although i am understanding little of your conversation, learning a little is better than learning nothing. thank you!
Upvote 0
Umarex Notos Porting
- Thread starter caliusoptimus
- Start date
springs are not the most constant things in the world. their tolerances are not exact, more like between here and here.
might be that both of you are correct in your approach but the differences in the energy in the springs storage and release are different. springs wear out too.
sorry, i’m not a math guy. i’m just a dude who’s been told i have a knack for stopping smart people from overthinking.
might be that both of you are correct in your approach but the differences in the energy in the springs storage and release are different. springs wear out too.
sorry, i’m not a math guy. i’m just a dude who’s been told i have a knack for stopping smart people from overthinking.
Upvote 0
You talking about jerk?
Jerk (physics) - Wikipedia
Definitely some calculus required there, which is beyond my math skills. Using a velocity that favors final a bit more than average seems like a reasonable approach seeing as we're dealing with MS and the difference from using 2/3 velocity vs 3/4 velocity is negligible for simple estimation, but using 1/2 final velocity probably isn't ideal.
You can simplify this formula in your sheet btw caliusoptimus, my head already hurts enough! Lol
=0.5*D30*(E26-E28)*(E26-E28)
=0.5*D30*(E26-E28)^2
I modified the above formula to accept hammer travel and pre-load which from the two, you can derive free spring length, decocked spring length and cocked spring length, thus requiring less inputs and being a bit more friendly as I find those measurements easier to come by.
Yea, technically the math here should require more inputs, a lot more, from spring mass, to its oscillations, to air resistance, effect of gravity, co-efficient of friction. The only one I included originally in mine was the force of gravity acting upon the hammer velocity.
-Matt
Last edited:
Upvote 0
Ahh…. So I was thinking like a jerk…
I had considered average acceleration and I think that’s as far as went.
Dave
I had considered average acceleration and I think that’s as far as went.
Dave
Upvote 0
That's pretty good, I don't think there is much more so adding more spring won't do a whole lot, at least based on my rough estimated calculations
4.2mm port
15" barrel
200 bar
50cc plenum (presumably)
20.2gr
Let me know if any of that data isn't correct. Definitely packing a wallop.
-Matt
4.2mm port
15" barrel
200 bar
50cc plenum (presumably)
20.2gr
Let me know if any of that data isn't correct. Definitely packing a wallop.
-Matt
Upvote 0
Yep! That's about right. More spring at 200bar won't do much good... but at 250bar? Maybe I'll give it a try and see, just for giggles.
Upvote 0
I looked into changing the spring for a stronger one and...
I already have the (very nearly) strongest possible spring that will fit. A custom spring could get another 5% or so but any more than that and the spring will be pushing into plastic deformation.
That said... a custom hammer might allow a longer travel. Maybe. This could kill two or three birds with one stone... since the stock hammer is soft with a bad surface finish.... might be possible to improve the trigger feel, reduce the hammer wear, and increase power. Hmm...
I already have the (very nearly) strongest possible spring that will fit. A custom spring could get another 5% or so but any more than that and the spring will be pushing into plastic deformation.
That said... a custom hammer might allow a longer travel. Maybe. This could kill two or three birds with one stone... since the stock hammer is soft with a bad surface finish.... might be possible to improve the trigger feel, reduce the hammer wear, and increase power. Hmm...
Upvote 0
There is a lot of space for a heavier hammer. 404 stainless should wear well but it would need a high polish
Upvote 0