REFLECTOR: Re: stainless exhaust length

["Al Gietzen" <alventures@email.msn.com>]

Fine Points of Exhaust Exit

Aiming the exhaust outward from the cowling causes drag (somewhat more
energy lost than that required to accelerate the intake air to airplane
speed).  It also affects prop efficiency by causing turbulence (and heating)
of the air into the area where the blades are most efficient.  So, if
possible, you'd like to have the exhaust exit rearward, and near the root of
the prop blades where they aren't doing much anyway.

Of course it is not always convienent, and there may be other
considerations; like heating of the prop.

Just thought you'd like to know.

BTW; I guess you'd have to carry duct covers for those big SUV ducts.  I'd
hate to park it where it might collect some ice and snow.

Al Gietzen  RGE 755V
-----Original Message-----
From: David Brown <velcty@earthlink.net>
To: reflector@awpi.com <reflector@awpi.com>
Date: Monday, April 26, 1999 8:09 PM
Subject: REFLECTOR: stainless exhaust length


>I was looking at David Parrish's great photos of the SUV and noticed the
>stainless exhaust out of the cowl.
>
>I too have the stainless exhaust for an IO-360 Lyc.
>
>I noticed on the SUV that the exhaust stack was cut off approx 1-2 inches
>below the cowl. If I cut mine to approx 2 inches below my cowl I could
>remove / install my cowl much easier.
>
>Is shortening the stainless exhaust something that many of you are / have
>done?
>
>Thanks
>
>Dave Brown
>