Resurrected Weapons: FIM-92 RMP Block II Advanced Stinger

The Stinger missile is a hugely successful MANPADS, but it does have cancelled variants, and that’s what we’re going to talk about today. First, a brief discussion of the Stinger.

The FIM-92 Stinger is a man-portable SAM, designed in the late 70s to replace the earlier FIM-43 Redeye. The Stinger is 5 ft. long, 70mm in diameter, and weighs about 34 lbs in its launch tube ready to fire. Unlike Mistral or Starstreak, Stinger is fired from the shoulder, not a tripod.

Stinger has an effective firing range of about 5 miles, due to the nature of its seeker. It uses a dual-spectrum IR and UV seeker. Adding the UV spectrum makes the job of countermeasures designers harder. The countermeasure now has to duplicate the signature of the aircraft across two spectra, not merely the infrared one.

Stinger has been deployed in several conflicts, and has proven effective. It’s easy to use and good at denying aircraft the use of lower altitudes, forcing them out of its engagement envelope.

In addition to use in the man-portable role, the Stinger is deployed on the M1097 Avenger SHORAD system, the Bradley Linebacker, the Stryker-MSL, and as an air-to-air defensive missile aboard Apache helicopters.

And now we come to the RMP Block II program. This integrated the focal plane array IR seeker from the AIM-9X missile onto the Stinger, which brought two key improvements. To understand these, let’s look at what exactly a focal plane array is.

A focal plane array is an array of light (in this case, infrared-spectrum) sensing receptors placed at the focal plane of a lens. It’s also known as a staring sensor, because that’s exactly what it does: it stares. Unlike a more conventional scanning array, it doesn’t build an image from narrow slices rastered across the field of view. Instead, it looks at the entire field of view all the time.

As I said, this brings two major improvements. First, the focal plane array seeker is a lot better at detecting targets than the old dual-wavelength scanning-type seeker, which gave the RMP Block II a larger engagement envelope and longer effective range. The second is a significantly better seeking capability, which translates into both improved performance in cluttered environments and significantly higher resistance to countermeasures. The imaging capabilities of a focal plane array seeker make them extremely difficult to deceive. The RMP Block II would have had good performance against advanced aircraft flying low and firing off decoys, cruise missiles, and UAVs.

The RMP Block II program was cancelled in 2002 for cost reasons. The war on terror was ramping up, and the money was needed elsewhere.

I can understand cost concerns for a MANPADS system if there are other vehicle-borne SHORAD systems available. For the US, there have been a wide variety of recent developments in SHORAD, helpfully linked above. Unlike previous attempts, these are deploying off-the-shelf missiles for the SHORAD role, including the AIM-9X, which has a motor that’s a better ballistic match for the range capabilities of the FPA seeker. The Stinger is already reasonably effective at denying lower altitudes and getting aircraft to fly higher, and low cost encourages wide deployment. I’m inclined to use the money for other things.

Verdict: Funding Denied by the Borgundy War Department Army Ordnance Procurement Board

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