REFLECTOR: Exhaust systems

Mike Pollock reflector@tvbf.org
Wed, 9 Jul 2003 23:05:28 -0500


The best way not to cook your prop is to get it further away from the
exhaust.  This can be done with a longer extension or changing where the
exhaust is dumped out.  We chose the longer 8" extension and we have never
burned a prop.  We do have a little soot, but no burns in 620 hours with an
IO-360 with 3-blade Performance propeller.

I guess some are lucky and some are not.

Mike

-----Original Message-----
From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On
Behalf Of Ronnie Brown
Sent: Wednesday, July 09, 2003 7:12 PM
To: reflector@tvbf.org
Subject: Re: REFLECTOR: Exhaust systems


Not only true with the M/T but also any three bladed prop.  No way to clock
it such that it misses the exhaust, even for 4 cylinder IO 360's.  No
pictures but I saw with my two beady little eyes a Velocity and a Cozy, both
with 360's, both with Performance props, both had charred spots on one blade
of the prop, looked like a wooden match that had burned, then extinguished.
Not pretty.  The Velocity prop was returned to Clark, he pronounced it dead
and unusable.  A two blade can be turned such that it misses, but as someone
mentioned, there are only two positions that a three blade can be installed,
both incur the wrath of the 1400 degree exhaust.

I have a three blade Catto and forward exit exhausts.  No soot on the prop
but some on the cowl.

Ronnie Brown
173 Elite RG 55 hours


----- Original Message -----
From: "Tom Martino" <tmartino@troubleshooter.com>
To: <reflector@tvbf.org>
Sent: Wednesday, July 09, 2003 4:01 PM
Subject: RE: REFLECTOR: Exhaust systems


| So is the conclusion truly that we cannot have a dual rear exiting exhaust
system with an MT prop because it will damage the blades?  That is a major
disappointment.
|
| -----Original Message-----
| From: Pat Shea [mailto:xl340hp@yahoo.com]
| Sent: Wed 7/9/2003 1:45 PM
| To: reflector@tvbf.org
| Cc:
| Subject: Re: REFLECTOR: Exhaust systems
|
|
|
| --- Jim Agnew <jim_agnew_2@yahoo.com> wrote:
| > All of this talk about cooking props yet I have not
| > seen any pictures of a charred or burning prop.
| This
| > sounds a lot like an urban legend.  Does anyone have
| > some pictures?
| >
| > Jim
|
| No pics but...
|
| Rodney Brim and the late Steve Drybread made a
| serious attempt at a rear exiting exhaust for Rodney's
| XL (IO-540 w/ 3 blade MT and I think one EI). They
| tried many different configurations (pipes exiting out
| the existing cowl openings, pipes exiting back thru
| lower & outboard openings, pipe tips turned out...)
| but were unable to prevent the exhaust from damaging
| the blades. Steve did have success getting a similar
| engine/exhaust combination to work on the Berkut, but
| since they run a 2 blade fixed pitch prop there are
| multiple clocking positions. There are only two
| positions for clocking the MT on this motor.
| Also, Scott Swing briefly tried a Berkut style rear
| exiting exhaust on the XL prototype (IO-540 w/ 3 blade
| MT) and blistered the prop.
|
| Pat
|
|
|
|
|
|
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