In answer to questions, I had to place the batteries forward because the DLE 20 is lighter than the OS 120 FS. Also info re power was incorrect. I flew the Hurricane today and with engine broke in and cooler weather it tached at between 8,900 and 9,000 rpm with the 15-8 three blade Graupner prop. The 120 turned it 8,250. With it unloading in the air it could be turning over 10,000 rpm which I think is too much. So I may put on a longer prop, maybe a 16-8-3. I didn't rebuild the firewall on either one, but did reinforce the Hurricane's