Air Machinegun Forum
General Air Machinegun Discussion Category => Drozd and Blackbird Discussion => Topic started by: East Milford on May 20, 2017, 10:56:37 PM
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When using stiffer spring rates to achieve 2,4 or 6k rpm speeds the additional force that is applied to the clutch can prematurely wear out the pressure plate surface on the larger gear. This might not happen right away bit, if you like to shoot a lot of single fire shots the additional torque will cause quick wear from the clutch constantly needing to slip during singe fire modes.
So this is what i did to resolve the problem. Additionally it makes for a much smoother sounding operation and increased durability.
Replaced all plastic gears with hardened steel alternates.
The gears requires some minimal machining.
The clutch has been replaced with a carbon fiber unit that is twice as thick at 1mm. The D shaped anti-rotation bore is still applied to the clutch.
If anyone is interested in a gear set, or just a new steel drive gear for your upgraded motors you may send me a message and I'll gladly help you out.
Enjoy.
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Thanks for the great info.
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Now you are talkin' turkey. I want to see that thing whine at 6K. This is what 5K sounds like.
https://www.youtube.com/watch?v=T4hNz1l9usE (https://www.youtube.com/watch?v=T4hNz1l9usE)
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Now you are talkin' turkey. I want to see that thing whine at 6K. This is what 5K sounds like.
https://www.youtube.com/watch?v=T4hNz1l9usE (https://www.youtube.com/watch?v=T4hNz1l9usE)
Hi Mason,
For the 6k i didnt use meshing gears. I used two cogs with a roller chain. I lost interest in the 6k, it was just superfluous in my opinion. It's so fast that it doesn't even sound automatic, its just a constant loud drone. I guess i prefer playing around with 2k the most fun. The velocity at 6k was stupid slow too. I had to use two separate hpa tanks fitted to one line to get enough volume to keep up with what the valve body can put out at those speeds.
Good luck with your 6k, im sure you will hammer it out soon enough.
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East Milford I sent you a pm
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Nah. Pretty much came up with the same conclusions on the bird. I did have to fit some burned out clutch gears with brass washers though. Just a different take from your CF plate, and metal gears which sounds superior.
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Mason, let me know if you want me to send a gear set your way.
P.S. Have a look at the BB feed tube mod i did. There is a significant gain in FPS to be had. It makes the gun a good bit louder too. I'll have to do a decibel test but I'd estimate that it gains more than 10db. It most noticeably increases the fps during full-auto strings.
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Here are more pictures, these better show the machining that is done to the gears. These are made specific for the Drozd drivetrain.
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Nice work! What pitch did you go with?
TBK
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Stock pitch is .5mod.
For the complete kits i did it in 48p, there are more styles of gears to choose from in this dimension.
2.3mm for the jameco motor shafts. 1/8 bore works for the middle gear, and 5mm bore works with a little sanding for the auger gear.