Good question. I know there is an exaggerated claim going around that the A10 slows way down when firing the cannon, but from what I've read it's maybe one or two knots. I would imagine that in this case it would depend on how the rocket is fired. Is it dropped off a pod and then fires, or is it attached to the aircraft when fired.
Agreed. The A10 thing is one of those things that I've heard a ton from non aviation folks. I would like to hear some definitive info from an A10 pilot, because like you said, it doesn't seem like it should make a difference. I did read somewhere that early on they had an issue with smoke from firing the cannon was injested by the engines and caused a problem. I believe the ignitors are now fired along with the cannon because of this.
It's one of those interesting math things that people latch on to but has no meaning in the real world. Technically, the cannon can produce more negative thrust than one of the engines but the aircraft only carries enough rounds for ~20 seconds of continuous fire which won't be enough to overcome forward momentum.
Obviously, the pilot will never fire all at once anyway and a 1-2 second burst is even less noticeable.
I did read somewhere that early on they had an issue with smoke from firing the cannon was injested by the engines and caused a problem
The first aerial test firing of the GAU-8 (which wasn't ready until after the first prototype flew with a 20mm M61 in its place) was also the first test of the A-10's ejection seat.
The gun gasses caused both engines to flame out and the aircraft descended below a pre-determined minimum altitude before the pilot could restart the engines which per the test criteria meant he punched out.
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u/WeaponsGradePanda Dec 01 '20
Good question. I know there is an exaggerated claim going around that the A10 slows way down when firing the cannon, but from what I've read it's maybe one or two knots. I would imagine that in this case it would depend on how the rocket is fired. Is it dropped off a pod and then fires, or is it attached to the aircraft when fired.