Time for another launcher

[Nick B]

no great surprise,


Upgraded the launcher for higher pressures with a new o-ring,



Now half of my bottles will not load, and the rest cannot be launched with reduced pressures for smaller staging areas.




It's gonna be more trouble loading an ftc onto a 200+ psi o-ring than wrapping one with fiberglass tape and spiderwire....

[Nick B]

Sanded the groove enough to barely get most rockets on.

2 FTC's ruptured near the nozzle bulkhead at 175 psi
1 FTC blew out the upper bulkhead at 185 psi


All three had one layer of strapping tape.

1 FTC, had a tee nozzle that cannoned out the lower bulkhead.

[U.S. Water Rockets1]

Sanded the groove enough to barely get most rockets on.

2 FTC's ruptured near the nozzle bulkhead at 175 psi
1 FTC blew out the upper bulkhead at 185 psi


All three had one layer of strapping tape.

1 FTC, had a tee nozzle that cannoned out the lower bulkhead.

What brand FTC tubes do you use? The ones we have been able to get will always fail at 160PSI.

[Nick B]

Lithonia.

maybe because these are T8s....?



I can tame the upper bulkhead ejections with some changes.
Right now it's 1 inch Propel caps inserted glued with hotmelt.

We can switch to PL, insert them 1/16 further in, melt over the 1/16 of tube, to retain linear pressure, and use a reversed nozzle bulkhead to cover the end and reduce ftc expansion.

I have not had any luck with grooving and using wire to compress the ftc/cap assy.

Not much options on the table for the lower end, yet, other than a few extra wraps of tape.

[Nick B]

Both t12's have not ruptured yet, but they also have alum tape reinforcement, and they have only had a few launches. I am having problems with upper..."salad dressing" caps leaking after a few pressurization events.

They fit to loose to begin with, tho.

[Nick B]

yeah....



The o-ring still has a release point beyond 160 for much of our FTC rockets, and maybe beyond our 200 psi hand pump, poly tubing, PVC, hot melt, and how knows what else. We are getting a handle on how much to partially load some rockets and get a lower pressure release, but a uncontrolled launch moment.

Today we blew up some more rockets. Seems the FTCs with glass tape or alum tape do not like to bond with hot melt or PL with the nozzle bulkheads overlapping the tape. So we will need to rebuild them with the tape only external, but with a few extra passes near the bulkheads, top n bottom.


Looks like we will alter the launcher for swappable launch tubes for a higher pressure o-ring and lower pressure o-ring. I want to keep this first launcher with poly air line as long as possible.


Or we will just make a copper launcher that supports pressure washer hose.,.....

.......which won't be fun to drag around.

[Nick B]

three new launch tubes tooled up.
one short one with 60 psi release, one medium long one with 60 psi release, one long one with 200 psi release,......per average bottle opening, of course.

Tapered seal launcher is looking good also.

[Nick B]

[quote="Nick B"

Tapered seal launcher is looking good also.[/quote]


Seems I now have a hail cannon for a higher pressure launcher.

Shoots a wave front of water out 50 feet in the air when launching a rocket, maybe 200 feet without a rocket.

It has a leak though where I welded a bracket to it and fed the rod too slow. Need to swap that part out or weld it up.

I'm better at welding Jeep air tank bumpers or sand rail frames, than small welds with air holes.

For some reason, it makes a much louder report, distinctively different, than our normal launcher.