Full Flap Take Off

[Guest drizzt1978]

So, I was watching the Big Rocks Long Props DVD series, and watching all the short take offs. Then i started looking a bit around on the net at videos. The practice in some aircraft is Full Flap, full power, for short take off, then up to one stage (1/2 flap) as soon as it is airborne.

 

Granted I have done emergency full flap take offs (ie, forgot to put them up during touch and go, or aborted landing etc etc)

 

My question is, does anybody use or teach a full flap takeoff??

 

I ask because the other day I did a short field take off on a very agricultural private strip, The JAB 230 wanted to get up... but almost bounced back down, and required some very rapid forward stick to keep her up.... (build air speed) And i got to thinking.... If she would have gotten up with a full set of flaps, and stayed up??

 

Don't want to start a slanging match, but perhaps I missed something in my short field lessons!

 

 

[Guest Baphomet]

My view is that you use whatever the aircraft operations manual tells you to use. Their published figures for performance, for various configurations are not a guess, they are actually based on a lot of test flying. In my case (Bantam), its full flap.

 

Baphomet

 

 

[nong]

Hey Driz

 

Its looks like fun to land a cub in the rocks at nil ground speed and to take off at Valdez in 79 feet.......yes, great sport.

 

You are looking at a lot of wing area lifting a bare bones airframe and sometimes with a big engine to add to the thrill. Hang on. Big wing? No weight? Isn't that just like a real ultralight and with the SAME RESULT in terms of field length required?

 

Theres no magic here, only the usual realities.

 

Big flap deflections will shift a lot of air downward and make a lot of lift for a given airspeed. This can only work when you have spare grunt to drag that exposed flap area through the air. Guess what? Old "Got Rocks" is a pretty light, stripped out Cub carrying no payload. The only flab on that Cub is the heavy bushwheel set up and "borer prop". He probably suffers fuselage cracking and has been pretty smart in running an uncovered structure.

 

So, what about professional Cub drivers carrying a real payload? It would be hard to go past the hard working agricultural pilots who inhabited Aus. and NZ in earlier times. Those PA-18A 135s and 150s were typically taking off at all up weights around 1000 to 1100 kg vs my quick estimate of 570 kg for " Got Rocks".

 

Ag pilots never used full flap for take-off because there was barely enough thrust to fly, let alone drag flaps through the air. "Got Rocks" has the spare thrust to drag the flaps because less power is needed to accellerate the lighter weight. I should also mention that the flap drag for a given setting is a lot lower at the slow lift-off speed of the lighter aircraft.

 

Cheers Nong

 

 

[motzartmerv]

Simple answer is no, you havn't missed anything.

 

The POH or flight manual will give you the "best" performance figures.

 

I would not reccomend using full flap for takeoff in any jabiru.

 

Sure the wheels will leave the ground earlier, but then what?, to climb properly you need to accelerate in more ways then one. The drag produced by the second stage (in a 160) is in excess (at low ias) of power available. So once back on the drag curve its difficult to get the wing flying properly without significant change in attitude ie pitch down, which at 5 feet obviously is not an option.

 

The cub is a fantastic acft to watch when set up for this type of thing, but, it aint a jabiru.

 

cheers

 

 

[Guest Walter Buschor]

Assuming you have enough power for a full flap take off ie: you're not in a Cessna 150 then it might be ok. There is more lift but there is also more drag. It will come down to the technique

 

used. If the plane is accelerated with the stick all the way back the nose will come up very quickly with a resultant big increase from high AoA etc. This is going to result in very slow acceleration and a slow climb at best or a stall at worst. If full flaps are used the climb out should/ must be shallow at fist until airspeed builds up and flaps can be retracted .

 

As long as a minimum speed take off is not followed by a steep climb all is well - if not - well things could get bad very quickly.

 

Walter

 

 

[Guest Howard Hughes]

The Twin Otter can do a full flap take off, not for the faint hearted though!:ah_oh:

 

The PA-32 can do a two stage (Flaps 25) departure!

 

Most LSA's have take off rolls of less than 400M, don't think there is any real need for full flap take off, high drag/low airspeed is

 

not a good combination!

 

 

[Guest drizzt1978]

Thanks guy I even had a Quick chat to the CFI today, He said very simillar things, just not enough power to over come the drag. He did say that he had seen guys dump an extra bit of flaps if they were slow getting off the ground.... But didnt suggest i mess with anything, he also said that hypothetically if you do try full flap take off, that you would be shocked at how slow the takeoff run was due to the drag on the flaps. Long story short leave it to maul guy and cubdriver...

 

 

[Guest ozzie]

The Twin Otter can do a full flap take off, not for the faint hearted though!:ah_oh:The PA-32 can do a two stage (Flaps 25) departure!

 

Most LSA's have take off rolls of less than 400M, don't think there is any real need for full flap take off, high drag/low airspeed is

 

not a good combination!

I had a full flap takeoff demonstrated to me in a Twin Otter when it was empty. Impressive to say the very least airborne in less than 100ft climbing in a nose down attitude. As soon as it was in the air you had to start retracting the flap in stages quickly to remain within the speed limitaions whilst at the same time trimming like mad to keep the control loads managable, the electric trim only just kept up with it whilst keeping a good eye on the power settings so as to not overtorque as the speed came up. Real 'leap tall buildings in a single bound' stuff. But definately not for the low time pilot. it takes a lot of training and skill to fly a Twin Otter to it's full potential. The guy who showed me had over 15,000 hrs TT with 10,000 in Otters nearly all in PNG.

 

Ozzie

 

 

[Guest Cloudsuck]

The technique I was taught on Super Cubs and Aviat Huskies (Standard 150 and 180 hp, two up), Is line up with no flap. Apply full power, once the tail is flying and airspeed starts to build, aggressively and swiftly pull on full flap. The aircraft will jump off the ground. Once flying, you then reduce to take-off flap and fly away. It is a well known bush pilot short field technique. I have done it many times and it works well on that type of aircraft.

 

Here is a video of it in application.

 

 

 

[MrH]

No electric flaps there :jump:

 

H

 

 

[johnm]

6 cylinders to ?

 

 

[Tomo]

Apply full power, once the tail is flying and airspeed starts to build, aggressively and swiftly pull on full flap. The aircraft will jump off the ground. Once flying, you then reduce to take-off flap and fly away. It is a well known bush pilot short field technique. I have done it many times and it works well on that type of aircraft.

Yep, that is what I was aware of as well.

 

 

[djpacro]

I'm sure that you guys would beat me in a take-off contest but when I was flying a Husky regularly I didn't see a need to do anything other than full flap, full power and keep the tail on the ground until it was flying. Not long to wait when its in the air in about 30 m or so at max weight.

 

The only time that I measured the ground roll myself was at max weight in a slight breeze at 8500 ft density altitude: 82 m (and still a frisky climb performance afterwards - some-one described it as a chandelle).

 

 

[Guest Howard Hughes]

Nosedraggers generally don't like full flap take offs!:ah_oh:

 

 

[Guest Maj Millard]

The normal take-off proceedure in the Slepcev Storch is with full flap (flaps on, only 2 positions, off or on) per the Storch POH. Obviosly the same for landing.......................Maj..

 

Below: Mmmm why is that control stick moving foward on it's own ????