X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from nk11p08mm-asmtp003.mac.com ([17.158.58.248] verified) by logan.com (CommuniGate Pro SMTP 6.0c2) with ESMTP id 5805978 for flyrotary@lancaironline.net; Wed, 10 Oct 2012 20:11:15 -0400 Received-SPF: pass receiver=logan.com; client-ip=17.158.58.248; envelope-from=steveizett@me.com MIME-version: 1.0 Content-type: multipart/alternative; boundary="Boundary_(ID_dmVzoQoGbyUi8Rgm8iuaEw)" Received: from [10.1.1.6] (58-7-133-152.dyn.iinet.net.au [58.7.133.152]) by nk11p08mm-asmtp003.mac.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Jan 3 2012)) with ESMTPSA id <0MBP002FWCHNA990@nk11p08mm-asmtp003.mac.com> for flyrotary@lancaironline.net; Thu, 11 Oct 2012 00:10:39 +0000 (GMT) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.7.7855,1.0.431,0.0.0000 definitions=2012-10-10_06:2012-10-10,2012-10-10,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 ipscore=0 suspectscore=0 phishscore=0 bulkscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=6.0.2-1203120001 definitions=main-1210100322 From: Stephen Izett Subject: Re: [FlyRotary] cooling airflow concepts Date: Thu, 11 Oct 2012 08:10:38 +0800 In-reply-to: To: Rotary motors in aircraft References: Message-id: X-Mailer: Apple Mail (2.1278) --Boundary_(ID_dmVzoQoGbyUi8Rgm8iuaEw) Content-type: text/plain; CHARSET=US-ASCII Content-transfer-encoding: 7BIT Thanks Tracy. So given the right inner and outer radius', do you believe creating a circular inlet over the current trapezoid shape? My concern with the current shape is that the largest area of the inlet is towards the hub. Steve Izett On 10/10/2012, at 9:54 PM, Tracy wrote: > Hi Steve, out here in Colorado again with limited access to internet. Somewhere in the archives is the report I did on the inlets. They were based on a NACA study which mainly defined the optimum inner and outer radius for the inlets. I found it made a very big difference in capturing off axis airflow (climb attitude and prop wash) . The difference between the raw tube inlet (like a huge pitot tube) and the radiused inlets was very noticeable, especially in climb. They were at least a factor of 2 better at capturing the prop wash in static conditions as measured by pressure at the face of the heat exchangers. > > Tracy > > Sent from my iPad > > On Oct 9, 2012, at 11:45 PM, Stephen Izett wrote: > >> Thanks Steve >> I wonder if Tracy is lurking and can comment on the value of reworking the cowl inlets? >> >> Cheers >> >> Steve Izett >> On 10/10/2012, at 1:32 PM, Steven W. Boese wrote: >> >>> Steve, >>> >>> I am not the right person to try to answer your question. Having retained the stock Van's cooling inlets for the coolant exchangers with essentially no diffusers, the result appears to be marginal cooling and high drag. So I am asking myself the exact same question. >>> >>> Steve Boese >>> RV6A, 1986 13B NA, RD1A, EC2 >>> >>> >>> From: Rotary motors in aircraft [flyrotary@lancaironline.net] on behalf of Stephen Izett [steveizett@me.com] >>> Sent: Tuesday, October 09, 2012 6:39 PM >>> To: Rotary motors in aircraft >>> Subject: [FlyRotary] Re: cooling airflow concepts >>> >>> Thanks again Steve >>> >>> My current snout looks similar to the attached image. >>> I'm considering going to the trouble of reworking the cowl into two circular duct openings, keeping them as far from the centre of the prop as possible. >>> Current opening is approx 7'' x 3'' - 21sqin. >>> Tracy I believe uses (Water Side) 5 1/4" so - 21sqin. >>> Multiply Tracy's by 2/3 (loose a rotor) + a bit for the extra side exhaust energy (Renesis) going into the coolant - say 15sqin's or 4 1/2 inch diameter. >>> The other attached photos are modified Glasair snouts >>> What do you think I should consider given the amount of work involved and the possible improvement factored in? >>> >>> Cheers >>> Steve Izett >> --Boundary_(ID_dmVzoQoGbyUi8Rgm8iuaEw) Content-type: text/html; CHARSET=US-ASCII Content-transfer-encoding: quoted-printable
Hi Steve,   out here in Colorado again with = limited access to internet.   Somewhere in the archives is the = report I did on the inlets.  They were based on a NACA study which = mainly defined the optimum inner and outer radius for the inlets.   = I found it made a very big difference in capturing off axis airflow = (climb attitude and prop wash) .  The difference between the raw = tube inlet (like a huge pitot tube) and the radiused  inlets was = very noticeable, especially in climb.   They were at least a factor = of 2 better at capturing the prop wash in static conditions as measured = by pressure at the face of the heat = exchangers.

Tracy

Sent from my = iPad

On Oct 9, 2012, at 11:45 PM, Stephen Izett <steveizett@me.com> = wrote:

Thanks Steve
I wonder if Tracy is lurking and = can comment on the value of reworking the cowl = inlets?

Cheers

Steve = Izett
On 10/10/2012, at 1:32 PM, Steven W. Boese = wrote:

I am = not the right person to try to answer your question.  Having = retained the stock Van's cooling inlets for the coolant exchangers with = essentially no diffusers, the result appears to be marginal cooling = and high drag.  So I am asking myself the exact same = question.

Steve = Boese

RV6A, 1986 13B NA, RD1A, = EC2

 

 

From: Rotary motors in aircraft = [flyrotary@lancaironline.net] on behalf of Stephen Izett [steveizett@me.com]
Sent: Tuesday, October 09, = 2012 6:39 PM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Re: cooling = airflow concepts

Thanks again = Steve

My current snout looks similar to the attached = image.
I'm considering going to the trouble of reworking the = cowl into two circular duct openings, keeping them as far from the = centre of the prop as possible.
Current opening is approx 7'' = x 3'' - 21sqin.
Tracy I believe uses (Water Side) 5 1/4" so - = 21sqin.
Multiply Tracy's by 2/3 (loose a rotor) + a bit for = the extra side exhaust energy (Renesis) going into the coolant - say = 15sqin's or 4 1/2 inch diameter.
The other attached photos are = modified Glasair snouts
What do you think I should consider = given the amount of work involved and the possible improvement factored = in?

Cheers
Steve = Izett 


= --Boundary_(ID_dmVzoQoGbyUi8Rgm8iuaEw)--