Anatomy of a N-Forcer (industrial gas spring)

[OleTomCat]

Tom,

Where do you get your N-Forcer Springs and how much does an off the shelf 100mm or 125mm one cost?

[QVTom]

Direct from the manufacture.  Automation Die Mold.  I think they were 38.50 ea., maybe 48.50.  Anyways, they are nice and easy to deal with.

Tom

[OleTomCat]

I emailed N-Forcer directly and they quoted me a price of $46.95 for the 100mm or 125mm and $90.00 to custom cut one.

I have one other question, how do you figure out the FPE output of the N2 Spring when installed in an air rifle?  I am looking at the final force on the cylinder being anywere from 65~206 lbs, how does that translate into energy to the pellet?

[QVTom]

I bought 8 springs and they did a mix and match of casings to pistons for me to get a longer projection of the piston shaft.   It would make sense that the longer springs may carry a  higher cost. Even at $90 for a custom, is hard to beat.  At least in my world.


Very crudely you can calculate your input power as foot/lbs.  ex. a 200 lb spring with a 12" stroke is 200 ft/lbs.  Then multiply by the expected overall efficiency ( .2 to .35 ) .2 being poor and .35 unobtainable with out combustion.  Somewhere scotchmo posted has a simple formula that takes force and stroke into account but still needs and efficiency factor plugged in.  Keep in mind that the swept volume, piston weight and bounce, transfer port design, pellet stiction and many more variables are all wrapped up in the efficiency factor.

For a more scientific analysis, google the Prospero pellet spring gun calculator.

I know my Gamo IGTs ( 3.13 in^3) operate @ .26  and my single piston bench gun ( 7.5in^3) @ .31 efficiency, both 22 cal.

Tom

[OleTomCat]

I bought 8 springs and they did a mix and match of casings to pistons for me to get a longer projection of the piston shaft.   It would make sense that the longer springs may carry a  higher cost. Even at $90 for a custom, is hard to beat.  At least in my world.


Very crudely you can calculate your input power as foot/lbs.  ex. a 200 lb spring with a 12" stroke is 200 ft/lbs.  Then multiply by the expected overall efficiency ( .2 to .35 ) .2 being poor and .35 unobtainable with out combustion.  Somewhere scotchmo posted has a simple formula that takes force and stroke into account but still needs and efficiency factor plugged in.  Keep in mind that the swept volume, piston weight and bounce, transfer port design, pellet stiction and many more variables are all wrapped up in the efficiency factor.

For a more scientific analysis, google the Prospero pellet spring gun calculator.

I know my Gamo IGTs ( 3.13 in^3) operate @ .26  and my single piston bench gun ( 7.5in^3) @ .31 efficiency, both 22 cal.

Tom

Thanks Tom,

That is the info I needed, going to call it 20% to be on the conservative side, if it is better than that then great, if not oh well.....

[gene_sc]

Was just wondering. Tom do you think that by opening the port on the tube that the gas ram would have less bounce? It is not wise to open the ports on spring operated springers but I was wondering if it would be an advantage for additional power with a gas ram? By the way I never got past a "D" in math and barely made it through Algebra..
Gene

[QVTom]

I do know that lighter pellets favor larger TP diameters when it come to perceive shot cycle smoothness. I haven't done any testing with coil s vs gas springs to have a clue.  Although it does seem logical that with the more linear extension force of  gas spring resulting in a larger impulse and  shorter lock time, some increased diameter in the TP may yield results.  Then again, logic and spring guns usually aren't used in the same conversation.

Going back to the Cardew's book, they saw almost no measurable change when opening TPs until they got too big.  Then of course it was always a negative result.

scotchmo has done a lot of work in this area, maybe he will chime in.

Tom

[gene_sc]

Thanks Tom. I guess we would need a mathematical engineer to calculate this all out... Or just raw testing.
Gene

[V12V12]

Hey thanks for taking your time to show us this very simplistic design... Now I wish Cros and the other lower end AG manu's would stop price gouging folks for the "Nitro-Supercalifragilisticexpialidocious-piston" upgrades for $100+ WOW....  As I've been saying for years; "these dang things are nothing but overpriced trunk-lid openers!!!" Thanks for confirming it yet again!

[OleTomCat]

Hey thanks for taking your time to show us this very simplistic design... Now I wish Cros and the other lower end AG manu's would stop price gouging folks for the "Nitro-Supercalifragilisticexpialidocious-piston" upgrades for $100+ WOW....  As I've been saying for years; "these dang things are nothing but overpriced trunk-lid openers!!!" Thanks for confirming it yet again!

All the parts from Crosman to convert one of their spring guns to a gas piston is about $50.00 shipped, I ordered a set not to long ago to convert a storm, and is as easy as pulling out the spring and piston and replaceing it with the ram and ram piston.

[QVTom]

As I've been saying for years; "these dang things are nothing but overpriced trunk-lid openers!!!" Thanks for confirming it yet again!

The Crosman and Gamo units certainly are no different than you describe.  The industrial units are another animal altogether, easily a magnitude better in design and durability with the benefit of being adjustable and re-buildable.

Tom

[willbird]

As I've been saying for years; "these dang things are nothing but overpriced trunk-lid openers!!!" Thanks for confirming it yet again!

The Crosman and Gamo units certainly are no different than you describe.  The industrial units are another animal altogether, easily a magnitude better in design and durability with the benefit of being adjustable and re-buildable.

Tom

Yea the industrial stuff is designed to go thousands and thousands of cycles a DAY :-). More cycles in  day than some cheap "nitro piston" air guns see in their whole lifespan.

Bill

[HYspd]

a question, how close to drop in are the N-Forcer gas rams?

[OleTomCat]

a question, how close to drop in are the N-Forcer gas rams?

It depends on the gun, the newer Gamos have too much little space for a 125mm and the stroke is too long for 100mm so the gun and ram have to be modified to make it work...

I am currently half way through a conversion on a Gamo Big Cat to a MR19-125-Red...