Search found 5401 matches

by Ragnarok
Sat Jan 20, 2018 7:54 pm
Forum: Pneumatic Cannons
Topic: Pvc pricing
Replies: 7
Views: 1047

Re: Pvc pricing

It's not uncommon for the US dollar price of things to be somewhat out of whack with the strict exchange rate. (Particularly depending on local taxes and whether they're shown in the price. In the UK, the vast majority of non-trade stores include all taxes in the list price. I'm lead to believe that...
by Ragnarok
Fri Jan 19, 2018 9:36 am
Forum: General How-To & Discussion
Topic: "In the world of spuds today"
Replies: 2423
Views: 181372

Re: "In the world of spuds today"

Do you have a data sheet on that valve? Use it for comparison to what you now have. Did you save the recently replaced valve for studying? I've certainly still got the one I removed a couple of days ago, but there's nothing visibly wrong with it (although the sealing face is very hard to inspect, a...
by Ragnarok
Thu Jan 18, 2018 9:51 pm
Forum: General How-To & Discussion
Topic: Short question topic
Replies: 1488
Views: 122953

Re: Short question topic

Cthulhu wrote:But if bbs go at ~750 fps with their magnetism...
The BBs are (ferro)magnetic, but they are not a magnet - that's a huge difference in this context.
by Ragnarok
Thu Jan 18, 2018 9:08 pm
Forum: General How-To & Discussion
Topic: "In the world of spuds today"
Replies: 2423
Views: 181372

Re: "In the world of spuds today"

Do you think that the screw clamp might be putting just enough side pressure to cause the damage under the conditions during firing? It's been some years since HEAL was configured that way. These days, everything is mounted in a wooden stock: http://www.spudfiles.com/resources/image/26434 In any ca...
by Ragnarok
Thu Jan 18, 2018 9:06 pm
Forum: General How-To & Discussion
Topic: Short question topic
Replies: 1488
Views: 122953

Re: Short question topic

The 880 is advertised as being "dual ammo" (able to shoot bbs and pellets) and the magnetic bolt tip is a feature made to make loading bbs easier (all Daisy steel bbs are magnetic). A magnet in the bolt tip is a completely different case. It's not moving relative to the barrel. A magnet in the proj...
by Ragnarok
Thu Jan 18, 2018 8:29 pm
Forum: General How-To & Discussion
Topic: Short question topic
Replies: 1488
Views: 122953

Re: Short question topic

You mean that there is a lack of data in my question, I mean the flow of the valve and the air temperature. Yes and no. There's not enough data, but getting good data and doing a broadly accurate calculation with it is impracticable. The supersonic region is very difficult to predict, as small chan...
by Ragnarok
Thu Jan 18, 2018 12:22 pm
Forum: General How-To & Discussion
Topic: Short question topic
Replies: 1488
Views: 122953

Re: Short question topic

What approximate pressure is needed to drive an airsoft ammo of 0.20 gr and a firing barrel of about 15 "at the speed of sound? It's not possible to answer that with any degree of accuracy. When you get near the speed of sound, specifics like gas temperature and valve flow become very significant, ...
by Ragnarok
Thu Jan 18, 2018 12:10 pm
Forum: Pneumatic Cannons
Topic: Advantage of QEV over Solenoid valve.
Replies: 5
Views: 960

Re: Advantage of QEV over Solenoid valve.

What my actual concern is, what kind of performance difference will I have between using a 3/4" QEV or running the chamber directly through a 1" solenoid valve. Honestly? I'd say that neither is really up to the task for a ~2.7" bore, particularly if you're looking to get the most out of 500 psi. A...
by Ragnarok
Thu Jan 18, 2018 11:45 am
Forum: General How-To & Discussion
Topic: "In the world of spuds today"
Replies: 2423
Views: 181372

Re: "In the world of spuds today"

Is it a ball bearing to seat or spool valve design type of check valve? Most pneumatic check valve designs are reeds type that I've seen. Of those, "ball bearing to seat" is the closest description to both the current valve and the one before, although it's actually a tapered cone. I can't remember...
by Ragnarok
Wed Jan 17, 2018 12:20 am
Forum: General How-To & Discussion
Topic: "In the world of spuds today"
Replies: 2423
Views: 181372

Re: "In the world of spuds today"

*Grumble* It seems the check valve in HEAL's trigger group is leaking air back through it. (Again rather vindicating my decision to incorporate redundant safety features - this isn't the first time a check valve has failed on me, although last time was a little more spectacular, as the valve actual...
by Ragnarok
Mon Jan 15, 2018 10:00 am
Forum: General How-To & Discussion
Topic: "In the world of spuds today"
Replies: 2423
Views: 181372

Re: "In the world of spuds today"

Zeus wrote:Rag, do you mean your brother doesn't want hot, moist air in his oiled "shock absorbers".
Possibly, but I also suspect he doesn't want them pressurised to 4000 psi.
by Ragnarok
Sun Jan 14, 2018 3:04 pm
Forum: Pneumatic Cannons
Topic: 2.5'' piston or dual 1'' metal sprinkler valves
Replies: 1
Views: 459

Re: 2.5'' piston or dual 1'' metal sprinkler valves

I was wondering if a 2.5'' piston valve would have more flow that dual 1'' sprinkler valves. Massively so. Flow is proportional to area, not diameter, and a 2.5" valve has more than six times the area of a 1" valve. Even with two valves, the sprinkler aren't even close. With my prototype, the canno...
by Ragnarok
Sun Jan 14, 2018 9:52 am
Forum: General How-To & Discussion
Topic: "In the world of spuds today"
Replies: 2423
Views: 181372

Re: "In the world of spuds today"

On the note of cheapo Chinese HPA pumps, my adaptors arrived yesterday, so I'm no longer relying on an improvised Schrader adaptor and I can pressurise things with abandon. My brother has been quite adamant, however, that I'm not allowed to pressurise his bike shocks with it. (Oh, the days when we t...
by Ragnarok
Thu Jan 11, 2018 1:13 pm
Forum: General How-To & Discussion
Topic: "In the world of spuds today"
Replies: 2423
Views: 181372

Re: "In the world of spuds today"

Even today we're still some distance away from this sort of hunter-killer drone We may be, but in the setting, they're not. Developed nations were deploying autonomous drones (drones here covering a range between aerial, humanoid, walking and tracked) by the mid-to-late 90s. Then once international...
by Ragnarok
Thu Jan 11, 2018 12:09 am
Forum: General How-To & Discussion
Topic: "In the world of spuds today"
Replies: 2423
Views: 181372

Re: "In the world of spuds today"

Myself and JSR have had them for a couple of months Like I said, me getting one isn't really earth-shattering news. Still, as far as spudding overall, it's pretty cool. For the price of a decent track pump, you're getting something with quite a lot of volume per stroke, but with an insane pressure ...