Gear Ratio & TPA

13408 Views 15 Replies 9 Participants Last post by Guges Mk3, 7 mo ago

MeusVox

Discussion Starter · Jan 28, 2019

I’m going to overhaul an ICS M4, and want advice for the lowest stress combination for my specifications.

So, a 22 TPA motor can easily pull an M120 on a 12:1 set. The stress on the gears, however, gets to be pretty impressive.
A 16 TPA motor can easily pull an M120 on an 18:1, and here the gears are experiencing less stress due to greater mechanical advantage.

I want to make a build that, unless there’s a grievous unseen error, functions reliably without subsequent tinkering. I already have a gun that requires that.

So, for the lowest stress possible, and achieving 20+ RPS with an 11.1v battery, what would you recommend?
Any motor, any ratio, and brand.

I already have a parts list for the rest of the gun.

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Lefse

· #2 · Jan 28, 2019

M120 spring on 12:1 gears is well within what they can handle, if they're shimmed properly they'll last several years before you'll see any significant wear. Heck, I've gone as high as SP150 (M170 equivalent) on 12:1 ratio gears, no problems, they would wear out relatively quickly with such high load though.

If trigger response and smoothness are a priority I recommend combining high TPA and low gear ratio, if you want higher efficiency and a tad more longevity you could do the opposite. In one of my AK's I'm running 12:1 ratio gears with an SP110/M120 spring at 30 RPS, and this is what I consider a "workhorse" setup that doesn't require much maintenance. I open it up once a year for a quick inspection and re-grease is needed, that's it.

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Guges Mk3

· #3 · Jan 28, 2019

Put in a good 40K motor on a 18:1 and you will hit 20rps and you don't need a 11.1V - 3S.

I have a 25rps setup on a 2S 45K - 18:1 setup

Reactions: 2

BOA_SP3CT3R

· #4 · Jan 28, 2019

13:1 gears+9 tooth bevel(15.17:1) gear and a 16-18tpa motor works quite well. Trigger response will be snappy, though RPS may be a bit higher than you’re wanting(27~33). The gears will last a very long time and run smoothly.

Reactions: 2

LightIsRight

· #5 · Jan 28, 2019

A 16 tpa motor on 18:1 ratio gears will easily be above 20 rps when using an 11.1v. The same setup in my MK18 is giving me around 17-18 rps on a 7.4v Lipo.

Reactions: 2

MeusVox

Discussion Starter · #6 · Feb 2, 2019

So, replying to all of you.

Trigger response is very important to me.
I’m hearing the consensus is that, while a low ratio high TPA setup may be higher stress on the gears, that ultimately it’ll still last quite awhile.
Is that correct?
And for trigger response, you simply can’t get that from a high speed motor because of wind-up time under load.

I ask because I’ve always followed the logic of high torque/low ratio is king.
I’ve never played with any ratio over 15.17:1 (nine tooth bevel).

BOA_SP3CT3R

· #7 · Feb 2, 2019

MeusVox said:
So, replying to all of you.

Trigger response is very important to me.
I'm hearing the consensus is that, while a low ratio high TPA setup may be higher stress on the gears, that ultimately it'll still last quite awhile.
Is that correct?
And for trigger response, you simply can't get that from a high speed motor because of wind-up time under load.

I ask because I've always followed the logic of high torque/low ratio is king.
I've never played with any ratio over 15.17:1 (nine tooth bevel).

Eh not really, low TPA motors can give excellent response when paired with the right gear ratio and battery. I've only done 2 low TPA setups:
Star Wei 14tpa, 15:1, M120
Custom 15tpa, 24:1 helicals, M140

Both were quite snappy. The 15T+24:1 setup was extremely efficient, the other was...well, not incredibly efficient...

MeusVox

Discussion Starter · #8 · Feb 2, 2019

Do you have any numbers, or are these “by ear”?

Wesley Coupland

· #9 · 7 mo ago

My experience I've noticed that a HS gear set with a HT motor with strong Neo magnets are the best for efficiency and trigger action timing. The other side being a 16:1-18:1 on a HS motor will give similar response if done correctly. These builds can create motor heat and straining on your battery. Personally I enjoy a short stroked 12:1 setup on a 22tpa 25k motor I also own a new 28tpa 20k with very strong Neo magnets and that gives me real good efficiency.

Guges Mk3

· #10 · 7 mo ago

If the battery is good...there will be no "Strain".

Wesley Coupland

· #11 · 7 mo ago

My race gun parts: shs 12:1, 22tpa 25k short stroked sector two teeth and as well the piston. I have a M130 and very smooth and the build gets ran off a 2200 3S 50c 11.1 LiPo fully charge for every game.day. I have achieved 27-29rps with the gate titan and 6% pre-cocking and hair trigger I can get snappy smooth shot to shot performance that always pleases me and with my compression and barrel, hop, bucking setup I get very consistent groupings and the motor is a king arms black and blue 22tpa 25k neo can HQA.

Reactions: 1

OutlawAirsoft

· #12 · 7 mo ago

There is something just so satisfying about a snappy, simple, semi build. I run a similar build as my primary and just love it.

Reactions: 2

Wesley Coupland

· #13 · 7 mo ago

Hey so I recently just took my gate Titan out of my vfc which was my longer done and installed it into my really short Poseidon. It's a high speed SSG build I've gone through it twice all the shimming is flawless I packed the bearings with grease gears have been greased correctly it's called a ultra lightweight piston which I've actually drilled more holes out of but got the piston and the piston head weighing at 22 g. It's a really nice clean set up and when I plug in my gate Titan there was a couple errors so I address those errors and one of them being overcurrent and I don't understand how I literally took it from a fully working healthy gun to put it into this other gun all I did was recalibrate it. And I thought I had it in the bag I literally just plugged in a 2200 mah 11.1 50c my day Titan beat correctly when I plug the battery in but then when I pulled the trigger I hear some sort of a weird click around the motor and that's a brand new motor I just put in there so I know the motor isn't bad when I corrected AOE I know that that motor pinion gear meshed perfect with the bevel gear and I don't know what to do now with you know a full-time job and the rest of my life going on it can be hard for me to sink a lot of hours at my work bench. Any ideas would definitely be appreciated I'm going to plug it back into the laptop to see what it says now I really don't know what to do and it didn't make any vibrations or signals when it did that so I don't know if it's fighting to turn it here which it shouldn't because everything is messed correctly don't know what more I could do.

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rm105

· #14 · 7 mo ago

Motor terminals hooked up correct? (pos to pos, neg to neg)

Reactions: 1

Leo Greer

· #15 · 7 mo ago

Sounds like you have the motor in backwards. Either that or your anti-reversal latch is incorrectly installed.

Reactions: 1

Guges Mk3

· #16 · 7 mo ago

If you ever here a motor click noise...its due to reverse polarity.

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