Servo Set Up

[Alex Hasell]

Hello there can anyone please leave posts describing the best way to set up servos and particullary "centering" of said servos what i am looking at is your basic 4 servo set up. Many thanks

[Bruce Richards]

Here's how I do it.

1Install servos in model with horns removed.

2. Connect up a Rx and power.

3. Center servos using Tx (trims and sub trims centered)

4. Fit horn to servo trying different positions to find best horn arm for 90 degrees to servo.

5. Set up push rod or closed loop so control surface is centered on holes furthest out from servo and control surface horn.

6. Check control surface throw and if its a long way off. Move to holes further in on servo horn for less movement and further in on control surface horn for more movement. Also make sure nothing is binding and sort it out if it is.

7. Recheck control surface centering and adjust control rod as required.

8. Set final throws using Tx ATV. (Adjustable Travel Volume I think)

9. Check control surface movement direction and change using servo reverse on Tx as required.

10. Set up dual rates and expo if required.

For throttle servo do 1 and 2 but then

3. Check to see if the servo needs reversing and revers if required.

4. Set servo to closed position with Tx (trim in the centre).

5. Set horn on servo at 45 degree position.

6. Install control rod so that carb is just barely closed.

7.  Use Tx to fully open throttle. if the servo stalls fiddle about with all variables (ATV, Horn position, control rod length and hole position) until the carb opens fully with reasonably linear operation and no servo stalling.

Simple as that

Hope this helps

[Alex Hasell]

Bruce,

Thankyou that is absolutely brilliant!!!

[Chris Ireland]

Bruce,

Very clear explanation, thanks for that. Can you explain to me (a complete newbie) why you recommend setting up the throttle servo horn at 45 degrees? I have set my Seagul Arising Star servo to 90 degrees and it seems to perform adequately, but, as I said I'm a newbie so I my be missing an important point here through lack of understanding/experience.

So far I have only flown once, with someone else performing the landing and take off for me, so I guess that in the intervening period I was too busy trying to get the hang of things that I wouldn't have noticed any of the finer points of throttle control.  

[Alex Hasell]

Hi Chris i am certainly no expert but from i have done and seen so far the reasonfor setting said servo at 45 degrees rather than at the right angle is really that by setting it so you will be operating the servo with its normal arc of travel if setting at 90 when the throttle is fully open you will probably be putting undue strain on the servo by asking it to move so far. Although you probably havent noticed any advervse effects as yet in time i think you might wear the gears in the servo out i have very similar trainer to your self and have use a "star" servo arm and positioned the push rod on the 45 degree arm of the star and find it gives me excellent controll over throttle trim throughout its range of movement.

Also there is a thread in the beginners section on setting up servos one by my self and one by some one else have a look at these as i found them usefull. Hope this helps you

regards, Alex

[Former Member]

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[Chris Ireland]

Thanks chaps....    What a dumbo, looking back I realise that is what I have done anyway as it seemed to make most sense at the time. I also changed the servo horn for a longer one so that the servo did not overdrive the pushrod at the ends of its travel. I also set the low end position so that at mid trim the throttle was cracked open enough to keep the engine idlng, making shutdown a matter of putting the trim down until the throttle closed sufficiently to stop the engine.

Sorry about the 'wild goose chase', sometimes you don't realise that you know the answer until after you've pressed the 'send' button. DOH!

[Alex Hasell]

we all do it i have asked many myself lol

[Former Member]

[This posting has been removed]

[Chris Ireland]

Eric, you're quite right, it was a 'hole' change on the throttle servo. I was confusing myself as I had replaced the horn on one of the other servos to give me more movement. Double DOH!

July resolution... triple check my posts before committing them to the ether! 

[Former Member]

[This posting has been removed]

[Alex Hasell]

[Bruce Richards]

Re the throttle servo at 45 Degrees. I just find this leads to less fiddling than other approaches. But I suggest you do what makes sense to you. This will mean you understand what the fiddling is likely to archive.