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|04-10-2010, 08:14 AM||#1 (permalink)|
Nelson valve tuning for efficiency.
So this is my understanding of Nelsons.
**This is assuming 12 gram usage**
I believe optimum efficiency can be achieved through several factors.
1. Strong Valve spring (Nelson length Red plus a spacer possibly, or a cocker valve spring since they're longer)
2. Lightest Main spring possible so that the hammer dwell time is as low as possible.
3. Underbore!! To what degree I cannot say...I like to run freak inserts sized at .680 or .675 on all my paint. Basically...if I am getting barrel breaks at .675, I just switch to .680.
4. 8-11" barrel.
5. how much internal volume is ideal for the valve? I know of opposing arguments, for ex. DSA's redux valve volume is 'stock', but he has an extended barrel, plus a counter-intuitive spring combination (red main and blue valve ), and gets 45+ useable shots.
Another redux user had 'stock' internal valve volume and was getting less than 20 shots. He then had his valve bored out by Mongo, and achieved a noticeable jump in efficiency.
6. Is better for the CO2 to be in liquid or gas state at the point of contact with the ball in the barrel??
7. Hammer bounce is a no no! Now the question arises, what is the ideal weight for a nelson based hammer? I'm thinking in the range of 23-30 grams. What is the "sweet-spot" for the hammer weight, i.e. is there an identifiable hammer weight where it becomes too light and results in you having to dial in your TPC, creating hammer bounce again?
A way to test this audibly would be to install a rubber band or spacer on your powertube so you can 'dry' fire your nelson. Cock and then fire it. A nelson which has hammer bounce makes a distinctly different noise from one which does not have hammer bounce. You can hear a noise like "brruuump"(hammer bounce) instead of "bump"(no bounce), which comes from the hammer bouncing.
Do you guys think that milling or dremeling a phantom hammer down to 23-24 grams will make a big difference over one that is milled to 29 grams? I do not have an accurate scale, I was thinking of just dremeling the **** out of my phantom hammer and trying that out, and getting one professionally milled to 29 grams to compare. If anyone has any actually data, like "I was getting 30 shots from my phantom before, and then I dremeled my phantom hammer till almost nothing was left, and then got 50 shots from a 12 gram", that would be really nice.
Thanks, sorry for the rambling nature of this post.
Last edited by ironchef97; 04-10-2010 at 08:17 AM.
|04-11-2010, 06:58 PM||#4 (permalink)|
Join Date: Jul 2006
|04-11-2010, 07:25 PM||#6 (permalink)|
Join Date: Jul 2006
|04-11-2010, 07:44 PM||#8 (permalink)|
Join Date: Apr 2006
Location: Albany. NY
Temperature and the style of 12 gram changer (distance from 12 gram to valve) will also play into how you tune the gun.
|04-11-2010, 11:07 PM||#9 (permalink)|
starts off small at first
Join Date: Apr 2006
Location: Bean Town, U.S.A.
I know this will hit some sour notes, but do any of you feel it's worth building a Nelson drop in kit able of operating at 250psi?
"Democracy is the worst form of government except for all the others which have been tried." Winston Churchill
THE-SHOOTIST Anyone chubbin' like me for this?
mailmanmike Since Monday! That's more than 4 hours though, so according to those cialis ads I should see my doctor.
tlane77 I think for a non-chemical chubby it's 6 hours before its time to see a doctor. So you should be good for another couple hours.
splattttttt I wasn't goin to google "chubbin" because I assumed it had to do with fat. The lard type, not the fun stuff. But what ever feelings Jeff's experiencing, then they must be of the fun like stuff...
tlane77 He's got a woody for your woods. splattttttt land
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