REFLECTOR: Cooling

[Ron Brown]

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 
  To: Reflector 
  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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