Received-SPF: pass
 receiver=logan.com; client-ip=64.136.30.75; envelope-from=alwick@juno.com
To: flyrotary@lancaironline.net
Date: Sat, 2 Jun 2007 07:54:59 -0700
Subject: Re: [FlyRotary] RV-7a cooling - continued!
Message-ID: <20070602.080053.2788.1.alwick@juno.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
From: al p wick <alwick@juno.com>

Congrats on success!
With some minor changes to your vane supports, you could make it modular
and adjustable. I'd do that for testing. So you loosen screw and can
suddenly change fin spacing and location. Loosen another screw and you
can swap out fin with one of different shape or size. Great way to
optimize design. When optimized, then throw away modular device and make
your ideal one.


-al wick
Cozy IV powered by Turbo Subaru 3.0R with variable valve lift and cam
timing. 
Artificial intelligence in cockpit, N9032U 240+ hours from Portland,
Oregon
Glass panel design, Subaru install, Prop construct, Risk assessment info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html

On Thu, 31 May 2007 22:38:51 -0500 Dennis Haverlah
<clouduster@austin.rr.com> writes:
> I took out the first splitter/duct that was shown in my 5/27 posting 
> 
> photo 1678.  Cooling was than back to slightly marginal not 
> critical!
>  
> I than built a rig with 3 turning vanes to direct air into the 
> radiator 
> near the front of the wedge. (See attached photos)  I achieved about 
> a 
> 16 deg. F drop in oil and water!  This told me that most of the 
> inlet 
> air was going through the radiator at the small end of the wedge.  
> Bobby 
> Hughes said he had seen data indicating a wedge duct had the highest 
> 
> pressure near the end of the wedge and lower pressure near the 
> opening.  
> I now am considering modifying the lower cowl - inlet duct bottom 
> -to 
> include a curved ramp to direct air upward over the first 30 - 40 % 
> of 
> the radiator and than transition into a wedge the rest of the way 
> back 
> to the trailing edge of the radiator.
> 
>  I have not found any information I feel comfortable to use to 
> design 
> the curved ramp and may try to build a wind tunnel in the cowl on 
> the 
> plane. I should be able to insert several ramps and wedge shapes in 
> the 
> test area and measure air pressure on the back side of the radiator 
> 
> using a sensitive manometer.  I have two electric leaf blowers that 
> may 
> provide enough air to run it.  I'm planning on a 3 in wide x 4 in 
> high 
> inlet size.   Any comments or suggestions?
> 
> Radiator to Duct Sealing:
> My radiators are sealed to the duct with silicone baffle rubber 
> strips 
> used on cowl-to-baffles on spam cans.  I believe my seals are very 
> good.   But - after several E mails concerning sealing the duct I 
> looked 
> more closely at the total air flow sealing package.  On the Griffin 
> 
> radiator the fins between the tubes do not extend to the water 
> tanks.  
> There is gap of 1/4 to 1/2 inch!!  This is on both ends of the 
> radiator. 
> The area of the holes is  0.375 in X 12.5 in X 2 ends = 9.375 sq in 
> of 
> holes just in the one radiator!  The Mazda oil cooler also has gaps 
> but 
> they are only about 1/8 inch wide. I also found about 2 more sq. in 
> of 
> other potential leaks I can fill using Leons light testl   Thanks 
> for 
> the info. to make me look harder at this area!   If I get the wind 
> tunnel working I will first test with the holes and no ramp/wedge - 
> fill 
> the holes and retest to determine how much the holes decrease the 
> outlet 
> air pressure.
> 
> Air Speed in Duct at Radiator:
> The inlet duct is 51 sq. in. (per James Cowls) and expands to about 
> 
> 17.25 X 8.5 inchs or 146 sq . in. at the start or forward end of  
> the 
> radiator wedge.  This gives a velocity of about 42 mph for the 
> cooling 
> air at the front entrance of the wedge at the radiator at a climb 
> speed 
> of 120 mph.   The duct is a wedge from that point on the the rear of 
> the 
> radiators.
> 


-al wick
Cozy IV powered by Turbo Subaru 3.0R with variable valve lift and cam
timing. 
Artificial intelligence in cockpit, N9032U 240+ hours from Portland,
Oregon
Glass panel design, Subaru install, Prop construct, Risk assessment info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html