What's new
What's new

Remember those little water/air pressure rockets? Steroid Time!

Bluechipx

Hot Rolled
Joined
Dec 29, 2008
Location
W. Mich
Here is the test stand for testing the rocket. There are five 4,500 psi tanks, three and two connected separately. All tig welded steel tube. Most are aware that an arc scratch makes a high pressure tank worthless. When I called the welding supply they said rental only on a 4,500 tank. I asked if I paid my rent on time every month, would they ever want to see their tank? This led to some laughs, then I found some from a paintball guy to buy. Before you think I am insane for welding on a high pressure cylinder, I'll explain in further pictures. This set up is a test for a carbon fiber tank that is going into a hydroplane. I put a two foot deep heavily re-barred pit for cement. The frame is bolted with fourteen grade eight one inch bolts to fourteen 3" diameter steel bars eighteen inches long with plates welded to the bottoms. There is roughly 14,000 pounds of cement-but-I have now seen 9,500 lbs of thrust so far and if I were to pressurize to the maximum 4,500 psi it would exceed the weight of the cement in pushing thrust. Of course it's not directly lifting so it's not a problem, but I'll never push it that far anyways.

Rocket 2.jpgRocket 8.jpgRocket 5.jpgRocket 7.jpg

The hole in the cylinder to connect tanks was cut on a cnc mill, the slugs that were removed were EDM'ed to make test bars to be tested on my tensile machine. The test bars were tested as is and after welding to insure strength at the welded joints. The tank is rated for 4,500 lbs, tank test pressure 6,750 psi. Tensile testing showed the burst pressure of the tank was at least 9,000 psi and more likely closer to 10,000 psi. All connecting tubes were 4130 chrome moly steel.
 
This is the destination for the rocket. 17 foot and only 240 pounds, mostly carbon fiber never in water since new.
Rocket boat.jpg rocket 1.jpg Rocket 6.jpg

This gauge with telltale needle shows thrust. The hydraulic cylinder is bored to a diameter that will read directly in lbs of thrust. I have seen 9,500 on a different pressure gauge, I out grew the 5,000 gauge after several tests. I will post some videos of a few tests soon. Both with air pressure over water and air pressure only. The rapidly escaping air chills the surrounding air and there is always a wide variation in the fog effect through the nozzle. High humidity and a high dew point make for quite a show. Unfortunately I didn't have video running for some exceptional firings.
 
Nothing new under the sun. They were doing this and more at Rocketdyne, Division of NAA when I worked there years ago. The only thing I'm wondering is why. And, yes, welding on a pressure vessel is a no-no.

I'll have to disagree about welding no-no. I worked in a mechanical testing aerospace facility for several years and did my homework before going ahead with this. The finished product, after welding easily passed a hydro certification, seeing as though all my work was over kill on materials and welding technique.
 
My question is, do I have a volunteer driver out there, the lighter the better?



Is this guy available? Lot's of experience!


Photo-Wile-E.-Coyote-Rocket.jpg
 
I'll have to disagree about welding no-no. I worked in a mechanical testing aerospace facility for several years and did my homework before going ahead with this. The finished product, after welding easily passed a hydro certification, seeing as though all my work was over kill on materials and welding technique.

OK. whatever you say.................:D
 
[video]https://photos.google.com/share/AF1QipMNXYIxSbE6ay6cBPrKC6M_ORj3qvY-9CsPRjjHBnahbwpGsRIOj70qkc_kmFOHPQ/photo/AF1QipO-XZGVbIa4xxg3QT-JfmRg79NQCyFpH4nmiwkA?key=ZXBqLVY0WGFPR25seUcxM0xP SUxnc21IcUVCYUdR[/video]

Here is a 1,200 psi test that showed 3,500 pounds on the thrust gauge. You might have to double click the picture to start video.
 
I'll have to disagree about welding no-no. I worked in a mechanical testing aerospace facility for several years and did my homework before going ahead with this. The finished product, after welding easily passed a hydro certification, seeing as though all my work was over kill on materials and welding technique.

Did it pass for repeated reversal loading ?
How many cycles ?

what is failure mode ?

There is a fair number of High pressure engineering firms here in Erie, and I have seen what a couple of test chambers look like.
 
EVERYTHING IS A NO NO. This is a VERY INTERESTING THREAD. Try to be a bit safer. The blast that you did show,looks strong enough to pick up a brick and throw it.You have inspired me to post some of my projects that will make the safety police go crazy also.Good luck. Edwin Dirnbeck
 
Erm, so... Judging by the video, this looks more like an explosion rather than a controlled release. So is there a different approach for running this "vehicle" than used in the test? Otherwise it will probably kill the driver as soon as the pressure is released. Is the plan to pressurize tanks to 4,500 and release at 1,200? Will be tough to get enough flow with a regulator if so. Tough to get much thrust time if no.
 








 
Back
Top