William wrote:

I agree that the issue is old, with one exception.

The fact that the tape got hot at idle/taxi speeds, but that the VAM

drew

well at flying, higher power settings is significant. I would interpret

this

to the need for significant gas momentum in the exhaust stream to be
required in order to create the suction on the inner tube.  At low rpm,

the

momentum doesn't doesn't overcome the pressure drop in the outlet tube,

and

some exhaust comes forward, giving the 'exhaust smell, and hot tape'
observation. At high power/rpm, the momentum of the exhaust creates a
negative pressure sufficient to cause a '45 mph' flow on the pitot tube.

We should use this information in any further changes to the design, to

make

it work even better.
Bill Schertz
KIS Cruiser # 4045

I totally agree but we must address the idle problem. Best way to do that
is have the VAM intake totally open to the forward cowl surface either

mounted

on a Coot pylon or a metal pipe connecting the VAM intake to a metal

opening

at the front surface of the cowl. Probably difficult to achieve with cheek

mounted radiators.

Paul

******************************************************************************

I too agree with Bill.....

With that said, here's my take and give on this, coming from a complete
different outlook.....Since the VAM is basically a Tangential muffler with a
built in Blast Tube why not just SHUT the Inlet to the VAM while Taxiing
(Shut-off the Blast tube) and just simply let it function as a true and tried
Tangential muffler (Idle power=Lower temperature), then as you fire up on the
runway OPEN the Inlet to the Tangential (Turn on the Blast Tube) and the
Tangential assumes the VAM's role (Higher power=Higher temperature).

This will shield the Engine compartment of excessive exhaust fumes etc.

a simple manually operated Sliding Gate or Butterfly can be employed.

This will increase the Life span of the muffler and allow the Vam Muffler to
be used on Tractors also....What say you all??

Butch

You need to read all messages Butch :) Dave McCandless came up with the same idea
and beat you to it :)

Paul Lamar
 
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