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P47 take offs.

I have just received a new edition update from Aces High Gallery in Buckinghamshire for Richard Taylors “Days of Thunder” picture.

I have a question.

The picture features P47 Thunderbolts of the 78th Fighter Group taking off with a belly tank and a bomb under each wing.

I have watched a step by step take off procedure in a wartime film and seen P47’s taking off in modern videos. None of these had any flaps down during their takeoffs.

In Richard’s picture the three main aircraft have a degree of flap lowered, my thoughts were that the use of flaps would slow the aircraft down.

Has Richard got this right?

Brian.

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By: pimpernel - 6th March 2008 at 23:50

Any idea of the supposed date of the picture?

Spring 1944.

Brian.

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By: Moggy C - 6th March 2008 at 22:28

Any idea of the supposed date of the picture?

Grass runways tend to get soft in the winter when it’s wet. This would suggest the use of flap for take off. Gets the weight off the wheels sooner.

Moggy

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By: k12479 - 6th March 2008 at 21:59

Conversely, modern P-47’s are probably a bit lighter without armour, lighter radio’s, etc.

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By: pimpernel - 6th March 2008 at 20:42

Thanks for the replies.

I now had time to scan a portion of the brochure showing the flap position.

http://i9.photobucket.com/albums/a90/pimpernels/Jug.jpg

If I am in breach of copyright then please let me know and I will remove it.

Brian.

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By: bazv - 6th March 2008 at 19:49

A little bit of flap also lowers the stall speed thus giving a better safety margin when heavily loaded.Bomb equipped P47’s had quite a few take off accidents when flying from Advanced Landing Grounds in GB.
Perhaps combination of pilot inexperience and short and rough runway surface – usually steel mesh/plank or similar .

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By: mike currill - 6th March 2008 at 16:34

True but I was actually trying to remember the ‘combat’ setting which I remember was only in single figures, just can’t remember the exact figure. I’m almost certain it was 7 degrees but can’t be sure without my books to hand.

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By: Mark V - 6th March 2008 at 16:16

For the P-51 the manual reccomends 15-20 degrees of flap on take-off for ‘best obstacle clearance’!

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By: mike currill - 6th March 2008 at 16:08

With that load on board it’s going to suffer anyway I would think.

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By: galdri - 6th March 2008 at 16:06

It is very likely accurate. With a heavily loaded aircraft, the use of take off flaps will shorten the take off roll considerably, particulary on aircraft with a high wing loading like the P47. However, the climb rate after take off will suffer a bit.

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By: mike currill - 6th March 2008 at 16:03

Not sure about the combat flap setting for the P-47 but I know there was one on the P-51 and also, I think, the P-38. IIRC the combat setting on the P-51 was 7 degrees.

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By: Ant.H - 6th March 2008 at 15:57

I would imagine that with a heavy load and a limited runway length, a certain amount of flap would be advisable to generate extra lift. If I remember correctly, the P47 has three pre-set flap positions; the first ‘combat’ setting to help the aircraft turn more tightly, then a take-off setting and then the fully extended/landing position.

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By: mike currill - 6th March 2008 at 15:53

Application of a little flap will give increased lift for little increase in drag. Given the loading you describe the chances are that the advantage of the extra lift outweighed the disadvantage of the extra drag. So there is every possibility that the picture is accurate

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