The first P-38, about 70 inch span, crashed in level flight after a 180 turn from takeoff. Probably poorly constructed.
The next 2 were large Ziroli's. The first of these died when throttle control was lost on one engine, which couldn't be turned off.
When the other engine quit, it rolled over and died.
The 2nd died due to one engine failure.. same thing.
Outthrust on a larger airplane is certainly something to consider, but if you're into scale, only the Ju-52 and Sunderland used it!
P-38s, Mosquitos, Comets... all poor choices for models which are not electric.
Speed must be kept up to maintain directional control.
Some means of engine cutoff isn't a bad idea. This could have saved the Zirolis, had a seperate remote kill-switch been available to the experienced pilots stuck with flying those.
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Before and after..