Moderators: richierich, ua900, PanAm_DC10, hOMSaR

 
Cathay744
Topic Author
Posts: 120
Joined: Tue May 25, 2004 3:06 am

Flap Setting

Fri Oct 29, 2004 7:40 pm

How much flaps would a 747-400 set for takeoff on a 4000 meter runway?
The Only Queen of the Skies 747.
 
dl757md
Posts: 1483
Joined: Mon May 24, 2004 9:32 am

RE: Flap Setting

Fri Oct 29, 2004 8:04 pm

I don't have access to 744 take off setting info, but someone who does would also need take off weight, ambient air temperature, and field altitude to answer your question accurately.

Dl757Md
757 Most beautiful airliner in the sky!
 
andrej
Posts: 1277
Joined: Mon Jun 18, 2001 8:31 am

RE: Flap Setting

Fri Oct 29, 2004 9:22 pm

Hello all,

as mentioned above there are many factors, as to what is TOW, wather, OAT, alt. of airport. However usually B744 has 2 T/o flap settings 10 and 20 degrees. It all depends on airline preferences.

The lower setting should give you lower V1, Vr and V2 speeds. But there are other disadvantages to this setting which I can not remember now.  Smile/happy/getting dizzy

Cheers,

Andrej Lippay
 
Mr.BA
Posts: 3310
Joined: Sun Sep 24, 2000 12:26 pm

RE: Flap Setting

Fri Oct 29, 2004 11:59 pm

To add on to what Andrej has said..

Flaps 10 would give a better climb performance on climbout and 20 would be otherwise. Takeoff roll for 10 would be longer and Vr and V2 would be higher as compared to flaps 20. Vr should stay the same.

 Smile
Boeing747 万岁!
 
wilco737
Posts: 7275
Joined: Sun Jun 20, 2004 12:21 am

RE: Flap Setting

Sat Oct 30, 2004 12:04 am

Hi there,

yes, Flaps 10 and 20 for the 744! And for example in FRA (4000m) runway I would guess you use 10, because higher flap setting you use when you are field length limited and if you are climb limited then you would chose a lower flap setting.

I only know it in the 737, flaps 1 on long runways, 5 for normal, 15 for short field and in the NG737 you can use 25 also, on real short runways!

The higher flap setting will give you more lift, so you can get airborne sooner (lower speed). But you have a poor climb performance because of the also higher drag of the flaps.
If you are climb limited, you use lower flap setting, and then higher speeds (V1,Vr,V2) and then you can climb a lot better (less drag) but you need higher speeds to get airborne due to the reduced lift...

I hope that answers your question

WILCO737
 
SlamClick
Posts: 9576
Joined: Sun Nov 23, 2003 7:09 am

RE: Flap Setting

Sat Oct 30, 2004 12:07 am

The generalities are as follows.

Small flap settings give you a long ground run and higher V-speeds but better engine-out climb performance.

Greater flap settings will shorten the ground run with lower V-speeds but engine-out climb performance will be degraded.

Other factors are:
Aircraft gross weight
Airport elevation.
Air temperature
Runway in use (length, slope, obstructions in the departure corridor)
MEL/CDL limitations or restrictions

We don't really set them for their affect on all-engines-operating performance, but with an eye to engine failure. That is because an engine failure scenario is usually what limits our allowable gross weight when it is less than maximum certificated gross weight.

I have a B-747 manual or two out in the garage and could look up some numbers but I'd rather someone who actually knows that airplane answer up here.

Where is B747Skipper when you need him?





[Edited 2004-10-29 17:11:24]
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
goboeing
Posts: 2580
Joined: Mon Jun 05, 2000 5:31 am

RE: Flap Setting

Sat Oct 30, 2004 2:31 am

From the B-747 sim that I flew numerous times this past summer, flaps 10 would be used. I don't have any charts in front of me but flaps 20 wasn't needed on the longer runways and lighter weights in general.

Nick
 
AJ
Posts: 2304
Joined: Wed Nov 03, 1999 3:54 pm

RE: Flap Setting

Sat Oct 30, 2004 2:58 pm

Some airline's SOPs dictate a specific flap setting, for example Qantas uses Flap 20 for all takeoffs on the 747-400.
 
Mr.BA
Posts: 3310
Joined: Sun Sep 24, 2000 12:26 pm

RE: Flap Setting

Sun Oct 31, 2004 10:55 am

Apologies, I meant V1 would stay the same from my previous psot not Vr. And SIA too, dictates only flaps 20 for all takeoffs on the B744s.
Boeing747 万岁!

Who is online

Users browsing this forum: No registered users and 11 guests

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos