mecam

My Feedback: (3)

Ok, I had three futaba 9402 1st gear (plastic) strip on me in less than 20 flights. It's always stripping on the right aileron, I also have them on the left aileron and two on the elevator and no problem. Airplane is a 1/4 H9 Edge 540.

1st servo lasted 7 flights
2nd servo lasted 3 flgiths
3rd servo lasted 7 flights

No binding at all on the aileron, aileron moves very smooth, hinge line is sealed and no flutter problem. I don't know what to do. I have a 9Z radio and my ATV is set to 140% but throws rates are set to 35% on low and 50% on high. Servos don't buzz so I know they are not binding. HELP PLEASE!!!

amcross

My Feedback: (2)

Mec, you are taking away all the mechanical strength, accuracy, and holding power of your servo with your throw setup. Adjust your linkages so your high rate is 100% of your ATV, and you'll find a lot less servo wear very quickly. also look CAREFULLY at the geometry on that servos linkage.

mecam

My Feedback: (3)

Actually, I found out the cause of my problems. It is the MOKI's IDLE vibration on the ground. Also all of my failures happend on the ground during aileron routine check while the engine was idleing.

amcross

My Feedback: (2)

good to hear! i would still look at your linkage and the throws you're asking of your servo. You are asking for more failures...

mecam

My Feedback: (3)

I really don't know what difference it is making the ATV 140% max vs 100% default. Some people say setting the ATV to 140% maximizes your servo's resolution and makes it more precise. I switched them back to 100% ATV and using my rates for the limit. Also the horns I'm using are only 1" long.

amcross

My Feedback: (2)

U are telling the servo that its total range is, lets say, 10" (for easy math). and it has 1,024 steps to cover those ten inches.

Now you decide to use just half of that travel -- 5". Now you've taken it down to 512 steps available....AND decreased teh power the servo has to hold each position, while also making each step larger and harder to hold....

going to 140% AND using all 140% means you are using the whole possible travel of the servo, and its max possible power, and DOES increase resolution and holding power but slows response time.

Cley

mecam said,

"I don't know what to do. I have a 9Z radio and my ATV is set to 140% but throws rates are set to 35% on low and 50% on high."

amcross said,
"Adjust your linkages so your high rate is 100% of your ATV,"


mecam said,
"I really don't know what difference it is making the ATV 140% max vs 100% default. Some people say setting the ATV to 140% maximizes your servo's resolution and makes it more precise. I switched them back to 100% ATV and using my rates for the limit. Also the horns I'm using are only 1" long."

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mecam,

I think that amcross was saying to increase your HI RATES in your radio (not lower the ATV) and then readjust your linkages for the desired Hi Rate throw....
This would give you mechanical advantage.... By setting your Hi Rates at 50 you are limiting the servo movement and compensating through the linkages.. This gives the control surface mechanical advantage to damage the servo versus the servo having mechanical advantage to move the surface... Setting your Hi Rates to 50 eliminates the benefit of setting your ATV to 140.....