Need help with replacing prop shaft on a gws 350
05-27-2005, 08:02 PM
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Need help with replacing prop shaft on a gws 350
The last (and only) time I tired to replace the prop shaft one of the ball bearings was stuck on the shaft, leading to its eventual demise. Is this pretty common? Whats the best way to strip the shaft of the gear and bearings? I'd think they should just slide off, but I tried everything to get that bearing off and it just wouldn't give. Thanks!
05-27-2005, 08:05 PM
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RE: Need help with replacing prop shaft on a gws 350
did you take the gearbox off of the plane first? did you try to slide the shaft forward toward the front of the gearbox?
05-27-2005, 09:27 PM
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RE: Need help with replacing prop shaft on a gws 350
Yes I took the gear box off and removed the motor. I got the shaft out of the gearbox but the bearing was frozen on the shaft. I don't remeber which direction I went. With one of the bearings frozen on the shaft my choices were limited. Whats the proper procedure? I can't find instructions anywhere.
05-28-2005, 02:03 AM
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RE: Need help with replacing prop shaft on a gws 350
From my files:
To take off the shaft:
1. Remove propeller. Unplug motor from ESC.
2. Remove 2 screws holding motor in the gearbox (do this in bag too if you want--they are rather hard to find if they fall).
3. Take out motor. Note how the e-clip looks when it is attached to the shaft (back of gearbox on the shaft)
4. Put nose of SS in bag (or take gearbox off SS and put the gearbox in the bag).
5. Get a small slot screwdriver (I think I used a 2mm precision head), place it in the e-clip so when you twist the screwdriver the clip will pop off.
6. Remove washer under the e-clip and put aside.
7. Remove shaft. The spur gear will come out with it.
8. The bearings should remain in place, but be aware that they may come out. One of mine came out as my shaft was really bent.
9. Note how the spur gear fits on the shaft. Mark both sides of the shaft with a felt marker for reference if you think you may mess up reinstalling the spur gear on the new shaft.
9. I put the shaft and spur gear on top of a slightly opened vise, shaft vertical between the jaws. Do not clamp it in. The jaws support the spur gear. Only open the jaws as wide as they need to be. You want to support the spur gear as close to the center as possible.
10. With a hammer, tap the shaft out.
11. Set the new shaft next to the old one and mark where the spur gear goes on.
12. Put new shaft in spur gear.
13. With same hammer, tap the new shaft into the spur gear until the lines match up.
BE CAREFUL--you want to pound so the force goes directly down the shaft through the hole in the spur gear. A force from the side is what bent it in the first place. I suppose you could wet it with water to lube it a bit so it goes in easier. The water will dry away leaving no slippery residue to dislocate the gear later.
14. Reinstall the new shaft into gearbox. Put on washer, e-clip, yadda, yadda, yadda.
To get the e-clip back on, I place it in the groove on the shaft with my fingers and then use needle nose pliers to pop it back in. Make sure it is in properly. You don't want to lose it in flight!
15. Lastly, I got this info for Great Planes gearboxes, but do it with the GWS ones as well. Don't know how important it is, but I do it anyway: With the motor back in the gearbox, before you tighten the screws to secure it in, take a small piece of paper (I use computer paper) and put it between the pinion gear and the spur gear. I place the piece of paper up to the gear and spin it in. Tighten screws, spin paper out. Reattach motor wires.
Go flying!
The 300 EPS powered gearbox has a 3mm prop shaft. When they bend, they often bend in front of the big black gear (the spur gear). Some people cut this off and use a prop adapter to mount other props. Alternately, you can take the thing apart and try to straighten the bent prop shaft. If the shaft bends between the bearings, I’d say you’re pretty well hooped and need a new shaft as it is really difficult to take a bend out of the middle of the shaft. Anyway, to straighten the shaft, you have to take the bent prop shaft out (described below except when straightening a bent shaft, you don’t have to remove the spur gear) and put it in a drill. Press the trigger of the drill and you will see the shaft wobble. Take a felt pen and hold it up to the spinning shaft. This will mark the spot that you will need to whack later. Stop the drill, ensure you’ve got a good mark, then put the shaft in a vise between two wood blocks so you don’t mar the surface of the shaft. The spur gear should be resting on the wood blocks. The mark should be pointing towards or away from the handle that tightens the vise. Tap the shaft lightly. Remove from vise, put shaft in drill, press trigger and if the shaft is still wobbling, use paper towel to wipe felt mark off and then use the felt pen to mark the shaft again. Repeat as necessary. Resist the temptation to really whack the shaft. It is bends quite easily and if you hit it too hard, you’ll find you are actually bending the shaft back and forth.
To take off the shaft:
1. Remove propeller. Unplug motor from ESC.
2. Remove 2 screws holding motor in the gearbox (do this in bag too if you want--they are rather hard to find if they fall).
3. Take out motor. Note how the e-clip looks when it is attached to the shaft (back of gearbox on the shaft)
4. Put nose of SS in bag (or take gearbox off SS and put the gearbox in the bag).
5. Get a small slot screwdriver (I think I used a 2mm precision head), place it in the e-clip so when you twist the screwdriver the clip will pop off.
6. Remove washer under the e-clip and put aside.
7. Remove shaft. The spur gear will come out with it.
8. The bearings should remain in place, but be aware that they may come out. One of mine came out as my shaft was really bent.
9. Note how the spur gear fits on the shaft. Mark both sides of the shaft with a felt marker for reference if you think you may mess up reinstalling the spur gear on the new shaft.
9. I put the shaft and spur gear on top of a slightly opened vise, shaft vertical between the jaws. Do not clamp it in. The jaws support the spur gear. Only open the jaws as wide as they need to be. You want to support the spur gear as close to the center as possible.
10. With a hammer, tap the shaft out.
11. Set the new shaft next to the old one and mark where the spur gear goes on.
12. Put new shaft in spur gear.
13. With same hammer, tap the new shaft into the spur gear until the lines match up.
BE CAREFUL--you want to pound so the force goes directly down the shaft through the hole in the spur gear. A force from the side is what bent it in the first place. I suppose you could wet it with water to lube it a bit so it goes in easier. The water will dry away leaving no slippery residue to dislocate the gear later.
14. Reinstall the new shaft into gearbox. Put on washer, e-clip, yadda, yadda, yadda.
To get the e-clip back on, I place it in the groove on the shaft with my fingers and then use needle nose pliers to pop it back in. Make sure it is in properly. You don't want to lose it in flight!
15. Lastly, I got this info for Great Planes gearboxes, but do it with the GWS ones as well. Don't know how important it is, but I do it anyway: With the motor back in the gearbox, before you tighten the screws to secure it in, take a small piece of paper (I use computer paper) and put it between the pinion gear and the spur gear. I place the piece of paper up to the gear and spin it in. Tighten screws, spin paper out. Reattach motor wires.
Go flying!
The 300 EPS powered gearbox has a 3mm prop shaft. When they bend, they often bend in front of the big black gear (the spur gear). Some people cut this off and use a prop adapter to mount other props. Alternately, you can take the thing apart and try to straighten the bent prop shaft. If the shaft bends between the bearings, I’d say you’re pretty well hooped and need a new shaft as it is really difficult to take a bend out of the middle of the shaft. Anyway, to straighten the shaft, you have to take the bent prop shaft out (described below except when straightening a bent shaft, you don’t have to remove the spur gear) and put it in a drill. Press the trigger of the drill and you will see the shaft wobble. Take a felt pen and hold it up to the spinning shaft. This will mark the spot that you will need to whack later. Stop the drill, ensure you’ve got a good mark, then put the shaft in a vise between two wood blocks so you don’t mar the surface of the shaft. The spur gear should be resting on the wood blocks. The mark should be pointing towards or away from the handle that tightens the vise. Tap the shaft lightly. Remove from vise, put shaft in drill, press trigger and if the shaft is still wobbling, use paper towel to wipe felt mark off and then use the felt pen to mark the shaft again. Repeat as necessary. Resist the temptation to really whack the shaft. It is bends quite easily and if you hit it too hard, you’ll find you are actually bending the shaft back and forth.
05-28-2005, 02:10 AM
#5
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RE: Need help with replacing prop shaft on a gws 350
Additionally, you could drill a 3mm hole in a block of wood, insert shaft with frozen bearing, and tap away. Put some light oil or WD40 on the shaft first--that may help get it off.
05-28-2005, 12:58 PM
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RE: Need help with replacing prop shaft on a gws 350
Thanks Time Pilot, I welcome your advice. Worked like a charm, except I used a small socket instead of the wood.
05-28-2005, 10:34 PM
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RE: Need help with replacing prop shaft on a gws 350
After a lot of use a burr will form at the slot where the circlip fits, stopping the bearings from sliding off. After you take off the circlip and washer, go around the shaft where the goove is with a fine file such as a point file or a fingernail file and the brgs. will just slide off and on. Hope this helps.
