Hello. I am new to gassers and am building a 31% CA Extra. I have a nice 3W 75iUS engine for the front of it. My question is about tank position. Is it as critical as it can be on glow engines? The location I would like to put the tank would put the top of the tank about 2" above the carb with the engine inverted. The tank would be on the CG about 14" behind the carb.

I hope to be educated!

Dave

Also, does the location of the refueler valve matter? Thanks.

Makes no difference at all, and the filler valve can be anywhere in the line between the carb and the tank, just be sure it seals well when not fueling...A gasser carb will pump fuel at least 4 feet straight up..

As you are new to gas engines I would like to recommend using Easyflex tubing from Aerotrend. It never goes brittle and rarely leaks. Check out:

http://www.aerotrend.com/shop_subcat.php?subcat=4

Put the tank on the CG of the airframe and don't worry about height.

Rather than use a refueling valve, try a Fuel Dot type filler. Use a Tee in the carb line that has a hose to the outside world for refueling. But keep the refueling point above the tank so it doesn't drain out while you have the "cork" removed.

I kind of have a space issue inside my plane. If any of you had to choose, would you put the fuel tank, or the smoke tank on the CG? The fuel tank is 32 oz and I went with a 24 oz smoke tank.

Thanks for the great info!

Dave