@_David_Bowie That is incorrect. The Mirage III weapons manual explicitly states that the forward canards of the R550 Magic are used to control the missile in roll. It then further clarifies that the moving tail is required to allow the missile to roll, not to stabilise it:
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Furthermore this page of the manual talks about the autopilot rotating the missile to align with the target’s vector:
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And finally this page clearly states that the autopilot controls the missile in roll:
The magic 1 stabilizes roll to target vector along missile axis which is in-line with the maneuvering surfaces (single plane). This changes clearly with the magic 2 as so far, I have found no documentation stating Magic 2 is 35G but rather 50G. This only makes sense if they improved the guidance by allowing it to maneuver in combined plane.
I think early on, they did not have such complex guidance properties to allow for the missile to deflect differentially the control surfaces when guiding towards target vector and as such, relied on two canards for roll, and two for pitch at any given time. It would appear as skid-to-turn style.
The magic 2 in some sources has been mentioned to have improved guidance.
Further, Magic 2 incorporated pitch and yaw gyros for “stabilization” of the two rates in the guidance system. This would only be useful if the missile were attempting to maneuver in combined plane.
(And if the Magic 1 didn’t need them, then the only real reason I can possibly imagine is for the Magic 2 to make it self capable of maneuvering in “X” configuration).
So you’re claiming the Magic had to roll to get two of it’s fins aligned with the target, then deflect those two fins to turn. That’s the guidance method used by the R.510 / R.511 and it proved to have severe limitations so I can’t see why the French would go back to using such a poor method of missile control for an advanced dogfight missile.
Also the manual states roll is achieved by “differential deflection of the pitch control surfaces”, that goes against the idea of there being dedicated roll control surfaces.
No, I’m claiming the Magic 2 could roll and pitch at the same time. It would only have a roll rate gyro which it would be attempting to have reach null by countering excess roll towards target.
All surfaces are “pitch control surfaces” depending on where target first appears. It is just maneuvering on the missiles axis’ as stated because that is in-line with the control surfaces and would be single plane. All Mirage III manuals currently available for public distribution state 35G for the Magic 1.
Most sources for Magic 2 (in fact, I cannot think of one that doesn’t) state 50G. This must be for a reason, and clearly with the aforementioned source it shows an improvement in guidance systems such as pitch / yaw rate gyros. These are generally only ever seen or necessary on missiles that maneuver in combined plane such as the AIM-54.
But going back to Magic 1 we agree that there is some sort of roll control going on there don’t we? I believe that roll control is seeking to keep the target vector aligned between the two missile planes while you think it is trying to keep the target vector aligned with one of the missile planes. Is that the correct interpretation?
When discussing missile axis it always refers to the “+” configuration. This would be single plane, and this is supported by the manuals which always state 35G for magic 1’s lateral maneuverability. The Magic 2 increases this to 50G in any public source and we can see there is incorporation of pitch / yaw gyros to maintain stability in combined plane rather than just a roll rate gyro.
The magic 1 is stabilized in roll by a roll rate gyro, and maneuvers in single plane… without roll stabilization it would suffer from instability. The AIM-9 solved that problem with rollerons, the Magic 1 must maintain single plane towards target vector instead. So where a target could by chance be 45 degrees between maneuvering surfaces and suffer the result of combined plane from an AIM-9L by chance… the magic 1 is always limited to 35G.
So why can’t AIM9 get its theoretical maximum overload?
According to the manual AIM9D/G/H should have 23G overload while AIM9L/M should have 32G. But now they only have 18G and 30G.
The primary reason for the control surface change is not aerodynamic. The R-27 was designed as a replacement for the R-24, and was supposed to be a modular design. The motor and seeker sections were to be mated to a common control and power section which would, for obvious reasons, be in the center. There were several reasons for this, the most important being simplifying logistics and production in the face of the number of required variants. The R-27 was intended to be produced in both thermal and radar homing variants (initially, like all Soviet Fox 1s, it was hoped efforts at an active seeker would pan out, but this would again not be the case), and in both medium and long range variants (for arming the MiG-29 and Su-27, respectively). A single weapons system requiring four separate production lines would be undesirable at best, and modularity would make planned modernizations (such as the hoped-for active seeker) much easier, so it was a logical choice.
The problem is that having power supplied through the central section meant power demand had to be unified. You couldn’t have different tail control schemes, and even if you could, the tail needing significant power supply would mean designing and ensuring the reliability of a robust power connector for the modular tail, which would add yet more complexity to a weapon system that was supposed to simplify things. A wing control scheme required more power to actuate, and was less aerodynamically efficient, but offered very significant design advantages for ensuring ease of production, reliability, and maintainability, in addition to better matching the desire for a common central body that provided control and power to the missile. Because of this, and because the aerodynamic disadvantages were not unacceptably significant, the scheme was chosen. A secondary factor was the then-recent experience gained with wing control schemes for AAMs of this class after the K-25 program.
The US F-4J tactics manual states the AIM-9D/G/H can pull 18g in the specifications list, but states it can pull over 20g in some conditions later on in the text.
I suspect 18g is the most it is can pull at certain launch conditions (say Mach 0.9 at sea level), and 23g is the most it is theoretically capable of pulling.
