REFLECTOR: Cooling

[michalk]

First order of business would be to retard mag timing before trying to 
fix baffling.
10:1 compression on an IO360 is pretty tough on detonation margins.

Ron Brown wrote:
>  
> I met Dean a couple of weeks ago and have looked at his Velocity's 
> engine installation.  It appears to be well built and well thought out 
> with very good attention to detail.  The IO360 engine has angle valve, 
> cross flow heads - intake ports on the bottom and exhaust on the top.  
> The builder installed a really nice set of baffles which appear to have 
> very little leakage.  It has cylinder wraps on the top side which have 
> an opening of about 1" to 1 1/2".  The exhaust pipes are routed to a top 
> center cowl exit with an augmenter configuration.  I have seen these 
> cylinders on a twin engined plane which also had an upflow engine air 
> cooling arrangement.
>  
> Everything looks good to me other than the gap at the cowl exit to M/T 
> prop seems excessive at 3-4".  My own Velocity (Catto prop and downdraft 
> NACA cooling) works very well with cruise CHT's in the 320-340 degree F 
> range.  I have my CHT alarm set at 360 and seldom ever reach it.  My 
> cowl to prop gap is more like 1" (recommended by Alan Shaw a long time 
> ago).  I don't even have any problems with long taxiing in hot weather 
> and attribute this to the prop effectively sucking hot air out of the 
> engine and cowl.
>  
> Dean's CHT's (they are mounted on the top side of the cylinders) are 
> running close to 400 degrees F in cruise.  I think the high compression 
> 10:1 pistons are contributing to this but still am of the opinion that 
> closing up the cowl to prop gap would help a lot.
>  
> Any thoughts and experiences from the Reflector gang would be greatly 
> appreciated!!!!
>  
> Ronnie Brown
> 173 Elite RG IO360 and Catto Prop
> http://home.sprintmail.com/~romott/  
>  
>  
> 
>     ----- Original Message -----
>     *From:* Naomi and Dean Unterreiner <mailto:naomi at yadtel.net>
>     *To:* Reflector <mailto:reflector at tvbf.org>
>     *Sent:* Sunday, October 22, 2006 4:47 PM
>     *Subject:* REFLECTOR: Cooling
> 
>     I purchased a standard retract with an IO 360 high compression & 225
>     HP. It has updraft cooling via two scoops mounted to lower cowl. It
>     runs a bit on the hot side. Any one done any cooling research for a
>     similar situation as mine?
>      
>     Dean Unterreiner
>     N74BC
> 
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