The M-SHORAD "Sgt. Stout"--> A New Generation of American SPAAG

Machinery of War Discussion Ground Vehicle
,
54

The following explicitly states that not all of the lift comes from the control surfaces, wich practically sinks Gaijin’s entire argument.

The desired-direction lift and quadrature lift ( the resultant force component in orthogonal direction due to the moment no longer being balanced caused by rotating frame of reference and motive fins being recessed at that instant)

which result are also shown in FIGURE 9. (US3010677A, see above)
Actually, the lift force generated by the wings is only a fraction of the required lift force. The remainder of the force is provided by the fuselage.

So at a reductive level yes, the Igla and the Redeye work effectively the same way (implementation is slightly different due to differing mechanization). For the Improved Guidance & Control section of the Stinger it has an additional set of oscillating, and Feedback inputs as to avoid building excessive inertia which it would then need to overcome.

Prior to the invention set forth in the hereinafter cited copening application, control of a rolling missile was effected by utilizing fixed incidence, variable area canards or wings which were extended into the missile air stream at a certain point in the revolution of the missile, as described (see Figure 9, above) The present invention constitutes another means for accomplishing the control of a rolling missile and is an improvement over the system described and claimed in (US3010677)

The servosystem of the present invention utilizes variable incidence wings or control surfaces as did the system disclosed in the above mentioned copending application. However, this invention provides an air vehicle such as a missile with a pair of fixed wings or canards and a pair of variable incidence control surfaces or canards which are continuously dithered or vibrated so as to provide instantaneous movement due to the elimination of the initial inertial force.

4 Likes
55

So the fins are strong enough to make it pull significant AOA (and thus generate body lift)?

56

Not, exactly. What happens with the Redeye is that in the instant when the paired set of control surfaces (one set of planar surfaces that can deflect), need to change orientation (Imagine the procession of the target the plane of wings though image 2, 3 & 4 of the series of five rotational states in Figure 9; or basic trig “Sin(ref and signal phase)” being of opposed magnitude ), due to the target falling behind the plane of the control surface they are suddenly commanded to change their defection to the opposite limit but until that occurs they are deflected to some degree and so generate lift in that direction for that half of the rotation for some period of time as rotates around its axis.

Due to the fact that as a rolling airframe it has to pick some rate, and either Clockwise or Counterclockwise rotation (and it does vary over the flight), the time it spent with surfaces deflected out of the desired plane of maneuver, either against or with the direction of rotation causes the net change to be towards the direction of the point of intercept, but due to having non-limited inertia and no method for fin AoA feedback it doesn’t take the shortest path, but a curvilinear one.

(in a sense its like one of those very basic line following robots with two wheels that students program where if it sees a Low return the wheels rotate in opposite directions, and once it sees High it reverses the motors and so can follow a path by oscillating backwards and forwards with the sensor and line’s width determining pathing)

The Stinger on the other hand has two sets of Planar Control surfaces (once deployed one set is fixed at some AoA, the other can freely deflect into the airstream) this allows it to use the fixed surface’s inherent lift generation (and implicit moment coupling) to allow it to maintain the rotation and thus control surface effectiveness and not need the motive surfaces to provide the moment coupling.

By dithering the motive surfaces, what is happening is that its avoiding the onset of the sustained inertia of the missile, by minimizing average out of plane rotation, because commands are no longer continuous (full deflection over a half rotation), but discrete inertial kicks in the more correct net direction of the target.

The relevant exerpt is as follows

Due to an oscillator, described presently, in the electronic portion of the guidance and control section 12 which causes continuous motion or dithering of the control surfaces 14, the motor 41 is sensitive to very small signals from the seeker section 11 since the dithering action overcomes the inertial effects of moving control surfaces 14.

Part of this is due the fact that the surfaces cycle around ~250 times a second, and the missile body rotates at approximately 14~17Hz or so. and actuating at much higher rate reduces the apparent inertial forces significantly.

2 Likes
57

Actually found a patent that might explain it in detail.

I’ll see how accurate my explanation was, or at least dig up some details.

2 Likes
58

Man, if you could find something that says that the autopilot system shown there is in the Stinger, their efficiency argument is gone.

59

There’s a lot of circumstantial evidence. How many Rolling Airframe Missiles was General Dynamics working on in 1975, when the patent was filed, would GD be patenting things and doing exploratory work before landing the contract? (Surprisingly two actually, the FIM-92 and what would become the RIM-116, which happen to both share a Seeker).

The biggest smoking gun linking them together would be, the presence of the Feedback loop in the block diagram(s), being introduced as a Difference (damping) mechanism via Pulse Width Modulating the power (and polarity) provided to the Torque motor.

( US4037806 ) The servo error signal, which is the difference between the control servo command and the wing position feedback signals, is superimposed on a dither oscillator signal, causing the servo switching circuit to pulse modulate power to a torque motor. The torque motor integrates this incoming pulse modulated signal so that the resultant wing deflection rate follows the servo error signal.

Happens to have a Stinger (note the four forward surfaces not two, as with the the Redeye), and further describes Shoulder launch, which the RIM-116 regardless of intent at 162lbs The RAM would require a very determined Soldier, let alone the requisite launcher.

Relevant diagrams

( US4054254 ) The pitch rate sensor illustrated in FIG. 6e is also responsible for the damping or decreasing of the output of the control surface incidence. The high initial pitch rate reflected by the trace 86 results from the high initial deflection from the control surfaces. In time, the output of the pitch rate sensor reduces the undamped control signal and produces a stabilized pitch rate as is suggested by the portion 88 of trace 86.

Since the movements of the control surfaces have been timed to correspond to the coincidence of the control plane with the direction toward the flight path intended (vertically upward), there is an acceleration of the vehicle in the earth related upward direction as is illustrated in FIG. 6c by the trace 90. It will be noted that the trace reaches a maximum level in approximately one and one-half revolutions and sustains that level throughout the duration of the control excursions with very little over-shoot. The corresponding trace 92 in FIG. 6d for the earth related horizontal plane shows that substantially all of the acceleration is in the direction of intended change for the flight path. When the input command terminates, as is illustrated in FIG. 6a at point 94, a wing incidence sequence substantially the reverse of that occurring when the command signal commenced is initiated. This wing incidence sequence is illustrated in FIG. 6f as portion 84 of the trace 82. It will be noted that the maximum signal now corresponds to the inverted position of the control plane and therefore, causes the vehicle to pitch back towards its original flight attitude. Since the input command terminated the wing incidence is almost solely a function of the acceleration signal 98, this acceleration signal then is the equivalent of static stability such as is utilized in open-loop control in maintaining a constant flight attitude in the absence of a control signal. The portion 95 of the pitch rate signal 86 in FIG. 6e reflects response of the pitch rate sensors to the opposite angular velocity. The effect of pitch rate damping summer 54 is to enhance the acceleration signal at this portion of the control sequence, to thereby produce a damping of the commanded wing incidence and as a result, to prevent over-shoot. It will be noted that only a minimal overshoot of the vertical acceleration as evidenced by portion 96 of FIG. 6c is experienced. The wing incidence and pitch rate damp out in the next five revolutions and reach zero at approximately the same point, representing the return of the airframe to a zero-angle-of-attack, stable-flight, mode.

2 Likes
60

Hellfires are crap anyways against anything other than armor targets.

Well, the blade hellfire is pretty effective against a few small targets at a time.

61

imo there’s enough information here to make a suggestion

62

This would be a really good addition to top tier US. But before that, I think they need to first fix stingers before it gets added at a higher br. Stingers can be slaved to IRST and can lock on once it gets in range. This will be great against helis.

This will also give us a chance to test Hellfire L’s without having to test them on helicopters

63

Currently away from any source of good info and my tech (hiking in the Backcountry), but i believe I have already tried making one and that with this+more info it didn’t go through. Perhaps thefe was a suggestion for it on the old forums?

64

Should we add something for which we basically know nothing about (NGSRI)

Uh, no.

Should we add something which is still in development, never mind trialshit (like the 2S38)

Also no.

Without NGSRI, this thing is basically an LAV-AD with a radar, which, while nice, doesn’t really fix what’s wrong with America’s top tier.

They should add Longbows, but that’s a different topic.

65

There’s the (X)M1211 30mm prox rounds for the M230 it could get.

66

Prox rounds at top tier won’t change anything either. Everyone is slinging 12km+ lock range FnF AGMs like MavDs and Gs and 8km+ range like Hellfires or Vikhrs. The only people you would touch with proxy are the loudest of the mouthbreathers.

1 Like
67

Worst case it could blow up an incoming missile. Its meant for taking out small UAV’s so an ATGM is well within its capabilities.

You’re not wrong though that something more is needed, but unless its Russian Gaijin just won’t add it.

68

I’d try making it again. There are suggestions on this forum with way less info than your Machinery post

69

We have a new variant of the Stryker, The C-UAS-DE, which is currently in the Technology demonstration phase, this will likely help inform the layout of, or serve as the basis for a follow on program to the Increment II & -III going forward.

c-uas-de-stryker-graphical-breakdown
c-uas-de-stryker-graphical-breakdown1921×1080 115 KB

but overall seems like an evolution of the earlier attempt to unify the M-LIDS system onto one Stryker / AMPV chassis instead of two or more M-ATVs’.

m-lids-pair

m-lids-stryker

2 Likes
70

This could be very interesting. It looks like it’s currently lacking any missile armaments - although I am a blind man so that could just be me not seeing anything. Do we have any more details on it? Or just the photos?

And again, while the DE concept is cool, it’s really only a concept for War Thunder. It’s not powerful enough to take out planes and until then, it can’t do much of anything.

71

It should have VAMPIRE turret which nominally consists of 4x (+ reloads) 2.75" (70mm) APKWS II w/ HE warhead (Likely to be testing the Proximity fuse), which you can see mounted to the chassis in the foreground just in front of the the Laser turret (26 Kw variant of the LOCUST), and between the radar (likely a variant of the AN/RPS-42 ) emitters in the first image in the prior reply.

ims-isr-vampire-product-gallery6

Also the R400 turret that the demonstrator uses could also be equipt with a module to additionally mount an FGM-148 Javelin. Though I think it would probably have been better off retaining the RIwP turret of the Sgt. Stout for compatibility with a wider set of systems, though it is probably due to internal space / power / weight constraints.

That’s where the (X)M914 30mm firing VT fused DPHE (effectively the same as the existing M789 as found on the AH-64) with a fancy new dual feed system comes in.

72

Although this is true, that would have it sit (quite awkwardly) at the 9.7-10.7 range. It’s nice, sure, but to be honest I wouldn’t take it over the LAV-AD or XM thingy since they have longer range missiles which are to be honest quite necessary at the BR. If it got its Stingers, however, that would be a different story since it has stingers AND proxy rounds, a huge win.

73

I wouldn’t be so sure of that, the ability to provide what amounts to a team-wide anti missile barrier is potentially extremely strong. You would be able to force larger weapons to be pushed off course by destroying their control surfaces, and smaller ones could be outright destroyed by the DEW. Aircraft would be forced to get in close to destroy your tank before being able to bully your teammates, opening them up to counterattack.