Airsoft Canada - View Single Post

MadMax · February 1st, 2007, 00:56

Well, I figured out the dying piston problem today.

I mangled two more pistons before looking at the problem really hard. I found that CA makes their piston heads differently from TM. They're shorter than the usual piston head so the piston sits about 1mm too far forward. This makes for crappy pick up engagement so the first sector tooth makes a mess of the first piston tooth and subsequently prangs the 2nd and 3rd tooth.

I changed the piston head and piston and managed to fire off about 2000rnds in very long bursts before ROF dropped considerably and I was treated to the stink of burning insulator.

I think I fired the stock CA motor on a 300-500rnd (hard to tell except for the shredded zone of cardboard) burst.

I really want a SAW which doesn't even notice that's working, but I think I'm hitting the practical limits of the AEG design. Maybe I have to go to brushless motors which have the coils on the motor casing so I can remove heat with conduction. Brushed DC motors have always had the problem of heat removal. The coils on the armature can only shed heat to the air in the can so they can overheat. Maybe I can make a water cooling jacket for a brushless motor and bolt on a radiator like a water cooled Vickers gun.

I may also have a heat buildup issue in the cylinder. Air can heat up when it's compressed rapidly so I'm wondering if I could be making the cylinder really hot when firing long bursts. It's an issue with aircompressors which are on for many minutes at a time.

February 1st, 2007, 00:56	#23
MadMax Delierious Designer of Dastardly Detonations Trader rating Join Date: Dec 2001 Location: in the dark recesses of some metal chip filled machine shop	Well, I figured out the dying piston problem today. I mangled two more pistons before looking at the problem really hard. I found that CA makes their piston heads differently from TM. They're shorter than the usual piston head so the piston sits about 1mm too far forward. This makes for crappy pick up engagement so the first sector tooth makes a mess of the first piston tooth and subsequently prangs the 2nd and 3rd tooth. I changed the piston head and piston and managed to fire off about 2000rnds in very long bursts before ROF dropped considerably and I was treated to the stink of burning insulator. I think I fired the stock CA motor on a 300-500rnd (hard to tell except for the shredded zone of cardboard) burst. I really want a SAW which doesn't even notice that's working, but I think I'm hitting the practical limits of the AEG design. Maybe I have to go to brushless motors which have the coils on the motor casing so I can remove heat with conduction. Brushed DC motors have always had the problem of heat removal. The coils on the armature can only shed heat to the air in the can so they can overheat. Maybe I can make a water cooling jacket for a brushless motor and bolt on a radiator like a water cooled Vickers gun. I may also have a heat buildup issue in the cylinder. Air can heat up when it's compressed rapidly so I'm wondering if I could be making the cylinder really hot when firing long bursts. It's an issue with aircompressors which are on for many minutes at a time. __________________ Want nearly free GBB gas?