Why can’t aircraft carriers just have longer runways?

Question

I’ve seen the Pearl Harbor movie where they make a big deal of taking weight off the planes because the ship’s runway is just too short. Why can’t they just be longer? Or was just that because they lacked the time during ww2?

It seems like the problem still exists today and i just don’t get how a massive ship would be affected by a longer runway. Maybe make it telescoping like a firetruck’s ladder so it can be retracted during bad weather.

What’s the limiting factor here?

In: Engineering

Answer 1

In the Pearl Harbor movie they were using bomber that were not designed to launch from a carrier. This is why they had to make them lighter, since it was a special mission, a symbolic move to bomb Japan, even when the USA didn’t have any airfield close enough to Japan to do it.

When you design a carrier and planes you need to reach a balance. A carrier can’t be long enough to launch any planes. Even most airfield are limited, the biggest one are longer than 3km long. Most airfield on the ground are not that long and can’t have some of the biggest planes land or take-off at max weight there.

That would be ridiculous to make a 3+km long aircraft carrier, so you need to make a decision, what is the optimal lenght, a good compromise between which aircraft you can launch and how costly your aircraft carrier will be. We don’t have infinite ressources, and so you need decide, do you want one very big aircraft carrier, or several a bit shorter. The second option give you more flexibility and it’s usually a better option. You also have to decide if you want to use the total lenght of your carrier for landing and take-off. If you choose that option, you can’t do both at the same time and this against limit your flexibility. This lack of flexibility is one of the reason that cost the Japanese the battle of midway, since they couldn’t recover the planes that attacked Midway and launch the planes to attack the incoming US carrier at the same time. The modern US carrier used only half of the lenght (roughly) for launching their planes with catapult for that reason. Everything in life is about compromise, if you want your aircraft carrier to be able to launch any planes, you gonna need to sacrifice so much in other aspect that it will most likely be a very bad ship and a big waste of money.