Originally Posted by das_peikko
Originally Posted by Astro14
In an F-15 carrier landing, that little hook would be ripped right out of the airframe a few milliseconds after the landing gear was crushed.
So I take it the F-18 landing gear is more beefier?
It's not just landing gear.
The entire structure of the airplane has to be built for carrier operations. The cat launch, the arrested landing, stress every part of the airplane. You can't just beef up the landing gear, you would be left with an airplane that isn't strong enough to handle the stress and the airframe would be damaged by the load that the landing gear imposes.
Take a catapult launch. An airplane goes from 0-180 Knots in 2 seconds at max gross weight.
So, that's about 90 m/sec, right? In 2 seconds. V=at. t=2 So, a is about 45m/sec2. G=9.8m/sec2 About a 4 G pull then...
So, working it back, that 65,000# F/A-18E has a load of about 250,000 pounds on the nose strut. You can't just beef up the nose strut on an F-15, or the nose strut would be pulled out of the airframe. The whole frame must be built to take that kind of load.
There is a similar load on the tailhook on landing.
Then there is the vertical load on the gear and airframe from the landing. Airliners and USAF airplanes are built for a maximum sink rate of about 600FPM on landing. USN airplanes are built for a maximum 1800 FPM. Three times the vertical velocity. That's NINE times the stress. The structure must be able to handle that.
In testing, Grumman dropped the F-14 airframe, loaded with weights, to test that kind of load. I've seen that kind of load on an airplane from a less than perfect landing. That kind of load on an F-15 would result in complete destruction of the airplane.
In this video, they show an F-14 airframe dropped from about 20 feet.