X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Fri, 05 Jun 2009 16:28:57 -0400 Message-ID: X-Original-Return-Path: Received: from web62505.mail.re1.yahoo.com ([69.147.75.97] verified) by logan.com (CommuniGate Pro SMTP 5.2.14) with SMTP id 3672200 for lml@lancaironline.net; Thu, 04 Jun 2009 17:58:28 -0400 Received-SPF: none receiver=logan.com; client-ip=69.147.75.97; envelope-from=charliekohler@yahoo.com Received: (qmail 50337 invoked by uid 60001); 4 Jun 2009 21:57:52 -0000 DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:X-YMail-OSG:Received:X-Mailer:References:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=Lvqqhl2AqnLwgsTMjPc9gzf4YR1AUMAILdqVMQfi+bLTtJuNRdOxl1bsIMumHZeygCjz9BTsLt2j45yIzzWwgNz+KJhaO1j81veMnhHsthk0K1lNzIfDGDUNeyz+LG/ukUIOeTz74gmK9HS4N/QT/wKkyM96TaFVT5iNfLahhSg=; X-Original-Message-ID: <599797.50172.qm@web62505.mail.re1.yahoo.com> X-YMail-OSG: ge5j1BUVM1kR9fQWQjVREznLVBWxM9yId2Nu.ww7.fCiTJn7ruW2oMdz37_vHA.ghkkATIjHPagZSAf3zX86wpn0q7s8NA8AbIpWhBuxHFlNxCauMvl2VDhclzw5v3OeSTPrrrNdM6UuoherqEPtOl.YvskEOMwSsfkBB_SfAE329KqVhujhTcJeLRtoZ0JkRy2vck_Rj2apwjoVDzNPfpeNw6mKqWxmtDMp4U5BiAknbHqXrcHek.BS4X0x12tRFDU4zM2nFfsmPZjtJMkKaPc_vDcJkBS71oTUNjSOepa4JZLxXIIbE.Hc25Sxe1VNSWmibyyrVIjl.6jvPL51 Received: from [97.104.160.94] by web62505.mail.re1.yahoo.com via HTTP; Thu, 04 Jun 2009 14:57:52 PDT X-Mailer: YahooMailRC/1277.43 YahooMailWebService/0.7.289.10 References: X-Original-Date: Thu, 4 Jun 2009 14:57:52 -0700 (PDT) From: Charlie Kohler Subject: Re: [LML] Re: L360 winglets X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-771824032-1244152672=:50172" --0-771824032-1244152672=:50172 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Yes Bill, that figure was up to 7 kn lower indicated airspeed with winglets= . The test was done on N5SV. It had a set of winglets that had been install= ed per factory and the builder was very particular about details. We flew t= he winglets first--and then when we removed thge winglets and=A0added the s= tandard wingtips. We duplicated the cruise powers exactly and at the same a= ltitudes up to 22,000. The average was about a negative five knot indicated= airspeed.=0AActually what we discovered is that the deck angle increased--= causing even more drag . This is due to the fact that the winglets area is = introduced at the position of the wing where the greatest washout. If you s= ight down the leading edge of the wing you can see the twist. And adding th= e winglets just put more area that is twisted down.=0AThe popular belief th= at adding winglets will cause the lower deck angle and reduce drag at high = altitude is not correct. Just the opposite. =0AThe deck angle the situation= was a big surprise --but shouldn't have been.=0AMy son is a program direct= or at Gulfstream and I spoke with one of their winglets engineers one time = and he said that I would need a cruise .55 mach to see any appreciable gain= from adding winglets.=0A=A0=0AWhile we're at it-- the latest greatest wing= lets are circular in shape and join back on the wing. Anybody familiar with= them?=0A=A0=0ACharlie K.=0A=0ASee me on the web at =0Awww.Lancair-IV.com= =0A=0A=0A=0A=0A=0A________________________________=0AFrom: Bill =0ATo: lml@lancaironline.net=0ASent: Thursday, June 4, 2009 12:02:11= PM=0ASubject: [LML] Re: L360 winglets=0A=0A=0AHi Rob,=0A=A0=0AI seem to re= call that Charlie K. gathered data on a IV both with and without winglets. = Charlie, was the number 7 knots?=A0 That is, 7 knots faster WITHOUT the win= glets. =0A=A0=0ASeveral knowledgeable folks have responded that winglets ar= e=A0mostly an advantage at very high altitudes, and this is true. I would a= dd that my conversations several years ago with some Boeing engineers indic= ated that the exact shape and placement of winglets was ultra critical. Pro= bably not something that any of us could design and install in=A0our shop a= nd have any hope of improving performance. Extensive wind tunnel testing wo= uld be required to get it right. My wind tunnel (powered by hot air) is out= of service. To be successful, the winglets would need to reduce drag by mo= re than the increase=A0in drag that they would necessarily cause by increas= ing=A0wetted area and=A0weight. Imperfectly done, they have=A0the likely ou= tcome of slowing you down. Keep it simple, leave 'em off.=A0=0A=A0=0ARob, d= o you fly out of YPPH or YPJT?=0A=A0=0A=A0=0ABill Harrelson=0AN5ZQ 320 1,65= 0 hrs=0AN6ZQ=A0 IV under construction=0A=A0=0A=A0=0A=A0=0A=0A=A0=0AI am bui= lding a L360 in Australia, and will soon have to make the decision about wh= at wing tips to use. The kit comes with the standard tips. However, I have = seen some Lancairs with winglets, and am wondering whether they are worth t= he investment in time and money. Has anyone out there in LML land done any = research into the benefits of winglets? I am interested particularly in bef= ore and after comparisons, both in terms of speed and general handling.=0A= =A0=0AAny info would be greatly appreciated.=0A=A0=0ARob Stevens=0A=A0=0APe= rth, Western Australia. --0-771824032-1244152672=:50172 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
=0A
=0A

Yes Bill, that figure was up t= o 7 kn lower indicated airspeed with winglets. The test was done on N5SV. I= t had a set of winglets that had been installed per factory and the builder= was very particular about details. We flew the winglets first--and then wh= en we removed thge winglets and added the standard wingtips. We duplic= ated the cruise powers exactly and at the same altitudes up to 22,000. The = average was about a negative five knot indicated airspeed.

=0A

Actuall= y what we discovered is that the deck angle increased--causing even more dr= ag . This is due to the fact that the winglets area is introduced at the po= sition of the wing where the greatest washout. If you sight down the leadin= g edge of the wing you can see the twist. And adding the winglets just put = more area that is twisted down.

=0A

The popular belief that adding win= glets will cause the lower deck angle and reduce drag at high altitude is n= ot correct. Just the opposite.

=0A

The deck angle the situation was a= big surprise --but shouldn't have been.

=0A

My son is a program direc= tor at Gulfstream and I spoke with one of their winglets engineers one time= and he said that I would need a cruise .55 mach to see any appreciable gai= n from adding winglets.

=0A

 

=0A

While we're at it-- the la= test greatest winglets are circular in shape and join back on the wing. Any= body familiar with them?


 
=0A
Charlie K.
= =0A
 
=0A
See me on the web at
=0A=0A
 
=0A

=0A

=0A
=0A
=0AFrom: Bill <n5zq@verizon.net>
To: lml@lancaironline.net
Sent: Thursday, June 4, 2009 12:02:11 PM
= Subject: [LML] Re: L360 wingle= ts

=0A=0A=0A
Hi Rob,
=0A
 
=0A
I seem to recall = that Charlie K. gathered data on a IV both with and without winglets. Charl= ie, was the number 7 knots?  That is, 7 knots faster WITHOUT the wingl= ets.
=0A
 
= =0A
Several knowledgeable folks have respon= ded that winglets are mostly an advantage at very high altitudes, and = this is true. I would add that my conversations several years ago with some= Boeing engineers indicated that the exact shape and placement of winglets = was ultra critical. Probably not something that any of us could design and = install in our shop and have any hope of improving performance. Extens= ive wind tunnel testing would be required to get it right. My wind tunnel (= powered by hot air) is out of service. To be successful, the winglets would= need to reduce drag by more than the increase in drag that they would= necessarily cause by increasing wetted area and weight. Imperfec= tly done, they have the likely outcome of slowing you down. Keep it si= mple, leave 'em off. 
=0A
=  
=0A
Rob, do you fly out = of YPPH or YPJT?
=0A
&nb= sp;
=0A
 
=0A
Bill Harrelson
=0A
N5ZQ 320 1,650 hrs
=0A
N6ZQ  IV under construction
=0A
 
=0A
&n= bsp;
=0A
 
=0A

 
=0A
=0A
=0A

<= SPAN style=3D"FONT-FAMILY: Arial; FONT-SIZE: 10pt">I am building a L360 in = Australia, and will soon have to make the decision about what wing tips to = use. The kit comes with the standard tips. However, I have seen some Lancai= rs with winglets, and am wondering whether they are worth the investment in= time and money. Has anyone out there in LML land done any research into th= e benefits of winglets? I am interested particularly in before and after co= mparisons, both in terms of speed and general handling.

=0A

=  

=0A

Any info would be greatly appreciated.

=0A

 

=0A

Rob Stevens

=0A<= P class=3DMsoNormal> 

=0A

Perth, Western Australia.

= =0A

--0-771824032-1244152672=:50172--