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747 Variable Camber Flaps

Blackbird From , joined Dec 1969, posts, RR:
Posted (11 years 7 months 2 weeks 7 hours ago) and read 2695 times:

How exactly do these work?

How do they bend like that?

Any good diagrams of them?

Do they form a slot (a gap between the wing and the flap) like slats do? Or do they just increase camber forward of the wing?

Why didn't the 747 use Slats?

Anyone can answer these questions, I'd be really grateful,

Thanks,
Andrea Kamarov

10 replies: All unread, jump to last

Western727 From United States of America, joined Jan 2007, 579 posts, RR: 4
Reply 1, posted (11 years 7 months 2 weeks 7 hours ago) and read 2627 times:

What I'd really like is an answer to my Obstacle DP question, oh ye 345.1 hour instrument rated pilot.

747-400buff From Australia, joined Jul 2001, 43 posts, RR: 0
Reply 2, posted (11 years 7 months 2 weeks 4 hours ago) and read 2617 times:

Hi Andrea

The L/E flaps (midspan and outboard) on the 747 are really quite ingenious in their design and construction.

The (inboard) Krueger flaps are not V.C.

The others though, are stowed FLAT under the Leading edge of the wing. As they are extended, the mechanics of their design forces them to bend (their highly flexible) and so create a FALSE or NEW leading edge infront of the existing one......its amazing to see this in operation....

I believe there IS a seal between the flap and the exisiting L/E.....its attached to the flap and touches the exisiting LE as it reaches its fully extended position.

Yes I have many pics and schematics (I own about 6 GENUINE Boeing maintenence/technical manuals each of about 500 pages of juicy info).

You have me talking about my favourite subject...(flaps gear and engines of the 747-400.

UNFORTUNATELY I have NO SCANNER.....but I am working on that issue. If you wish to keep in touch I'll try and zap you something privately on this issue.

Finally I have recently purchased a large model of my beloved 744. I have cut off all of the L/E and T/E flaps (they were modelled in the UP position) as I intend to rebuild these from scratch depicting this A/C in a landing configuration....."flaps 30" position......no small task I assure you.

Kind regards
Dave Hollingsworth
Perth
Australia

Panman From Trinidad and Tobago, joined Aug 1999, 789 posts, RR: 0
Reply 3, posted (11 years 7 months 1 week 6 days 22 hours ago) and read 2587 times:

Might I also mention that it's an absolute BASTARD to wind the leading edge flaps out by hand when doing a change of the motor. About 6 weeks ago I had to change one on one of Virgin's 744s and I can tell you I swear my wrists were swollen to twice their normal size - and then hold them their while they were rigged to their proper extended position.

Panman
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WhalePilot From United States of America, joined Jun 2001, 91 posts, RR: 0
Reply 4, posted (11 years 7 months 1 week 6 days 13 hours ago) and read 2570 times:

747-400 buff, you need to get a life!
Yes I have many pics and schematics (I own about 6 GENUINE Boeing maintenence/technical
manuals each of about 500 pages of juicy info).

747-400buff From Australia, joined Jul 2001, 43 posts, RR: 0
Reply 5, posted (11 years 7 months 1 week 6 days ago) and read 2548 times:

Whalepilot

Somebody has asked a legitimate comment, I am simply endearvouring to answer it.

As for the manuals..........I am studying aviation mechanics, so ummm i guess it is my life.

Finally, your comments only serve to reinforce what I've heard about the arogance of (some of) those, who work in your profession.

Regards, ANYHOW
Dave Hollingsworth

Musang From United Kingdom, joined Apr 2001, 754 posts, RR: 7
Reply 6, posted (11 years 7 months 1 week 5 days 9 hours ago) and read 2522 times:

On a related subject, I'm still searching for enlightenment on the design, purpose and application of the Trailing Edge Wedge concept, tested, I believe, on a 747 among others.

And of what material are the 747's LE flaps constructed?

Regards - Musang

VC-10 From United Kingdom, joined Oct 1999, 3677 posts, RR: 37
Reply 7, posted (11 years 7 months 1 week 5 days 8 hours ago) and read 2523 times:

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Panman,

Why would you have to wind out the LE's by hand to change a LEFDU ? If the Drive Unit is inop pneumatically the flaps can be extended electrically. Apart from which to get at the LEFDU the LE's have to be already extended. Additionally once the drive shafts have been diconnected from the drive unit the LE's can pushed by hand.

VC-10 From United Kingdom, joined Oct 1999, 3677 posts, RR: 37
Reply 8, posted (11 years 7 months 1 week 4 days 10 hours ago) and read 2490 times:

Musang,

The 747 LED's are made from Glass Fibre Reinforced Epoxy Laminate

Panman From Trinidad and Tobago, joined Aug 1999, 789 posts, RR: 0
Reply 9, posted (11 years 7 months 1 week 3 days 12 hours ago) and read 2457 times:

Since it would appear that you dont believe here's a summary of what happened:

- The aircraft came in to clear a deferred defect on the #1 LEFDU which could not be operated pneumatically.

- We extended the flaps electrically and then pulled the CBs, the APU was also flagged inop so that we could work on the flap drive in safety.

- We took out the three bolts that connected the unit to the aircraft, removed the two screws that held the translating sleeve in place, slide the sleeves back and removed the motor (after removing the two electrical connectors of course).

- Gravity demanded that the #1 and #2 LE flaps hung down in a near vertical position.

- We attached the new motor to the aircraft and reattached the two electrical connectors.

- Please explain how it is physically possible for two men on a lifter can now push out by hand a very heavy leading edge flap so that I can do it next time. As I am sure you are aware that the flaps have a very nice scissor joint arrangement to them which has to also be overcome in addition to the weight.

- In this event while the certifier i was with pushed on the flap I wound the lime green drive shaft by hand until the flaps were in an almost rigged position (compounded by the fact that the shaft was greasy). This is a very long process as you would know that for every full rotation of the shaft the flaps moved linearly by a very very small amount. I appreciate the speed with which that motor spins after doing this.

- I then held the flap extended (by the drive shaft) while the certifier attached the rigging rod to the aircraft with the rod extended to the correct length for the flap we were working on.

- It was then necessary for me to either release the pressure or wind out the flap some more in order to get the flap into the correct rigging position (I believe i released the pressure for flap #1 which was extended to much - and wound out the #2 flap which was not extended enough)

- While i held on to the drive shaft the certifier slid the translating sleeve over the spur gear at the end of the flap drive shaft and over the gear on the flap motor.

- The two screws were then placed into the translating sleeve and wire locked.

- The CB's were then reset and the inop tag removed from the APU.

- While I was downstairs on the headset the certifier function checked the motor to ensure proper operation.

Panman
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VC-10 From United Kingdom, joined Oct 1999, 3677 posts, RR: 37
Reply 10, posted (11 years 7 months 1 week 3 days 6 hours ago) and read 2439 times:

Panman

OK, OK I believe you.

I read your original post as implying that you had to wind the LE's out completely to change the LEFDU. I will also agree the Krugars Flaps are heavy to move. The last motor change I did was a Variable Camber Flap on the line at LGW. The flap was easy to push into the correct position, I suppose because it was over centre for the sissor mech. I must say though that I would have thought it easier to hold the flap in position by holding the flap LE rather than gripping the shaft.

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