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From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-321463@logan.com>
Subject: Re: [FlyRotary] Re: New Scoop
Date: Wed, 14 Jul 2004 15:49:28 -0400
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Steve,

    I personally would not like to see things exceed 200F Max for WOT cruise
for any extended time.  Your temps do seem a bit high to me for 55% power.
I think you can do better.  My ideal is 180F for both oil and coolant - that
is just my personal preference, not to say there is anything magical about
it or that problems will happen if you exceed that.  But, I just would not
feel comfortable (that all important comfort zone {:>)) with temps exceeding
200F for long periods of time.  I think 200F is a reasonable boundary - but,
that is just my opinion.  others will have a different and equally valid
viewpoint.

Ed

Ed Anderson
RV-6A N494BW Rotary Powered
Matthews, NC
----- Original Message ----- 
From: "Steve Brooks" <steve@tsisp.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Wednesday, July 14, 2004 3:19 PM
Subject: [FlyRotary] Re: New Scoop


> Ed and John,
> I understand that if I have adequate cooling at cruise, it will not enable
> me to do an extended climb while keeping temperatures down.  At his point,
I
> seem to have enough cooling to allow me to do a reduced power (55% or so)
> cruise.  And that is with temperatures toward the upper end of the scale.
>
> If I can get a 75% power cruise with oil temperature of 200-210 and
coolant
> of 190-200, I'll be happy.  I need to improve my cooling temperatures by a
> good 10-15 degrees to accomplish that.
>
> Is that a reasonable objective, or am I trying to hit a target that is too
> low ?  It seems to me that 217 oil and 200 coolant is a little on the high
> side.  And that is at about 55% power.
>
> If my objectives aren't right, it would be really easy to just raise the
> target.  In fact, it would make my day.
>
> Steve
>
>
>  -----Original Message-----
> From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]  On
> Behalf Of Ed Anderson
> Sent: Wednesday, July 14, 2004 2:43 PM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] Re: New Scoop
>
>
> > Sorry to harp on this Steve. I just have a feeling that you're working
> hard
> > to get the temps lower than they really need to be. If you want minimum
> drag
> > at cruise, then the temps SHOULD be marginal on a hot day take off and
> > climb. So... get the gear up and back off the throttle till you get in
> > cooler air at cruise speeds. If necessary give it a rest half way up, or
> use
> > the technique of doing a long approach to cool off before climbing that
> > someone described. If it'll cool ok at full power at cruise height, then
> > you're in good shape. My 2c.
> >
> > John
> >
>
> Steve, I have to agree with John on his main point.  Any cooling system is
> going to be a compromise.  If you design and tailored your cooling system
> for cooling in a steep climb on a hot day, you will have excessive cooling
> capacity at cruise (read - more cooling drag) than is necessary.  On the
> other hand if you do optimize for cooling at cruise (min cooling drag)
which
> is the way a lot of Canard types do as that is one of the reasons for
their
> choice of aircraft type - high cruise speed, then you will be somewhat
short
> of cooling capacity needed for take-off/climb.  Things like cowl flaps can
> help in some cases, but like everything else with an aircraft has benefits
> and draw backs - its all a flying compromise.
>
> So as suggested you can moderate power and/or  airspeed during the climb
> portion to get through that heat gauntlet and then be set up for lowest
> cooling drag at cruise.
>
> Also, keep in mind, you are probably flying in the hottest time of the
year,
> so if it will cool adequately now, it will be fine the rest of the time.
>
> However, if that does not fit with your comfort zone, then you will simple
> need to keep plugging away until you get the conditions you are
comfortable
> with.
>
> Ed  Anderson
>
>
>
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