convertimate Specific impulse

Seconds to pounds of fuel per pound-force per hour

Type a value in s to get it in lb/(lbf·h) instantly.

10.29lb/(lbf·h)

That's 1.01× as efficient as a Merlin vacuum engine, while a Space Shuttle main engine in vacuum is 1.29× more efficient. Its exhaust leaves at about 3.432 km/s.

What it means

How efficient is that engine?

Rocket figures are typical published values, at sea level unless marked vacuum. The jet-engine figure is for an airliner at cruise.

The math

How to convert s to lb/(lbf·h)

Effective exhaust velocity is Isp × 9.80665. Thrust-specific fuel consumption in lb/(lbf·h) is 3,600 ÷ Isp.

Example: 350 s = 10.2857 lb/(lbf·h).

Every unit

Your specific impulse in every unit

Tables

s to lb/(lbf·h) conversion table

s to lb/(lbf·h) conversion table
slb/(lbf·h)
200 s18 lb/(lbf·h)
250 s14.4 lb/(lbf·h)
282 s12.766 lb/(lbf·h)
300 s12 lb/(lbf·h)
350 s10.2857 lb/(lbf·h)
380 s9.47368 lb/(lbf·h)
450 s8 lb/(lbf·h)
900 s4 lb/(lbf·h)
1,600 s2.25 lb/(lbf·h)
3,000 s1.2 lb/(lbf·h)
lb/(lbf·h) to s conversion table
lb/(lbf·h) to s conversion table
lb/(lbf·h)s
200 lb/(lbf·h)18 s
250 lb/(lbf·h)14.4 s
282 lb/(lbf·h)12.766 s
300 lb/(lbf·h)12 s
350 lb/(lbf·h)10.2857 s
380 lb/(lbf·h)9.47368 s
450 lb/(lbf·h)8 s
900 lb/(lbf·h)4 s
1,600 lb/(lbf·h)2.25 s
3,000 lb/(lbf·h)1.2 s

Quick answers

Quick answers

How many lb/(lbf·h) is 1 s?
1 s is 3,600 lb/(lbf·h).
How many lb/(lbf·h) is 10 s?
10 s is 360 lb/(lbf·h).
How many lb/(lbf·h) is 350 s?
350 s is 10.2857 lb/(lbf·h).

The units

About these units

Seconds (s)

The usual rocketry figure, the same in every unit system.

Pounds of fuel per pound-force per hour (lb/(lbf·h))

Jet-engine fuel consumption, the inverse of specific impulse. Lower is better.

Learn more about specific impulse units

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