Quoted from dwightlooi, taken from WAFF:
Do can believe the Russian's claim on the range of the R-77 if you
want and you can believe that the AIM-120 is a 48km missile. But
the truth is probably that the R-77 won't hit anything at 120km and
the AIM-120C will kill something way beyond 48km. Why do I say
that? Because the US leads the world in solid propellant
technology. American solid motors have the highest specific impulse
-- this is true in both military and space applications. Basically,
there are two ways to get better kinetic range in a missile. You
can make the motor more energetic or you can make the airframe,
warhead and guidance lighter. The US already leads the field in
solid motor performance -- detailed explanation on this issue is
another topic for another time -- so that leaves lightening and
payload reduction. It is possible to reduce the warhead, guidance
package size/mass fraction in relation to the missile's propellant
fraction. This will yield a notable increase in range. This is what
is done on the AIM-120C7 -- the electronics are shrunk, the warhead
is moved forward and the length of the rocket motor extended.
However, nothing about the R-77 suggests this. In fact even the
pre-C7 AIM-120C5 has a higher motor volume fraction than the R-77
and I won't bet on russian electronics being featherlight despite
the volume they take up.
So why is it that the Russians can claim that the R-77 as a 150km
missile? Are they lying? Probably not! You there is no such thing
as "a" maximum range for AAMs. The range a missile is effective
depends on the launch profile and the target profile.
Ballistically, both the R-77 and the AIM-120 will fly out to more
than 200km if they are launched at a high altitude. However neither
missile will hit anything but a Zepplin at the range. The effective
envelope for a missile can range from less than 20km to more than
100km depending on how you shoot it and against what. Flying at
Mach 2 against another Mach 2 aircraft coming ahead on at a lower
altitude gives your missile a lot of range. You can probably launch
in excess of 150km and you will likely kill your enemy he he
doesn't break and turn tail immediately. If you are just coming out
of a tight turn near sea level and you are shooting at a Mach 2
aircraft flying away from you at high altitude, chances are your
missile won't catch him if he is more than 15 km away! There can be
a factor of ten difference effective range for an medium range AAM
depending on the tectical scenario. So, yes, the Russians probably
are not lying when they say that the maximum range of the R-77 is
over 150km -- because the missile should be able to kill something
flying in some kind of scenario. But, you can say the same about
the AIM-120C! Hence, official range claims are quite meaningless
and highly misleading.
The AIM-120C has a very impressive, proven combat record. In fact,
nothing has thus far proven effective in jamming it. When launched
within its proper envelope it almost always hits.
