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jb1024 · 03-04-2012, 09:03 PM

Hey guys I have a problem with the front servo on my Gcp it's not getting full up and down travel any one know a fix for this thanks in advance

Heli-opolis · 03-04-2012, 09:13 PM

It depends on what is causing the limited range.

I don't know the GCP specifically, although I am sure others who do will chime in but on different TXs and RXs, the range of a given servo can be limited/controlled by either the TX, RX or both.

Generally servos don't have a range of motion problem so it is probably setting on the TX or RX. But again, someone with more experience than I, which is just about EVERYONE, should be along to help you more.

jb1024 · 03-05-2012, 01:41 PM

Thanks maybe my servo is dead then lol

Intheway · 03-05-2012, 08:21 PM

The servo's will do that and the easy way to think of it is this way...

Imagine a gear that turns CW and CCW as you move the servo back and forth via the xmitter. Now imaging that this gear needs only turn part way in each direction to cover the FULL swing of the servo arm. That isn't imaginary since that is what really goes on. When a tooth or two from this gear gets torn off in a crash or whatever, it means that instead of encountering constant jerky motion problems like you would expect, if the gear had to rotate several times to move the arm to each end (and there are some of those too in there) in this case it is the gear everyone complains about. it is the gear that connects to the gear that makes up the servo shaft. I think there was hope out there in servo land that someone had found compatible gears. You need to replace the one you have for now, and since you are in this for the long haul, get a spare or two, or use your backup bird to get you through the down time a stripped or in this case a missing tooth or 2 might cause.
Hope this helps.
Paul

p.s. Be sure to take the old servo apart and learn from it. The 4 screws release both covers. Take the arm off and pop that end off the servo off. You don't need to take the electronics cover off on the 'wire end' of the servo unless you're curious. (You want to be that in this hobby too!) When you get the gear end off being careful to keep the shaft cover facing up so you don't spill the gears you will at least be able to remove and rotate the gear with the missing tooth so that the 'gap-tooth' is limited to a portion of the gear that isn't used. See other posts for details on that. I've seen them.

bytemuncher · 03-05-2012, 08:32 PM

Do the servo saver mod, no more stripped servos. I have a bag full of spare servo gears (bought during the short time Walkera made them available) which I don't need now because the servo saver mod works.

http://benmlee.com/Genius_Servo_Saver.htm
http://www.rcgroups.com/forums/showp...postcount=2066

jb1024 · 03-05-2012, 10:43 PM

I changed to a new servo and the front servo still will not level with the others so the heli wants to fly forward all the time

Intheway · 03-06-2012, 11:51 AM

Turn sw-1 on the receiver off to disable the computer from the control loop that moves the servos. At this point only the radio will move the servos, not the position (tilt) of the bird, just the transmitter. In this mode you can turn on TH to stop the motors. If your pitch curve in TH on mode goes from -100% on the left of the curve and +100% on the right, then moving the throttle stick should move the swash plate up and down. The swash should be level if you don't move the cyclic (right) stick at all. With the throttle (pitch) set to mid-point (50%) the swash will be in the center where there is zero pitch. Be SURE that all 3 servo arms are relatively horizontal. I'm guessing that you will notice that the arm on the "front servo" (ELE) is not horizontal like the other 2 servos. This is because when you replaced it, you have the servo arm installed incorrectly on the servo shaft. As you know the shaft and arm have groves in them to keep from slipping. These groves limit what angle you can put the arm at to a 'click' at a time. If you are a 'click' off in either direction because when you put the arm back on the new servo shaft you were off by a click, then pull the arm back off and get it as close to level as you can with the above setup. When this is done the swash should be level again. If not you may need to tweak the connecting rod length on it. My experience has been that if you just replace the servo and leave the existing arm in place with the linkage etc. then as long as you get the arm back on in the same 'click' point as the old one was, you should be level and ready to fly.

Don't forget to turn sw-1 back on using the switch on the receiver board. You won't be able to fly it without the computer helping with the servo movements!

Hope this helps.

03-04-2012, 09:03 PM	#1 (permalink)
jb1024 Registered Users Join Date: Jan 2012	Gcp servo problem Hey guys I have a problem with the front servo on my Gcp it's not getting full up and down travel any one know a fix for this thanks in advance

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03-04-2012, 09:13 PM	#2 (permalink)
Heli-opolis Registered Users Join Date: Feb 2012	It depends on what is causing the limited range. I don't know the GCP specifically, although I am sure others who do will chime in but on different TXs and RXs, the range of a given servo can be limited/controlled by either the TX, RX or both. Generally servos don't have a range of motion problem so it is probably setting on the TX or RX. But again, someone with more experience than I, which is just about EVERYONE, should be along to help you more.

03-05-2012, 01:41 PM	#3 (permalink)
jb1024 Registered Users Thread Starter Join Date: Jan 2012	Thanks maybe my servo is dead then lol

03-05-2012, 08:21 PM	#4 (permalink)
Intheway Registered Users Join Date: Oct 2010	The servo's will do that and the easy way to think of it is this way... Imagine a gear that turns CW and CCW as you move the servo back and forth via the xmitter. Now imaging that this gear needs only turn part way in each direction to cover the FULL swing of the servo arm. That isn't imaginary since that is what really goes on. When a tooth or two from this gear gets torn off in a crash or whatever, it means that instead of encountering constant jerky motion problems like you would expect, if the gear had to rotate several times to move the arm to each end (and there are some of those too in there) in this case it is the gear everyone complains about. it is the gear that connects to the gear that makes up the servo shaft. I think there was hope out there in servo land that someone had found compatible gears. You need to replace the one you have for now, and since you are in this for the long haul, get a spare or two, or use your backup bird to get you through the down time a stripped or in this case a missing tooth or 2 might cause. Hope this helps. Paul p.s. Be sure to take the old servo apart and learn from it. The 4 screws release both covers. Take the arm off and pop that end off the servo off. You don't need to take the electronics cover off on the 'wire end' of the servo unless you're curious. (You want to be that in this hobby too!) When you get the gear end off being careful to keep the shaft cover facing up so you don't spill the gears you will at least be able to remove and rotate the gear with the missing tooth so that the 'gap-tooth' is limited to a portion of the gear that isn't used. See other posts for details on that. I've seen them.

03-05-2012, 08:32 PM	#5 (permalink)
bytemuncher Registered Users Join Date: Dec 2011	Do the servo saver mod, no more stripped servos. I have a bag full of spare servo gears (bought during the short time Walkera made them available) which I don't need now because the servo saver mod works. http://benmlee.com/Genius_Servo_Saver.htm http://www.rcgroups.com/forums/showp...postcount=2066

03-05-2012, 10:43 PM	#6 (permalink)
jb1024 Registered Users Thread Starter Join Date: Jan 2012	I changed to a new servo and the front servo still will not level with the others so the heli wants to fly forward all the time

03-06-2012, 11:51 AM	#7 (permalink)
Intheway Registered Users Join Date: Oct 2010	Turn sw-1 on the receiver off to disable the computer from the control loop that moves the servos. At this point only the radio will move the servos, not the position (tilt) of the bird, just the transmitter. In this mode you can turn on TH to stop the motors. If your pitch curve in TH on mode goes from -100% on the left of the curve and +100% on the right, then moving the throttle stick should move the swash plate up and down. The swash should be level if you don't move the cyclic (right) stick at all. With the throttle (pitch) set to mid-point (50%) the swash will be in the center where there is zero pitch. Be SURE that all 3 servo arms are relatively horizontal. I'm guessing that you will notice that the arm on the "front servo" (ELE) is not horizontal like the other 2 servos. This is because when you replaced it, you have the servo arm installed incorrectly on the servo shaft. As you know the shaft and arm have groves in them to keep from slipping. These groves limit what angle you can put the arm at to a 'click' at a time. If you are a 'click' off in either direction because when you put the arm back on the new servo shaft you were off by a click, then pull the arm back off and get it as close to level as you can with the above setup. When this is done the swash should be level again. If not you may need to tweak the connecting rod length on it. My experience has been that if you just replace the servo and leave the existing arm in place with the linkage etc. then as long as you get the arm back on in the same 'click' point as the old one was, you should be level and ready to fly. Don't forget to turn sw-1 back on using the switch on the receiver board. You won't be able to fly it without the computer helping with the servo movements! Hope this helps.

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