1/2" PVC motor - 6-21-2008 Tests 1-4

[joshb]

I made some PVC sugar motors this weekend.

Videos results are up:

1/2" PVC Sugar Rocket Motor - Assembly and 6-21-2008 Test 1:

1/2" PVC Sugar Rocket Motor - 6-21-2008 Tests 2 3 4:

Click the "Watch in High Quality" link below the view count if you have enough bandwidth and can wait a minute for it to load.

 

[Quick_Nick]

Neat! I'm getting more and more persuaded to make some of these.
Also, going from your video I found this one which involves some interesting ideas for fuel and motor design:

 

[joshb]

Yeah I saw that one, too. That's actually a more common technique that what I did. There's a couple videos that show that method. I wanted to try one that was completely reusable though, since I was still learning how to make the fuel correctly. Saves cash!

Search for James Yawn and Richard Nakka and read everything on their sites. That will get you up to speed.

Also be safe and don't blow yourself up! As some of those sites say, it's what you don't know that will hurt you, so I say "try to know everything!"

 

[reverend]

Neat! I'm getting more and more persuaded to make some of these.
Also, going from your video I found this one which involves some interesting ideas for fuel and motor design:
YouTube - how to make a sugar powered PVC rocket......REALLY COOL!!!!!

I love this kids safety shoes...

This method has been shown on YT for a long time, and wasn't invented by this kid. Come to think of it, I think the original author also had bare feet... Weird.

Re: Josh
I'm a little worried about the paper fuse inside your motor. It's probably not likely, but it's not a good idea to put things in the motor that could clog the nozzle. Also, your attempt at a reusable PVC motor is a valiant effort, but in my opinion, PVC is best used for disposable single use motors... Every burn erodes away the inner wall of the PVC. Even if it doesn't burst during the burn, as you noted, the motor is extremely hot, this destabilizes the PVC, and makes the motor likely to CATO on the next burn.

I like it though, and welcome to the forum

 

[joshb]

Re: Josh
I'm a little worried about the paper fuse inside your motor. It's probably not likely, but it's not a good idea to put things in the motor that could clog the nozzle. Also, your attempt at a reusable PVC motor is a valiant effort, but in my opinion, PVC is best used for disposable single use motors... Every burn erodes away the inner wall of the PVC. Even if it doesn't burst during the burn, as you noted, the motor is extremely hot, this destabilizes the PVC, and makes the motor likely to CATO on the next burn.

I like it though, and welcome to the forum

All good points. For this particular motor, the nozzle is way oversized, so wasn't worried about that. Also, the very tiny amount of napkin (like 1/16th of a regular napkin) I believe is entirely destroyed during the fuse burning. (I verified this while testing the fuse design... nothing left but tiny pile of carbon. KNSU is energetic!) The cardboard liner, which you and I both use, is more likely to clog the nozzle if that were to happen. I doubt a bit of burned paper will cause a CATO though, since that is still the weakest material in the motor.

I will try to measure the PVC wall thickness for future tests to see if it is eroding. I don't have calipers though. I bet the burn time has more to do with messing up the PVC though. Before these tests, I filled up another pvc motor without the nozzle completely with 15g of dry KNSU. It burnt for about 15 seconds and the tube was not straight where it met the adapter anymore. So after several fires my test motor may warp or even blow up, but that is cool and still beats throwing away single use motors. (For actual flights definately need fresh pvc though!)

For larger motors with smaller nozzles, I'll definitely think about those points. For this one the focus is on quick turn-around so I can teach myself how to make flame (more like white smoke) shoot out of a tube, so to speak. :speakcool:

 

[reverend]

Cool... I'm not worried about the cardboard liners, they pretty much end up right where they started. I have had nozzle clogged by big paper ignitors before and a massive CATO happened. Not so much of a safety concern with such a small motor, but definetely something to keep in mind building bigger.

 

[Cosmos]

I've never seen or heard of these, really cool! Maybe I can get my niece and nephew involved.