Above The Clouds (your #1038 to
Stanwell),
I'd like, if I may, to clarify some points in your Post.
...Danny42C had, earlier in this thread, suggested that, in light of his experience with PT-17s, the prop could have inadvertently, prematurely been knocked into coarse pitch...
I think you may be referring to my (#926), in which I said:
...No engineer, I, just operated a Wasp Junior with similar prop for 70 hrs, so stand to be shot down by a real expert...
I should have elaborated. The PT-17 I flew at Primary School with the Army Air Corps was in standard fit with a 220hp Continental and a fixed metal prop. Then I moved up to Gunter Field in good ol' Alabam': they gave me a BT-13 Vultee "Valiant" (it was said that you needed to be valiant to fly it at all). This was reluctantly dragged through the air by a 450hp P&W Wasp Junior with a Hamilton Standard two-speed and it is of this I speak. I originally thought that this was the assembly fitted to the "Spirit of Artemis" (it was, it seems, the kit often put on postwar crop-sprayers, wing-walkers and the like). But I was wrong: "our" Stearman has a 9-cyl radial Lycoming of very similar appearance.
AFAIK what "Artemis" has is the R-680-E3A; Wiki quote:
...Specifications (R-680-E3A)[edit]Data from Jane's.[1]....Performance Power output: 330 hp (246 kW) at 2,300 rpm at sea level...
Nevertheless, I would think the (2-speed) prop would be much the same in both cases.
The 220hp PT-17 reckoned to take off in a 700 ft run (ground level). Even hot and high, I would have thought "Artemis" with 50% more power and in fine pitch would have got off comfortably in 7100 ft at Winston (in "coarse" it wouldn't have got off at all), as there would be no need to load any extra fuel for the short trip ahead.
Now to the "nitty-gritty": I cannot speak for the cockpit fit of the pitch lever in a Stearman, as I have never seen one. In a BT-13 it was on the left on the thottle quadrant (as are all the RPM levers on all the S/Es I've flown). IMHO, it would be impossible to "accidentally" knock the lever from full forward ("fine") to full back ("coarse"): the mixture lever came between throttle and "Pitch" anyway.
As for the incident: it would seem that the "Accident Investigation" was nothing of the sort, the wreckage was not examined; now it is all long gone, we have nothing to go on but the one indistinct photograph of the crashed propellor which drew my attention.
Cold oil in the prop cylinder ? RPM levers being pulled back to "min" for shut down ? Can't remember that at all. All I can say is that the Harvard constant-speed prop invariably went back to "min RPM" ("coarse") of its own accord on switch-off, and as soon as you cranked-up would revert to full fine, you could watch the cylinder (and bobs) move out as the blades returned to (max RPM) angle. No reason a two-speed would behave any differently (anyway it's just the same thing but without a CS Governer unit).
A BT-13 would always be kept in "fine" for climb until reaching cruise level, and then put back to "fine" for descent, approach and landing. So, if a cruising BT-13 cruised into a hillside, you would expect the prop (if it survived) to be still in the same mode "coarse" (and vice versa) in which it had just been flying.
Any chance of persuading Ewald to come on board and give us his take on this ? No ? Then we'll all have to forget it !
Rather long - but the devil really
is in the detail !
Danny.