X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from nf-out-0910.google.com ([64.233.182.189] verified) by logan.com (CommuniGate Pro SMTP 5.2c1) with ESMTP id 2490772 for flyrotary@lancaironline.net; Thu, 15 Nov 2007 22:15:18 -0500 Received-SPF: pass receiver=logan.com; client-ip=64.233.182.189; envelope-from=wdleonard@gmail.com Received: by nf-out-0910.google.com with SMTP id 30so704321nfu for ; Thu, 15 Nov 2007 19:14:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:references; bh=ke1xkfHArf/QjuzETt5qF0zdluYg3nkXKGtAA1FfZow=; b=qLEawowu7s7MgThbh/JfTlS2CUYNIE1nFuGiCz3BuNIH8tCdfYFv/lOiMr0XrE0xYN0ku957Jq+86btioNXNk0fnGB+Gk0M6d5vfVyR/jXgc2Ot7yRCsR7/WgHl1D3oxN66mAaKPy/Xc4ODMnctrQJFfR/k1eVWuWTudTiRgutQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:in-reply-to:mime-version:content-type:references; b=Fb1nlfzwjH5B1yi9yZ75GFQX4T0Ycx+iKGtUCjXHhJOeDIzxAC6w9znRoS1yu0EjDWmT0N7f/mSJCEzvxqB7r4BspCYp+YzaYnzz503HDu1zDM7EgkgqDEXY3amG+4dsV+NfNIj9hEFYoSKdMB/VpNQfNg21rhe8v5yCWLMUw7U= Received: by 10.86.70.8 with SMTP id s8mr1329035fga.1195182880478; Thu, 15 Nov 2007 19:14:40 -0800 (PST) Received: by 10.86.98.1 with HTTP; Thu, 15 Nov 2007 19:14:40 -0800 (PST) Message-ID: <1c23473f0711151914l7cb6734dk212b730c1f5dc41@mail.gmail.com> Date: Thu, 15 Nov 2007 22:14:40 -0500 From: "David Leonard" To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Re: Thick vs Thin was : Diffuser Configuration Comparison In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_6673_30388331.1195182880465" References: ------=_Part_6673_30388331.1195182880465 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Ed Anderson Wrote: > So IF in installing the thicker core, I slow down the mass flow through > the duct by 1/2 (which I can easily do - increasing it might be more > difficult) then the air velocity through the core will be reduced. With the > velocity decreased, the air will take longer to transverse the core. The > longer the air takes to move through the core the more heat it will absorb, > the more heat the air absorbs the greater the DeltaT of the air. The > greater the deltaT of the air the more heat will be removed even with the > slower velocity and mass flow ( the drag would also be reduced, just had to > throw that one in {:>)). > Ok, I'll let you slow down the air for the thicker RAD. But then I am going to slow the air for the thin RAD even more than that. Afterward, we can both make a fortune selling my new idea: Seven-minute Ab videos! (and maybe radiators that need no air at all) :-) Tracy Crook Wrote: > This is where it starts to go badly wrong and/or misses the whole > point. The main object of using a thick rad is to use fewer CFM > (lower mass flow rate). If you want to assume same mass flow, there > is no advantage *(and probably a disadvantage) for a thick rad*. > Ah HA! You heard it folks, right there in black and white. If 2.75" IS a thick rad, then I must be on your side of the discussion all along, as my rad is 3" thick. Yet it is as wide and long as I could reasonably fit under the cowl. This brings me to my final point (promise I won't make anymore points). Use the widest-thinnest radiator you can reasonably fit under the cowl and make appropriate ducting. I guarantee that you don't want to use the thickest-narrowest rad you can fit. That would not cool well at all. -- David Leonard Turbo Rotary RV-6 N4VY http://N4VY.RotaryRoster.net http://RotaryRoster.net ------=_Part_6673_30388331.1195182880465 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Ed Anderson Wrote:
So IF in installing the thicker core, I slow down the mass flow through the duct by 1/2  (which I can easily do - increasing it might be more difficult) then the air velocity through the core will be reduced.  With the velocity decreased, the air will take longer to transverse the core.  The longer the air takes to move through the core the more heat it will absorb, the more heat the air absorbs the greater the DeltaT of the air.  The greater the deltaT of the air the more heat will be removed even with the slower velocity and mass flow ( the drag would also be reduced, just had to throw that one in {:>)).

Ok, I'll let you slow down the air for the thicker RAD.  But then I am going to slow the air for the thin RAD even more than that.

Afterward, we can both make a fortune selling my new idea: Seven-minute Ab videos! 
(and maybe radiators that need no air at all)   :-)

Tracy Crook Wrote:
This is where it starts to go badly wrong and/or misses the whole
point.  The main object of using a thick rad is to use fewer CFM
(lower mass flow rate).   If you want to assume same mass flow, there
is no advantage (and probably a disadvantage) for a thick rad.
 
Ah HA!  You heard it folks, right there in black and white.

If 2.75" IS a thick rad, then I must be on your side of the discussion all along, as my rad is 3" thick.  Yet it is as wide and long as I could reasonably fit under the cowl. 

This brings me to my final point (promise I won't make anymore points).  Use the widest-thinnest radiator you can reasonably fit under the cowl and make appropriate ducting.  I guarantee that you don't want to use the thickest-narrowest rad you can fit.  That would not cool well at all.

--
David Leonard

Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net ------=_Part_6673_30388331.1195182880465--