=20 Ed True enough, but most rules don't change until supersonic flow enters = the picture.=20 The turn vanes look remarkably like the vanes in the compressor = section of jet engines.=20 In all cases the losses would be lower at the lowest possible speeds.=20 Would there be any savings in drag, if the size of the inlet openings = could be changed along with the cowl flap openings? My friends Bonanza = has plates that fit into the inlets for winter operation, as just closed = cowl flaps are still too much cooling.=20 Lynn E. Hanover=20 I agree, Lynn most rules do not change. However, making air turn at = different velocities can be a factor that is affected. A curve that = will turn air with minimum turbulence at 10 mph velocity may create = severe turbulence at higher velocities. From what I read, the Reynolds = number plays a key role in boundary layer interaction on surfaces even = when not supersonic. On the other hand, since 99 % of what we do is at = the eye-ball engineering style - any examples is bound to be helpful. Ed ------=_NextPart_000_000C_01C7A1E3.488E1E30 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

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

Sent: Tuesday, May 29, 2007 = 10:54=20 AM

Subject: [FlyRotary] Re: = Cooling=20 Recommendations

In a message dated 5/29/2007 10:31:53 A.M. Eastern Daylight Time, = wilenius@sympatico.ca = writes:

Be aware that HVAC ducting is generally not = dealing=20 with air flows that they have to slow down from 160 + MPH. = While I do=20 not pretend to be HVAC knowledgeable - the environment and = conditions are=20 different - that is not to say there may not be good ideas there - = just a=20 different environment.

<snip>

Ed

True enough, but most rules don't change until supersonic flow = enters the=20 picture.

The turn vanes look remarkably like the vanes in the compressor = section=20 of jet engines.

In all cases the losses would be lower at the lowest possible = speeds.=20

Would there be any savings in drag, if the size of the inlet = openings=20 could be changed along with the cowl flap openings? My friends Bonanza = has=20 plates that fit into the inlets for winter operation, as just closed = cowl=20 flaps are still too much cooling.

Lynn E. Hanover

I agree, Lynn most rules do not = change. =20 However, making air turn at different velocities can be a factor = that is=20 affected. A curve that will turn air with minimum turbulence at = 10 mph=20 velocity may create severe turbulence at higher velocities. From = what I=20 read, the Reynolds number plays a key role in boundary layer = interaction on=20 surfaces even when not supersonic. On the other hand, since 99 % = of what=20 we do is at the eye-ball engineering style - any examples is bound to = be=20 helpful.

------=_NextPart_000_000C_01C7A1E3.488E1E30--