My Hayabusa PCP - The Experiment Continues

[rsterne]

Turned it offset in a 4-jaw.... Milling it?.... I don't have either a CNC or a rotary table.... or a mill, for that matter.... just a milling attachment for my lathe....

Bob

[SeanMP]

Lol...yes O1.

Sloppy fingers.

[SeanMP]

WOW.....Okay so firstly I'm sitting here p!$$!ng myself I'm laughing so hard. Glad you and the barrel are okay (good thing I put carbon fiber armor on it eh)

And ....
EUREKA....ya did it!
106 FPE is freekin outstanding! And a damn nice string to boot.
Initial accuracy looks good and I'm sure it will get better once you work that horse. Polish it out between sessions with the red (bore bright) The velocity should come up and group size down.

[SeanMP]

A 70 duro Oring is certainly feasible but the gap is critical at 3000psi

PRESSURE-DUROMETER.jpg

[rsterne]

These might help....

http://www.ablesealanddesign.ca/cate...esign/183.html

http://www.ponnmachine.com/groove_design.html

Bob

[SeanMP]

Excellent Now that you have a working valve your back to not needing as much spring.

photo (2).jpg

I still think there is merit in this design

[rsterne]

Here is a graph showing the Hammer momentum vs. the Sum of (Opening Force plus 2X FPE) for the .224, .257, and .308 versions of my Hayabusa....



The trend is very close to linear as you can see.... However, before this can be used for predictions, there is one big caveat.... All three calibers are tuned in a similar manner.... They all have the valve closing at nearly the same point in the pellet's travel down the barrel (43-46%), and they all have nearly identical efficiencies (1.11-1.15 FPE/CI).... Therefore, the only real variable left is the caliber, hence the bore volume, and the associated FPE.... If any (or all) of these examples were tuned for a different power level, the hammer strike would change.... Whether or not it would stay on the trendline I can't say....

Bob