X-Virus-Scanned: clean according to Sophos on Logan.com From: "Charlie England" Received: from mail-pa0-f43.google.com ([209.85.220.43] verified) by logan.com (CommuniGate Pro SMTP 6.1.2) with ESMTPS id 7677306 for flyrotary@lancaironline.net; Thu, 07 May 2015 00:42:25 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.220.43; envelope-from=ceengland7@gmail.com Received: by pabtp1 with SMTP id tp1so29183861pab.2 for ; Wed, 06 May 2015 21:41:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type; bh=H0YiKaHRsy3i63Ni0wry1CQCcnnq+zAaFUCWm9e9qNY=; b=iOv3iiUKokYIH7SVzxyk29PPMoAH4Mc/s/ifX6p9/2oyjTnhis6FQ+lA+Y+u8Va9OJ YlDPvAw50TUU5WelDSWHz8B1IaKM7e4hFZkziksDjFCiqybtBPGMrn+52aj+VoW9CkNQ wsfS9Cmgqjin3UG50a54KkOEd4/LCyAsxomeVYsIuKFtXQzigvmVNx9yvDP3KcWFTT20 bZvIJ/a3L2smYVbj2jWTBAujYeJsUCEDM4UiL1ki1petqgLBQOgr8zoaNaPv1bYeOHlK VuKrCAB+2Si66+b0b2MxHqefQcqNYNjb2ecjj3RyNDcbdp1TWJ5jW8CiSJmJzkA4dNpa Ej0A== X-Received: by 10.70.38.195 with SMTP id i3mr3694183pdk.82.1430973710121; Wed, 06 May 2015 21:41:50 -0700 (PDT) Return-Path: Received: from ?IPv6:2602:306:25fa:be29:c44c:1b92:f115:44b? ([2602:306:25fa:be29:c44c:1b92:f115:44b]) by mx.google.com with ESMTPSA id ia3sm619617pbc.31.2015.05.06.21.41.48 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 06 May 2015 21:41:49 -0700 (PDT) Message-ID: <554AED5F.3070206@gmail.com> Date: Wed, 06 May 2015 23:43:11 -0500 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: Return to Flight References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------000808030602010708070501" This is a multi-part message in MIME format. --------------000808030602010708070501 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Agreed, assuming proper execution, and that's what Ross claims. But he still has the original cowl, with both inlets and outlet(s), and the area around/above his new duct inlet looks like a mess, with the original cowl exit hanging down in front of where the boundary layer splitter should be. He claims net zero cooling drag, but there are no hard numbers showing fuel flow/speed/weight to give us some way to do a sanity check. Charlie On 5/6/2015 11:34 AM, Bobby J. Hughes wrote: > > Charlie, > > If you have a turbine type cowl then moving the inlets to the belly > duct should not increase the flat plate area. At least that’s my theory. > > Bobby Hughes > > N416AS RV10 223 hrs > > *From:*Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] > *Sent:* Wednesday, May 06, 2015 10:35 AM > *To:* Rotary motors in aircraft > *Subject:* [FlyRotary] Re: Return to Flight > > On 5/6/2015 8:01 AM, Tom Mann wrote: > > Mind you, my rotary is not flying yet and I have a Canard design > but I often wonder why the RV guys don’t relocate the radiator and > use a P-51 style scoop? > > I’ve seen many that have the radiator almost perpendicular to the > direction of the inflow. > > I would think that a radiator mounted just behind the seats would > give you the distance to properly expand the air and recover the > pressure more efficiently. > > Just thinking out loud ...... > > T Mann > > > I agree, a perfect P-51 style setup would be better, but.... > > Ross Farnham in Canada has done it (sort of). > http://www.sdsefi.com/air9.html > http://www.sdsefi.com/rv17.htm > http://www.youtube.com/watch?v=QT8njoirTkU > http://www.youtube.com/watch?v=gPpWHvr1kJw > He won't publish hard numbers, but has vaguely hinted at a 6-8 knot > speed gain over his old cooling system, which was pretty convoluted > (multiple air inlets/outlets in random places for multiple random heat > exchangers), so it was probably a net 0 gain over a well done > under-cowl setup. > > It's pretty complicated to run the plumbing, and since a complete > rotary installation that's built with careful attention to weight can > come in lighter than a Lyc (I put my entire FWF on a scale: 310 lbs, > dry), moving the heat exchangers aft is likely to adversely affect the > CG. Ross got away with it because he's running a turbo Subaru, which > is pretty heavy. The P-51 rad is partially submerged in the fuselage. > Submerging the rad in the aft fuselage sounds great, but even if you > can deal with the CG issues, with a metal fuselage you have to be very > careful what & where you cut to get the air in & out. And the scoop > itself is extra weight (the cowl is already there for the outside of > the 'scoop'). > > Water cooled engines beg for an airframe designed around them, just as > air cooled engines have planes designed around them. > > Charlie > > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html --------------000808030602010708070501 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: 8bit
Agreed, assuming proper execution, and that's what Ross claims. But he still has the original cowl, with both inlets and outlet(s), and the area around/above his new duct inlet looks like a mess, with the original cowl exit hanging down in front of where the boundary layer splitter should be.

He claims net zero cooling drag, but there are no hard numbers showing fuel flow/speed/weight to give us some way to do a sanity check.

Charlie

On 5/6/2015 11:34 AM, Bobby J. Hughes wrote:

Charlie,

 

If you have a turbine type cowl then moving the inlets to the belly duct should not increase the flat plate area.  At least that’s my theory.

 

 

Bobby Hughes

N416AS RV10 223 hrs

 

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
Sent: Wednesday, May 06, 2015 10:35 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Return to Flight

 

On 5/6/2015 8:01 AM, Tom Mann wrote:

Mind you, my rotary is not flying yet and I have a Canard design but I often wonder why the RV guys don’t relocate the radiator and use a P-51 style scoop?

I’ve seen many that have the radiator almost perpendicular to the direction of the inflow.

I would think that a radiator mounted just behind the seats would give you the distance to properly expand the air and recover the pressure more efficiently.

 

Just thinking out loud ......

 

T Mann


I agree, a perfect P-51 style setup would be better, but....

Ross Farnham in Canada has done it (sort of).
http://www.sdsefi.com/air9.html
http://www.sdsefi.com/rv17.htm
http://www.youtube.com/watch?v=QT8njoirTkU
http://www.youtube.com/watch?v=gPpWHvr1kJw
He won't publish hard numbers, but has vaguely hinted at a 6-8 knot speed gain over his old cooling system, which was pretty convoluted (multiple air inlets/outlets in random places for multiple random heat exchangers), so it was probably a net 0 gain over a well done under-cowl setup.

It's pretty complicated to run the plumbing, and since a complete rotary installation that's built with careful attention to weight can come in lighter than a Lyc (I put my entire FWF on a scale: 310 lbs, dry), moving the heat exchangers aft is likely to adversely affect the CG. Ross got away with it because he's running a turbo Subaru, which is pretty heavy.  The P-51 rad is partially submerged in the fuselage. Submerging the rad in the aft fuselage sounds great, but even if you can deal with the CG issues, with a metal fuselage you have to be very careful what & where you cut to get the air in & out. And the scoop itself is extra weight (the cowl is already there for the outside of the 'scoop').

Water cooled engines beg for an airframe designed around them, just as air cooled engines have planes designed around them.

Charlie



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