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From: Steve Brooks <prvt_pilot@yahoo.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Remove Turbo
Date: Thu, 15 Jun 2006 09:51:57 -0400
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Message-Id: <200606150951.59081.prvt_pilot@yahoo.com>

Thomas,
You could design a cooling system for extended climb, but you would be adding 
significant drag to the aircraft.  There is only so much you can do with cowl 
flaps.  

I believe that most builders (and also most certified aircraft) design cooling 
for cruise, and tolerate temperatures climbing somewhat in climb.  There do 
have to be tolerable limits, however.

I'm afraid that if I built my cooling system to maintain temps on an extended 
climb, at full power, on a 95 degree day, I would have much cruise speed when 
I leveled off.

I've seen several discussion on this group, where people leveled off for a 
while, or reduce power and go to a cruise climb, in order to let thing cool 
back down.  

On my aircraft, the oil temperatures are fine, but coolant is marginal on hot 
days.  On a 95 degree day, I could only get to about 2000 feet AGL before my 
coolant temperature was at redline.  Leveling off and reducing power, cools 
it down, and then I can increase power and continue climbing at a cruise 
speed.  

I have some more gains that I can make on mine cooling system by making 
improvements in air flow.  Currently I have some dead space below the 
radiators which I'm sure allows some air to roll back out.  I also have a 
couple of spots that are allowing air to leak through, which I need to fix as 
well.

Steve

On Wednesday 14 June 2006 09:30 pm, Thomas y Reina Jakits wrote:
> ""
>
> > While it doesn't make sense to try to have sufficient cooling for climb,
> > I think that I can still make some air flow improvements and get a little
> > better cooling.
> >
> > Steve ""
>
> Steve, what makes you think/believe that!?
> I always assumed that one would design/plan for the worst case scenario:
> Slow/steep/pro-longed max power climb....
>
> You always can close the flaps/louvers (streamline/reduce drag) when you
> change into a less severe regime.
> But what good is a 250hp engine if you can't use it for more than 2 min....
> I would at least want a 5 min limit for T/O-power. As Rotaries go, they
> will hold up fine with max power for cruise/racing/etc. fine too - but if
> you can't cool it.....
>
> What if you are in line on really hot day? You might not even get 2 min of
> max power.
> I would rather err on the wild side of cooling - you always can cut down
> and close off, once you know your ride...
>
> TJ
>
>
> --
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