Search found 3167 matches

by jimmy101
Fri Apr 03, 2020 1:10 pm
Forum: Pneumatic Cannons
Topic: Pnuematic Cannon Making Very Loud Noise....!
Replies: 2
Views: 331

Re: Pnuematic Cannon Making Very Loud Noise....!

You can search these forums for "honking" for a number of posts about the problem.
There is also a brief page on the wiki at spud_wiki/index.php?title=Honking and spud_wiki/index.php?title=Sprinkler_valve_modification
by jimmy101
Mon Sep 09, 2019 11:17 pm
Forum: General How-To & Discussion
Topic: New Guy
Replies: 10
Views: 2090

Re: New Guy

That is TRUE, in 35 years I never installed a PVC gas system. I have installed Polypropylene. PVC is not used on gas because it is FLAMABLE. SCH.40 PVC IS pressure rated to about 220lbs and SCH 80 to about 320lbs. OF course the Explosion of Propane probably creates more than those pressures, which ...
by jimmy101
Wed Apr 10, 2019 4:07 pm
Forum: General How-To & Discussion
Topic: Short question topic
Replies: 1463
Views: 85098

Re: Short question topic

You could also just use a neodymium magnet if you are just trying to keep the BBs from rolling out'a the barrel.
by jimmy101
Fri Mar 01, 2019 2:48 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: GGDT for modeling BBMG?
Replies: 13
Views: 2037

Re: GGDT for modeling BBMG?

Another challenge is that the chamber pressure probably oscillates a fair amount (pressure goes up when a bb is actually in the barrel, down when the barrel is empty). One approach might be to start with ROF and muzzle velocities for a BBMG some has already built, use that to calibrate GGDT, then mo...
by jimmy101
Sun Dec 16, 2018 4:53 pm
Forum: Pneumatic Cannons
Topic: First ever pneumatic potato cannon
Replies: 3
Views: 581

Re: First ever potato cannon

Welcome to the forum!

Post some pics and specs, people are usually glad to help (or at least chime in with criticisms :) )
by jimmy101
Thu Dec 06, 2018 12:28 pm
Forum: Combustion Cannons
Topic: Self Contained Hydrogen Repeater
Replies: 30
Views: 5063

Re: Self Contained Hydrogen Repeater

If you want to be taken seriously quit using the stupid name "HHO". There is no such thing. You are using 2H2 + O2.
by jimmy101
Thu Nov 01, 2018 11:34 am
Forum: Combustion Cannons
Topic: Ignition types
Replies: 5
Views: 1746

Re: Ignition types

Hi, I was wondering what the best ignition (other than a stun gun) is for spud guns. I generally use 2 nails and the piezoelectric thing from a bbq lighter but I have heard that grill igniters work better. So if anyone knows of any other (under $20 ideally) ignition sources please let me know. "Wor...
by jimmy101
Wed Aug 29, 2018 7:00 pm
Forum: Hybrid Cannons
Topic: Troubleshooting piston valve hybrid
Replies: 12
Views: 1034

Re: Troubleshooting piston valve hybrid

If the mix is right then the spark is wrong. You may have have an internal short in the spark gap.
by jimmy101
Mon Jun 18, 2018 10:57 am
Forum: General How-To & Discussion
Topic: Short question topic
Replies: 1463
Views: 85098

Re: Short question topic

Either you aren't actually getting a spark or your mix is wrong. Pretty much any electrical spark should ignite a correct mixture. (Though at high compression ratio's it'll take either a higher voltage or a narrower gap to get a spark.)
by jimmy101
Sun Jun 17, 2018 3:14 pm
Forum: BB, Airsoft, and Pellet Guns
Topic: Controlling ROF in a BB SMG without a hammer/bolt (v2)
Replies: 4
Views: 718

Re: Controlling ROF in a BB SMG without a hammer/bolt (v2)

The problem with Huricane's design is that the next BB inhibits air flow needed to for the previous bb. I think you want the cam to keep the next bb in magazine, instead of the barrel until, the first bb has cleared the barrel.
by jimmy101
Thu Jun 14, 2018 10:49 pm
Forum: Pneumatic Cannons
Topic: Twist and Shoot
Replies: 6
Views: 617

Re: Twist and Shoot

Wouldn't it have some of the same problems as a ball valve? In particular, slow opening time?
by jimmy101
Sun Apr 08, 2018 11:36 am
Forum: Combustion Cannons
Topic: Question on 3D printed canon design and regulators
Replies: 2
Views: 1073

Re: Question on 3D printed canon design and regulators

Regulators don't vent to relieve pressure once they are set. The only time they vent is when you drop the set pressure. If you aren't fiddling with the pressure it wont be venting. I don't think using a regulator is the norm. I think it is more common to assume a particular pressure in the propane t...
by jimmy101
Fri Apr 06, 2018 1:20 pm
Forum: Pneumatic Cannons
Topic: Water cannon
Replies: 7
Views: 897

Re: Water cannon

Should work... but 1000 ft*lbs of recoil is pretty significant.
by jimmy101
Sat Mar 24, 2018 11:49 am
Forum: General How-To & Discussion
Topic: simple diy ballistic chronograph
Replies: 22
Views: 2652

Re: simple diy ballistic chronograph

That looks like a good setup. You might need to adjust things a bit but your setup will probably work. I went with the open design to avoid having the chrono jig act like an extension of the barrel. The 1K resistor should be about right and overall the chrono setup is pretty insensitive to details l...
by jimmy101
Fri Mar 23, 2018 4:08 pm
Forum: General How-To & Discussion
Topic: simple diy ballistic chronograph
Replies: 22
Views: 2652

Re: simple diy ballistic chronograph

I left out one more source of error and uncertainty; the accuracy of measuring the distance between the detectors. An advantage of a longer detector is that the uncertainty in that distance has a smaller affect compared to a shorter detector.