May 13 and 17, 2003 Meeting notes
We were a little bit light this week, because I had E3 business,
and Russ and Phils company had their respective industry trade show, but we
still got a lot done.
Joseph is all ready to pour concrete for our peroxide
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 shouldnt 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 arent 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
wouldnt 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
wont stay there in the long term, because they would be in the passengers
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
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 dont 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 wont 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.