sprstdlyscottsmn wrote: Well, c) is negated by the fact that it weighs three times as much as an AMRAAM. d) means it has in all likelyhood ten times the drag of an AIM-120 at any given speed, and because it is an older missile it has no loft at all. Look at the published ranges. 50-80km? And that is the MiG-25 launch profile anyway. Compare that to the AIM-120D 160km from an F-15, at best, launch profile.

The R-40 is NOT a long range missile and it never will be.

Let's look at the numbers.

3.125x the weight means it needs 3.125 times the thrust for the same duration to accelerate the same when in a zero drag environment. Having a faster start will help, but...

1.72x the diameter. This tells me it will have is three times the frontal area (drag) from this alone.

1.7x the length. if it had the SAME diameter this would mean 1.7x the surface area for skin friction (drag), but since it isn't the same diameter we are looking at 5x the drag just from the body.

3.2x the wingspan. If we remove the body diameter the wings are now 4.2x as wide. This would mean almost 18x the surface area (drag) IF they had the same fin shape, but they don't. R-40 has MASSIVE fins compared to AIM-120.

the ONLY advantages I would give the R-40 over AIM-120D is agility (not relevant to a BVR joust, this is a first shot question). There is just no way that an AIM-120D doesn't smack the MiG-31 in the face.

Personally, i always skeptical of published engagement range for missiles because they do not specify the situation where it can reach such range or the kind of target that it can engage at that range. Moreover, AFAIK, the max range of R-40 on Mig-25 is limited by the illuminating capability of the radar. I have no idea whether R-40 can be lofted, so i will take your words for it

R-40 is indeed heavier than AIM-120, however, it is launched from altitude 35k feet higher than AIM-120D, thus, in my opinion, gravity work in its favor instead of against it. While AIM-120 have to climb up to hit Mig-31, R-40 is surfing down to hit F-15. Hence, heavyweight help accelerates the missile

Furthermore, while R-40 is bigger than AIM-120, the air density at 75kft is 0.06 kg/m3 vs 0.245 kg/m3 at 40kft, the air at 40k ft is more than 4 times denser.

Additionally, i think the extra fuel R-40 can carry is more than enough to solve the issue of greater drag, weight. AIM-54, R-37, R-33, RVV-BD, SM-2, SM-6 ..etc are all heavier and draggier than AIM-120, but they can all fly greater distance by carry more fuel, why would it be different with R-40?

For instance, HAWK is many time heavier and draggier than AIM-120

HAWK max range is 40-50 km whereas SL AIM-120 max range is 25-30 km.

HAWK can fly further than surface launched AIM-120 even though they are both launched from the ground where the air is significantly denser and HAWK doesn't have the advantage of higher altitude and starting speed.