Have seen people hide their batteries in the diorama that they've made and then used somekind of paint to carry the power from the battery....don't aske me how they did it or the name of the paint, I haven't the foggiest, was just like "riiiight"
Looking forward to your progress matey!
Make new contacts, different sized but same voltage battery in the drop tank. The drop tank removable and able to 'split' to change battery. Voila!
Or, forget it, and just leave the prop blades off!
Just get a thin clear disc, sand the edge thinner but not as thin as you run a risk of cutting yourself and then spraypaint blurred propellerblades on the disc to finish it off.....