July 25, 2004 update

 

More construction

 

Moving to the 48” tank initially looked like “bolt the flanges to the new tank and we are almost done”, but because we also moved the motor drives, reworked all the jet vane actuators, and built a brand new wiring harness with shielded cables, it has taken a bit longer than expected.

 

We got the new interface cone bonded onto the 48” tank, and the cutouts made for the vacuum line and all the cables.  The top cone was 1/8” aluminum, and weighed 50 pounds.  We added a cross brace and lifting point, which allows us to just barely stand the vehicle up inside under our hoists if the shocks aren’t on the feet.  On our next vehicle revision, we are going to arrange to mount all the electronics around the base  of the vehicle, and use a fountain tube from the bottom to draw vacuum in the tank.  With those changes, we really will be able to literally bolt different tanks on without changing anything, and we won’t need a ladder to turn the electronics on and attach the vacuum hose.

 

http://media.armadilloaerospace.com/2004_07_25/topSection.jpg

 

We are beginning the design of a custom board that will replace all the connectors, terminal strips, and random wiring on our electronics system.  That should increase reliability, save space, and allow us to rapidly put together extra systems for crash replacement or redundancy.

 

We are using shielded cables with solder-shield termination for everything, and using metal shell connectors with the proper contact directions for all new connectors.  It is a trivial little thing, but I had always wondered why you could get CPC connectors in both normal and reverse sex, and I only just found out the reasoning for it a couple weeks ago (while reading http://workmanship.nasa.gov ): live power contacts should be sockets instead of pins, so they are harder to short.  Makes sense to me.

 

http://media.armadilloaerospace.com/2004_07_25/cables.jpg

 

Each jet vane actuator is now wrapped in insulation and enclosed in a stainless steel sheet metal enclosure.  We are going to avoid burning off residual propellant while on the ground (dumping it to a holding drum instead), which is how we melted our last set of actuators, but with a 120 second flight we will probably see significantly higher heating.

 

http://media.armadilloaerospace.com/2004_07_25/actuatorInsulation.jpg

 

We have started putting together the A-frame that we will use for erecting the vehicle in the field, so we don’t need to have a lift truck on site, which was going to be a logistics issue at the distant launch sites.

 

http://media.armadilloaerospace.com/2004_07_25/longPipes.jpg

 

We are renting the lift on Tuesday, so we expect to be hover testing by the end of the day.  If that goes well and the weather doesn’t give out, we will do a boosted hop next Saturday.