Demarquis wrote: ↑Thu Jul 27, 2023 2:52 pm
"An aircraft designed as a high altitude interceptor will often have poor low-altitude performance"
Why does it have to fly low altitude to hit ground targets? All sorts of aircraft are designed to shoot at ground targets or sea targets from high up.
You could, but it's all about trade-offs due to the differences in payload sizes required to execute ground attack vs anti-air missions.
Compared to aircraft, ground targets like armored vehicles, trenches, and buildings are significantly more durable. This means you need a larger payload to do enough damage to make actually striking the target worth it.
The AIM-9 air-to-air missile has a ~20 lb warhead while a
JDAM equipped bomb can clock in at up to 2000 lbs. And both only go boom once. Depending on what you're shooting at, you might need 100 times the payload mass to destroy an equivalent number of ground targets as air targets. And you can't carry that much extra payload without trade-offs; you either fly lower, slower, or take less ammo.
At the design stage, this trade off leads to different classes of aircraft. When the decision is made to fly low, but fast and with lots of ammo, you get a dedicated ground attack aircraft. If you take lots of ammo but fly high up, you get slow high altitude heavy bombers. If you decide to stay fast and high, you wind up with a multi-role or "strike fighter" aircraft that has less payload than the other two options.
At the operational phase, this trade off still exists. The physical geometry of each aircraft is optimized for best performance in the flight regime you expect to be operating at. You can strap ground attack munitions to your high altitude, high performance interceptor but you won't be able to take a lot if you want to stay in that high performance envelope. Or, you can take more ammo but you'll be performing outside your optimal regime.
[EDIT]
Compare the "Armament" sections of the Air Force's
F-22 data sheet and the
A-10 data sheet. Despite more than 3 times the thrust, the F-22 can carry at most two 1000 lb bombs, while the A-10 can carry upto 16,000 lbs of different ordnance in addition to a larger gun with (it's not on the data sheet) almost 3 times as many rounds.
The different design decisions made while optimizing each aircraft for it's specific role is what lead to the huge disparity payload capacity.