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.
Saturday we got the rib up to 2.2 psi. At that pressure it supported a 55 pound side load without distorting. I think this rib has told us all it can. The next test rib will incorporate mounts for the leading and trailing edge inflated spars and a few upgrade to the end cap interfaces.
Mark had these great Away 35 pictures hiding in his camera from last August:
A big thank you to Shawn Carlson for this one:
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