takeoff flap setting

[plattsburgher]

I was interested to know if anyone had a reference for a general guidance regarding takeoff flap setting in any airplane. Obviously, the flight manual and the PIC are the guidance for a specific type and a specific flight when the decision is made as to the flap setting for takeoff. But is there anything from the FAA, or elsewhere, that makes some kind of general statement? Something like: "All other things being equal, the flap setting should be the largest/smallest, etc...."

Anybody ever seen anything like this?

Thanks

 

[Tooslow]

Nope, Sorry

 

[profile]

91.126 has a section that applies to large turbine powered aircraft, and through the various caveats, it applies to all U.S. operations under which Part 91 applies. My recollection is that it applies to landing, though, not takeoff.

 

[Donsa320]

This may help. When I had my Aztec and I was going up to a fishing spot on God's Lake, Manitoba I worried about denting things on take-off as it was a gravel strip. A high time Aztec pilot mentioned that adjusting the take-off flaps to a setting that was the same as the down aileron deflection would result in the best lift over drag. Of course engine out performance was going to be nil for a while after lift off. But it worked fine, no dents.

 

[JetBlast2000]

I can’t find the ref at present, but general speaking the first 50% of flaps gives you the most lift vs. drag while the second 50% give you more drag vs. lift. So I think this is your basic answer. The manufacturer determines specific flap settings. And I believe they set the flap degree based on the numbers they desire and part 25 and part 23 limitations. Hope that helps. Although I suspect you already knew all this…

 

[plattsburgher]

I didn't think there was anything out there written on this, but I just thought I'd ask.

Thanks for the inputs.

 

[Peanut gallery]

TO Flaps

Using flaps reduces ground roll, but decreases climb capability after liftoff. Runway problem use increased flap setting, Climb problem use decreased flap setting.

 

[FN FAL]

Using flaps reduces ground roll, but decreases climb capability after liftoff. Runway problem use increased flap setting, Climb problem use decreased flap setting.

I don't know, the caravan (empty) climbs at about 1,000 feet minute with or without 20 degrees of flaps. The only difference is indicated speed with the flaps is about 85-90 and without is about 115.

I would think that you are not limited in climb capability with flaps, or you wouldn't use em for short field takeoffs, where climbing off the field as soon as possible is desired.

 

[Lead Sled]

When it comes to turbojet operations...

The general rule of thumb is to use the least amount of flaps necessary for the existing conditions. For example, on our aircraft, we normally takeoff with slats and flaps 12; however, we will sometimes use slats and flaps 20 if the runway is short and slats and flaps 0 if the runway is long enough. (The less flaps you use on takeoff, the better your second segment climb performance is.)

Why is this important? FAA regulations require that transport category aircraft (both airliners and bizjets) be operated at a weight and with a center of gravity location that will allow them to achieve a certain minimum level of performance in the event of an engine failure during takeoff. The required performance level varies upon the terrain and obstacles surrounding the airport. However, the basic requirement is that in the event of an engine failure during takeoff, the aircraft must be able to either (1) stop on the remaining runway; or (2) continue the takeoff and clear all terrain and charted obstacles on the assigned flight path by a designated vertical distance. In other words, if an engine fails on takeoff, the aircraft must either be able to stop on the remaining runway or be light enough to continue the takeoff on the remaining engine and be able to climb to a safe altitude and return to an airport for landing – a guaranteed safe takeoff if you will.

Hope this helps you to understand.

'Sled

 

[Oakum_Boy]

Flap drag is why second segment climb performance is impacted. Basically the theoretical point where the gear is retracted all the way to the acceleration height, which is where the flaps will be retracted. You have better gradient during that period with a smaller flap setting. Slats only takeoffs will improve that gradient, due to the greater lift per unit of drag they create. Most airplanes though cannot do this because of the unusually steep deck angle created when slats only are used. Tailstrike becomes an issue.

 

[satpak77]

also...

be cognizant that "takeoff flaps" may get you airborne sooner, it (depending on airplane) will have an obvious affect on performance if you loose one engine after takeoff

like you said earlier, POH offers the correct guidance, also Flightsafety/Simuflite/NBAA/etc standards which are applicable for that specific airplane

later

 

[gear_guy]

My thoughts are:

If you've got the required runway....use it. (ie. less flaps)

Second segment has always been more important to me.

 

[pilotyip]

What type of airplane

If you are flying part 121, you need runway analysis. The runway analysis will dictate the proper flap setting for takeoff at a particular weight, temperature and for each specific runway.

 

[Long Time Gone]

This may help. When I had my Aztec and I was going up to a fishing spot on God's Lake, Manitoba I worried about denting things on take-off as it was a gravel strip. A high time Aztec pilot mentioned that adjusting the take-off flaps to a setting that was the same as the down aileron deflection would result in the best lift over drag. Of course engine out performance was going to be nil for a while after lift off. But it worked fine, no dents.

I'll second that one. I've got about 500+ in an Azwreck, and, although it's not in the POH, that flap setting does wonders for "short field" takeoffs. Besides, the flaps come up relatively quick (unless you're wrong engine out and have to hand pump them up).

LTG