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Post by Gimpalong on Sept 5, 2013 7:07:24 GMT -5
Hi guys,
I recently bought an LCT AKM, and the motor is very underpowered for the M120 spring currently installed. As such, I am looking to replace it with a motor that provides a decent rate of fire, but more importantly, a rapid trigger response on semi-automatic.
I've seen two motor brands widely suggested:
Lonex SHS
My thought was to buy a high-torque motor from either of these companies. Should I be looking at one more closely than the other? I've read of some possible QA/QC issues with SHS motors, but am not sure how current or reliable that information is. Are there other, lesser known or lesser used motors that I should be looking at? For example, I've heard people talk about TM, G&P and even CA motors, which I could likely find cheap as used. Remember, I'm not looking for an insane 25+ RPS rate of fire, just reliable, rapid trigger response with a "decent," 16-18 RPS, rate of fire.
Second, when installing a new motor in a V3, do I need to re-shim the entire box or can I simply install the new motor in the cage, attach the cage and then adjust the motor height until it sounds "normal?"
Thanks, guys!
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Post by Pagan on Sept 5, 2013 7:19:30 GMT -5
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Post by X on Sept 5, 2013 7:45:26 GMT -5
I would be in that group. When you switch motors you may get a motor with a slightly different thickness which would cause the shimming to be off. All you need to do is open the gearbox and check to make sure its still good. Obviously, if there's no change then don't reshim.
Sent from my XT1080 using proboards
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ctres
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Post by ctres on Sept 5, 2013 7:49:28 GMT -5
I'd also add a JG blue m42 to that list. With an 11.1 it will put you at around 20r rps and be very efficient and have great trigger response. The lonex A2 and SHS will both be faster and the lonex would probably be the more efficient of the two. Current SHS motors have supposedly gotten much better than the old ones which were very power hungry and ran hot. Any of those options should easily fit your needs, but I personally am a fan of the JG blue as far as off the shelf motors go. They have more torque than anything else widely available.
The shimming question is a toss up really. People had upgraded for years before the idea really became popular, and shimmed the gearbox on its own and then just adjusted motor height based on noise. So in short, the answer is NO, you do not HAVE to reshim it via bevel to pinion, but YES it is the ideal to do it. It's more of a question of whether you just want what works or what is best. Obviously if you don't use the bevel to pinion method then reshiiming for a new motor is useless. The premise, however, is that every motor is different in both length and pinion so just putting it in could change either a lot, or very little, depending on how tight the tolerances are. You ideally want the bottom edge of the pinion in line with the edge of the bevel and have the bevel shimmed as close as possible to the pinion while still allowing 100% free movement.
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Post by Gimpalong on Sept 5, 2013 11:31:23 GMT -5
Thanks for the great responses, guys.
I'll add the JG Blue M42 and AMP T5000 to the list.
Any recommendations for retailers? I'm looking at Brill and Clandestine for parts.
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ctres
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Post by ctres on Sept 5, 2013 12:50:48 GMT -5
Both are good to go. I have ordered from both of them within the last month. I think coletrain on here has a JG blue for sale. Just make sure you get the kind with the silver magnets (neodynium). Brill also had some custom motors (22 & 28 TPA neo magnets) similar to the JG blue that he never listed on his site. I think he was selling them quite cheap so you could maybe inquire whether he still has them. I actually sold him my jg blue and he said that the 22 TPA motors he had performed within 1 rps of it IIRC.
For reference I ran my JG blue on 16:1s and it did 24rps on a buffer tube 11.1. I now have a frankentorque motor I built from a dboys armature and an SHS can/magnets. It did 16 rps on the 16:1s with the same battery and was doing somewhere around 25 rps with my riot 10:1s with nearly instant trigger response until I foolishly shorted it. I'll be fixing it soon and maybe I'll post a video or something.
Edit: I just remembered you need a short type. Lonex and SHS are available in short types but I don't think the JG is. You can always take off the pinion, and cut the shaft down if you want to though. I'd say any of the motors would accomplish your goals just fine so your choice will come down to how much you care about the small differences that each motor has. By the way, what battery are you running? Are you staying with a stock gear ratio?
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Post by Gimpalong on Sept 5, 2013 14:10:44 GMT -5
Yup, standard gear ratio. Battery is a 1000 mAh 7.4 20C lipo. Gun is wired to deans.
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ctres
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Post by ctres on Sept 5, 2013 14:36:14 GMT -5
The 7.4 and JG blue will probably put you just below your 15-16 rps mark. It is really slow but has tons of torque and great trigger response. If you run an 11.1 then it will put you a bit above.
An SHS high torque with a 7.4 would probably put you at about 20. I'm not sure about the lonex but it should be similar to the SHS.
You can estimate RPS quite accurately by the following equation (credit to HS5 on ASM) (809.5*battery voltage)/(Motor TPA*gear ratio)
I know offhand that an shs ht has 16TPA and stock gears are about 18.7:1, hence my estimate for the SHS. The JG blue has 22 TPA so it should do about 14.5 rps. The equation isn't perfect but I have found it quite accurate in reality and quite a few others have as well.
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Post by Gimpalong on Sept 5, 2013 15:08:49 GMT -5
Cheers,
Thanks for the info! I spotted that equation from HS5 earlier, but didn't really have a context to place it in.
My primary goal is basically to not have a motor that sounds like it's straining to turn over. I'm leaning towards the SHS as both Brill and Clandestine have them in stock and they're quite inexpensive.
I had heard bad stuff about current draw and heat in regards to SHS motors, but for $30 I'm pretty willing to experiment.
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ctres
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Post by ctres on Sept 5, 2013 15:42:58 GMT -5
Everything I have heard about the recent SHS motors from Brill has been very positive. I have never actually used a complete SHS motor myself but the can and endbell I have are quite nice and I like the fact that they are easy to take apart. I'd say SHS is a good choice.
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Post by X on Sept 5, 2013 16:17:01 GMT -5
The 7.4 and JG blue will probably put you just below your 15-16 rps mark. It is really slow but has tons of torque and great trigger response. If you run an 11.1 then it will put you a bit above. An SHS high torque with a 7.4 would probably put you at about 20. I'm not sure about the lonex but it should be similar to the SHS. You can estimate RPS quite accurately by the following equation (credit to HS5 on ASM) (809.5*battery voltage)/(Motor TPA*gear ratio) I know offhand that an shs ht has 16TPA and stock gears are about 18.7:1, hence my estimate for the SHS. The JG blue has 22 TPA so it should do about 14.5 rps. The equation isn't perfect but I have found it quite accurate in reality and quite a few others have as well. I find this intriguing. Wouldn't spring strength factor into this? I'm assuming that the equation assumes battery current to be infinite. Sent from my XT1080 using proboards
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ctres
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Post by ctres on Sept 5, 2013 16:45:37 GMT -5
Yeah, one of the basic premises is that you are using a nice powerful lipo which can easily supply more than enough current than the motor demands. IIRC the equation is mainly meant for neodymium magnet motors which are more powerful than ferrous magnet motors, and can pull much stronger springs without a major increase in current draw. There clearly is no perfect equation because of the issues you have brought up, as well as other differences between motors and setups such as materials, how the armature is balanced, etc. If your battery is less than ideal for what your motor demands, then you will likely have to adjust for it in the equation by decreasing the constant. I suspect however that to a high torque neo magnet motor like any of those being discussed, Gimp's build is far from stressful seeing as he is running only a 120 on stock ratio gears, hence his battery can most likely fully, or at least nearly supply all of the current demanded by the motor. I would bet that the equation will be accurate within 1-2 rps, but I guess we will have to wait and see.
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Post by Gimpalong on Sept 6, 2013 8:56:29 GMT -5
Alright,
Ordered the SHS high-torque. Once I get it installed I'll let you guys know what it's doing.
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Post by Gimpalong on Sept 10, 2013 18:56:14 GMT -5
Well, I attempted to install the SHS motor into the LCT this evening.
Unfortunately, the SHS motor appears to be a bit fat. While the stock motor fits in the cage and allows the cage to closely entirely (i.e. all of the screws threaded in all the way, no gaps, etc) the SHS motor won't allow this.
Anyone ever have any issues with this or is this "normal?"
I did get the SHS motor installed and cycling, but I think the cage fit around it so tightly that the motor could only be adjust up and once up the spring didn't have enough pressure to force it back down.
Anyway, reinstalled the stock motor. Everything went together and "felt" right as far as everything fitting and screwing together neatly.
I should note that neither cage allows the motor to be fully disengaged from the gears in the gearbox. For example, with the stock motor, the adjustment screw can be all the way out and the motor will still engage the gears. If I adjust the screw all the way in, it will eventually be so tight that the motor can't turn over.
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ctres
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Post by ctres on Sept 10, 2013 21:13:35 GMT -5
That ammount of adjustment is perfectly fine, you don't ever want the motor fully disengaged anyways. The fact that the SHS motor is tight is not normal. I'd say find out where the part (s) are too tight and carefully remove material with a file until the motor can be freely adjusted up and down. Another option would be to just find a different motor cage.
Things being out of spec like that are pretty common and are what makes teching very frustrating but they can almost always be fixed if you have the patience.
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