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Thread: Mechanical advantage of Spring Guns vs Pneumatic pump airguns

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    Mechanical advantage of Spring Guns vs Pneumatic pump airguns

    In collecting vintage Airguns in the US you find mostly pump guns. My focus of collecting lately have been prewar spring guns. I have always heard that cocking spring guns is more efficient given pumping of air gives off wasted heat? Has anyone ever calculated the efficiency difference?

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    I’m sure that has been done.

    This was Jim Tyler’s explanation, though without quantifying how much more efficient a springer is, but suggesting that it’s not all down to heat:

    https://www.airgunshooting.co.uk/exp...work-1-5181958

    For what it’s worth, a back of an envelope calculation based on the cocking/pumping effort figures in Tom Gaylord’s blog suggests that a typical 12-14 ft-lbs springer requires 30-40 lbs (equivalent) to cock, whereas pumping a Sheridan up to achieve similar power needs more than 200lbs of effort.

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    Quote Originally Posted by Geezer View Post
    I’m sure that has been done.

    This was Jim Tyler’s explanation, though without quantifying how much more efficient a springer is, but suggesting that it’s not all down to heat:

    https://www.airgunshooting.co.uk/exp...work-1-5181958

    For what it’s worth, a back of an envelope calculation based on the cocking/pumping effort figures in Tom Gaylord’s blog suggests that a typical 12-14 ft-lbs springer requires 30-40 lbs (equivalent) to cock, whereas pumping a Sheridan up to achieve similar power needs more than 200lbs of effort.
    That is a insane number need to find Gaylords blog.

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    https://www.pyramydair.com/blog/2019...reak-part-2-2/

    You do the math.

    Basically, with most regular 12ish ft-lbs pumpers, the major pump strokes once you get past the first 3 or 4 are each the rough equivalent work of cocking a fairly powerful springer. Even a typical Beeman R1 takes about 40 ft-lbs.

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    Quote Originally Posted by Geezer View Post
    https://www.pyramydair.com/blog/2019...reak-part-2-2/

    You do the math.

    Basically, with most regular 12ish ft-lbs pumpers, the major pump strokes once you get past the first 3 or 4 are each the rough equivalent work of cocking a fairly powerful springer. Even a typical Beeman R1 takes about 40 ft-lbs.
    Fascinating, it’s really the amount of effort it takes at each pump to get a diminishing increase in power. At each pump you have to fight that air volume already in the gun to get even more in? What a stupid system when you think of it. Lol

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    Quote Originally Posted by 45flint View Post
    Fascinating, it’s really the amount of effort it takes at each pump to get a diminishing increase in power. At each pump you have to fight that air volume already in the gun to get even more in? What a stupid system when you think of it. Lol
    As I was educated on this forum, don't forget about 'Boyle's Law' cheers Al.

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    Quote Originally Posted by cringe View Post
    As I was educated on this forum, don't forget about 'Boyle's Law' cheers Al.
    https://imgur.com/a/jWkjvPr

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    You need Cardews “Airguns from trigger to target”. Iirc he does the maths in there.

    Every air gunner should have this book, it is British men-in-sheds at its finest.
    Morally flawed

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    Wasn’t it Cardew who experimented with a spring gun using nitrogen rather than air, and found the power considerably down due to the lack of dieseling? Another factor regarding energy comparisons.....

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    Quote Originally Posted by springfieldm6 View Post
    Wasn’t it Cardew who experimented with a spring gun using nitrogen rather than air, and found the power considerably down due to the lack of dieseling? Another factor regarding energy comparisons.....
    It was indeed.

    According to cardew he got an overall efficiency of 5% pumping up a pneumatic

    He got 25-35% efficiency from springers. So pneumatics c six times less efficient , about where Geezer and Tom Gaylord had it.
    Morally flawed

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    Quote Originally Posted by Jerry Cornelius View Post
    It was indeed.

    According to cardew he got an overall efficiency of 5% pumping up a pneumatic

    He got 25-35% efficiency from springers. So pneumatics c six times less efficient , about where Geezer and Tom Gaylord had it.
    Thanks for the info

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    Apologies in advance for pulling things out of my rusty memory instead of looking them up, but one way to think of it is that a springer uses a small volume of air at high pressure, where an MSP uses a larger volume of air at lower pressure. I vaguely recall reading "somewhere" that the pressure difference is an order of magnitude, like maybe 200 PSI stored in the pump gun's chamber, vs. 2000 PSI generated for an instant in a 12 FPE springer?

    I grew up on "pump guns" and as much as I've come to prefer springers in my dotage - the light weight, variable power, fixed barrel, and recoil-free firing cycle of my ancient Benjamin "Tootsie Roll" 347 are still great. When I am asked by a "non airgun" friend to recommend one airgun for plinking or pesting, I most often steer them toward an MSP.

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    Quote Originally Posted by MDriskill View Post
    Apologies in advance for pulling things out of my rusty memory instead of looking them up, but one way to think of it is that a springer uses a small volume of air at high pressure, where an MSP uses a larger volume of air at lower pressure. I vaguely recall reading "somewhere" that the pressure difference is an order of magnitude, like maybe 200 PSI stored in the pump gun's chamber, vs. 2000 PSI generated for an instant in a 12 FPE springer?

    I grew up on "pump guns" and as much as I've come to prefer springers in my dotage - the light weight, variable power, fixed barrel, and recoil-free firing cycle of my ancient Benjamin "Tootsie Roll" 347 are still great. When I am asked by a "non airgun" friend to recommend one airgun for plinking or pesting, I most often steer them toward an MSP.
    You might find this recent thread interesting.

    http://www.airgunbbs.com/showthread.php?879722-Pumpers

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    Quote Originally Posted by MDriskill View Post
    Apologies in advance for pulling things out of my rusty memory instead of looking them up, but one way to think of it is that a springer uses a small volume of air at high pressure, where an MSP uses a larger volume of air at lower pressure. I vaguely recall reading "somewhere" that the pressure difference is an order of magnitude, like maybe 200 PSI stored in the pump gun's chamber, vs. 2000 PSI generated for an instant in a 12 FPE springer?

    I grew up on "pump guns" and as much as I've come to prefer springers in my dotage - the light weight, variable power, fixed barrel, and recoil-free firing cycle of my ancient Benjamin "Tootsie Roll" 347 are still great. When I am asked by a "non airgun" friend to recommend one airgun for plinking or pesting, I most often steer them toward an MSP.
    I bought my first and only Airgun 20 years ago a Beeman R1. After retirement 5 years ago I started collecting all kinds of vintage Airguns. The American vintage forums were so enamored by pumpers I have tried my share. I just have fallen in love with prewar springers and am about ready to unload my small pumper collection. They just make no sense to me anymore? I can appreciate the history in the Crosman 101 etc. but but after awhile you start to find the guns that make the most sense to you and those you just love.
    Last edited by 45flint; 07-03-2021 at 10:01 PM.

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    The math(s) is interesting, but there’s also personal experience, which is that even if you are a body-builder pumpers are arduous repeatedly to pump to full power (and slow, compared to a springer, and tend to go clacky-clack each pump which scares things off).

    As above and in the other thread, they have a lot to be said for them if you mostly use them at lower power while reserving the option of full-charge when needed.

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