As I mentioned in my last post, I decided to do some testing on the difference in rate of fire with a stock DBoys Full Metal M4A1 and different motors and battery voltages. At the time I had available to me the stock motor that came installed in the M4, a Tokyo Marui EG700 motor and a Systema Turbo motor. Batteries used for testing were the standard 8.4v mini battery which the M4 came with and an Intellect 1400Mah 9.6v battery.
Onto the tests..
To calculate the average rounds per second, I used my laptop with a standard pc microphone and used Audacity to record the sound of the gun firing. Each wave peak recorded and graphed by audacity can be counted as a single shot. For each test, I fired one 2 second burst followed by a 3 second burst.
From the sound wave produced in audacity, I then counted the number of peaks in a given second. I took 3 seperate seconds and calculated the average based on those. Below is a table of the results achieved. Note that there is no figure for the Systema Turbo motor running on the 8.4v battery, the cheap batteries that come free with clone AEGs do not appear to be powerful enough to push this motor with a 1 Joule (or close to it) spring installed. However I have tested with a good quality 8.4v battery and it ran quite well, although it was at a skirmish so I was unable to record the rate of fire at the time.
ROF
8.4V-1
8.4V-2
8.4V-3
8.4V Average
9.6V-1
9.6V-2
9.6V-3
9.6V Average
Stock
11
11
12
11.33
13
14
14
13.67
TM EG700
11
11
11
11
14
14
14
14
Systema Turbo
N/A
N/A
N/A
N/A
17
17
17
17
And while we’re at it… here’s a nice shiny graph of the whole lot:
Motor and Battery Rate of Fire Comparison
It should also be noted that the Systema Turbo motor is a very heavy drain on a battery, the Intellect 1400Mah battery I used lasts less than a thousand rounds, so you pay a price for that kind of rate of fire.
Interestingly the stock Dboys motor and the TM EG700 motor performed exactly the same, running with a 9.6v, the TM motor did average 14 rounds per second as opposed to the stock motor’s 13.67, however this is not a significant enough difference to be conclusive. Physically the two motors are identical and performance wise they also appear to be the same.
There’s not much more to say on the matter really, the results above say everything I could, any questions or comments though, feel free to click the comment button below.
Oh and while we’re here, here’s some nice pictures of the various wave forms recorded in Audacity:
Well, it’s been a few weeks since I posted anything, but just wanted to put up a post of what to expect on here soon…
Cyma Glock 18 Review
As promised in my first post on this blog, I will eventually get around to posting a review of the Cyma Glock, this is a nice little AEP which costs about half the price of it’s TM counterpart.
Cyma Glock External Battery Install
The main disadvantage of the Cyma Glock AEP (and alot of other AEPs) is the limited space for a battery, hence the reason why they only have a 7.2v mini battery installed, so instead I decided to custom make a lanyard which clips onto the bottom of the handgrip and can be run to a belt/vest/pocket to utilise a larger external battery. So far I’ve briefly tested this and installed some wiring but it hasn’t quite performed as expected, right now it looks like the wiring is causing the problem, so this will have to be re-wired with some higher quality wire, although this is difficult given the limited space inside the pistol.
Molybdenum Disulphide Gearbox Mod
Moly…. WTF? Indeed, I read about this on a thread over at arnie’s airsoft, it’s commonly known as dry lube, the basic concept is that it acts similarly to a teflon coating on the gears allowing the gearbox to perform very well without wet grease becoming dirty and clogging up the gears. I’ve been waiting about 6 weeks now for a can of this stuff to be delivered to me and it finally arrived today. I hoped to test it in my Cyma mp5-J, looks like I’ll have to wait another couple of weeks to test it out (see below), but when I do, I’ll post a full review here and an update after several thousand rounds have been run through it.
ACM “Silent” Piston Head
Picked one of these up on rsov.com with an order a few weeks back, haven’t yet decided which AEG to test it in, but as soon as I do I’ll be posting a review along with audio comparisons of noise output from the gearbox.
Right now, I’m limited on time, this coming Wednesday (18th) I’m flying to Barcelona to spend a month travelling by rail around Europe, I’ll aim to check out at least one european airsoft site while I’m there and will post here any (airsoft related) experiences I have over there.
I aim to post the Glock review before I go anyway, and the rest as soon as I can. I’ve a few other ideas in mind and will be updating this blog as those ideas come to fruition.
So way back in the day when I bought my first airsoft AEG (A little less than a year ago now, since the law in Ireland has only recently changed), I bought a Cyma Mp5-J from actionhobbys, I think it cost me around €130 at the time, which is an average price for a clone. Service from actionhobbys was very good, I think I was one of their first customer’s from Ireland and they were very helpful in looking up shipping costs for me. Anyway, being my first AEG, I loved it, but even now that I’ve bought more airsoft guns and fondled plenty of other people’s, it is still a great gun for the price. It is well made, sturdy and I’ve yet to have any major problems with it. It fires at around 260fps with 0.2g bb’s, which is decent enough.
Since it didn’t cost too much, and I’m currently using a TM P90 as my main aeg, the mp5 has become my project gun. I think I must have stripped and rebuilt the gearbox at least 20-30 times now, and that’s no exaggeration. The first of my many upgrades on this gun was a Systema 6.04 tightbore barrel, one of the downsides of the Cyma is that the hopup unit is a little weird and non-standard, so a bit of dremel’ing was involved to make it fit, but this wasn’t too hard to do, taking about an hour or so to complete. All went well and I brought it to my next skirmish the following weekend at hrta, before the first games of the day, I was out in the firing range and had my first experience of “THAT horrible grinding noise”, yup I’d stripped a gear, I cursed the gun and ended up using a Galaxy mp5k for the day which was a rental gun, I also had my HFC m190 pistol at this stage, but not the P90.
Eager to get my mp5 back up and running, I ordered a Guarder Full Tune Kit from ehobbyasia. I had a few problems getting the FTK installed in the Cyma gearbox, it would often jam up after several shots or jam before even firing one shot. After several days of frustrated rebuilding, I eventually found the problem to be the Guarder upgraded piston, I swapped out the piston with the original Cyma one in the gearbox and had the mp5 up and running quite well for a while with the stock spring and piston and the rest of the gearbox upgraded. At this stage, I’d had my p90 a few weeks and the mp5 became a little less used, it was under-powered and nowhere near as fast as the p90.
About two weeks ago I decided it was time to give myself a reason to use the mp5 again. I went ahead and ordered a PDI 120 spring, which is good for 300-330fps and also a Systema Turbo motor. I’d read some information on the Systema Magnum and Turbo motors, they offer high speed and high torque in the one motor, ordinarily it’s a choice between one or the other. They are pricey motors at approx USD$80 without shipping, but I figured why not? While I was browsing, I decided I’d throw a 9.6v battery into the order for good luck, I was still using the 8.4v that came with it and needed a new battery anyway.
Last Friday I installed the new motor and spring with the rest of gearbox as it was, holy shit are those motors fast. With the stock motor and spring in my mp5, I was getting around 12/13 rounds per second, with the new motor and a 1 Joule spring it was pumping out an amazing 24 rounds per second, pretty damn fast I have to say.
After my initial excitement about the rate of fire, I started actually listening to the gearbox between shots, it didn’t sound good at all, I knew what the problem was at once, the stock piston just couldn’t handle the upgraded power and speed, I left the piston in and decided to go ahead and bring it to a skirmish at hrta the next day. After some initial showing off of the rate of fire (people have commented on the speed of my p90 at 17rps), I attempted to chrono the mp5, unfortunately the semi-auto has never really worked all that well since I got it and no longer works at all, so firing a single shot is a matter of being very quick on the trigger, it was impossible to get a proper reading. I also noticed after my showing off that it didn’t seem to be firing very well at all and the gearbox noise had gotten worse, I left it in my bag knowing I would have to rebuild it when I got home.
Got around to opening the gearbox tonight and it was not a pretty sight at all. Eleven (yes, that’s right 11) teeth are stripped off the piston, and the next one is not looking too good either.
The sector gear didn’t look too good either, a few of the teeth (around 11 I would guess ) had the gaps in between them filled in with a collection of the plastic from the piston and the grease in the gearbox.
I spent a few mins cleaning the gunk out from between the gear’s teeth and grabbed the upgraded piston that came with the full tune kit, I had decided I would dremel the piston if necessary to fit it in, the problem appeared to be caused by the rails not sitting correctly in the gearbox, I had a look and it seemed there was a bit of plastic which had been badly formed on one side of the piston rails, although it was barely visible to the naked eye, I could feel it if I put the piston into the rails inside the gearbox. A few rubs with a sharp screwdriver and the extra bit of plastic was gone, the piston now slid freely inside the gearbox.
So fast forward a half hour and I had the gearbox rebuilt, re-greased, the PDI 120 spring installed and the gearbox mounted back into the lower receiver with the motor installed. Now where the hell did I leave that bloody battery…
They say a picture paints a thousand words, so below is a video of it firing, at this stage I was just testing so just had the gearbox mounted in the lower receiver:
As you can see, it’s pretty fast, with the new piston in, it’s getting 20 rounds per second now, still not too bad at all, the reason it has slowed down is because now all the piston teeth are intact, it’s not releasing the piston early anymore, if I was to remove a tooth or two on the piston, the rate of fire would increase again, probably back up to around the rof it was with the original (damaged) piston in place.So there you have it,
Cyma mp5-j = Great clone/starter gun
Systema Turbo Motor = Bloody fast motor
Cyma mp5-j + Turbo motor = CQB Support Weapon
Now I just have to find a box-mag for an mp5.
Oh and incase anyone asks, yes the original mag can handle the higher rof just fine, no jams or misfeeds with it yet. Below is a video of it firing at a target net.
) had the gaps in between them filled in with a collection of the plastic from the piston and the grease in the gearbox.
