[AR] Re: Valley Tech throttleable restartable solids (!)

  • From: Henry Spencer <hspencer@xxxxxxxxxxxxx>
  • To: Arocket List <arocket@xxxxxxxxxxxxx>
  • Date: Sat, 28 Mar 2020 18:28:09 -0400 (EDT)

On Sat, 28 Mar 2020, roxanna Mason wrote:

Titan SRB's had 2 configurations, 1.5MF and 1.7MF which had a half segment added.

I think those may be *peak* *vacuum* thrusts. Isakowitz 2nd says Titan SRB average thrust was 1.4Mlbf vacuum, and 1.4 is also the number that the Commercial Titan Customer Handbook quotes. Several references, notably Sutton 4th, say total *takeoff* thrust of a Titan IIIC was 2.4Mlbf, i.e. 1.2Mlbf per motor at sea level at startup. (That's also about right for acceleration, which the CTCH shows as a bit over 1.5G at takeoff aboard a 1.5Mlb vehicle.)

But the vacuum thrust of an F-1 (an as-flown F-1, not even the F-1A) was over 1.8Mlb -- Saturn V total thrust at the moment of center-engine cutoff was about 9.2Mlbf.

Anyway, no argument on your main point: thrust was in the same league. Which is no great surprise for nozzles with about the same exit diameter under the same conditions, on not-too-aggressive designs with no exotic propellants or other unusual aspects.

Henry

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