Throttle linkage hummm

[Tripler]

Just spent "hours" trying to get the throttle linkage how I like it,
ie; 50% carb = 50% throttle curve,,
I know it can'nt be exact but to say its been a pain would be putting it lightly
Managed to get it as near as dam it after messing about with horn + rod lenghts

Just wondered if anyone else had this trouble, is it me or is it down to the design?

[jamiem]

Make the link the same length as the distance from servo horn screw to servo horn screw, then loosen the carb barrel and make it 90 degree to the link, make sure throttle is at 50% on the tx, now put the barrel at 50% open and tighten. Job done shouldn't take more than a few mins

[Tripler]

Make the link the same length as the distance from servo horn screw to servo horn screw, then loosen the carb barrel and make it 90 degree to the link, make sure throttle is at 50% on the tx, now put the barrel at 50% open and tighten. Job done shouldn't take more than a few mins

Thanks Jamie
easy for you to say,,, took me ages to work out,, as above
I knew I should have asked you after about ten mins of trying, cos,,
As I've said before " you know everything "

[waveydavey]

If your talking about the N5 I had the same. So much so that I gave up twice before I just accepted defeat and left it the way it was. There is defo something odd with the geometry.

[debrooker]

i may be being a bit thick but other than eye balling the carb position how did you get 50%, i'm 70%sure there's no markings as such.

i thought setting the linkage was simply getting the servo horn 90degrees to an imaginary line between the centres of the servo arm and throttle arm, and ensuring that the servo balls were the same distance from their respective centers
it that makes sense.... or may be i've got a crap setup

[paul35]

I'm not sure about other motors but on ys they have a Mark for min half and full throttle on the carb spindle


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[Tripler]

Yes the os55 has marks on the carb, 0-50 and 100%,
Forgot to mention I have a GV1 gov and had some settings wrong in that , which did'nt help,,
all I can say is it has been the hard'st heli I've found to setup,
I agree with wavedavey there is defo something odd with the geometry

[waveydavey]

If you follow the manual with an up and over link, something (the maths are beyond me) goes completely AWOL. Even with it parallel and measured with a vernier it didn't go as it should.

[pchristy]

Bear in mind that most model throttles are pretty non-linear devices anyway! ie: 50% barrel opening probably gives you a lot more than 50% power!

I normally make the pushrod length the same as the distance between the servo centre and throttle centre, then make sure the barrel is fully open at full throttle, and fully closed at low throttle with the trim fully back. Center trim will then usually get you in the ball park for tickover, and if you've set all the arms right, they should be about 90 degrees to the pushrod at half throttle.

Its also important to try and get the mechanical setup right first, and only use the travel adjusts for fine tuning. Travel adjusts should also be adjusted symmetrically (for example 5% at BOTH ends) for it all to work as intended.

Final adjustmment are carried out using the throttle curve in flight testing. For FAI style hovering, I often find my "mid-point" throttle curves are in the 40-45% region.

[waveydavey]

That's the odd thing Pete, with the suggested linkage layout you can't get close to normal setups. I've done a few and never walked away from one like I did with the N5.

[pchristy]

I must confess to being unfamiliar with the N5, but I have built dozens of helis over the years and the above method has always worked for me! I have had to use throttle arm extenders occasionaly to stop the pushrod fouling on the chassis or cooling shroud. You used to be able to buy these for OS (which would also fit on Super-Tigres!) and they made life a lot easier on some models.

I've also had models where I had to use bellcranks to move the throttle linkage from one side to the other, but if none of these can be made to work, it sounds to me like a serious design flaw!

[Spanner]

Hmm, mine is set up as per manual and done the way that Jamie sugests, and all is fine.

[waveydavey]

Hmm, mine is set up as per manual and done the way that Jamie sugests, and all is fine.

Mine didn't. Done all the normal sane things. Maybe I was being abit anal in that I was looking for 100 either side. I couldn't do it. Neither it sounds like could Tripler. I just got it as close as I could, not as the manual but as a normal linkage setup and left it at that