They are not experimenting on these, and for a long time now, on the issue of SAMs. How many times do I keep telling you that the flight requirements of a SAM and an AAM is not the same.
Now why does it suck for a SAM? Because the amount of the rocket propellant stored in the chamber is dictated by the design of the ramjet engine. This is not tailored per se with any vertical lifting requirement that a SAM must entail, and for that requires much more propellant and power. All these missiles that you have been mentioning are either ground attack missiles or AAMs that are more or less, air launched and tend to have more horizontal flight profiles than a SAM. When you're talking about speed, ramjets have better
sustained velocity over rockets, while rockets have superior
peak velocity over ramjets. You figure out why rockets are used to put things into orbit.
Some textbook information on ramjets.
Ramjets generally give little or no thrust below about half the speed of sound, and they are inefficient (less than 600 seconds) until the airspeed exceeds 1000 km/h (600 mph) due to low compression ratios. Even above the minimum speed a wide flight envelope (range of flight conditions), such as low to high speeds and low to high altitudes, can force significant design compromises, and they tend to work best optimised for one designed speed and altitude (point designs). However, ramjets generally outperform gas turbine based jet engine designs and work best at supersonic speeds (Mach 2-4)[11]. Although inefficient at slower speeds they are more fuel-efficient than rockets over their entire useful working range up to at least Mach 5.5.
The performance of conventional ramjets falls off above Mach 6 due to dissociation and pressure loss caused by shock as the incoming air is slowed to subsonic velocities for combustion. In addition, the combustion chamber's inlet temperature increases to very high values, approaching the dissociation limit at some limiting Mach number. In the scramjet, or supersonic combustion ramjet, the ram air is not slowed to subsonic speeds for combustion and as a result, shocks are not encountered and pressure loss is avoided.[12]
Textbook info on ducted rockets.
It might be envisaged that such an increase in performance would be widely deployed, but various issues frequently preclude this. The intakes of high-speed engines are difficult to design, and they can't simply be located anywhere on the airframe whilst getting reasonable performance – in general the entire airframe needs to be built around the intake design. Another problem is that the air eventually runs out, so the amount of additional thrust is limited by how fast the rocket climbs. Finally, the air ducting weighs about 5 to 10x more than an equivalent rocket that gives the same thrust. This slows the vehicle quite a bit towards the end of the burn. Thus in practice, use of an air-augmented design will normally reduce the overall performance of a rocket due to the extra weight.
Furthermore the definition of a ducted rocket:
"These are a slight variation on the ramjet where the supersonic exhaust from a rocket combustion process is used to compress and react with the incoming air in the main combustion chamber. This has the advantage of giving thrust even at zero speed.
In a solid fuel integrated rocket ramjet (SFIRR) the solid fuel is cast along the outer wall of the ramcombustor. In this case fuel injection is through ablation of the propellant by the hot compressed air from the intake(s). An aft mixer may be used to improve combustion efficiency. SFIRRs are preferred over LFRJs for some applications because of the simplicity of the fuel supply but only when the throttling requirements are minimal i.e. when variations in altitude or Mach number are limited.
In a ducted rocket a solid fuel gas generator produces a hot fuel-rich gas which is burnt in the ramcombustor with the compressed air supplied by the intake(s). The flow of gas improves the mixing of the fuel and air and increases total pressure recovery. In a Throttleable Ducted Rocket (TDR), also known as a Variable Flow Ducted Rocket (VFDR), a valve allows the gas generator exhaust to be throttled allowing control of the thrust. Unlike an LFRJ solid propellant ramjets cannot flameout. The ducted rocket sits somewhere between the simplicity of the SFRJ and the unlimited throttleability of the LFRJ."
I'm sorry to say, the MA-31 and its ilk, e.g. Kh-31 family, the 3M-90 Sunburn, and all the similarly looking ramjets, do not belong to this category of being called a ducted rocket. The ramjets that are mentioned put rocket propellant in the combustion chamber to act as an integral rocket booster, so you don't have to physically put a first stage rocket booster on the end. Once the rocket propellant on the combustion chamber is burned out, the ramjet function takes over.
