Ive got one with 190 exhaust timing , 110 trans. ! ( corrected . YES ! 190 ! Ex . ) just a trifle of overlap .
Sceptre Flight tests show other figures . As there were outboard & who knows what else .!
I think it was Lew woolard , at some time , did custom ' STUNT ' K & B ' SR II 's , with CUSTOM P/L assys .
So anyone out there with a F I R E SR II K & B set up for CONTROL LINE , has a iota of a chance it is a C / L stunt engine . though unlikely unless it is .
As youcansee , there a 20.000 rpm peak engine. Stock .Tho thats a 6.5 . 7.5 is similar .
Some of the 8011? ABC 40 parts interchange . Like rods maybe . These the R C & C/L arnt diferant internally . so both do for C/L .
There were a few differant rods in the SR II s as prolonged high rpm operation could throw early skinny ones .
Intresting, MY 7.5 came with a 6.5 head . And will chunter along slow & steady on a 11 x 7 !!!!!!!!!!!!
Though havnt done more than a few flight , so cant coment as to if it'd ' run away ' . But if it did youd think it'd be to olympic sprint standards .
My feory is the fuel / charge - up insideb the gap outside the chambers pulled down & feeds the second half of the downstroke .
Some vauge disimilarity to the bathtub lean burn tecnology, vaugely .