So, most if not all off us have heard about KWA's GBB Kriss vector/super v, so i was wondering, why not make an Aeg version of it? (Yes, I know KWA has announced an AEG version, but then again who wants to wait? )
For the gearbox, I was considering using an svd gearbox. the svd gearbox has the motor at the very back of the gearbox, which would be ideal for the Kriss because it has nothing behind the grip to expand into. However, there is one issue with this gearbox-its too fat. Another option I have would be to use a modified p90 gearbox, for which I would have to drill a hole in the bottom of the gearbox and re position the motor there, straight down. I can assure you there is space above the trigger to fit the gearbox-end for the p90 gearbox, without the motor. For these designs, the battery would either go into the receiver (SVD gearbox), or be inside the grip (p90 gearbox.). I have ideas for the hop up and barrel, dont concern yourself with that just yet.
I think you are underestimating the amount of work it will take to make this happen. Just at a glance some problems I see:
- Trigger and contacts. I don't know what SVD box you are referring to (there are several), but the P90 uses a progressive trigger. Both designs will be difficult, if not impossible, to adapt the GBB trigger, safety, or select fire controls to. A MOSFET could be lined up with some form of micro switch (BTC Spectre is an example) but that will only allow full auto as there is no external timing source for the gears besides the cut off lever cam.
- Mags. GBB mags don't make for very good AEG mags. First and foremost is the problem of the nozzle/feedlip/hop up interface. You claim to have ideas, but mechanically you are limited by two very important things.
1. First, the stroke of the tappet plate. Typically in an AEG gear box the tappet plate moves maybe 1/2". AEG's have their bb's crammed up a tube from the mag. Pull the nozzle back far enough to get one, push it forward, done. A GBB has to strip the bb from the mag lips, push it along the feed ramp, then into the hop up, and form a seal. I don't think you can accomplish that task in 1/2". I know people short stroke race GBB pistols so maybe it can be done, but I don't think so. You technically can adjust the tappet plate stroke by moving the post on the sector gear, but the travel will be limited by how far the tappet plate can go before it hits the cylinder head. My guess is that it is already really close.
2. Second, the tappet plate is pulled back by the gears. No problems with strength there. It is pushed or pulled forward however by a rinky dink little spring. I would hazard a guess that the typical tappet spring is both not strong enough to strip a bb from a GBB mag and does not have enough force when near fully extended or compressed to accomplish the job. I've felt some pretty strong tappet springs before so maybe you can find one to work. The key though will be finding one with the grunt when near it's limits. Keep in mind that the stronger that spring is the harder the gear box has to work.
- Mounting the gearbox in the body isn't going to be an easy task. I'll say it right now, YOU CAN'T SUPER GLUE IT IN. It just will not work. I know most airsofters run to that damn bottle of glue every time something is wrong, but it won't work. I haven't seen the inside of a KWA Kriss first hand but I'm willing to bet it will need a lot of machining to fit a gearbox in there. Not the "moms nail file and some sand paper I found in the garage" approach, but a real milling machine that will leave you with something to mount the gear box to. Keep in mind that all the material you remove was probably helping to hold that pot metal frame together. KWA uses fairly resilient pot metal, but it is still brittle (look at the KWA USP trigger). I just can't see a realistic way to remove enough material to fit a gear box and still be able to hold it together.
- There may be enough space above the trigger to fit the gearbox end of the P90 gearbox, but that won't help you. The P90 nozzle is near the top of the gear box. How do you intend to get the nozzle to feed and send air down the barrel which is a good 2" lower than it? Not to mention the off axis load that will put on the nozzle to cylinder head interface. You can't just flip it over either as there is a groove for the tappet plate, and the tappet plate. Also, a vertical difference of 2" is bad for air flow. Look at the Bingo Airsoft G&G EBR Polarstar conversion for an example of a horrific flow path. That is similar to your nozzle/hop up locations.
- If the SVD gearbox is wider than the body (I'm assuming cylinder since that is typically the widest part) the P90 box won't help you as the cylinder is (thankfully) a fairly standardized diameter. TM spec AEG's are wider than real steel rifles because of the gear box. GBB's tend to be true to size which means they make bad homes for AEG gear boxes.
- Relocating the motor on a V6 gearbox is more than just "drilling a hole" in the bottom. Do you have a plan for motor height retention, a frame to resist the motors torque, can you put the Kriss receivers together with a motor sticking straight down? Don't think of Super gluing/JB welding some aluminum foil to the bottom. Neo magnet AEG motors are very strong. Welding pot metal is not worth it, and may not be possible for such a thin butt joint if you just cut off the existing frame and moved it.
These are just observations that came to me in 20 seconds. That means there will be a whole bunch more when you actually try it. I don't like to discourage people into not trying things or giving up. This is similar to taking a Powerstroke V8 and trying to stuff it into a Ford Fiesta while keeping the front wheel drive and keeping the exterior look. It just isn't worth trying because there are too many compromises. If you want to hack up a KWA Kriss, stuff a KS P90 gear box in it and have random holes covered with tape, random levers poking out of areas they don't belong, and still have to invest in $40+ mags then so be it. Personally I think you would be better off using the GBB Kriss as it is. GBB is better anyway.
The End, that is one beautiful reply. 1-Well, first thing first. The initial problem you see would be the magazines. the magazines i would use would be CYMA's AEP glock magazines. Those magazines work in the same way midcaps do,and are designed to be used in an aep and feed into a hop up, so feeding would not be an issue.
2-For mounting the gearbox, im going to make it clear and state I AM making my own body, not butchering a KWA. The gearbox will be mounted into the new body through the traditional way of making the inside of the reciever being shaped for the gearbox, and the motor cage being mounted to the weapon body. the motor cage will be either be CNC'D or a v3 motor cage, which looks like it might be able to be mounted to the bottom screw holes for the original v6 motor cage.
3-The cylinder's width isnt an issue, when i said it was too fat, I meant that the gearbox extended down into where the Kriss's trigger would be. A mosfet would probably be what controlled the fire modes in theory, but ill probably just leave it at full auto.
The nozzle location is a legit problem though. Not sure how to fix that. Thanks!