Bettering your Version 2 Gearbox

[Franatix]

I am asking for suggestions on how to improve my M4. I want to improve the rate of fire as well as the range it has on it.

Im also looking at switching out the tamiya's to deans.

Any suggestions or help will be much appreciated.

[Sonkut]

Re: Bettering your Version 2 Gearbox

Typically you adjust the gearbox for one or the other, rate of fire or FPS. If you want to do both it could be awquard to do, first you need to know what sort of fps your hitting and what you want to go up to. high speed motors are good for upping your rate of fire and a bigger battery too.. The problem with higher rate of fire is greater stress on your gearbox, if you put in a better spring then thats more load which may cause issues on your motor.

Long story short.
replace your O-rings to make sure you have a good seal.
if you can upgrade to a teflon cylinder, this will help your rate of fire.
Piston with titanium teeth wouldn't go amiss, stops you ripping it appart.
high speed motor
slightly bigger spring.

This should do it, hopefully withough mangling anything.
Additional options - high speed gears - upps the rps at cost of strain on your motor
bigger battery - upps fps at cos of strain on everything.
oh, make sure you have metal bushings too.

[RedHawk]

Re: Bettering your Version 2 Gearbox

high speed motors are good

Nope. High torque motors with neodymium magnets are the only motors you should ever buy. The rest are pointless.

Also, I wouldn't ever use a full metal tooth piston. Why? What happens when a polymer piston strips? You replace it, quite cheaply. What happens when your piston's teeth are metal and two metal surfaces are put together? You could end up destroying gearsets or the gearbox. They are simply not needed at sub 350fps unless you're doing a monstrous 60 RPS setup.

Here's what I'd personally suggest.
1. Bigger battery - Can either up the MAh or the volts, your choice. Voltage has a bigger effect on ROF
2. High Torque Motor - Preferably something like SHS or X-HighTech that doesn't cost £100
3. MOSFET - If you want your gearbox to survive LiPos then get one.
4. Deans - One of the better types of connectors available. They can give an obvious increase in ROF
5. Angle of Engagement - You need to ensure that your sector gear properly engages with the piston. Some people shave the 2nd tooth down on the piston (another reason to avoid metal pistons) so that the first tooth on the sector gear engages with the piston at the correct angle. This is VERY important at high speeds.
6. Sorbothane - More commonly known as a sorbo. Can be used to reduce the force of the piston when compressing as well as push the piston forward to allow a better engagement angle on the first sector tooth. They make your gearbox quieter too.
7. Remove any clone/nasty China pot metal parts. They may work ok, but for a decent gearbox you're going to need decent parts. This includes:
O-Rings
Cylinder
Cylinder head
Piston
Piston head
Gears
Bushing/bearings (apparently bushings on all gears except the bevel gear where a bearing is recommended)
Gearbox
8. Spring - High speed setups works better at a lower FPS. This is due to a less powerful spring being more easy to pull back. 280-300 FPS is good for high speed.

If you know how to shim then it will allow you to install your gears and get them in the correct position. I can't stress how important it is to have correctly shimmed gears. If they are mm's out of place then they can contact other surfaces or not engage properly. This causes a loss of energy.


If you want any more advice, go on forums.airsoftmechanics.com but bear in mind that Americans like 500 FPS guns doing 30 RPS - A lot of the mods they do would be overkill for the best possible gun in the UK (such as full metal teeth on the piston). If a lot of it seems like jargon then feel free to PM me.

[Franatix]

Re: Bettering your Version 2 Gearbox

Thanks for the help guys.

I just received some dean connectors in the mail. Will get them installed as soon as i find the soldering iron. From what i hear, just this simple upgrade should make a pleasing difference. My brother recently acquired a Marui CQBR. Im pretty jelly of what it was capable of throwing out. Rate of fire was just nuts!

Also looking into a new motor. Im not to sure what the gear box is like internally. The gentleman i got it from had it as a completely custom build built professionally.

Bear with me, as there's a mix of parts in the build.

G & P Body - MUR Upper and Novekse Lower.
Madbull Stock - Long - can take a Lipo battery with ease, has a QD sling swivel on it
Front End - a Real Steel KAC RAS II , fitted with ladder protectors and an VFG.
Pistol Grip - Falcon Ergo , running a CA Motor.
Gearbox - scratch built for me, runs happily on a Lipo all day. Still bedding in. Currently doing 320 fps (ish)
CA HOP Unit and inner barrel
ACM Larue Mount and Aimpoint red dot sight.
Suppressor and Collar (remove this and it makes a nice CQB tool)