TAKING OFF WITH FLAPS
 

Would it be fair to say that using flaps on take off (flaps down) would allow a model take off in less distance. Have just set up a GP Stick 60 with flaps and have only experimented using flaps on landing only, with a bit of wind I can land vertically from quite a height, the plane literally floats down!

RE: TAKING OFF WITH FLAPS
 

Yes, but full flaps is not necessary. 10-20 degrees of flaps will increase mostly lift while going further than that will increase mostly drag which you don't necessarily want on take-off. Next time you fly on an airliner you can observe that they only use about 10 degrees for take-off. Only planes with ground clearance limitations on the tail, such as the Dornier DO-335 Pfeil use full flaps because they cannot rotate enough on take-off. I hope this helps...
Brad

RE: TAKING OFF WITH FLAPS
 

On that model- quite effective - even down to almost 90 degrees!
The full scale comparisons are not very good because they have far less power - relatively and are very heavy -relatively
The little FunCub by Multiplex is a case in point - two small flap positions -about 20 degrees and about 85 degrees -
full throttle creates a extremely short take off and with no trim inputs a 75 degree fuselage attitude -
rolling flaps back to zero the model then requires a big dose of down elevator to pitch over to level flight.
On landings I use coupled flaps and elevator - (down elevator) - this allows for a very high sink rate which needs throttle app to prevent a pancake.
Flaps be fun!
PS the wheels are correct scale for the plane

RE: TAKING OFF WITH FLAPS
 

I could'nt agree with Brad anymore.They are Helpfull for lift on take-off But, to much Flaps on take-off will Hinder you getting up to airspeed and the plane might take off at an uncontrollable airspeed.And they do slow your airspeed quite alot in the full down position almost allways when landing.You also may need to set flaps at les than full down on windy days when you have to actually Fly it in all the way to touchdown.Hope I Helped Good Luck

RE: TAKING OFF WITH FLAPS
 

Fierce consensus Dick, but you should even try a Multiplex radio... :D

A bit more serious, using ailerons as flaps (flaperons) makes for severe adverse yaw, even if the plane floats. On a stick-type model (which doesn'nt really need flaps), I'd rather use up ailerons (spoilerons) to diminish lift for a steeper and more controlled (by power) approach - for landing. For take-off, you may use flaperons but models are usually so overpowered that they take off in a ridiculously short distance, anyway.

RE: TAKING OFF WITH FLAPS
 

I have the quad flap option on my Ultra Stick, but it isalso quite overpowered. I use full flap for takeoff just for fun, it will taxi about 10' and go almost straight up. Do be careful of takeoff speed, flaps do create a lot of drag.

RE: TAKING OFF WITH FLAPS
 

Just to elaborate a little on the last post. With (full scale) lightplanes that have flaps, standard practice is not to use them for takeoff unless you need to because your runway is too short for a safe takeoff without them. No point in creating extra drag unless you have to. But most of our models, especially sport models, are so greatly overpowered that a little extra drag won't hurt. Do what's fun.

RE: TAKING OFF WITH FLAPS
 

The Multiplex would do the same thing if I was setting it up
My new camera plane has flaperons (and spoilerons ) -ala the glider setups - basically a knob trim for the flapperons

RE: TAKING OFF WITH FLAPS
 

Real flaps increase the coefficient of lift greatly and the AOA during take-off, making the same wing's area lift more at the same velocity or lift the same (weight of the plane) at slower velocity.

The roll distance to reach certain velocity is a direct function of the thrust minus drag.

Flaps increase drag, increasing the distance at which the old take-off velocity (no flaps) is reached.

However, as the take-off velocity with deployed flaps is lower, the take-off roll distance with moderately deflected flaps is normally shorter than without flaps (for the same thrust force).

A caveat: the flight velocity with deployed flaps is lower than the flight velocity with flaps off; hence, velocity must be increased while flaps are turned off, or the wings will be unable to sustain flight.

This article explains it better:

http://www.airdock.cz/doc/teo/flaps.pdf

RE: TAKING OFF WITH FLAPS
 

Power however must increase for same velocity-
The model airplane shows this much more clearly and easily .

RE: TAKING OFF WITH FLAPS
 

Right. I misread this the first time. Thought it said your "velocity" had to increase with flaps deployed.

RE: TAKING OFF WITH FLAPS
 

If you want to really knowho they work- set up a model and use em-
all the formulas and atricles and textbook stuf -is nice as a background
Until you do it -you really don't know squat about it. One of the big problems today with our multi jillion fighters etc.,which are now mothballed (rust etc.,) is that the shoools are turning out experts with no practical background. Is this my opinion?. no- I heard it directly from a friend who writes the tests for engineering/physics at some of the top schools in the country.
If you want to hear a real thought provoker - get him going on the value of the space programs
One of the biggest wastes of money ever .
Not politically correct, to be sure -

RE: TAKING OFF WITH FLAPS
 

"Would it be fair to say that using flaps on take off (flaps down) would allow a model take off in less distance?"

Yes.

Simple question, simple answer (no formula) :)

Link to real life (no formula):

http://www.youtube.com/watch?v=9WPb5k4-HnY

Link to practical use of STOL (Short Take Off and Landing) by experts with much practical background:

http://www.youtube.com/watch?v=bPSEl...eature=related

RE: TAKING OFF WITH FLAPS
 

The bush pilot setups are same as the model airplane setups
Lots of flap and some of these guys use NO2 injection on the modified Lycoming engines .
In my case , I have model weighing 40 ounces with a motor pulling over 400 watts on full throttle
You should try it -nothing beats doing it, for fun!

RE: TAKING OFF WITH FLAPS
 

When I was a Kid I had a control line Nobler It gave reverse flaps with elevator.Meaning Flaps went Down when Elevator went up. And Up when elevator went down.It responded very good in loops and inverted loops.Have'nt seen it on any R/C.s Though?

RE: TAKING OFF WITH FLAPS
 

I use it - on very small model -
the radio is setup to give flaperons -one switch
then flaps only in two positions - on another switch
This works extremely well for short landings /takeoffs
The model weighs 40 grams including battery
fully porportional with exponential and coupled controls as desired
Working with these new tiny setups are a boon for experimenting - cost is minimal and you actually see what can be done -
You can't beat experience

RE: TAKING OFF WITH FLAPS
 

If you are really looking for a good two motor setup with one channel control- these are plentiful
just buy any outrunner and appropriate ESC , plus a y harness to plug into your motor channel.
The power you wan will befound using any 150/200 watt setup (per motor) - batteries are now available for little money ($15.00 Lipo in 30 c configuration)
You can easily duplicate the arrangement in larger sizes -up to 10,KW -very easily.

RE: TAKING OFF WITH FLAPS
 

Thats exactly what I need.I will get back to you soon Thanks Alot