=20 My cooling system now seems well (if not optimized) matched to my = current installation. Full power take offs on hot days see my cooling = temps elevate to 200F for oil and 210-220F for coolant. Once I hit 120 = MPH IAS the cooling system catches up and starts to eliminate the = cooling deficit. =20 At my normal retired-man cruise of 7- 8 gph, my coolant and oil range = from 155-170F depending on OAT. When I push it to my max fuel = flow/power 10.5-12.5 gph at altitude the temperatures of both increase = until they are in the 190-195F range. This gives me my maximum true = airspeed. So it appears my cooling capacity is about right where I = need it. Certainly a surplus at low power cruise, but just adequate on = take/off climbout on hot days and adequate for full boogie flight. I really don't know how much drag (if any) I have eliminated, but I am = convinced that it is less than if I had more of the core exposed to high = velocity airflow. =20 Sorry, I can't be more definitive about it - I would like to know as = well, but only so much time to get all the wonderful projects on my list = done. Perhaps someone with the inclination and time will someday put = this idea in a wind tunnel and tell us {:>) Ed =20 -------------------------------------------------------------------------= ----- AOL now offers free email to everyone. Find out more about what's free = from AOL at AOL.com. ------=_NextPart_000_0008_01C790D3.6386B420 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable =EF=BB=BF

Thanks, Bill

That's what this list is all about - = sharing the=20 good, the bad and the ugly. Hopeful, such discussion (regardless = of=20 outcome) aids others to develop a fuller understanding of some of the=20 complexities involved.

Yes, I am looking forward to somebody = who is able=20 to cram a full up streamline duct into his installation. That = should give=20 them best duct airflow, pressure recovery and cooling. You may be = the=20 first!

----- Original Message -----
From:=20 wrjjrs@aol.com
To: Rotary motors in = aircraft

Sent: Monday, May 07, 2007 3:47 = PM

Subject: [FlyRotary] Re: = Pinched=20 Duct

Ed, It=20 does really sound like you have a good handle on things. Truly for = best=20 efficiency you want to run a bit hotter. Most of the cars now use = 180=C2=B0F=20 thermostat and many 190=C2=B0! They are after mileage for the CAFE = requirements=20 though. Lynn has mentioned several times that the best power range is = around=20 170 for the rotary and that sounds about right. The interesting part = is that=20 as you inprove your cooling your max power changes, usually towards = more,=20 thank goodness. I intend to have my radiators in a "cheek" position so = I can=20 run a longer wedge duct to them. Time will tell if this is any better = than the=20 evap cores. At least on the rotary you don't have as much stuff = blocking the=20 exit. We would all do well to consider that factor when designing our=20 setups.

I would really like to thank you Ed for your efforts to = help all=20 of us who come later to the party. Your chronicles of both the = good and=20 the bad will save many people from peril, THANKS AGAIN. Fly safe=20 and often!

Bill Jepson

-----Original Message-----
From:=20 eanderson@carolina.rr.com
To: flyrotary@lancaironline.net
Sent: = Mon, 7=20 May 2007 11:19 AM
Subject: [FlyRotary] Re: Pinched Duct

Hi Bill,

<SNIP>

My cooling system now seems well (if = not=20 optimized) matched to my current installation. Full power = take offs=20 on hot days see my cooling temps elevate to 200F for oil and 210-220F = for=20 coolant. Once I hit 120 MPH IAS the cooling system catches up = and starts=20 to eliminate the cooling deficit.

At my normal retired-man cruise of 7- = 8 gph, my=20 coolant and oil range from 155-170F depending on OAT. When I = push it to=20 my max fuel flow/power 10.5-12.5 gph at altitude the=20 temperatures of both increase until they are in the 190-195F = range. This=20 gives me my maximum true airspeed. So it appears my cooling = capacity is=20 about right where I need it. Certainly a surplus at low = power=20 cruise, but just adequate on take/off climbout on hot days and = adequate for=20 full boogie flight.

I really don't know how much drag (if = any) I have=20 eliminated, but I am convinced that it is less than if I had more of = the core=20 exposed to high velocity airflow.

Sorry, I can't be more definitive = about it - I=20 would like to know as well, but only so much time to get all the = wonderful=20 projects on my list done. Perhaps someone with the inclination = and time=20 will someday put this idea in a wind tunnel and tell us = {:>)

Ed

=20

AOL now offers free email to everyone. Find out more about what's free = from=20 AOL at AOL.com.

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