It's lithium ion. Better information than I can give is available through Duralite batteries and Fromeco.

They are larger than li-pos and are in their own can instead of a thinly wrapped case. Energy density is relatively high and need to be regulated down to 6 volts, as would a li-po. Much better than nicad or nimh batteries, IMO.

The final dollar cost will vary tremendously depending on how you set up the plane. I went to the high side using all JR 8611 servos, Matchboxes, dual aileron servos, redundant batteries with adjustable regulators, and a 105cc twin engine. Without being specific, the final cost of my 35% Giles was double the final cost of a 28% Edge or Extra. It could be done for much less than what I put in mine. It could also be done at a higher cost.

Talk to Ralph at RCIGN1 about the GT80. I'm certain that he can provide you with some solidly accurate information about how to get the most out of the engine. I'm not going to suggest any one engine or manufacturer over another. In the 80cc and up sizes, most all of them are good, with some being better than others for certain tasks. It will come down to what you want to do with the plane to determine the engine size and type. I like 3D along with normal and IMAC type aerobatics, so a larger engine is usually required for this purpose.

There's nothing wrong with being new to giant scale and gassers. Few have started in the larger sizes. Did you receive the pictures that I sent you?

Pat