Another close up view of the exhaust gizmo.
This picture was taken by me at OSH 2000.

Charlie, how come you did not streamline the exhaust pipes?

Charlie is obviously attempting to create a vortex using the exhaust gases

inside

the augmentor tube with this gizmo. A vortex would have an extremely low

pressure at

its core. There appears to be a lot of potential here and I would really

like

to see a pressure survey all over the inside of this device.

Paul Lamar

Looks to me like he is trying to both muffle the exhaust, and use the Coanda
(sp?) effect on the center body. The Coanda effect is used to draw air
around a body by blowing a high velocity jet across the surface of the body.
You can actually make air turn 90 degrees by doing this. Think of the air
blowing through the slot of a Fowler flap for a visual. Streamlining the
tubes might help some, but the velocity should be rather low in the duct
after the radiator, but every bit helps! I would also like to see a pressure
survey on the duct. One problem with using a submerged inlet is that it is
not ideal for pressure recovery. That is why I have been advocating the P-51
style inlet, with a Kucheman and Webber streamline diffuser to the radiator.
The nozzle and venturi throat can all be calculated pretty well if you know
the temp of the exhaust, volumetric flow, and speed you are flying at. The
main thing not known is the pressure drop across the radiator, which is
dependant on the heat transfer characteristics, as well as how much heat is
rejected, and the geometry of the radiator. A lot of variables.

Monty

 
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