Is a dedicated helicopter-destroyer a feasible idea?

delft

Brigadier
They shouldn't cancel each other out if they are at different frequencies. The advancing blade would increase the frequency of the return wave and the retreating blade would reduce it, giving two slightly different frequencies range to the one sent out.

The radar would have to be quite sensitive to freq shift because the mechanical turn rate of the rotor is still low by electromagnetic frequency sense.

The BBC once told me that radar traps for speeding motorists were detecting targets going at 800 km/h, 500 mph: low flying RAF Tornado's.The rotor tips are just as fast or faster, but much smaller. But a military radar must be far superior to a police one. The mechanical turn rate is irrelevant.
 

Ambivalent

Junior Member
So the best bet against helicopter is IR sensor and heat-seeker missiles, then?
But what about radiation detection? Radome like those carried by Longbow Apache?

Depends on the seeker. The inability of the range gated doppler radar in the DIVAD gun (based on an F-16 radar) to successfully track helicopters is well documented. Doppler radars will never pick out a crossing target (no doppler return), and despite what the fanbois allege, it could not get a doppler return off the turning rotors of a helicopter.
The radar on a ZSU-23/4 can be deadly accurate against a helicopter. There was also effective optical tracking if the radar was jammed, though in Soviet literature of the optical system required a lot of time to acquire and target a helicopter, their best crews required more than 30 seconds to effect a kill, which is eons in combat. Still, it was our most feared system, the one thing you did not want to find in front of you.
Many Soviet infrared seekers could not pick out a helo if it was low enough to the ground, so you had SOP's not to fly above that altitude ( it was a very low altitude but practical for a helo if you didn't go fast ). Even over water, we knew to stay below a certain altitude when Iranian boats were nearby so they could not acquire us with a MANPAD. Newer IR MANPADs probably no longer have this limitation but I don't know that for a fact, and an awful lot of the older stuff is still out there so the tactic remains relevant. With flares and the AN/ALQ-144, most IR missiles are not a threat.
An IR weapon on the wing of a jet might not pick out a helo flying nap of the earth. Remember, the seeker has to "see" a contrast in the IR spectrum, not the visible spectrum. You have to consider background heat relative to the helo. The helo might not stand out on IR when viewed from above the way it would when viewed against the sky from a soldier standing on the ground (or sailor in a small boat). Two color seekers, IR and UV, look for the UV hole in the background. That is where the target is, if the target is against a sky background (flying at the UV hole allows the missile to ignore certain IR countermeasures) but this is completely ineffective against terrain or foliage. An imaging seeker has to be able to "see" enough contrast to generate an image. Again this may not be possible against some backgrounds.
Your Apache will most likely be flying below the tree tops or a ridgeline. There is a reason the radar is mast mounted. The helo can mask behind terrain or foliage, exposing only the radar. It is very difficult to locate this way, and the body of the helo is protected from fire. There is no reason to radiate until you are in the target area. The big fear, again, is flying along nap of the earth and stumbling across a ZSU-23/4. That would ruin your whole day!
 
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