Hi,

I'm relatively new to this amasing and yet frustrating hobby and hopefully just getting through that more time repairing after a crash than flying stage.
I'm now looking to increase the throws on my plane, is there any set ratio / differential between moving the pushrod further out on the servo arm or moving the pushrod closer on the ailerons and are there any general guide lines or will they both have pretty much the same effect.
Any advice / help would be graetly appreciated !!!!!!!!!!!!!!!!!!

Neville

Yes, both of those actions have the same effect. Moving the pushrod closer to the control surface increases throw as well as moving the pushrod further out on the servo control horn. As as far as knowing "how much" it's really hard to tell. The best way to know is to just physically move them and see if you have enough throw after you move the pushrod.

Ken

Pretty much the same effect. I usually go out more on the servos first, then in on the control horn.

In either case, once you've changed it, move it with the radio and check for any clevis binding

And since you are talking ailerons and probably using torque rods be sure to check with the wing on the plane. Some people only check with the wing off and get surprised when things bind when it's installed.

Check the manual it will tell you what the High rates and Low rates should be on the plane for all surfaces. If your radio is computer driven you can even toggle them in flight. As to setting the rates, first it's usually it's easier with two people. One holding the ruler and doing the adjusting and the other moving of the controls.

This is the process for one control surface: (depending on how many you have you will need to repeat this that many times)

1. Place the plane level in a stand and ensure the control surfaces are centered.
2. Taking a sturdy ruler and mark (visually or with tape) on the ruler where the center point of the control surface is.
3. Then move the surface up. (The distance up should be the rate noted in the manual.)
4. Repeat the movement a few time to ensure consistancy and accuracy.
5. Do the same thing for the down it should be of equal rate.
6. After you get the throws where you want them move to the next control surface and repeat.

Hope this explains it well enough.

There was a great article on Model Aircraft News this month about servos.

One of the things discussed was the amount of power and force the servos need when you adjust the linkages this way.

The bottom line is that you want the BEST mechanical advantage, which comes with having the linkages connected to the inner holes on the servo control horn arms, and the outer holes on the control surface control horns.

While this may diminish actual surface movement, it results in the best holding power with the least amount of drain on your system.

The inference is then to adjust the servo arm movement as high as possible to gain additional surface throws instead.

That's true. If you were to move the pushrod all the way out on the servo arm, and all the way in on the control horn, it will take more power to keep the control surface in position. I wouldn't suggest doing that on full strip ailerons though, unless you're using high torque servos and 4-40 pushrods.
Another option is longer servo arms. You might have to turn the servo around or put the arm on the other side of the servo, but you will get your best torque on the control surface using the outermost hole on the control horn.
You never said what plane this was on. Something else to think about also ... the faster you go, the less control surface movement you'll need.

Also, if you have not sealed the gaps, do that before moving any linkage

Thanks for the help /advice- much needed and so much to learn when you 1st start !!!!!!!! I assume the idea is as you become more comfortable you move them further and further so it's not such a shock when you go to a more advanced plane ??????????
Someone asked what plane it is, it's a Multiplex MiniMag with a GWS Brushless motor, have a Hobbyzone Super Cub, had (past tense) a Hobbyzone Swift which I flew quite a bit but eventually destroyed, tried a Ultrafly PC Phantom and reduced it to rubble in about 8 seconds as it took off like an exocet missile with too much up elevator to make sure it didn't hit the dirt and lost it whilst trying to trim it out / contain it, have a rebuilt Art-Tech Mustang with a Ultrafly Frio in it as the original motor burnt out but have gone back to the MiniMag as I think I was biting off too much with not enough hours under my belt so wan to rebuild my confidence as much as anything.
Neville

Most of all, remember to re-center the control surfaces after moving the position on either the servo end or the aileron end. It may change slightly. How much it changes is depending on the amount you change the position of the rods. It may not require an adjustment but always worth the check to make sure they are properly centered.

Remember, no matter what you do, you will also need to re-trim the aircraft in flight so your first flight after the adjustment should be done with some caution and very slowly. In other words, don't go off full throttle and start to make violent maneuvers until you are able to fly straight and level with 'hands-off'.

DS.

In addition to all of the above, remember to re-center the control surfaces after moving the position on either the servo end or the aileron end. It may change slightly. How much it changes is depending on the amount you change the position of the rods. It may not require an adjustment but always worth the check to make sure they are properly centered.

Remember, no matter what you do, you will also need to re-trim the aircraft in flight so your first flight after the adjustment should be done with some caution and very slowly. In other words, don't go off full throttle and start to make violent maneuvers until you are able to fly straight and level with 'hands-off'.

DS.

A good piece of advice given to me by an "old timer" at the field ( not that I'm not in the same league... ).

Get it up and HIGH first, then trim out as needed.