~30 rps on 9.6v battery help!

Soberts

I have been working on a VFC scar for a while now and i am looking to get about 28 rps with a 9.6v battery.

At the moment its at about 22rps. Currently running 13:1 high speed gears (shimmed well! ), 7mm bearings, lightweight piston with 1 metal tooth (last two teeth removed to fix AOE), deans connectors with stock wiring (looks decent enough to me) and a classic army high torque motor.

I dont really want to fork out on something like a systema turbo motor so any tips would be highly appreciated. If i did get a turbo motor what would the ballpark rps be?

I was thinking of swiss cheesing the piston as the next thing but will this make a big difference or not? Im not really a fan of short stroking so if at all possible i wish to avoid this.

I see videos of people with 50rps guns but i cannot see how they manage it!

Puding

Why the high torque motor? Your limiting yoursef with that one, a g&pm120 should help you get to the target, also swiching to a7.4v lipo with a high c rating will also help you out and still fit in the scar

you seem to have focused on the complicated stuff but neglected some of the simple bits and bobs

Soberts

Puding wrote: »

Why the high torque motor? Your limiting yoursef with that one, a g&pm120 should help you get to the target, also swiching to a7.4v lipo with a high c rating will also help you out and still fit in the scar

you seem to have focused on the complicated stuff but neglected some of the simple bits and bobs

Am i correct in saying that a high torque motor will give better trigger response that a high speed motor? That was my understanding so i bought a second hand CA high torque motor (my brother also has one in his scar)

Thanks for the reply by the way!

$kilkenny

yes a high torque motor will bring up trigger responce,infact its quite nice really
or you could use a G&Pm120 as stated above and use a decent mosfet?
got one fitted in my G&P magpul last week with an m120 in it and i have to say im impressed... no lag on semi auto at all whereas with a high torque its just not as crisp.
worth a look into a mosfet anyway.
are they worth it? yes!
just another idea

defenderdude

Soberts wrote: »

Am i correct in saying that a high torque motor will give better trigger response that a high speed motor? That was my understanding so i bought a second hand CA high torque motor (my brother also has one in his scar)

Thanks for the reply by the way!

What FPS are you pulling at the moment?
A lower power level will increase your rof while not stressing the components as much.
The G&P high speed motor is probably the next move - don't think I'd bother with drilling holes in the piston till I knew the max was achieved with a good battery and the right spring.
I'm interested in seeing your results as I bought a set of 13:1 gears myself a while back for putting into a spare scar gearbox I have. Which make gears did you go for btw?

Soberts

Thanks for the reply lads! The scar is shooting 310 fps at the moment. Yeah i have a mosfet on the cards for the next upgrade alright, deciding between an active breaking and the tree round burst fancy pants one at the moment!!

It sounds like the g&p m120 is going to be purchased!! Might go for the m140 or something either.

I use the 5KU 13:1 gears from ebairsoft, i am very impressed with them, no sign of any wear at all after about 2000 rounds. I will be putting another set of 13:1 gears into a KWA m4 soon also, they arrived today, x high-tech 13:1 ratio and they also came with a suprise nylon piston with 1 metal tooth and the back 2 teeth removed as standard (also from ebairsoft, both sets of gears coming in at around 17 euro, so worth it!!)

Inari

Stick to the M120 - if you go higher than that, you're back into the realms of high torque.

High torque motors have a quick acceleration, but have a slower top speed. High speed motors have slower acceleration, but higher top speed. So for pure trigger response (read: uncaring toward ROF) then high torque is your friend. But if you're looking to up your ROF, then you need to start with the most basic of all; battery and motor.

Your first port of call with anything pertaining to speed is your power source i.e. upgrading from 8.4v to 9.6v etc, or from NiMh to LiPo (not necessarily 11.1v). Then if you're not happy, you move to the next in-line which is your motor. Swap it out for a high speed motor, and re-check. If still not happy, then you go for things like MOSFET, Gears and piston etc. This stops you spending more money than necessary.

Soberts

I dont really want to go down the lipo route as i dont want to have to check the voltages etc so they dont get too low. Are they really that much hassle or are stories over exaggerated? i heard that you dont have to do this so much with 7.4v ones?

If i was to get a lipo, it definitely would not be an 11.1v, it would be a 7.4v with a high C rating. I would also have to get a decent charger which is quite expensive

defenderdude

Soberts wrote: »

Thanks for the reply lads! The scar is shooting 310 fps at the moment. Yeah i have a mosfet on the cards for the next upgrade alright, deciding between an active breaking and the tree round burst fancy pants one at the moment!!

It sounds like the g&p m120 is going to be purchased!! Might go for the m140 or something either.

I use the 5KU 13:1 gears from ebairsoft, i am very impressed with them, no sign of any wear at all after about 2000 rounds. I will be putting another set of 13:1 gears into a KWA m4 soon also, they arrived today, x high-tech 13:1 ratio and they also came with a suprise nylon piston with 1 metal tooth and the back 2 teeth removed as standard (also from ebairsoft, both sets of gears coming in at around 17 euro, so worth it!!)

Good stuff - I have the same set myself, bought ages ago fro
EB also. Just was a bit unsure of the quality - must stick them in this week. Thanks for the info.

Inari

Soberts wrote: »

I dont really want to go down the lipo route as i dont want to have to check the voltages etc so they dont get too low. Are they really that much hassle or are stories over exaggerated? i heard that you dont have to do this so much with 7.4v ones?

If i was to get a lipo, it definitely would not be an 11.1v, it would be a 7.4v with a high C rating. I would also have to get a decent charger which is quite expensive

A bit of both. There is no argument, LiPo is more volatile than NiMh...but it is not like if you talk trash about them they'll blow your gun up. They just require more caution when charging and using them. RC enthusiasts have been using LiPo batteries for years, because of their significant advantages over NiMh (i.e. much better discharge rates, smaller overall size, while still being able to deliver significant current).

Realistically all you need to do for LiPo batteries is:
- Get a good LiPo smart charger
- Get good quality LiPo batteries (do not cheap out on this one); good C rating; 25 - 50 C is optimal
- Don't go crazy with the power; 7.4V is more than enough for most needs, unless you're going for absolutely crazy ROF, in which case 11.1v will be better suited
- Charge your batteries in a metal box, fire bag, fireplace, plant pot etc (just a basic precaution)
- Keep your eye on the batteries

When using LiPo batteries you don't need to check the voltage...you'll be able to tell when to change batteries. Performance out of your gun/battery will dip - ROF will slow, trigger response will slow. As soon as you notice this, change batteries. The reason being if you let a LiPo battery run all the way down, you cannot rescue your battery - tis dead.

There is a stigma with LiPo batteries, but that stigma is there largely because people assume 11.1v when they hear LiPo, and they also think it's too much hassle, just because it requires extra thought in charging

Soberts

That doesnt sound too bad to me at all! Sounds like the type of thing that will suit my needs. Ill more than likely end up moving to lipo when i gather some funds now!!

$kilkenny

Soberts wrote: »

Thanks for the reply lads! The scar is shooting 310 fps at the moment. Yeah i have a mosfet on the cards for the next upgrade alright, deciding between an active breaking and the tree round burst fancy pants one at the moment!!

It sounds like the g&p m120 is going to be purchased!! Might go for the m140 or something either.

I use the 5KU 13:1 gears from ebairsoft, i am very impressed with them, no sign of any wear at all after about 2000 rounds. I will be putting another set of 13:1 gears into a KWA m4 soon also, they arrived today, x high-tech 13:1 ratio and they also came with a suprise nylon piston with 1 metal tooth and the back 2 teeth removed as standard (also from ebairsoft, both sets of gears coming in at around 17 euro, so worth it!!)

you could get one with both? and if you dont like the 3rd burst just turn it off? altough they are dearer with the burst in them
i had the same problem until the guy that installed mine said he has one and he just turned off the burst.
so i just got the standard one and just shoot with short bursts on full auto

glicster

Soberts wrote: »

That doesnt sound too bad to me at all! Sounds like the type of thing that will suit my needs. Ill more than likely end up moving to lipo when i gather some funds now!!

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=7028 for your charger

http://www.hobbyking.com/hobbyking/store/__378__85__LiPo_LiFe_NiMH_Battery-Turnigy_nano_2Dtech.html for your lipos

and maybe this if your worried about the voltage drop
http://www.hobbyking.com/hobbyking/store/%5F%5F7224%5F%5FHobby%5FKing%5FBattery%5FMonitor%5F2S.html

and the prices are amazingly cheap:eek:

Soberts

$kilkenny wrote: »

you could get one with both? and if you dont like the 3rd burst just turn it off? altough they are dearer with the burst in them
i had the same problem until the guy that installed mine said he has one and he just turned off the burst.
so i just got the standard one and just shoot with short bursts on full auto

I think i will just stick to the active breaking one, i am generally a semi only guy. if i had 3 rnd burst i might use it though, but for the amount of money i save by buying the normal one i dont think its worth it

glicster wrote: »

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=7028 for your charger

http://www.hobbyking.com/hobbyking/store/__378__85__LiPo_LiFe_NiMH_Battery-Turnigy_nano_2Dtech.html for your lipos

and maybe this if your worried about the voltage drop
http://www.hobbyking.com/hobbyking/store/%5F%5F7224%5F%5FHobby%5FKing%5FBattery%5FMonitor%5F2S.html

and the prices are amazingly cheap:eek:

Thanks very much for those links, i actually came across that site earlier and it looks promising, just have to check out shipping etc

glicster

Soberts wrote: »

$kilkenny wrote: »

you could get one with both? and if you dont like the 3rd burst just turn it off? altough they are dearer with the burst in them
i had the same problem until the guy that installed mine said he has one and he just turned off the burst.
so i just got the standard one and just shoot with short bursts on full auto

I think i will just stick to the active breaking one, i am generally a semi only guy. if i had 3 rnd burst i might use it though, but for the amount of money i save by buying the normal one i dont think its worth it

glicster wrote: »

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=7028 for your charger

http://www.hobbyking.com/hobbyking/store/__378__85__LiPo_LiFe_NiMH_Battery-Turnigy_nano_2Dtech.html for your lipos

and maybe this if your worried about the voltage drop
http://www.hobbyking.com/hobbyking/store/%5F%5F7224%5F%5FHobby%5FKing%5FBattery%5FMonitor%5F2S.html

and the prices are amazingly cheap:eek:

Thanks very much for those links, i actually came across that site earlier and it looks promising, just have to check out shipping etc

shipping is maybe 10working days but you can choose what % of the value of purchase to be declered on package for customs but if you vet a charger customs might look for reciept. but either way 2 battries and a charger wont cost you too much

Soberts

shipping seems to be reasonably priced also. As a matter of interest, what happens if i get caught with say 70% of the actual price marked on the package?

Leftyflip

Customs get slightly annoyed and ask for the Paypal reciept or invoice.

Soberts

Just stuck a G&P M120 motor in and im getting 30rps with a 9.6v 1600mah battery (using audacity to measure, ill wait untill i get a chrono reading )

THE MINDER

Soberts wrote: »

Just stuck a G&P M120 motor in and im getting 30rps with a 9.6v 1600mah battery (using audacity to measure, ill wait untill i get a chrono reading )

Nice one Steve:)If you are going to run that speed on full auto with 7mm bearings consider changing to metal bushings-if not all at least under the Spur gear-7mm bearings have a tendency to collapse at those R'sOF.Also if you get the taste for the full auto game:D:D stick to a high capacity standard mosfet-it will not overheat as much as the active brake and will increase ROF a little more by reducing resistance.

Soberts

THE MINDER wrote: »

Nice one Steve:)If you are going to run that speed on full auto with 7mm bearings consider changing to metal bushings-if not all at least under the Spur gear-7mm bearings have a tendency to collapse at those R'sOF.Also if you get the taste for the full auto game:D:D stick to a high capacity standard mosfet-it will not overheat as much as the active brake and will increase ROF a little more by reducing resistance.

Cheers Dave, i think i have some solid bushings somewhere ill have a look. I always thought that bearings were better than bushings so i never used them. Definately have a mosfet on the cards, just have to work out how to wire it up as the battery contacts run through the hinge in the stock.

Also having a nightmare shimming that KWA gearbox, the bearings all stick out of the inside of the gearbox giving me hardly any space to work with, cannot get it right, spent a good hour at it so far! Might have to switch gearbox shell

Leftyflip

Yeah, bearings collapse and make a mess of the insides when used with a high ROF - bushings will be far better for this kind of thing. There's no bit's that can get lodged in gear teeth and the last time I saw one collapse, it just sat in the shell and dropped out when I removed the gearbox from the gun. It still did it's purpose.

THE MINDER

If you decide to open it again to fit bushings-here are a couple more pointers-
If you have'nt already done it take a round file and round the four corners on each side of the cylinder window-these will help prevent cracks developing in the casing.
Sand and polish da bejasus out of the rails on which the piston runs-smoother surface=less friction+faster piston movement.
I'd also advise short-stroking the piston and sector gear by two teeth,This is not purely for higher ROF but it will help diminish the chance of piston/sector gear 'prengagement' That is the sector gear catching the piston before it has sprung back=PISTON FAILURE .It does this in two ways(A) The piston does'nt have as far to travel to get back.
(B) You will be compensating for the shorter stroke by using a stronger sprig to maintain FPS. The stronger spring will also push the piston back quicker-again reducing the chance of prengagement and piston failure.
In relation to your piston you said it has 1 metal tooth-you will need to get one with at least five as you will be removing two.You also said there were two teeth removed at the rear next to the large tooth(PICKUP TOOTH) to correct AOE -this is in fact done to again help reduce risk of prengagement.
Removal of two teeth is okay(I've done it) but on a plastic type piston it can weaken the piston structure- I would favour full removal of the second last tooth and filing a 'Step' on to the third.Revove piston head bearings to reduce the overall weight of the piston assembly and use something like a pom or polycarb piston head-you can 'swisscheese' the piston if its still too heavy. Retain the bearings on the spring guide-this is enough to keep the spring rotating freely.
Check AOE-this is the angle at which the first tooth of the sector gear makes contact with the pickup(Last large tooth on the piston) tooth-it must be as flush as possible.You will achieve this by laying the cylinder with head in placcceand pushing the piston(with head attached)into its starting position.Place the sector gear in its bushing and rotate it manually te check its contact with the piston pickup tooth-if it is not flush you may have to use a spacer or something like that between the piston and piston head to attain the best possible contact at the beginning of the cycle-hope you get my drift:) Enough of that I'm going out for my dinner:D

Hope this helps more than confuses:)


PS:Could help you more with a scar but I sold mine to someone lol:):)

'

Leftyflip

Bloody ROF junkie! :P

Never got much of an improvement by "swiss cheesing a piston", only ever .5-1rps. Maybe I did it wrong! :pac:

Soberts

Thats a serious mouthfull!!! I will do as much of that as i can with the tools i have the next time i open it up (will be soon enough i think), appreciate all the tips! Dont have a dremmel so short stroking could be a pain in the ass!

Im lovin the Scar, dont think i could ever let it go! Dont know how you let go of it!

THE MINDER

Leftyflip wrote: »

Bloody ROF junkie! :P

Never got much of an improvement by "swiss cheesing a piston", only ever .5-1rps. Maybe I did it wrong! :pac:

Would'nt expect it to increase ROF -its just another measure to help avoid 'prengagement' of sector gear and piston:)

Leftyflip

THE MINDER wrote: »

Would'nt expect it to increase ROF -its just another measure to help avoid 'prengagement' of sector gear and piston:)

A lot of the stuff I heard said it was to increase ROF - experimented and found it did sweet FA. As for pre-engagement, AOE mod is my preferred way to go, take off the second and third tooth, in at least 2 years I've never had an issue.

tomaswatkins

what cylinder are you using? some cylinders can add to fps i found out using an ultimate one instead of a brass one

Soberts

tomaswatkins wrote: »

what cylinder are you using? some cylinders can add to fps i found out using an ultimate one instead of a brass one

Its the bog-standard VFC one thats in it at the moment

Leftyflip

Soberts wrote: »

Its the bog-standard VFC one thats in it at the moment

You say it like it's a bad thing - VFC cylinders, o-rings, nozzles and cylinder heads are some of the best I've used. I get 320-325 everytime I use them in upgrades, on a M85 spring. I've had time's where they'd bring it over too, with the M85.

tomaswatkins

oritey ho. id say a new motor. theres plenty hi speeds out there for good money try a site like mid west airsoft they have plenty good ones
hope this helps:D