I can place a 15k Geiger battery at the front. Dimensions 442mm/284mm/85mm. There is still enough room for the feet underneath. It protrudes a little from the fuselage, like a small petrol engine! If this does not pose a connection problem, this would be the best solution for the balance. We would thus have at the front a load of about 20k, (battery + electric motor), like a petrol engine. And there might not even be a need to move the wings back!