Sunday, April 13, 2008

Update...

Congratulations to Cal State Long beach/Garvey Space, (The team members overlap a lot so I’m not sure which group was the lead, the rocket I saw pictures of had decal for both) I heard  they successfully flew a Lox Methane rocket this weekend.   (I think this is the first ever) This adds to that groups firsts:



  • First Flown composite Lox Tank.

  • First flown aerospike

  • First flown Lox Methane.

 


For Unreasonable Rocket we think we were able to repair the tank. We will do a new Hydro test on Monday night or Tuesday. We re-welded the entire seam with a lot more heat. In any case I’ve been investigating new tank concepts and I’ve found a tank concept that will be stunningly light for peroxide. We may work on this for the 180 second vehicle. 


I finished machining my first Jet vane and shaft out of billet stainless (I hate machining stainless) I’m going to try to finish a couple more tonight. The Lathe work is done on all four ,the mill work still needs done on three of them.


OneJvane


I hunted down the cause of my helicopter crash and resolved that. I had a gain constant off by a factor of 2 when switching from position hold mode to position  and altitude hold mode. I flew it again and it flies nicely, but the tail rotor started acting really flaky. It would drift all over the place and not hold heading. Something is wrong, but all my field diagnostics gave me no info. I’m a bit stumped. I’m tempted to give the computer direct tail rotor control and remove the tail rotor gyro using only the IMU for tail rotor control. Just Like Jack did a while ago…

3 comments:

Timothy J. Massey said...

The vanes are so tiny! From what I remember, the AA vanes seemed to be something like 3 inches on the longest side... Is your motor significantly smaller than their peroxide motor?

Jesse said...

Agreed! One thing I was wondering is how the heat soak from your engine will affect the vanes, and whether that depends on the size of the vane. i.e., large vs small radiator fins on small engines. It seems to me that you'd want your vanes to be large enough that the surface away from the nozzle would act as a mini radiator, thereby keeping the vane temperature down and not looking like:
Heated Vane

Paul Breed said...

We will see soon....
Realize that most of Armadillos vane work was done with a mixedmonoprop motors. These have a higher temperature than pure monoprop peroxide. We are also putting the vanes VERY close to the engine exit cone and if you turn all 4 vanes 90 degrees they completely cover the exhaust exit. No way to make them larger without spacing them away from the exit cone.