Post Crash Servo Testing
12-10-2003 | 01:12 PM
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From: Pasadena,
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Post Crash Servo Testing
What goes up must come down, right?
In the past, I have just guessed at the severity of a crash and then determined whether or not to replace the servos. In helis, where one servo failure will result a really bad day, I usually try to error on the side of caution.
Other than the usual checking for obvious signs of failure (cracked case, freespinning gears, etc.) has anyone come up with a test or tests to determine if a servo will fail under load? Does anyone know if there is a way to test them, other than just going for it and putting them in the air?
thanks
In the past, I have just guessed at the severity of a crash and then determined whether or not to replace the servos. In helis, where one servo failure will result a really bad day, I usually try to error on the side of caution.
Other than the usual checking for obvious signs of failure (cracked case, freespinning gears, etc.) has anyone come up with a test or tests to determine if a servo will fail under load? Does anyone know if there is a way to test them, other than just going for it and putting them in the air?
thanks
12-11-2003 | 08:14 PM
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From: New Haven , MO,
RE: Post Crash Servo Testing
Usually, stripped gears are about the only thing to happen as a result of a crash.
If a crash is the result of a possible failed servo, it gets a little more complicated.
Check for stripped gears first.
Tap on the servo sharply on all sides and watch for movement or jitter.
Checking for frayed wires at the board, wiggle and jiggle the wires going in to see if it affects the movement or position.
Check the connector end for corrosion, bent pins, loose fit or frayed wires.
Apply a resistance to the servo arm with your fingers while someone moves the stick slowly through it's full range of travel.
If you see, hear or feel any change in pressure as you go, it may have a worn pot.
If it has a lot of time on it and it jitters at center but is good everywhere else, it may need a pot.
If it fails any test, don't use it.
If it is an expensive servo, send it in for repair describing the problem.
It usually doesn't cost too much for repairs.
Kirk
If a crash is the result of a possible failed servo, it gets a little more complicated.
Check for stripped gears first.
Tap on the servo sharply on all sides and watch for movement or jitter.
Checking for frayed wires at the board, wiggle and jiggle the wires going in to see if it affects the movement or position.
Check the connector end for corrosion, bent pins, loose fit or frayed wires.
Apply a resistance to the servo arm with your fingers while someone moves the stick slowly through it's full range of travel.
If you see, hear or feel any change in pressure as you go, it may have a worn pot.
If it has a lot of time on it and it jitters at center but is good everywhere else, it may need a pot.
If it fails any test, don't use it.
If it is an expensive servo, send it in for repair describing the problem.
It usually doesn't cost too much for repairs.
Kirk
12-12-2003 | 05:11 AM
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From: San Francisco, CA
RE: Post Crash Servo Testing
You can invest in any one of a number of electronic servo testers made for the hobby. They start at $25 but one I saw
recently at a friends shop was the Servo Exciter for about $75. It tests quite a number of functions and seems to be a worthwhile piece of gear especially if it willidentitfy a faulty servo BEFORE you install it. I had a bad servo in my Raptor 60 at first but didn't know it as it would intermittantly tilt backwards in a hover. I made many inspections and changes before I discovered the servo was bad. Had I used a servo checking device before installing that new "bad" servo I would have resolved the problem easily. It could have caused a serious crash. I was lucky.
recently at a friends shop was the Servo Exciter for about $75. It tests quite a number of functions and seems to be a worthwhile piece of gear especially if it willidentitfy a faulty servo BEFORE you install it. I had a bad servo in my Raptor 60 at first but didn't know it as it would intermittantly tilt backwards in a hover. I made many inspections and changes before I discovered the servo was bad. Had I used a servo checking device before installing that new "bad" servo I would have resolved the problem easily. It could have caused a serious crash. I was lucky.
