REFLECTOR: Early model Velocity RG Engine Cooling

[David Smith]

Thanks to all for input, 
 
As to engine and mods, Lycoming IO360, don't know of any mods (fill me in) other than internal rudder bell-cranks. I am building new wings and will go with smaller lower winglets. As for cooling, I had thought about building a Carbon fiber plenum over top of engine and continue with the armpits unless they are inadequate. A top NACA to me seams to be aesthetically better but would it not need to extend forward onto the cabin roof to be effective? I am putting a smaller NACA on lower cowl for induction air. Is there a place that posts pictures and details of mods for these?
 
Thanks Again
David
 
Date: Tue, 20 Nov 2012 13:10:08 -0600
From: none <markinchampions at gmail.com>
To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
Subject: Re: REFLECTOR: Reflector Digest, Vol 92, Issue 46
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I have an OLD SCHOOL Std FG that was setup for a water cooled engine with the NACA scoops on the bottom. I am changing to a Lyc. 4 cyl. with possible updraft cooling. However, I may install NACA scoops on the top of the airframe as well and use the bottom scoops for ram air to the carb. Any thoughts from the group?


On Nov 20, 2012, at 12:52 PM, Willem Huisman wrote:

> Larry,
> 
> Armpitscoops with plenum and Franklin is what I have, and very,very
> low CHT as well.
> My previous Velocity had armpits with Lycoming and baffles, always had
> to battle high CHT.
> 
> In both cases however CHT temp probes are on same side where cool air
> is. You need to add around 50 degrees thet claim to derive to real
> CHT.
> 
> Still however, Armpit with plenum seems the best way keeping CHT low.
> I  planned top Naca , but Scott Baker convinced me to keep as is, and
> he was correct.
> 
> Wim Huisman
> N59WH
> 
> >> Date: Tue, 20 Nov 2012 12:12:40 -0600
>> From: "Laurence Coen" <lwcoen at hotmail.com>
>> To: "David Smith" <dwsmithaircraft at yahoo.com>, "Velocity Aircraft
>>  Owners and Builders list" <reflector at tvbf.org>
>> Subject: Re: REFLECTOR: Early model Velocity RG Engine Cooling
>> Message-ID: <SNT117-DS853B8BAC61073A417C89AD3550 at phx.gbl>
>> Content-Type: text/plain; charset="iso-8859-1"
>> 
>> David,
>> 
>> I have the armpit scoops and they work very well.  I have a Franklin engine with a downdraft plenum that is connected to the air inlets with 4" scat tubing.  This time of year I have trouble keeping my CHT above 200 F.  I made a modification to the scoops by adding an internal venturi to the scoops to enhance pressure recovery.  I think it worked pretty well since I blew a scat tube off one side of the plenum during 200 Knt flutter testing.  I make sure I get the clamps real tight now.  To get top NACA scoops to work, most find that they have to put vortex generators ahead of them.  IMHO the only reason for going with NACA's is they look cool period.
>> 
>> Larry Coen
>> N136LC
>> 
>> P.S.:  As a way to solve all your problems, you could buy my plane and go flying right away. :>)
>> 
>> 
>> From: David Smith
>> Sent: Tuesday, November 20, 2012 8:15 AM
>> To: reflector at tvbf.org
>> Subject: REFLECTOR: Early model Velocity RG Engine Cooling
>> 
>> 
>> I have bought and am rebuilding a damaged Standard Velocity RG. It appears it has gone through a couple of air inlet mods with the latest being under strakes at wing to fuselage corners. I am at the stage where I would like to incorporate the best cooling to drag design before paint. The baffling that came with the aircraft is all wrong for the flow in the cowl. I have looked and thought about differences between up-flow and down-flow cooling with down-flow being simplest with baffling, but with low air inlets being simplest at modification. Any suggestion or a point in where to go for info will be appreciated.
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