator up while in the flare.  = ;Given a forward C.G. and a huge amount of flaps, this can be an issue. (as= k me how I know...)

Next I wou= ld like to mention that not all small tails trim the same.  Some use a= spring system to bias the entire elevator.  Others use trim tabs. &nb= sp;I have a tab that due to its placement and odd elevator deflection has a= limited functional envelope.  Another driving force to change inciden= ce.

Now the often obvious question people ask = is why haven't I fixed it yet.  Well, because the job of fixing it is = going to totally suck, and I wanted it to be the last thing I do as my othe= r aerodynamic changes may affect the angle of incidence.  This brings = me to the next subject, what I have changed.

So I have this airpla= ne going faster than most and figured why stop now.. I made a rather drasti= c change that some call the beluga belly.  It has been done to a few L= egacys that race with varied applications of the same idea.  Those fam= iliar with the 320/360 fuselage will notice it in this picture:
http://www.n54sg.com/images/tu= ft_test_04.jpg
I'm working on a write up for my website detail= ing the project and its purpose and will have that posted sometime soon. &n= bsp;But, I will report that this did change the downwash on my horiztonal a= nd did change my required angle of incidence. Hence, I'm glad I waited to c= hange that.  It actually requires less up elevator than it did before = so less negative incidence.  The general theory is I have corrected so= me flow around the fuselage thus making the entire horizontal a bit more ef= fective.  Some modified Legacys experienced something similar.  I only wish it=0A would have corrected it more!  I now know mor= e about this mod and maybe would have applied it differently.  Just no= t sure I'm willing to do the work again for unknown gains.

The ot= her aerodynamic change I made (that relates to the original stability post)= is I removed the cusp from the bottom surface of my flaps as suggested in = a book about GA airfoils by Harry Riblett.  Below is a simplified vers= ion of his drawing.  (Not accurate, just for explanation purposes) &nb= sp;The solid black is the modification.
http://www.n54sg.com/images/Flap_Drawing.j= pg
So, what I have done to the camber of the wing is a bit odd I supp= ose, but it was odd to start with.  Keep in mind, the 320 / 360 ailero= ns already have this modification.  I didn't get the 10 kts I thought = I would.  (Aren't all mods worth 10 kts? haha)  But, it is a diff= erent airfoil.  Stall was no different, but the pitch force did increa= se with flaps extended.  Not a bad thing in my opinion.  Overall = it is hard to explain, it is a different wing, just can't pinpoint how.&nbs= p;

In the end I think I have made the airplane aerodynamical= ly better, but I have moved the problem.  It seems with just a little = bit cleaner airplane I ran in to the limit of the propeller.  Previous= ly more rpm always netted more speed.  Now the top 250ish rpm doesn't = do much at all.  Total bummer!  Having to learn a lot more about = propellers than I ever thought I would now...

Results of my airpla= ne at Reno this year:
Qualifying: 268.272 mph
Sport Medallion: 1st 261.906 mph (only= 2600 rpm!)
= Heat 1C: 3rd 268.300 mph
Heat 2C: 2nd 265.030 mph
Heat 3C: 2nd 266.717 mph
Bronze Race: 2nd 266..944 mph

I have some really cool video from my helmet/dash cam= eras, just trying to get it all edited.  Hear is a teaser of some VERY= close racing with Dave Morss in his Legacy: http://youtu.be/iegd6ylVHI4
= Best to watch in full screen in HD.  Keep in mind, objects in a wide a= ngle lens are closer than they appear! haha

Tom McNerney
www.N54= SG.com 





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