Throws

[Taff]

When you come by a model with no instructions i.e. control throws, CG etc...... where do you start ? I have seen plenty of info about calculating the CG but nothing about start points of throws for ailerons/elevator/rudder /even flaps . by this I mean where do you start with setting the control throws? sorry if I have missed a thread on this but cant seem to find any start points! Don't want to just guess and throw it into mother earth

Regards Taff

[Allan Bowker]

I've always found that most aircraft need very little throw for normal flight, it all depends upon the model and style of flying.

In your situation I would setup the radio with varying degrees of dual rates and expo.
Perhaps a 30degree regular mode and a 45degree emergency mode?
After the maiden flight, you could then adjust to your preference.

Do you have a photo of said model Taff?
Size, all up weight, engine/motor size, etc, might help other comments.

[Keith Evans 3]

Hi Taff

I can't remember which book I got this from but I seem to recall that a safe guide would be 20 degrees up and down on all moveable surfaces . I'm not talking about those wild beasts some people fly , but something more like a trainer , and for ailerons and elevator .

It was given in degrees as the width of the surfaces are variable from model to model and therefore to , the linear distances they will move from neutral .

I'm sure someone will correct me if this info is duff! !

[Bob Cotsford]

20 degrees sounds good to me too for initial flights. I tend to over control on maiden take-offs if there's a lot of movement available but this seems a good start point on most models I've flown.

[Dave Hopkin]

I would set rates and expo on the throws - 40% Expo and 20/25/30 for Lo/Med/Hi rates

[Dave Bran]

I'm fairly regularly asked to maiden models for people, and it always amazes me how little throws are usually set up , and far too often with no rates. I refuse to maiden until this is done.

OK, you can over control, but the plane will also be lost if the throws are so little that recovery from a particular situation is not possible. Because they are there, you do not HAVE to use them, this is called piloting!!

In the last year I have been twice unexpectedly handed a Tx of a plane in trouble or where the pilot has lost it, only to find that the throws are nowhere near enough, and not even available enhanced on a rate switch.

One classic a few years ago now was being called and handed without warning a Tx of a plane heading away and down a long way out of bounds across a tree'd road and into a visually dense tall woodland. I managed to keep it looping back into sight, but even aileron and rudder together were so tame on the single rate set that I could not half roll it enough to get away from the loop near the top in sight. In the end I just had to invisibly "level " it, cut throttle and hope. It was found several days later, luckily relatively intact and the £100 Rx survived.

So I say this...................ALWAYS set rates up, always with a high rate set for significantly more than you feel required, and smooth all rates out with expo.

My personal planes (of any type) are always set up with the switched possibility of max throws, as much as the chamfering will allow, and for a start 40% expo, though rudder often is set no expo. You can't use it if its not available!!

[Chuck Plains]

I would have said use at least 70% of the full available movement for a maiden flight. And if you don't have rates or expo, (budget tx) the pilot obviously takes that into consideration and ramps up their attention level.

[Cuban8]

Interesting points made by Dave. I have to say that I never recall ever having a model to test that lacked control surface movement. Beginners usually set the throws much too high in the mistaken belief that "more is better". Very often I've been told about a model that's "a real pig to land" and on inspection have found the elevator movement set way beyond that which would ever be needed and not a scrap of expo either.

Beware of the suggested settings given by ARTF manufacturers - for example, the throws given in the manual with my Hanger 9 P47 were excessive even on low rates - I doubt whether the full sized Thunderbolt ever pulled a square loop or would perform two rolls per second, so why have the model set to perform in such a manner? I've found 15 -20 degrees of surface movement is plenty to check out a model on its maiden.

I try to harmonize control throws so that (approx) 25% of total stick movement is used for general circuit flying, 50-75% for most aerobatics and full whack for flicks and spins. Very much personal preference it's true - one flying mate has all his models set so that the slightest pressure on any stick will have them gyrating at an alarming rate!

 

 

Edited By Cuban8 on 02/06/2015 21:03:57

[Frank Skilbeck]

A few years back I had an ARTF aerobatic model, which when set up with the manufacturers control throws lacked some elevator authority, so I increased the throw where upon it would stall coming out of a loop if you pulled to much elevator. I guess the manufacturer had come across this problem and "cured" it by reducing the elevator movement. With the higher movement it was like walking on ice, you never knew when it would go into a high speed stall which was very sudden. Not a nice model to fly.

[Cuban8]

Posted by Frank Skilbeck on 02/06/2015 23:02:41:

A few years back I had an ARTF aerobatic model, which when set up with the manufacturers control throws lacked some elevator authority, so I increased the throw where upon it would stall coming out of a loop if you pulled to much elevator. I guess the manufacturer had come across this problem and "cured" it by reducing the elevator movement. With the higher movement it was like walking on ice, you never knew when it would go into a high speed stall which was very sudden. Not a nice model to fly.

Wasn't by any chance a Weston UK Groove?

[Frank Skilbeck]

Posted by Cuban8 on 03/06/2015 07:27:25:

Posted by Frank Skilbeck on 02/06/2015 23:02:41:

A few years back I had an ARTF aerobatic model, which when set up with the manufacturers control throws lacked some elevator authority, so I increased the throw where upon it would stall coming out of a loop if you pulled to much elevator. I guess the manufacturer had come across this problem and "cured" it by reducing the elevator movement. With the higher movement it was like walking on ice, you never knew when it would go into a high speed stall which was very sudden. Not a nice model to fly.

Wasn't by any chance a Weston UK Groove?

No it was a Yak 54, but I can't remember the manufacturer though, but I had a Graupner Extra that was the same, increase the elevator throw from the recommended value at your peril.

[The Wright Stuff]

I suspect the answer is very much dependent on experience of the pilot, and how docile the plane is.

For an experienced pilot maidening a new plane, more throw is probably needed than for the case when a new pilot is getting to grips with their new purchase.

For what it's worth, for almost all of my ARTF models, I find I increase the elevator throw and decrease the aileron throw relative to the suggestions in the instructions. this may be just my personal flying style, but I find my thumb naturally does more movement from side to side, compared to up and down.

For tail draggers, I'll tend to up the elevator throw more than on tricycles, for obvious reasons...