Where are the Mythbusters when you need them?

[Spin]

I went googling after Nev's comment above on the 727 slat issue - I didn't realise it was such contentious territory, having read an essay on the whole schemozzle many years ago and understood that the whole thing had been put to bed. Not hardly... I see it was TWA Flight 841.

 

 

[facthunter]

B727 flaps.etc

 

When you have a hydraulic failure you CAN extend the flaps electrically, with switches, incrementally. IF you then restore the hydraulic power, all the flaps will run to where the flap lever is selected. By flap 5 ALL LED's should be extended, This is checked on all extensions by observing the lights indication. There have been lot's of incidents with these flaps. There is nothing wrong with the system as it is, when operated normally, and in accordance with the manual.

 

The connection with this thread is that when you slow down or reach somewhere near the highest cruise height that you would use, You don't use reflex flap. In between those two limits there is excess wing capability, and you could get a gain by trimming the wing. ...Nev

 

 

[Spin]

, and you could get a gain by trimming the wing. ...Nev

Is that established fact Nev? That was the point of my posting the incident in the first place, because quite a lot of the evidence before the NTSB was to the effect of "BS, what trimming and what benefit??"

 

 

[facthunter]

Conjecture?

 

In the Boeing you have a VERY accurately made, state of the art wing. I wouldn't attempt to improve it by fiddling with flaps. It also has a very high critical Mach number. Going to the highest safe cruising altitude is the way to go with this sort of aircraft. My statement is a general one not relating to High altitude capability. Once most aeroplanes such as the ones we fly are airborne, cleaned up and cruising along, they could do with a bit less wing, certainly if they are lightly loaded, and the wing is meeting the airflow at a low angle of attack. It is my understanding that the "reflex" flap and aileron set-up can reduce parasite drag in these conditions. The only aircraft that I have flown featuring this is a Murphy Rebel and it is only used when cruising. I have not done tests so the advantages are in the category of "claimed".. Murphy do build/design some reasonable aircraft of their type, but I am only going on their word. Nev