Hey Guys,

I've got a question for you all. I just finished installing my control horns on my alerons and am now working on adjusting the pushrods to the right length. At each extreme, up and down, my servos make a humming noise like they are being overexerted. I think it is because the servos havent reached there maximum value yet and the aleron has reached its maximum travel range, ie. it is in contact with the trailing edge of the wing. If this is the case I think I just need to adjust the endpoints on my tx right? Some Guidance would be appreciated, thanks in advance.

That is exactly what is happening. You are stalling out the servo. That bad thing about this situation is that when the servo is stalled like that it draws a tremendous about of power from your battery. And in flight it can drain your battery quickly. So the situation needs to be resolved.</p>

You can adjust it with your endpoints. However, you need to try to fix this problem mechanically first before you start making adjustments with the endpoint settings in your radio. You can adjust the amount of throw on a control surface by moving the position of the pushrod on the control horn or servo arm. At the servo arm moving the pushrod in towards the center of the arm results in less travel on the control surface. At the control horn moving the pushrod further away from the control surface reduces the amount of travel in the surface. By adjusting at these two points you should be able to fix the problem you are having here.</p>

Ken</p>

Well there I also learned the answer to a question I was having in my mind the past 2 weeks - more of where on the servo and control horn gives you the most throw. </p>

Thank you Ken.</p>

The best situation when adjusting the mechanical linkage is to get the best movement with total servo throw, meaning that end to end movement for the desired movement of the surface.  This gives the best combination of control and resolution while maintaining total control of the servo movement and minimizing the battery current draw.</p>

It takes some time to get it right, but somwhere in the combination Ken displayed, and the effective use of end points (last thing to do because this effects resolution or precision if you wish).  </p>

You have to understand the throw constraints that the model manufacturer has listed, those being recommendations, usually based on experience with that plane, and should be approached from the least to the max, of course, starting at the least or smallest deflection.</p>

Get the thing ready to go and carefully adjust the throw to match the lowest throw listed by the manufacturer.  No dual rates for now, leave that for after you have maidened the plane and have "ironed out" any issues you have found.  Once you are comfortable with the flight performance, and want more radical movement, then go ahead and make the adustments, but be careful not to over extend the movement of the servo that will push it to the end points and beyond.. that is where you run into problems with excessive battery current draw and maybe a broken servo.</p>

CGr.</p>

CGretired gave you some excellent advice.  While some may not agree, I'd also suggest that, if your transmitter allows it, put some exponential into the elevator before first flight.  It is nice to be sure that you will have enough throw on the elevator to acomodate any extreme initial CG misplacement yet not have to risk erratic pitch changes near neutral position of the stick.

Good point.  I should have added that.. I definitely use a bit, perhaps 20%, of expo on my first flight.  It sort of eases the stress of that first flight.</p>

CGr.</p>

Good point.  I should have added that.. I definitely use a bit, perhaps 20%, of expo on my first flight.  It sort of eases the stress of that first flight.  And I might add, watch that roll rate.  Be very moderate with aileron throws.  Excessive roll rate will get you if you are not careful, especially when trying to land a plane that is very sensitive to roll.</p>

CGr.</p>

Good point.  I should have added that.. I definitely use a bit, perhaps 20%, of expo on my first flight.  It sort of eases the stress of that first flight.  And I might add, watch that roll rate.  Be very moderate with aileron throws.  Excessive roll rate will get you if you are not careful, especially when trying to land a plane that is very sensitive to roll.</p>

Again, this is for maiden flights for those that are beginners in this fine craft.  Those experts already know what I'm talking about and usually take appropriate measures to prevent serious problems on that first flight.</p>

CGr.</p>

Thanks everybody for the wealth of information. I'm pretty sure I've got it all set right now.