Randall Clague wrote:
> 
> So the five hour turnaround would have been a three hour turnaround
> had you been using a non-cryogenic oxidizer?  :-)

Or if I'd had another dewar delivered the day before with a single phone
call- I just dropped the ball on Monday :)
 
> What does your turnaround consist of?  I was tweaking Aleta a little
> bit about XCOR shooting for ERPS' 2:10 turnaround time for KISS II,
> but all we have to do is:
> 
> 1) Wait for rocket to land
> 2) Go get rocket
> 3) Safe pyro
> 4) Bring rocket back
> 5) Split modules
> 
> (Propulsion module track)
> 
> P6) Load rocket on launch rail
> P7) Purge tank
> P8) Take rocket off launch rail
> P9) Mate propulsion module with recovery module
> 
> (Recovery module track)
> 
> R6) Download flight data
> R7) Clean pyro area of residue
> R8) Load new pyro
> R9) Pack/load parachute, attach nosecone
> R10) Mate with propulsion module
> 
> 11) Load rocket on rail
> 12) Fuel rocket
> 13) Pressurize rocket
> 14) Arm pyro
> 15) Launch
> 
> Gosh, not as simple as I remembered, and that's with some
> oversimplification.  So what kinds of things do you have to do to turn
> around EZ-Rocket?

For a fast turnaround without helium reclaim, the aircraft crew must:

1) Vent fuel tank [pilot can do this from cockpit during rollout]
2) Meet pilot at tower at end of rollout
3) Open access panel, vent LOX tank
4) Close helium valve
5) Tow back to hangar
6) Load fuel
7) Fill 5 liter dewar with LOX for helium loading
8) Load helium (goes fast with chilling)
9) Tow out to runway
11) Load LOX
12) Pressurize tanks, test igniters
13) Put pilot in plane and fly

This takes three people (Mike, Johnny, and me) about 90 minutes in real
time, but we had a few pauses for discussions like, "Do we want to
offload a portion of the fuel for lighter weight?"  (The fuel tank is
oversized because we originally made allowance for using watered alcohol
at lower O:F, and didn't need that capacity after all.  We have a set
procedure for this, I just wanted to consider dropping that page.) 
Also, I forgot to move a helium bottle that we needed from the shop to
the hangar the day before & had to send Johhny off to get it

In parallel, the video tech is replacing the tapes in the onboard
recorders and charging the aircraft batteries.  If I had been more
ambitious, we could have loaded helium and LOX at the same time by
mounting the prechiller heat exchanger on the LOX tank vent, but chose
to separate the tasks to reduce the workload.

14) Change video tapes, charge aircraft batteries
15) Download GPS data

Of course, I've oversimplified too; I think the key difference is that
we don't take apart or reassemble anything, but our propellant loading
is much more complex.  I've said it before but it bears repeating- we're
doing what we must to prepare for our future vehicles; ERPS is making
useful progress by working at the scale appropriate for their goals and
capabilites.  No particular solution is THE solution.

Doug Jones, Rocket Plumber
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