Episode 41 - Systm Builds a Cannon [Discussion]

[travislopes]

There's nothing wrong with potato guns... we love sparking up Right Guard as much as the next geek. But compressed air, now that makes for a seriously fun cannon.

Watch and download now! (http://revision3.com/systm/tennis)

(Sidenote: Post #300.)

[lordbyron]

For the record I would have to say their measurements were off. They stated that the longer one as 24" and the shorter one as 12". Looked more like 36" and 24" to me. Or were they talking about the air tank? Also David referred to the pipe as female and the fittings as male. That is reversed the pipe is male. It goes into the fitting, hence being the male. But I am glad again to see a complete show.

[1_1_1]

the cannon was weak and having the U in it makes it weaker just ask a good HS or College physics teacher

back in HS we made ones with 12" combustion chamber whatever leanth barrel and used hair spray with a BBQ igniter and shot 100 yards easy.

I used a 5'x2" barrel 4"-to-2" reducer 1'x4" combustion chamber and a clear out cap

then put two screw to get the spark into the combustion chamber and one screw to hold the ball out of the combustion chamber

and did a "test fit" assembly then a sharpy to get the correct amount of primer/cement in place

it did great some did a 6' barrel some did a 4' none messed up and all reached close to or beyond 100 yards

[pyro_boy_dj]

I have personally made about three or four of these air cannons myself and can say with confidence that they are way better than their hair-spray powered counterparts. One thing that they could do even now to improve their range is to supercharge the valve. If you remove the solenoid and instead attach a regular air compressor valve(like the one at the end of the hose) you can dump the air much faster and gain considerable distance. In addition to that the honking noise will disappear. I have one with a 6 ft barrel and if somebody were to cough it would cover up the sound of the cannon firing.

This is an excellent intro to the art of pneumatic cannon construction and there is way more that the guys didn't get a chance to get into. Have fun but be safe. PVC doesn't show up on X-ray.

[ebar]

Is anyone else unable to get to the episode? When I try to get there, I just end up at the main page.

[eca]

I would like a discussion on the comparison of SMAL High pressure over Large LOWER pressure..

Would it be better to have a SMALL High pressure
or
Large cylinder with MORE volume..

[mikec]

Is anyone else unable to get to the episode? When I try to get there, I just end up at the main page.


iTunes burped on this episode for most of the night. This site here was running slow earlier, that might have been part of the issue. I finally got it downloaded while watching several other podcasts. Hopefully all troubles are over and you can get this episode.

[viron75]

I thought that it was strange that during the whole episode they talked about safety and then the first thing they show us is Patrick shooting it at another person?

[master1228]

Watching the time lapsed setup of Patrick cutting and fitting all the PVC pieces in what looked like a garage towards the end of the show was great, it really made the show!

[murphy1d]

22 years ago I was using de-natured alcohol as the propellant. Is the Right Guard/Hairspray mix a better way?

[technobob]

I have been making spud guns for many years and I know all to well the dangers these things can cause. I was out with a few buds having some fun when it went all bad real fast. My friend thought it would be cool to fire his cannon from his shoulder like a bazooka. The cannon exploded taking out his eardrum and scaring his face forever. So never fire these things anywhere near your face it's best to keep them below you waist.

I'm just building a new cannon for this year as my old one is now a couple years old. I'm using a 5' X 4" air chamber with 2 3" elbows and a 2" brass air valve with blow gun mod a 6' X 2" barrel. All of my PVC parts are SCH80 so I can up the pressure to 200PSI and plus I'm all about safety now.

Another safety tip: PVC does not do well in the cold don't fire these if it's colder then 10 degrees Celsius

[xplorer]

I love the episode, it looks like you guys had a blast making it.
Pat in super speed Benny Hill-O-vision was great!
Not to mention how giddy he gets when outside firing the thing!

But alas I do see one glaring issue. Whats with the constant repetition? Every time some point was made, a few minutes later in a different location we hear the same info again.

I love the content, but I feel the show could use a little trimming / more prep.

Just my $.02

Keep up the good work!

[eca]

Bob,
Also at 10 degrees C..
MOST propellants STAY liquid...NOT a good thing for the PVC, as it might tend to EAT the PVC.

[technobob]

I use propane and I have been out a few times at 10 degrees with no issues. I build my cannons with the heavier SCH80 for SCH40 I don't think I would risk it at 10 degrees.

[eca]

there should also be a warning...
NEVEr leave a cylinder CHARGED... Heat and TIMe can/will destroy the integrity of the cylinder..

[xplorer]

there should also be a warning...
NEVEr leave a cylinder CHARGED... Heat and TIMe can/will destroy the integrity of the cylinder..

No doubt and for that fact not only does that apply to pneumatics but hydraulics as well.


When finished remove all pressure from the system!

[lordbyron]

I thought that it was strange that during the whole episode they talked about safety and then the first thing they show us is Patrick shooting it at another person?

But for legal reasons they have to say it !

[kevincollateral]

love the bouncing soulds shirt patrick! mad props

and keep up the good work