X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 06 Oct 2013 08:44:58 -0400 Message-ID: X-Original-Return-Path: Received: from nm8-vm8.bullet.mail.gq1.yahoo.com ([98.136.218.231] verified) by logan.com (CommuniGate Pro SMTP 6.0.7) with ESMTPS id 6504041 for lml@lancaironline.net; Sun, 06 Oct 2013 02:14:47 -0400 Received-SPF: none receiver=logan.com; client-ip=98.136.218.231; envelope-from=wfhannahan@yahoo.com Received: from [98.137.12.191] by nm8.bullet.mail.gq1.yahoo.com with NNFMP; 06 Oct 2013 06:14:12 -0000 Received: from [98.137.12.192] by tm12.bullet.mail.gq1.yahoo.com with NNFMP; 06 Oct 2013 06:14:12 -0000 Received: from [127.0.0.1] by omp1000.mail.gq1.yahoo.com with NNFMP; 06 Oct 2013 06:14:12 -0000 X-Yahoo-Newman-Property: ymail-3 X-Yahoo-Newman-Id: 32049.70811.bm@omp1000.mail.gq1.yahoo.com Received: (qmail 47750 invoked by uid 60001); 6 Oct 2013 06:14:11 -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=CpLuVzCicqrdqy3pytL6jQVNJAEE3gwTNm9zvIF8taqUiinJhGnwiuvJv6kgj4WXsb2jiPChqwpE6X+wYKNhfQvug/F2Orb4ZOkI/2uF2WwwWaihNSJLCCF31LrkRmbtzynoXVpaw1dJI6sT2ByJSlxnZbAM+40nJCw8VPAcofE=; X-YMail-OSG: Kk1VNxAVM1mzbs9UR4zgNUt2HGomUsyh8bsClsTbSdTk9TC DOYjt7Ur5yzadRVDeRXDfDux6M2gEKEUN2wgj.L.B.Sb78ZxanABj6HTssbJ Pb07v5uvrGyz4dFFO_gOdzSWpq6QcgP2EOZdnd8gwZoCNtL5xaQuv8eSQGjX CkQBZ6SiRJLkOfF27mRlG9wCNnNCyn1KS1TS2eSNpQ7nIuJVMyDDyyCvq8TI a9iPrIstakURtqmr_VNb6s5j3RShc.mwNAsCmUoPgWPR_uNYfjcTePJTDPs3 nXIHAcX3aXuzoNqyvaWl5ljviyOEIzb.zhgUO7jGfCs.MtCiwfj0U.ThwDQp mDTSYJfHOBYk__pWx7iA4XyQ51mVnaQdGcoaaWt03kq2y.KKS3JmFUzZ8n6c OIo_OhzFhROqdx2UcsKi66Hc2vGJSty09MppMl2Rl81Zho9kCG_93YngxVMe 7PTHEIrpzAB4OLu7F0oYakm87L76WjXrHqt7Fj4FT1H8uD7w3jisvG4BWG4x BUXd6UjUfF17jL_lzn_C0IK1AQQOlIzW3FXUggRWpwk7685zfVlmzbMmq.tf DSLB0368WlKkINjtaQRR6V4Fr7U1inPIqesuUWsQpQYtdD422pJ6wV8a4Ixu abB8F08i6o8KZWrCcyXiNwAx.iT7N_sFU6UICm0hikDZkQardXQJ7I75Z_NJ gLWNmijMzX3gcQixtT0qA Received: from [75.173.30.195] by web121806.mail.ne1.yahoo.com via HTTP; Sat, 05 Oct 2013 23:14:10 PDT X-Rocket-MIMEInfo: 002.001,CgrCoArCoFRvbSwgdGhhbmtzIGZvciBzaGFyaW5nIHlvdXIgd29yay4KCkp1c3QKIHdvbmRlcmluZyBpZiB5b3UsIG9yIGFueW9uZSBlbHNlLCB0cmllZCB2b3J0ZXggZ2VuZXJhdG9ycyBpbiB0aGUgCmNvbmNhdmUgd2luZy9mdXNlbGFnZSBpbnRlcnNlY3Rpb24gYmVoaW5kIHRoZSBzcGFyLiBUaGUgaWRlYSBiZWluZyB0byAKcmVkdWNlIGRyYWcgYnkgbWFpbnRhaW5pbmcgYXR0YWNoZWQgYWlyZmxvdyBpbiB0aGF0IHJlZ2lvbiB3aXRob3V0IHRoZSBiaWcgbW9kLgoKClJlZ2FyZHMsCkJpbGwgSGFubmFoYW4BMAEBAQE- X-Mailer: YahooMailWebService/0.8.160.587 References: X-Original-Message-ID: <1381040050.41023.YahooMailNeo@web121806.mail.ne1.yahoo.com> X-Original-Date: Sat, 5 Oct 2013 23:14:10 -0700 (PDT) From: Bill Hannahan Reply-To: Bill Hannahan Subject: 320/360 performance and stability X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="836554814-1016882459-1381040050=:41023" --836554814-1016882459-1381040050=:41023 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable =0A=0A=A0=0A=A0Tom, thanks for sharing your work.=0A=0AJust=0A wondering if= you, or anyone else, tried vortex generators in the =0Aconcave wing/fusela= ge intersection behind the spar. The idea being to =0Areduce drag by mainta= ining 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: l= ml@lancaironline.net =0ASent: Wednesday, October 2, 2013 5:49 AM=0ASubject:= [LML] 320/360 performance and stability=0A =0A=0A=0AReaders,=0AI have been= watching this conversation with interest. =A0I have some odd experiences w= ith 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 waiti= ng 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' is = seat of the pants, thus not worth mentioning. =A0But, figured I could expan= d 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. condition = (header fuel only, single pilot), flaps in reflex and, well, going as fast = as an RV-7 will go in formation. :)=0Ahttp://www.n54sg.com/images/tuft_test= _08.jpg=0A=0A=0ASo, this problem poses a few issues.=0AFirst, this is obvio= usly drag, probably a measurable amount thus for me the driving force behin= d correcting it one day. =A0Second is the available elevator travel. =A0If = you read the manual, I have the correct amount of up / down elevator travel= . =A0But, if the photo is my starting point, it means I have much less up, = and way too much down available to use. =A0The important part being the ele= vator up while in the flare. =A0Given a forward C.G. and a huge amount of f= laps, this can be an issue. (ask me how I know...)=0A=0ANext I would like t= o mention that not all small tails trim the same. =A0Some use a spring syst= em to bias the entire elevator. =A0Others use trim tabs. =A0I have a tab th= at due to its placement and odd elevator deflection has a limited functiona= l envelope. =A0Another driving force to change incidence.=0A=0ANow the ofte= n obvious question people ask is why haven't I fixed it yet. =A0Well, becau= se 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 in= cidence. =A0This brings me to the next subject, what I have changed.=0A=0AS= o 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 bee= n 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 pictur= e:=0Ahttp://www.n54sg.com/images/tuft_test_04.jpg=0A=0AI'm working on a wri= te up for my website detailing the project and its purpose and will have th= at posted sometime soon. =A0But, I will report that this did change the dow= nwash on my horiztonal and did change my required angle of incidence. Hence= , I'm glad I waited to change that. =A0It actually requires less up elevato= r than it did before so less negative incidence. =A0The general theory is I= have corrected some flow around the fuselage thus making the entire horizo= ntal a bit more effective. =A0Some modified Legacys experienced something s= imilar. =A0I only wish it would have corrected it more! =A0I now know more = about this mod and maybe would have applied it differently. =A0Just not sur= e I'm willing to do the work again for unknown gains.=0A=0AThe other aerody= namic change I made (that relates to the original stability post) is I remo= ved the cusp from the bottom surface of my flaps as suggested in a book abo= ut GA airfoils by Harry Riblett. =A0Below is a simplified version of his dr= awing. =A0(Not accurate, just for explanation purposes) =A0The solid black = 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, but it= was odd to start with. =A0Keep in mind, the 320 / 360 ailerons already hav= e 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. =A0Stall= was no different, but the pitch force did increase with flaps extended. = =A0Not a bad thing in my opinion. =A0Overall it is hard to explain, it is a= different wing, just can't pinpoint how.=A0=0A=0AIn the end I think I have= 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 o= f the propeller. =A0Previously more rpm always netted more speed. =A0Now th= e top 250ish rpm doesn't do much at all. =A0Total bummer! =A0Having to lear= n a lot more about propellers than I ever thought I would now...=0A=0AResul= ts of my airplane at Reno this year:=0AQualifying: 268.272 mph=0ASport Meda= llion: 1st 261.906 mph (only 2600 rpm!)=0AHeat 1C: 3rd 268.300 mph=0AHeat 2= C: 2nd 265.030 mph=0AHeat 3C: 2nd 266.717 mph=0ABronze Race: 2nd 266..944 m= ph=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 clo= ser than they appear! haha=0A=0ATom McNerney=0Awww.N54SG.com=A0 --836554814-1016882459-1381040050=:41023 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable

 

 Tom, thanks for sha= ring your work.

Just=0A wondering if y= ou, or anyone else, tried vortex generators in the =0Aconcave wing/fuselage= intersection behind the spar. The idea being to =0Areduce drag by maintain= ing attached airflow in that region without the big mod.

Regards,
Bill Hannahan

From: "dudewanarace@yahoo.com" <dudewanarace@yahoo.com&= gt;
To: lml@lancaironl= ine.net
Sent: Wednesd= ay, October 2, 2013 5:49 AM
Subje= ct: [LML] 320/360 performance and stability
<= div class=3D"y_msg_container">
Readers,
I have been watching this conversation wi= th interest.  I have some odd experiences with stability in my small t= ail 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 given my totally odd arrangement and l= ack 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 prob= ably few have visited just for interesting reading.

This is my elevator angle with t= he airplane in a forward C.G. condition (header fuel only, single pilot), f= laps in reflex and, well, going as fast as an RV-7 will go in formation. :)=
http://www.n54sg.com/images/tuft_test_08.jpg
=

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

Next I would like to mention that not all small tail= s trim the same.  Some use a spring system to bias the entire elevator= .  Others use trim tabs.  I have a tab that due to its placement = and odd elevator deflection has a limited functional envelope.  Anothe= r driving force to change incidence.

Now the often obvious question people= ask is why haven't I fixed it yet.  Well, because the job of fixing i= t 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.  This br= ings me to the next subject, what I have changed.

So I have this airplane going fast= er than most and figured why stop now.. I made a rather drastic change that= some call the beluga belly.  It has been done to a few Legacys that r= ace with varied applications of the same idea.  Those familiar with th= e 320/360 fuselage will notice it in this picture:
http://www.n54sg.com/images/tuft_test_04.jpg
I'm workin= g on a write up for my website detailing the project and its purpose and wi= ll have that posted sometime soon.  But, I will report that this did c= hange the downwash on my horiztonal and did change my required angle of inc= idence. Hence, I'm glad I waited to change that.  It actually requires= less up elevator than it did before so less negative incidence.  The = general theory is I have corrected some flow around the fuselage thus makin= g the entire horizontal a bit more effective.  Some modified Legacys e= xperienced something similar.  I only wish it=0A would have corrected = it more!  I now know more about this mod and maybe would have applied = it differently.  Just not sure I'm willing to do the work again for un= known gains.

The other aerodynamic change I made (that relates to the original stabi= lity post) is I removed the cusp from the bottom surface of my flaps as sug= gested in a book about GA airfoils by Harry Riblett.  Below is a simpl= ified version of his drawing.  (Not accurate, just for explanation pur= poses)  The solid black is the modification.
http://www.n54sg.com/images/Flap_Drawing.jp= g
S= o, what I have done to the camber of the wing is a bit odd I suppose, but i= t was odd to start with.  Keep in mind, the 320 / 360 ailerons already= have this modification.  I didn't get the 10 kts I thought I would. &= nbsp;(Aren't all mods worth 10 kts? haha)  But, it is a different airf= oil.  Stall was no different, but the pitch force did increase with fl= aps extended.  Not a bad thing in my opinion.  Overall it is hard= to explain, it is a different wing, just can't pinpoint how. 

In the end I think I have made the airplane aerodynamically better, bu= t I have moved the problem.  It seems with just a little bit cleaner a= irplane I ran in to the limit of the propeller.  Previously more rpm a= lways netted more speed.  Now the top 250ish rpm doesn't do much at al= l.  Total bummer!  Having to learn a lot more about propellers th= an I ever thought I would now...

Results of my airplane at Reno this year:
Qualifying: 268.272 = mph
Sport Medallion: 1st 2= 61.906 mph (only 2600 rpm!)
Heat 2C: 2nd 265.030 mph
Heat 3C: 2nd 266.717 mph

I have some really cool video from my = helmet/dash cameras, just trying to get it all edited.  Hear is a teas= er 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 angle lens are closer than they appear! haha

Tom McNerney
www.N54SG.com&nb= sp;


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