Unknown propellor

Came late to this. Nice one Mark12. Just to add, in any normal flight condition the force on the props will be in a forwards direction, as an equal and opposite reaction to thrust. It’s only if the prop is already acting as a brake – a negative angle of attack (not pitch) – that they would be pushed backwards. A stopped/windmilling prop, or one that can’t attain sufficient pitch to match forward speed. Much more likely the former!

…thanks Mark12 .. i do now understand how the efforts of the prop are far outweighed by the drag of the frame…Cheers

It will be dependent on the speed of the aircraft hull relative to the water and the power setting and RPM of the propeller and its pitch.

At high power as the propeller enters the water it will bite and try to churn forward but be restrained at the hub by the drag of the fuselage. The blades in consequence will bend forward at the tip.

Low power settings, fine pitch, high entry speed and the blades will bend back.

Mark

Agreed. Interesting physics…think about it.

…reading about the phenomenon has always fascinated me…can anyone please explain the physics behind it ?

Blades under power, on striking water, get bent forward,

Anon.

Agreed. Interesting physics…think about it.

Blades under power, on striking water, get bent forward, which is why I suggested the scenario of the late pull-out.

All conjecture, of course.

Anon.

Keep in mind the direction the blades get bent during belly landing / ditching depends on whether the prop is producing thrust (bent forwards) or just windmilling (bent backwards), so the scenario suggested by Anon in post #3 is very plausible.

If you assume the aircraft cartwheeled after, say, a wingtip touched the sea, then it is possible that at least one of the engines was actually moving ‘backwards’ in relation to a nominal ‘line of flight’ at the time it contacted the water. You might, I suppose, get a similar effect if the tail was shot off – the rest of the airframe would then tumble in the vertical and could enter the water backwards as a result.

Thanks guys, I have also asked on AiX and the question of the prop bent the wrong way is discussed on there too.
http://www.airfieldinformationexchange.org/community/showthread.php?15251-Unknown-Propellor

Thanks for your help so far

Cheers

Rich

I’d agree that it’s probably a Hercules engine but it looks like the blades are bent forwards rather than backward.

Yes, probably Beaufighter. Obviously under considerable power and aircraft reasonably level when the prop struck the sea. Maybe the aircraft concerned was pulling out after a diving attack and didn’t quite make it.

A few pics of the hub might be useful.

Anon.

It’s a Bristol Hercules propeller…..so it could well be Beaufighter! 😉