EVO 9 pulse width
 

Hi Mike,

I need a little help with my EVO 9. I'm using the radio on precision aerobatic planes. I have noticed that my neutral on elevator, rudder and aileron varies slightly when the sticks are moved to each end point and back to neutral. This is obviously a problem when trying to fly accurately as it's like having constant trim changes... At first I thought it was a servo centering issue but have subsequently eliminated that. I set-up a 5955TG on a piece of ply and attached a 12" piece of carbon rod to it's control horn. The thinking is that any error will be amplified by the length of carbon rod... Anyway, at the end of the carbon rod I made a pencil mark on the ply to indicate center. When I move the sticks to either extreme I get variable centering accuracy. It can be up to 1/8" variation at the end or the carbon rod... If I plug the servo into my HFP on manual mode the center is 100% repeatable so that eliminates the servo. I then plugged the programmer into the Rx to measure the received pulse width. As it turns out the servo is only following what the TX tells it. I'm seeing neutral variation of up to 5uS which explains my variable neutrals. Is this problem fixable or is it related to the quality of the plastic gimbals? The gimbals seem to be a little flexible.

It should be noted that I'm using the long sticks and the spring tension is set to maximum.

Cheers
Jason.

RE: EVO 9 pulse width
 

This is not an issue I have heard of... but I suppose it is posible. You might want to have the radio checked out and the gimbles recalibrated.

I would also suggest you use the programmer and set the deadband on the Hitec digital servos to "1" (defaults is "2") to obtain the best centering possible. You should also use the shortest horns (mounting location) on the servo as possible and utilize the maximum EPA in the radio for the desired travel. If you reduce the EPA with a longer horn you will sacrafice resolution and centering.

Mike.

RE: EVO 9 pulse width
 

Hi Mike,

All my Hitec digitals have their dead bands set to 1 as none of my models have ganged servos. On my pattern plane I'm using the small aluminium control horns that come with the 5245MG servos on all but the rudder. They are very rigid and the linkage connection is on the second hole out from the horn mounting screw. The gimbals on my EVO seem a little flimsy i.e. flex in the stick and plastic so this is why I suspected the gimbals. I did have to adjust the elevator pot a fraction because when switching between dual rates the trim center would change. This was only an issue on the elevator.

I have an old MC2020 and I tried it on the HFP to see how it performed and found that it was worse... The gimbals on that radio are tighter and more rigid than my EVO so perhaps I'm barking up the wrong tree.... lol

Cheers
Jason.