It's a 32 oz (950 cc) Dubro tank. It's a bit of a squeeze to get in, you have to put it through the cockpit opening sideways & roll it over once inside.

There's a thread on the model here: http://www.rcuniverse.com/forum/m_4588799/tm.htm

Probably better to post plane questions there. Mostly IC stuff but a bit of turbine talk. See you over there! - John.