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Originally Posted by luke strawwalker
Yeah just a heads up but you better be REAL careful with those PVC "air tanks"... PVC will shatter and fragment like a hand grenade when used with air, and go off like a bomb when they let go. Why you're not supposed to use PVC pipe to plumb air into a shop-- supposed to use PEX or black poly tubing instead, because it "fails gracefully" if anything goes wrong-- it just splits at the weak spot. PVC will actually shatter like glass into shards propelled at high speed by the expanding pressurized air inside it. Not good.
Might want to look into converting a little portable steel air tank or something which would be much safer... Looks like great fun, but if you had one of them PVC tanks turn loose on you could be a VERY bad day!
Later and good luck! OL J R  |
I still have my tanks. You are correct they are dangerous to use. Mine are wrapped in fiberglass fire blanket, but are several years old. Quit doing the air tanks many years ago. Designed other projects before finally getting back to Estes power conversions, something been meaning to do for some time.
Received several shipments of engines and parts, will keep converting as time allows. Have about 40-stomp and air tank powered rockets to convert.
Looks like fairly decent weather ahead for a few days, might be able to launch a few.
Waiting on parts for the Atlas. This weekend will install most parts to get it ready for flight. Once the fin material gets here can finish.
If I were to do the air tanks again, will purchase a compressed air / nitrogen cylinder from a welding store, rig up a system with a 1/4 turn ball valve that can handle air pressure. Line would be schedule 80 2" ID pipe. That way if wanting to use higher pressure for testing different designs, it will be available. The pipe can act as an air tank. The volume of air will be slightly more than the rocket's full length plus the volume of any downstream piping that leads to the end of the launch barrel.
Allows you to control the air pressure with a regulator, giving control over all aspects. You can close the valve on the air tank reducing risk if the there are any problems. In other words, open the valve adjust regulator to desired pressure, close the valve and launch rocket using 1/4 turn.
Designing a rocket made out of paper for the full 2000lbs of pressure would be interesting!
Only real issue is how many N-sec is that.
Who else will be testing rockets like this?
Trying to get the engine conversions done before building the air launch system.
Been thinking about a safe air system for launching. The small air tanks rust from the inside out due to the up and down pressure of filling/emptying. The compressed gas cylinders are hydro tested to verify safe to use. They come in cubic feet, so a small 80ft3 could offer several re-loads for a day and is fairly portable.
Big issue with air rockets is how to deploy a recovery system? now there are several electronic devices to take care of that. In the past tested wind up toy parts to pull a pin releasing a spring loaded capsule. This worked but found a better answer in the rocket design.
Mike