Military Power

After reading the flare countermeasures thread, I got to thinking. How much heat does a heat seeking missile need to lock on? I remember in Final Countdown they shot down a Trophy Class Mitsubishi A6M with what appeared to be an AIM-9 Sidewinder. I didn't think propeller aircraft would produce enough heat for that.

I am open to correction on this (any physics experts out there?) but I was rather under the impression that a heat seeking missile worked by detecting the Infa-Red radiation given off by the heat source (normally another aircraft’s engine) on a sensor which converted it to an electrical current to operate the missile’s control fins. The nearer the missile gets to the target the more IR it detects which increases the missile’s accuracy.

Hobilar wrote:I am open to correction on this (any physics experts out there?) but I was rather under the impression that a heat seeking missile worked by detecting the Infa-Red radiation given off by the heat source (normally another aircraft’s engine) on a sensor which converted it to an electrical current to operate the missile’s control fins. The nearer the missile gets to the target the more IR it detects which increases the missile’s accuracy.

I think you are exactly right about that, but I don't know how well that actually answered the question. I think you would have to get a target lock first, and that would require you to be able to register a somewhat sizable heat differential (I would think). I know that even prop planes would have exhaust, but not sure it would be warm enough to get a lock. In theory I guess you could point and shoot and hope it gets close enough to pick up a strong enough heat source, but that might be a little hazardous and expensive...

Hobilar wrote:I am open to correction on this (any physics experts out there?) but I was rather under the impression that a heat seeking missile worked by detecting the Infa-Red radiation given off by the heat source (normally another aircraft’s engine) on a sensor which converted it to an electrical current to operate the missile’s control fins. The nearer the missile gets to the target the more IR it detects which increases the missile’s accuracy.

If an aircraft knew a heat-seeking missile was inbound, could the pilot idol back his aircraft to a point where it did not stall-out, and fake the missile? Or will the missile still be locked on to the remaining heat signature which would still be there on the aircraft? What I'm really asking, does the missile detect the 'active' radiation, or will it still be locked onto the aircraft once it is turned back?

I don't think that it would make much difference. I have read that some of the newest missiles are able to target on the infa-red signature of air-friction on a wings leading edge,

Wow Hobilar, I didn't realize that. I wonder how close it has to be, and if that could be used to find "stealth" aircraft, much like Radar.