Interesting idea..... internal Jet with pop up pipe

Noise? No problem. It is in the air, and you are
on the ground with your remote control transmitter!
But seriously, could it be any worse than a Caproni
A-21J?

Cooling? All in the inlet. You would have to bring
in not only enough aire for the jet, but also to help
in circulating the air to dissipate the heat. Use
the exhaust as the power source for a jet pump to help
in drawing the surrounding air out of the cavity.

Bending the tail pipe? Man, will you ever loose out
big time on thrust. But in a model that will typically
have orders of magnitude more thrust than a full size
plane, you can loose half and still look pretty good.

Best bet is to stick it out into the breeze. It is
small and won't add that much drag while it is being
started. Ask Bob C about how much his Silet performance
degrades with the jets out but not running. Measureable
and noticable, I am sure, but nothing like hanging
an engine and 5 foot diameter prop out there!

But, an interesting thought.

Steve

EGT temps are monitored by an ECU on board. Guessing 600 degrees or
more. The problem with this install is not so much the tailpipe
design but the inlet design. Where did they hack a inlet for this
turbine? The tank is right in front of the turbine inlet so the
efficiency of this one is probably pretty lousy but enough to get it
up in the air. Most of the turbines are 10 to 17lbs thrust which is
more than enough for a 4 or 5meter salto.

A better way to go is like this: http://www.letmodel.cz/sls22.htm