X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 03 Apr 2010 20:03:41 -0400 Message-ID: X-Original-Return-Path: Received: from web62507.mail.re1.yahoo.com ([69.147.75.99] verified) by logan.com (CommuniGate Pro SMTP 5.3.5) with SMTP id 4194231 for lml@lancaironline.net; Sat, 03 Apr 2010 08:27:00 -0400 Received-SPF: none receiver=logan.com; client-ip=69.147.75.99; envelope-from=charliekohler@yahoo.com Received: (qmail 29387 invoked by uid 60001); 3 Apr 2010 12:26:24 -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=1I6JVfWUYBJ3PSe3yGAcli2uUYqRDYERPu5ahXtPflZadxQUtdV82pvIH7hdIRe6MigeZQyw6MQPj+w/MITon+b5nDXKPdexFbG36P310hkenU9bXtTSHbGkNT2OKAYEXVbVyc65aATvi4SoJQP8IY3Bc1ARrCPkLL1UGuCzmSI=; X-Original-Message-ID: <816736.28775.qm@web62507.mail.re1.yahoo.com> X-YMail-OSG: iBWR6.IVM1nMQRQ98IsHvZXJnGu7TfdTqB_NGvYUhsoSfUh 5RyrP.K7UFSsQoYyPPfSypksuJNayqteqjeeg.h6eq1CPUDUMPzJX_axexIq ftaAk.qtlKjr7t5IrkQwEd9GeUrduJzvgO8AWz3Z2pjsDNkYwA2AOiS5r0Gn QDW.de0zSRR_W6HoQzv5A_iyWq8EETE0lCprxx0u6cTZ7y0MKSLS94DnSbPk DqPxOrDFFUMcxeA5T.0MYM5J4Y1_BNZO4k24mYwCeLfdfgU3ektjZolgnr3i z3qQ0Wkz975aqD63iv2KtMiKrg8lk7hnQeBYpmSSMsEsKf2abGv8GaJHWp4G 0JUE.qzNkRA-- Received: from [68.204.28.90] by web62507.mail.re1.yahoo.com via HTTP; Sat, 03 Apr 2010 05:26:24 PDT X-Mailer: YahooMailRC/324.3 YahooMailWebService/0.8.100.260964 References: X-Original-Date: Sat, 3 Apr 2010 05:26:24 -0700 (PDT) From: Charlie Kohler Subject: Re: [LML] IV-P AC X-Original-To: Lancair Mailing List In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-1301364683-1270297584=:28775" --0-1301364683-1270297584=:28775 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Hi Bob,=0AIt would be interesting to note whether your AC is the early vers= ion/or late. The difference is the dimension that the scoop extends down fr= om the fuselage. I don't recall the exact figures but the next time you're = at the airplane with a rule--- get the measurement from the center of the f= uselage down to the top of the scoop. This will tell me whether or not you = will gain anything from the conversion. The later models with the scoop tuc= ked up close to the fuselage had very little drag.=0AAt any rate-- if you d= o intend to make this change-- do a test flight before you start and get so= me indicated airspeed runs at various altitudes. Make sure the engine power= figures are recorded also. =0AThen we can have=C2=A0definitive=C2=A0data t= o support this long-standing debate.=C2=A0=0AAfter I installed mine, I comp= ared that data from a prop test I had done a year earlier for MT propeller-= -testing the three Blade versus the four blade. And compared that data with= the AC data at the same altitudes in power settings. There is always some = scatter but I found that 3 kn was the=C2=A0average penalty. =0AAnd--what yo= u will be able to establish that I was not-- how much does the condenser co= oling exhaust causes drag. As you can imagine if this exhaust air is strong= enough you will have to trim the airplane nose up (causing drag). Also, ve= ry exhausting at 90=C2=B0 to the flow of air over the skin, will cause drag= . How much we don't know.=0AAt any rate it will be a very interesting test.= =0A=C2=A0Thanks=0A=C2=A0=0ACharlie K.=0A=0ASee me on the web at =0Awww.Lanc= air-IV.com=0A=0A=0A=0A=0A=0A________________________________=0AFrom: Bob Ri= ckard =0ATo: lml@lancaironline.net=0ASent: Fri, Ap= ril 2, 2010 2:06:28 PM=0ASubject: [LML] IV-P AC=0A=0A=0AIV-P Experts:=0A=C2= =A0=0AI am contemplating replacing my air conditioning unit in my IV-P from= the under fuselage scoop to one that is installed in the tail.=C2=A0 Purel= y for speed benefits.=C2=A0 My unit works fine but I hear that it may slow = me down by 10-20 or more knots.=C2=A0=C2=A0 What are your recommendations?= =C2=A0 Is there already a thread on this?=C2=A0 I have the room in the tail= , CG shouldn=E2=80=99t be an issue, but I want to know the bad news.=C2=A0 = I have the airplane in Phoenix part of the time (yep, it=E2=80=99s really h= ot, and the current AC is adequate) and I need the system to work at least = a little on the ground so I don=E2=80=99t die before takeoff =E2=80=93 this= is my major concern.=C2=A0 And I would love to hear if some of you have ac= tually made this change and if so what speed benefit you have observed.=C2= =A0 Lastly, is there more than one vendor option?=0A=C2=A0=0AThanks for you= r comments=0A=C2=A0=0ABob Rickard=0AIV-P ( I didn=E2=80=99t build it!) --0-1301364683-1270297584=:28775 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable
=0A
=0A

Hi Bob,

=0A

It would be i= nteresting to note whether your AC is the early version/or late. The differ= ence is the dimension that the scoop extends down from the fuselage. I don'= t recall the exact figures but the next time you're at the airplane with a = rule--- get the measurement from the center of the fuselage down to the top= of the scoop. This will tell me whether or not you will gain anything from= the conversion. The later models with the scoop tucked up close to the fus= elage had very little drag.

=0A

At any rate-- if you do intend to make= this change-- do a test flight before you start and get some indicated air= speed runs at various altitudes. Make sure the engine power figures are rec= orded also.

=0A

Then we can have definitive data to support= this long-standing debate.

=0A

 

=0A

After I= installed mine, I compared that data from a prop test I had done a year ea= rlier for MT propeller--testing the three Blade versus the four blade. And = compared that data with the AC data at the same altitudes in power settings= . There is always some scatter but I found that 3 kn was the average p= enalty.

=0A

And--what you will be able to establish that I was not-- = how much does the condenser cooling exhaust causes drag. As you can imagine= if this exhaust air is strong enough you will have to trim the airplane no= se up (causing drag). Also, very exhausting at 90=C2=B0 to the flow of air = over the skin, will cause drag. How much we don't know.

=0A

At any rat= e it will be a very interesting test.

=0A

 Thanks


 
=0A
Charlie K.
=0A
 
=0A
See m= e on the web at
=0A=0A
 
= =0A

=0A

=0A
=0A
=0AFrom: Bob Rickard= <r.rickard@rcginc-us.com>
To= : lml@lancaironline.net
= Sent: Fri, April 2, 2010 2:06:28 PM
Subject: [LML] IV-P AC

=0A=0A=0A
=0A=

IV-P Experts:

=0A

 =

=0A

I am contemplating replacing my air cond= itioning unit in my IV-P from the under fuselage scoop to one that is insta= lled in the tail.  Purely for speed benefits.  My unit works fine= but I hear that it may slow me down by 10-20 or more knots.   Wh= at are your recommendations?  Is there already a thread on this? = I have the room in the tail, CG shouldn=E2=80=99t be an issue, but I want = to know the bad news.  I have the airplane in Phoenix part of the time= (yep, it=E2=80=99s really hot, and the current AC is adequate) and I need = the system to work at least a little on the ground so I don=E2=80=99t die b= efore takeoff =E2=80=93 this is my major concern.  And I would love to= hear if some of you have actually made this change and if so what speed be= nefit you have observed.  Lastly, is there more than one vendor option= ?

=0A

 <= /P>=0A

Bob Rickard

=0A

IV= -P ( I didn=E2=80=99t build it!)

<= /html> --0-1301364683-1270297584=:28775--