May 13 and 17, 2003 Meeting notes

 

We were a little bit light this week, because I had E3 business, and Russ and Phil’s company had their respective industry trade show, but we still got a lot done.

 

Joseph is all ready to pour concrete for our peroxide storage building.

 

We got in the rolled and welded cones for three small crush cones and two large ones, so we did all the hole marking and drilling.  We are not adding vent holes on the small cones, because there is still 4x the volume in uncrushable cone and coupler underneath it, so overpressure shouldn’t be an issue.

 

We got in the conical flanges that will be permanently mounted to the tanks, allowing us to unbolt the entire cabin section for work or swapping to another tank.  Unfortunately, they aren’t quite long enough.  The were 7” long, but at a 10 degree angle, the 1/8” thickness and manufacturing tolerances caused the cabin to sit about 3” higher than expected.  We could just barely have made it work, but I decided to get new flange hoops made that are 11” long.  The annoying thing is that I should have realized that there was no downside to making them taller in the first place (except a little weight) – I was worried about it interfering with the hatch reinforcement plate, but that sits on the outside of the cone, so it wouldn’t have mattered.

 

We got a new belt sander for preparing to bond the conical flange to the big tank.  We have used flox on our previous bond filets, but we are going to use chopped fiberglass on this one, because it will be highly stressed in the pull-out direction.

 

We have built a combination tank flange / computer mount for the big vehicle.  For our initial hover tests, we will take the isolation mounted electronics bulkhead out of the small vehicle and mount it directly on top of an oversize flange closure on the top of the tank.  The electronics probably won’t stay there in the long term, because they would be in the passenger’s way, but this will be convenient for our early unmanned flights where we may be going back and forth between flight tests of the small vehicle and the big one.  Eventually the electronics will be reconfigured to fit on the pilot side support panels, where they will be out of the way.

 

We replaced the bad pressure transducer on the drogue ejection tank.  The McMaster “General Service Transducers”, part number 31685K1, have failed twice on us in ways that were bad enough to mess up other electronics, so we are never going to use them again.  The heavy duty transducers we used to use don’t seem to be available any more, so we are moving to the PX176 series from Omega.

 

We installed a new rolled-sheet parachute guide tube in the small vehicle.  We had concerns that the parachute might be able to hang up on the bulkhead, and the bulkhead also proved to be a hot spot that melted a hole in the parachute bag.  The new guide tube should solve both problems.

 

A reader pointed me at this company: http://ourworld.compuserve.com/homepages/seacatch/  These look very good for our purposes, so we probably won’t bother making more of our “mousetrap” releases if they work out.

 

Some early tests with peroxide / methanol show some promise, but we are waiting on getting some platinum catalyst to try the combination in an engine.  Preheating the catalyst will be absolutely necessary.

 

We replaced the 24v solenoid coils on the XCOR igniter with 12v coils, and also put a fresh spark plug in it.

 

We are hopeful that we will have some 90% peroxide within a month to perform hover and flight tests on the 2’ diameter vehicle.