Is the cox 0.49 engine throttle or non-throttle?

Typicaly non-throttled. The ones without an intake in front of the cylinder are simple reed valve engins that are typicaly throttled, although poorly, by exhaust restriction. They also have a TeeDee line that have a throttled carb in front of the cylinder. It's a large metal block with the typical lever on one side and needle on the other.

Which is not to say that all Tee Dee engines are throttled. They will say so specifically if they are, or state that they are for R/C, not C/L.

The only Cox engines currently being made are non throttled. I have seen Cox TDs as small as the .010 that do very well with the exhaust throttle.

So how do we stop these engines?Do we use nitro fuel?

The engine runs until it is out of fuel, or you do something dumb like stick your hand in the prop.(I have done that)
After it stops you make a dead stick landing. You need "1/2 A fuel" for the cox engine. I use Byron's 1/2 A fuel. 1/2 A means .049-.061 size.
It is 25% nitro and 16% castor oil. I add more castor oil to make it 20%.

Originally posted by daryl
....Do we use nitro fuel?

To clarify....

You CAN run them on lower nitro fuel but they will typically run very poorly, unevenly and with low power. They don't really work well until you use 15% nitro and they really sing with the 25% suggested already. For sport flying or training where you don't mind a bit less power 15% is OK.