Tonight we went from vehicle ready to wire…
To almost passing hydro test… For our operating pressure of 300 PSI the FAA minimum is 360 PSI, the sphere has a design burst of > 600 PSI, we got to some where between 350 and 370 we wanted 375 to 400. (We will never presurize in the presence of humans.)
Its clear we did not get enough penitration, the weld only went ~half way through the base metal. Very discouraging.
Tuesday, April 08, 2008
Best of Times woorst of times..
Subscribe to:
Post Comments (Atom)
9 comments:
damn it looked so good on the first pic.
Looks like a lot of work went into that vehicle; I hope it is largely salvageable. Do the legs serve a double function, legs and catalysis tanks?
Good luck. Phil.
If only the many tales of the magical welding elves were true. Sorry to see this happen guys :-(
The Legs are the catalysis tanks.
I also fear that the legs and motor are the only salvageable parts.
btw, maybe i missed something in earlier posts, but didnt you hydrotest this tank earlier without assembling the vehicle ?
No we were going to hydro, but did not have a good way to support the
tank when full. So we bolted the legs on to support it...
It's sad, but on another level, i remember AA bursting a lot of tanks in hydrotest before mastering tanks welds, and you are very close to your target pressure. Best of luck for next one.
Paul,
Is it not possible to have the tank sit on a cylindrical piece of sheet-metal (Al?) with straps around it? You could just take a strip, bend it round, optionally weld it shut and then put a couple of heavy-duty straps around it for strength in the radial direction. The sheet-metal should be able to take the load in the z-direction, right?
BTW, have you been into contact with AA about having James Bauer weld up your tanks (for money)? They are the same manufacturer and material, right? They were also willing to sell some of their old fibre tanks to SpeedUp (if I remember correctly). And you helped them out at the LLC as well. My outside view is that they could be up for it in good sportsmanship.
Anyway, good luck with the rebuild. I'm really looking forward to seeing you get something in the air!
Cheers,
Wouter
If it's any consolation, the concept of "all up testing" also led to cost and budget overruns on the SSME.
see
http://books.google.com/books?id=wtyLSdh69fIC
Note that halfway penetration leads to 1/6 or less of the strength due to the sharp edge where the weld ends.
Did you chamfer the edge completely before welding?
Post a Comment