Not too many '47's ever burnt, I know of two out of a very large number over a thirty year period when they were used extensively right across Northern Oz by a number of companies. One hit the ground so hard that it had to burn, another back in '71 or '72, an American pilot in the Kimberlies WA, we never really worked it out but reports were that he was on fire before he hit the ground..
Heliduck that training pilot of yours (not BC by any chance?) suffered from the same problem that VF does, A stigma based on blaming the goods instead of the poor training as many have indicated is the main problem. And as I have reminded him before, plenty of those plastic tanks squirrel turnouts have burnt to a cinder of late.
I could up until recently have shown you about thirty '47 wrecks, not one of which lost the fuel tank mounting integrity or were ruptured.. So, yes definitely he was dribbling utter bulloney. We on the other hand viewed the Hillier with very much the jaundiced eye with their history of engines and xmon's complete crashing thru the cabin over the centre mounted pilot and then burning with the ruptured belly mounted fuel tank. That is how one dude got killed not far from here in fact back in '76..
The thing most of us worried about in a '47 was the stab bar coning down to take the top of one's head off, however that seems to have been merely hypothetical also, as I can't recall any that did..
I don't dispute at all that R44's suffer badly in mainframe distortion upon a severely heavy arrival, even when the skids are level, but I know of only a very small number of R22's that have burnt and they were ONLY those that arrived so hard and fast that they had to burn and there was no hope at all for those on board. Even so we constantly see many examples of terrible crashes in R22's where there was no fire, the one in England a bit more than 12 months ago being typical..
The reason I don't like the R22 for a trainer is that it's tight RRPM limits and low inertia system don't allow a trainee to have time to make a mistake and then still have time to realize / recover before the instructor has to rescue it. Even the Hughes is much better in that regard.