# If You Strapped An Aeroplane Engine To An Aircraft Carrier, Would It Go Faster?

This is Aviation Machinist's Mate 3rd Class Christopher Cogar. He's testing a F-414 jet engine's afterburner aboard the aircraft carrier USS George Washington. And spectacular view, no doubt, which made me wonder:

If he's testing this on the stern of the carrier, would the ship go faster? It seems logical that it will, since any force would affect a mass, even if the mass is huge. But can anyone with some solid physics knowledge tell us by how much?

Here's some data:

F-414 jet engine maximum thrust: 22,000 lbf (98 kN)

USS George Washington displacement: 104,200 long tons (116,700 short tons)

USS George Washington maximum speed: 30+ knots (56+ km/h; 35+ mph)

An estimate will be good. [Flickr]

US Navy photo by Mass Communication Specialist 3rd Class William Pittman

## Comments

It would, but you wouldn't notice it. There's no figures there that would allow you to calculate drag, but with 94,000 newtons acting on 105872000kg - 0.0008m/s2 , or 0.8mm per second squared. Now if someone can tell you what the drag is on the ship, you might get a little further.

GTs are too inefficient anyway, they guzzle too much fuel.

Afterburners are certainly fuel intensive. Well designed gas turbines can be very efficient though (as proportion of the Carnot efficiency)

OBJECTION!

I work with a large GT company, we run gt's here as power generation 24/7 running liquid nat gas. quite effecient for the power output. There are many many many different designs of gas turbines which produce different results and efficiency.

But yes, in this application its obviously useless....

they may be inefficient, but so is attaching 50 people with long oars. he is asking if it makes a difference. Hope somebody can get a bit more detailed! How many would we need to strap in to get some serious movement!

Short answer, yes. Long answer, yeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeees.

Going at Mach 1 in an aircraft carrier across the pacific ocean. . . possible, yes, probable, unlikely.

Technically if you spit off the back of an aircraft carrier, it will go faster.

Soo. the whole crew should take turns at doing this? Sounds like an idea!

Ball park estimate. From Wikipedia the ship has a shaft power of 194MW. If this power is used to reach top speed of 56 km/h this equates to about 12.5MN of thrust. Thrust of the jet engine is about 0.7% of this. So not much of an increase :(

A lot of navy ships already use gas turbines but the drive the propeller through a gearbox and they along at quite a clip

If Voyager's gravity assist from Jupiter cause the planet to be 1m out from its supposed position by the end of the solar system in five billion years, I think that the movement of the carrier from this engine can be measured.