What’s Happening at JPA

It’s a rainy day here in Sacramento. The original plan was to hold a team rocket training day. Everyone has been building small model rockets. Today we were going to fly them all. Next the team is going to build “G” motor sized rockets then go up from there. The idea is to get everyone brushed up on rocket skills and procedures. We want everyone comfortable with 10,000 newton/sec plus rockets by summer.

There is still a lot to do today in spite of the rain. Today we’re building two new antenna stands, adding camera booms to the test high rack and sewing on the new balloon launch bag.

Here’s the last four seconds of the flight of Away 36.

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The front office is getting a little crowded.

Admit it, whenever you are in an air and space museum this thought comes into your mind, “With a wrench and pickup truck…”

We never follow up on ideas of a better use for that Titan rocket engine just sitting there. After all we want be able to come back to the museum and also we’d rather not go to jail. This week I made an exception. It’s OK, really, don’t call the police.

Two factors were involved: One, are needing to do rocket training and two we had two rockets on loan to the California Aerospace Museum for the last several years. The museum had been using the rockets for an education program, however the program was over. One pickup load later and the ML-2 rocket and the Big Red Rover Rocket are back at the shop. We also picked up the ML-1 Rocket that was being used for promotion by one of our sponsors.

All the rockets need a lot of work and TLC. They all might not fly again, but they will make excellent training platforms.

The new end cap design is better, but still not there. The problem is not that it can’t be sealed. It that we want to seal it with end caps that only weight a few ounces.

The team took a break from beam work last Saturday for sewing on the new launch bag and making ground planes/shields for flight GPS antennas.

We had a handful of ideas on how to better seal the end caps. Our goal was to reach 3.4 psi. The new caps weren’t ready yet so we used the existing caps. This made the test easer to measure. We know how much the existing cap seals leak. We tried each modification. On each we could barely get the air beam above 1 psi! The frustration was showing on everybody’s faces. Nothing was working. We setup the air beam as we had it before when we reached 3 psi. Still, we could get no higher than 1 psi.

We finally found the source, small cracks had formed in the foam around the gauge seal. That was it for the day. We could eject a sealant into the cracks, but than it would take 24 hours to cure. We decided to pull the valve and gauge and use them in the new cap design.

The working pressure for the ribs on Ascender 100 will be 1.7 psi. At that pressure the rib has the strength needed. We want the rib to be able to take double that, 3.4 psi as a safety margin.

I’m writing up some notes on 2008. It was a great year for JPA. I’ll have it here in a couple of days.

We repaired the test air beam then glued support strips over the end seams.  The end cap  was changed to add another inner cell clamp. The strength is good, it will sit and hold 3.05 psi all day. The seals still don’t cut it. I had to keep the compressor running continuously to maintain pressure. The next goal is to make a wider seal without adding any weight.

Anthony gave a shout of “Open the Valve!” as the end began to let go. It was all too fast. The foam and glass end cap went hurling across the shop. Work continues on our gossamer pressure vessels. Solving one problem allows you to push into a new level of problems. Today was no different. We had two solutions to test. A glued seam reinforcement and fiberglass channels in the end caps. For this round we used the six foot straight air beam instead of Ascender test rib.

The new glue reinforced seam was a big success. The sewn seam alone has big stretch issues above 1.7 psi and starts to fail just above 2 psi. The new seam handled 2.4 psi without any signs of stress. The fiberglass on the end cap channels were still not sure about. The harder surface held up better but was much harder to seal.

The new issue we discover was the strength, or lack of strength, of the nylon shell end closure. At a touch over 2.4 psi it all let go.

While we were shooting giant pellets past his head Mark was steadfastly getting pocket sewn for the new launch bag.

I couldn’t resist going to the shop for a little pre-turkey fiberglassing.

These are the new rib end caps. We’re fiberglassing the channel around the perimeter. This will make a stiffer backing for the rubber seal.  One cap will get high and low volume valves and a pressure gauge. Both will get a smaller foam disk glued to it for stiffness.

Any bets for 3 psi on Saturday anyone?

We took a break on rib work to catch up on some other projects.

We nearly completed refurbishing rocket launch box. The last touches included mounting stops on the base of the internal rail, this prevents the rocket from sliding out of the bottom, an important feature, sealing the box, attaching the external support rings and making and gluing on forty foam gussets.

We sold two of our balloon launch bags. This means it’s time to breakout the sewing machines and make some more! The team cut out the twenty-eight foot fabric panels, ten in all. Next all the panels will be hemmed, then the 240 pocket, all with Velcro closures get made and added then the attachment loops and tear panels…..  If we are sewing our way to space, are we there yet?

We need to find a adhesive that will bond the silicone/Nylon fabric we use. We bought a set of candidates glues and have begun trials. I wasn’t expecting a success in the first batch. However number five in the first ten passed load under flex test. We’ll be using the adhesive to reinforce a rib seam. Before applying it to a full rib we’ll test it out on a six foot straight air beam. That will also give us a chance to test another upgrade to the rib end caps.