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Old 12-20-2015, 11:47 AM
PaulK PaulK is offline
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Join Date: Nov 2005
Location: WI
Posts: 1,847
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Have you considered the F42-4T? Much faster getting up to thrust than 3xD12, and good sustaining thrust. Anyhow, doing quick sims with SmartLaunch, on my MDRM (36oz), using a 5' Rail (I use a 6' rail, but subtract 1 ft for the offset of the top rail button):

F50 - 6.8:1 Thrust-to-weight, 28.5MPH off the rod, 391 ft, 3.8s delay
F42 - 6.4:1 Thrust-to-weight, 26.9MPH off the rod, 282 ft, 3.1s delay
D12x3 - 7.9:1 Thrust-to-weight, 25.2MPH off the rod, 203 ft, 2.6s delay

I'm not sure how exactly SmartLaunch calculates thrust-to-weight, it seems optimistic with the D12, given the short thrust peak.
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