Hi Ken,

thanks for writing....

First - the muffler question...... go here
http://www.rcuniverse.com/forum/fb.asp?m=3495337
(thread regarding the 60LX, but its the same sorta info)

You will not break that engine unless you break a prop and have a full throttle shaft run. Worry not.

The Patriot is a quick plane, but it is also a big plane - lots of surface area - it does not fly at 140-160 mph like the Q-500 planes (and a few others). Some of the q-500 props end up spinning their wheels so to speak - they do not work all that well on an aircraft like this.

Turning 17,900 is actually about where you want to be - maybe a little bit on the high side for the standard jett-stream muffler. Prop selection anywhere from 17,000 to about 17,500 is ideal. Launch it about 500 rpm down from there.

On the patriot you need more prop than you are running now. Load the engine down a bit more.

The 8.8x9 or 8.8x9.25 is a good place to start with the D-1 props.

The standard blade APC 9x8 and 9x9 are also popular choices for the Patriot. Many folks fly those.

Bob