Featured Another DSG question....

Discussion in 'Gun Building, Modifications & Repairs' started by Jimps, Apr 19, 2021.

  1. Jimps

    Jimps Active Member

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    Looking back I am regretting getting 14:1 DSG gears, If I had to do it all over again I would go 20:1 DSG gears. I plan on building another, or after I get my current one perfect. I built a MP5K and fell in love with it the last month or so. I'm back to the DSG, which works okay I suppose. I have a 28TPA motor with SP150, I'm at about 325 on .25s bbs. Motor gets pretty warm and feel a little sluggish, trigger response is not the best either. 14:1 just has such little torque paired with such a tough spring. I've had a couple configurations with different parts trying to find the best mesh of parts. I feel as if it is close. Question is, could I drop to Guarder SP140 spring? I have room in the FPS, just wondering about PME I guess. Dropping the spring would help cycle time, RPS, amp draw..... I'm using a 18k motor, so not a super fast motor. Don't really care about RPS much, just efficiency.
     
  2. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    Nothing about your build says "efficiency"...DSG is really about RPS.

    Back in the day a stock ferrite motor turning at 18K on some 9.6V NICD could barely touch 15 rps. But it had the Air Volume to deliver pressure to spit out a bb at 375fps with .20g

    This was achieved with a EG1000, PDI 150 on a TM platform that drew about 16Amps This equated to 3 shots per mah on a Sanyo 600AE NICD Mini-pack, before the pack couldn't put out the power to turn the AEG over.

    Now slim down that Air Volume down to about 1/4th of that volume yet having to maintain a high FPS (325 with .25 g is near 375 with .20g). You need more force to generate the same pressure level. That is not efficiency....just admit it...you want the trigger response and with the the speed that a DSG gives...at a power consumption rate of 35amps (hip guestimation)...depending on internal components...
     

  3. Archer627

    Archer627 Active Member

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    Brother. I think you're out of your element here. Leave it to the techs.
     
  4. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    I am just referencing AMP draw..., you can run a 375fps DSG with only 16A per stroke?
     
  5. Jimps

    Jimps Active Member

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    Well sure, this build is not an efficient build, that is my problem.... I'm trying to make it as efficient as I can. DSGs can be more efficient than SSGs with similar performance. I have the wrong gear set to achieve that though. That is why the next build will be 20:1 instead. I just want to get the lowest amp draw without destroying my piston with PME. I'm at about 40amp in semi and about 32amps in auto. Dropping spring would lower it by by a good bit.

    Sure you can build a SSG that is super efficient, but it wont have sub 30ms trigger response, or fire 20RPS in binary. To build a SSG to do that would be super inefficient compared to a 20:1 DSG setup correctly. I built a DSG, obviously I want trigger response and high rate of fire (in semi/binary) I care nothing about shooting 40+ RPS in auto.

    70% of the people at the fields I play at use PolarStars. We all know what they can do, which puts most people with AEGs at a disadvantage. I want to be on the same playing field, or as close as I can, as those players. I will never use a polar star, can not get past the hose, and it is no fun. I enjoy building and tech work. So in order to build a AEG that can compete, DSG is the way to go, if setup correctly. I was an idiot and got 14:1 gears, which is not very torquey in comparison with the spring I am using. I can give up a little FPS to increase efficiency. Just not sure if SP140 will hit PME.

    If "the guns don't matter" and "it's about the player" why do countries spend so much money on designing weapons? M-16? Just give them a bolt action, if they are good, they can kill all the people with AK74s. Higher preforming AEGs and PolarStars give you an advantage, period.
     
  6. Raven1st

    Raven1st Well-Known Member

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    What's the RPS on your setup right now? Going off the numbers I get from the HS5 calculator I get the impression you're falling a little short of 38rps, is that correct?
    What are the specs on the battery as well?


    I don't get how air volume is factoring into Jimps drivetrain efficiency, could you elaborate?

    DSG's will never have the same energy figures as SSG's because they charge a spring to a similar level of energy in significantly shorter distance and have 2 power cycles per full rotation of the sector gear.
    Comparing SSG and DSG power figures is fun and all but there are critical differences between the two systems that there will never be true parity and unless the singular focus is on energy efficiency to the detriment of everything else it is not useful to stress it in a DSG.

    I've seen guys run test setups with cylinders like this and still get those numbers.
    It's not hard, you just have to accept that efficiency is not going to be stressed over and the final overall performance is what you're going for.

    IIRC one guy also had his test rig setup and actively tested velocity changes with several springs on several lengths of barrels, different ID barrels and even did some different cylinders sizes in various barrel lengths to test how they held up.
    My old bookmarks are all dead for this stuff and I don't have useable links anymore.
     
  7. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    I am talking about Air Volume, which leads to pressure waves that is the factor in propelling a bb, ie. the piston driving all the air out of a cylinder.

    If the pressure wave is to be maintained with less Air Volume, you need to get the smaller volume of Air volume to move much faster to do the same level of work. And to do that you need the heavier spring. Heavier spring means more stress on motor and electrical draw...thus the supposition of it being a less efficient system is - true. Jimps even confirmed he is pulling around 40A in SA and 32A in FA, I just guestimated at 35A

    Your are doing more with less, thus you need more going in to give you more going out with less. Fundamentally this is a basic application of the conservation of energy, no?

    But, my original comment was being more facetious and teasing about him having a DSG setup being "efficient" over say an old TM that ran a long time with an old NICD pack which is more inline about efficiency versus RPS of a DSG.

    As for the whole better weapon thingy, design and money into development...that is a interesting read about how we went from the .30 cal to a .22 cal for a military service weapon...and it's not just about the weapon itself...yes, I annoying read and retain information in small amount over topics of interest.
     
  8. Topper

    Topper Resident Donkey Supporting Member

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    bro stop worrying about drawing amps and start trying to draw in some hoes
     
    Last edited by a moderator: Apr 20, 2021
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  9. richman992

    richman992 Well-Known Member

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    Your hesitation to run an SP140 gives me anxiety about my DSG running a plain old M140. But honestly, I haven’t hit PME yet. Bit of a different setup though, 18:1 dsg with a 40k motor. No idea on rps but it’s FAST.

    I guess I’m saying that if I were in your shoes, I’d try the SP140. And I’d do so knowing full well I might destroy my piston. I’m not the technician that some of these other guys are, but it sounds like the motor is struggling with that spring.
     
  10. Lefse

    Lefse Well-Known Member Supporting Member

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    Can't compare a Guarder SP140 to a standard M140. Guarder uses the ".25 gram standard" so their springs give their rated velocity with a .25 gram BB rather than a .20 gram BB. A Guarder SP140 is closer to an M155.
     
  11. richman992

    richman992 Well-Known Member

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    Yes, that’s what I had meant with my comparison. I think he could run an sp140 just fine. I had to experiment with getting the lowest possible spring in mine to get it below 350, which eventually led to running the m140 despite everyone telling me it was too light of a spring.
     
  12. Lefse

    Lefse Well-Known Member Supporting Member

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    Lowering the piston weight is also a way to reduce muzzle velocity FYI.
     
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