Just curious as I move to larger size warbirds as to using flaps on take-off. Do you?
Pat

Flaps aren't always required for take off. A few degree's of flap can reduce the take off roll but if you're not careful you can get into a stall situation much quicker. In other words easy on the elevator if you use flaps on take off. A lot of full size aircraft (warbirds) didn't use flaps for take off unless they where fully loaded. Pilots manuals for any particular aircraft can lend a lot of info there.
[&:]

I agree with post #2. Always best to gain as much speed as possible before going into a gentle climb out, best way to avoid a stall on takeoff. More speed and a nice gentle climb out also gives you better odds should the engine decide to flame out.

Flaps provide additional lift. If you have a heavily wing loaded warbird it is sometimes advisable to take off with some flaps. Flaps increase the amount of lift to your wing without increasing the angle of attack of your wing. If anything your wing develops more lift at a lesser angle of attack, thereby decreasing the probability of a tip stall. As the two previous writers noted, be gentle on the elevator because you can increase the angle of attack by applying too much elevator and climbing out at too steep of an angle. A friend of mine has a 40 pound PMC ME 109 and he regularly takes off with flaps applied.

I have recently started using about 10 to 15 degrees of flaps on takeoff with my 30+ pound Byron Hellcat. I have found that takeoff and climbout is far more steady using them. The climbout remains shallow and when good altitude is reached, I dial the flaps back to zero. Works great for me.

Someone step in here if I'm wrong, but doesn't taking off with flaps usually increase the chances of a tip stall? While I do agree that in the hands of a well seasoned warbird pilot this shouldn't be a problem, but taking off with flaps is usually gonna put the plane in the air at a much lower airspeed than normal. This in turn would seem to set up the possibility of a tip stall should the wing become out of level as the rest of the wing is not really flying yet. Any aileron input at that point would likely make the situation worse.

No, quite the opposite. Flaps increase the local camber at the root area of the wing, which in turn increase the local angle of attack. Meanwhile the wingtip is at a lower angle of attack than the root, making tips stalling much less likely. The slight downside is that flaps also increase drag, albeit take off flap of circa 15% amounts to only a slight increase. Nontheless, heaving the nose up too high on the climb out is slightly more likely to induce a stall since the model will decelerate a little more quickly than when clean. However, this is only likely to be noticable on a marginally powered model.
The prevoius advice is good. Use flaps and be careful of the elevator. Allow the speed to build up and clean the gear away quickly.
Also, the rudder has a part to play in scale models. smooth coordinated turns are unlikely to cause a tip stall whilst slipping or skidding turns can and do lead to tip stalls.
I hope this helps,
Regards,

john.

Using flaps for take off on swept wing aircraft like the F86 is very helpful. The full scale F86 used 50% flap for take off. I found that 50% flap reduces the extreme angle of attack that is normally needed at rotation to get the swept wing to fly at lift off. They have the same impact on landing, they reduce the high angle of attack needed to keep the swept wing flying at landing speed. Of course with full flap on landing more drag is added to slow the Sabre on the glide slope.

Using flaps on takeoff is a good idea because their use LOWERS the STALL SPEED. RC pilots fly visually without the aide of an airspeed indicator. As such, they often accelerate the plane on takeoff beyond the speed needed to fly, then apply elevator. The aircraft may be traveling at 1.2 to 1.5 times the stall speed. In hot weather the same visual runway speed may yield an airspeed below that needed to maintain VMC (velocity for minimum control). That is why more stall accidents occur on hot humid days than cool days. Air that is less dense causes the wing to develop less lift, the propeller to be less efficient, and the engine to develop less horsepower. Couple that with no headwind down the runway and it often spells disaster for someone who yanks their plane off the ground because they have passed the point of no return. Now, flap use on takeoff would increase the safety margin by lowering the stall speed so that on the takeoff roll, the aircraft would accelerate past the stall speed sooner and thus would prevent more stalls from occurring, all other things being equal.

In regards to rudder use, most would find it surprising that using the rudder instead of the ailerons on takeoff as well as on the landing flair, helps to prevent stalls. At low airspeeds near the stall speed, as one wing drops, opposite aileron initially creates drag and adverse yaw. The increased drag may stall the wing at that point causing a snap. Using opposite rudder however, will cause the lower wing to accelerate, develop more lift, and level the wing.

Happy flying,

Frank