Fiery-it's about 2 years since I last ran it-and it had a DC 5-1/4 x 3-1/2 prop on it when I dug it out today. I vaguely recall it was quite a bit faster-not surprisingly-but harder to start- on that one. I'll make up some fuel 'according to Rustler' and do some more running. I have quite a range of suitable props. I don't think I've run it on the Cox 6x3 before-and this prop is a heavier load than some others. A few more tests will establish what it's happiest on. My VA Bambi is very happy on the same 5-1/4x 3-1/2 prop (originally produced for the 0.75cc DC Bantam!) so it is not inconceivable that the little Frog with 2/3 more displacement might turn something a bit bigger with authority........

ChrisM
'ffkiwi'