Overspin with High Speed Motor and 18:1 gears. Replace with High torque motor and smaller lipos?

[Asomodai]

Hello gents. 

 

The Real Sword T97B has developed overspin since cleaning up the gearbox, downgrading the spring to around 330FPS with perfect compression and adding a non AB mosfet. I use Nuprol 7.4V 1450mAh Lipo 30C. This means it will double fire on semi and lock up the gearbox, meaning I have to clear with full auto before trying semi again. The stock motor is a Real Sword Ferrite High Speed motor. Very good motor for what its worth. 

 

I have been planning to get a tightbore barrel which may take me over the 350FPS limit which means I may have to downgrade the spring to something even lighter, which means more overspin. 

 

So I am looking at either smaller 7.4v Lipo batteries which will have a lower 20 or 25C rating which would fit better in rifle anyway...

 

Or replacing the High Speed motor with a Rocket Green 16TPA High Torque to improve Semi trigger response at the price of ROF. 

 

Will both of these help defeat the overspin? The battery will probably make a big difference, my only issue with just getting smaller lipos is that high speed motors are fairly inefficient and I am worried that the batteries wont last particularly long. 

 

[Iceni]

Try partially discharging a battery with a few bursts of full auto.

If the gun is right on the limit for overspin then it's the easy fix. As you just use full auto when you drop in new batteries for a few minutes.

Heavier piston would help, As too would lighter gears.

Another thing to check is the trigger dolly. The reason I say this is true overspin will not result in a gearbox lock. The trigger will reset like normal.

What yours sounds like is the dolly is slow or catching in a slightly up position. The return spring on the AK/Aug contacts does sometimes have a prefered orientation, So try reverse the spring.

If you look at the spring you will see the loop that connects to the dolly can be put in up or down relative to the axis of the spring.

It could also be the COL is catching in the up position and is just stopping the dolly seating. Switching to auto would push it back down automatically. If it locks and you can unlock it just by switching to auto and then back to semi the COL would be a key part to investigate. Normally this wouldn't double shoot by itself unless the COL is also holding the dolly forwards as well.

Also check the spring that pushes the COL back down.

[Asomodai]

28 minutes ago, Iceni said:

Try partially discharging a battery with a few bursts of full auto.

If the gun is right on the limit for overspin then it's the easy fix. As you just use full auto when you drop in new batteries for a few minutes.

Heavier piston would help, As too would lighter gears.

Another thing to check is the trigger dolly. The reason I say this is true overspin will not result in a gearbox lock. The trigger will reset like normal.

What yours sounds like is the dolly is slow or catching in a slightly up position. The return spring on the AK/Aug contacts does sometimes have a prefered orientation, So try reverse the spring.

If you look at the spring you will see the loop that connects to the dolly can be put in up or down relative to the axis of the spring.

It could also be the COL is catching in the up position and is just stopping the dolly seating. Switching to auto would push it back down automatically. If it locks and you can unlock it just by switching to auto and then back to semi the COL would be a key part to investigate. Normally this wouldn't double shoot by itself unless the COL is also holding the dolly forwards as well.

Also check the spring that pushes the COL back down.

 

It has no issues firing semi on the same battery but in storage mode. 

 

The piston and gears are proprietary as is the trigger dolly, which is brand new along with the rest of the gun so are not easily replaceable. the entire rifle was stripped and checked today. 

 

Ultimately would a lower C rated 7.4v do the trick much like a discharged lipo would? Or a torque motor like the Rocket 16TPA to replace the High speed motor? I can barely fit my current 7.4v lipos in the gun as it is so smaller batteries with a lower C rating are likely to be purchased anyway. 

[Iceni]

C-rating will have an effect but I couldn't work out a reasonable way to calculate it. 

Your basic load is 10-15 amps so anything that can deliver 15+amps will be safe.

C x Ah = discharge amps.

So a 1450 10C is still capable of 14.5amps.

It'll get hotter faster, and you will have less performance, but the duration the battery shoots for should be about the same.

Personally, If I were adding a HT motor I'd do the 13:1 gearset as well. It's an extra £15 and the gun will be lovely to shoot after. Snappy sticatto trigger and a decent ROF.

Edit: Damn Real Sword T97B ! it's not a V3 gearbox. Nothing I posted above actually matters with the gearbox as it's a different layout!

In that situation, I'd probably opt for the gears and motor just because there known variables.

[Asomodai]

7 minutes ago, Iceni said:

C-rating will have an effect but I couldn't work out a reasonable way to calculate it. 

Your basic load is 10-15 amps so anything that can deliver 15+amps will be safe.

C x Ah = discharge amps.

So a 1450 10C is still capable of 14.5amps.

It'll get hotter faster, and you will have less performance, but the duration the battery shoots for should be about the same.

Personally, If I were adding a HT motor I'd do the 13:1 gearset as well. It's an extra £15 and the gun will be lovely to shoot after.

 

 

Much as I would like to, the sector gear is completely proprietary as it spins in the opposite direction to most gearboxes and the spur gear is Version 7. I am also not willing to short stroke the gearset for the same reason, difficult to get replacements!

 

I am not fussed about the ROF tbh, I would rather the rifle shoot reliably for a long time then for any uber performance.

 

Would you recommend I go for a high torque motor to stop the overspin or a lower C rated battery if I had to pick one?

[Iceni]

5 minutes ago, Iceni said:

Damn Real Sword T97B ! it's not a V3 gearbox. Nothing I posted above actually matters with the gearbox as it's a different layout!

In that situation, I'd probably opt for the gears and motor just because there known variables.

I was just editing that in lol!

It makes things much harder to work out.

I'd always go motor over lower C batteries. I always pick the highest C rating I can. Most of my batteries are 7.4v 35/70c 2200mAh - 77-154 amps!

That way I know there is no chance in hell my batteries are stressed, regardless of how much I spam the trigger. That's me tho and I don't know anyone else that runs batteries as big.

 

[Asomodai]

13 minutes ago, Iceni said:

I was just editing that in lol!

It makes things much harder to work out.

I'd always go motor over lower C batteries. I always pick the highest C rating I can. Most of my batteries are 7.4v 35/70c 2200mAh - 77-154 amps!

That way I know there is no chance in hell my batteries are stressed, regardless of how much I spam the trigger. That's me tho and I don't know anyone else that runs batteries as big.

 

 

Okie doke. Should I order a 16TPA torque motor, or a 22TPA High torque motor? I presume 22TPA gives me less chance of overspin and a better trigger response?

 

Whats the theory behind a High speed motor being more likely to overspin in comparison to a high torque?

[Asomodai]

8 hours ago, Iceni said:

C-rating will have an effect but I couldn't work out a reasonable way to calculate it. 

Your basic load is 10-15 amps so anything that can deliver 15+amps will be safe.

C x Ah = discharge amps.

So a 1450 10C is still capable of 14.5amps.

It'll get hotter faster, and you will have less performance, but the duration the battery shoots for should be about the same.

Personally, If I were adding a HT motor I'd do the 13:1 gearset as well. It's an extra £15 and the gun will be lovely to shoot after. Snappy sticatto trigger and a decent ROF.

Edit: Damn Real Sword T97B ! it's not a V3 gearbox. Nothing I posted above actually matters with the gearbox as it's a different layout!

In that situation, I'd probably opt for the gears and motor just because there known variables.

 

 

Bit the bullet and bought the RA Green 16TPA neo motor. If it doesn't stop the overspin I can switch it with the 22TPA SLD in my L85, gain some much needed ROF in the L85 and enough torque to slow down the T97B. 

 

At least with the 16TPA I can probably use a lower capacity battery without too much of a performance loss. 

 

Just thought that my Ares Soc-AR overspins quite a bit on a 11.1v lipo even though its designed for it. Might change the motor on that as well for something more torquey. 

[Asomodai]

So the RA Green motor is a little bit longer then the RS stock one, I had to take out the metal disk adjustment to get to stop complaining. Luckily the height its at now is pretty much perfect Obviously I wont be adjusting the height anyway without the metal disk in place. 

 

Seems fine now! No more overspin even on a fully charged LIFE 9.9v. 

 

I'll be taking the motor back to Chewie to get the pinion chopped slightly so I can make fine adjustments. 

 

I was really surprised how little resistance the RS High Speed motor had compared to the new Neo one. 

[Iceni]

Yeah that's the difference in ferrite V/s neo.

I don't think ferrite actually has a place in upgrade motors anymore, Neo motors are cheap enough and have better performance.

The RA motors usually have a D-type pinion. You might be able to make your adjustment sliding the pinion in a little.

You could also remove the pinion and file the back of it if it sitting right back already. The metal is not normally super hard and a standard bastard file will cut them.