[lurkingknight]

there's a few things to be concerned about when putting that much current and voltage into an AEG... one is shimming.. this prevents gears from twisting off axis when put under extreme torque forces when the motor starts up. Shimming also ensures you have good meshing of the gears so you don't grind them together in those extreme torque conditions.

secondly, angle of engagement... the extreme torque of the motor starting up slams the first sector tooth into the pickup tooth repeatedly. At full rest, the piston in the p90 sits so the pickup tooth is grabbed by a tiny bit of the first sector tooth. It's like chiseling away at the same spot over and over again. AoE correction moves the piston out so the first sector tooth hits flush with the pickup tooth every time and distributes the impact force evenly on the face of contact. This prolongs piston and gears.

thirdly, the p90 trigger contacts are pretty weak on the semi side. They generally arc and burn even when using a 9.6v nimh, but it's not as hot or pronounced as going to higher current 11.1 lipos. This is a good reason to get a msofet, which prevents trigger arcing.

These are generally the 3 concerns when going to high voltage/discharge batteries.

Kos-Mos is describing pre-engagement, the piston assembly will not reach full forward position before the gearset starts a second cycle, this is due to a weak spring (<350fps) This generally plows the sector gear teeth into the middle of the piston rack and is what kills pistons, or since you have a metal rack, it may kill your sector gear, or if not shimmed properly, jams the gears and the softest metal bends first in the path of least resistance... probably an axle or bearing, if not the gear teeth.

There are things you can do to lighten the piston assembly to make its return speed faster... you can swisscheese the piston... drilling out as much excess material as possible to save weight. You can pull out the bearings on the piston side and put a set on the spring guide side. But it's generally accepted that a sub 350fps full stroke setup has ROF issues that will lead to something blowing up.

The more accepted way to get <350fps and greater RoF (I'll just pull a number out here... let's say 20+) is to use a higher rated spring, let's say a 130 spring that would normally shoot 450 fps, and you file teeth off the sector gear to short stroke the piston cycle. A fraction of the distance pulled = a fraction of the return speed from full stroke.

This won't effect RoF as the gears physically don't change ratios (the gearing that determines RoF is on the spur gear itself and the spur side of the sector gear), you're just not pulling the piston back as far. You will actually probably lose a bit of RoF since you're using a stiffer spring.

On my p90, I use 11.1v lipos at a 20C-25C discharge for really fast trigger response, but I also use a computerized mosfet to slow the RoF down to reasonable levels. The unit I use allows me to shoot every semi shot or the first shot of a burst at 100% motor speed, then immediately after the first cycle, drops the voltage to lower my speed to 50% of maximum. Which means I get a semi trigger that will shoot as fast as I can pull the trigger. Some guys at nightfall thought I was shooting full auto when I was not. My typical game speed I run the gun at is 15rps full auto, but the trigger response is that if I can pull it fast enough, I can probably shoot up to that speed, if not faster, only limited by the mechanical portion of the trigger (length of pull and return speed of the trigger shuttle).

100% motor speed induces a white laserbeam of BB death, which in 99% of the case, is way too much fire. Unless someone isn't calling hits.