Machbet "Red Slope" Modification - Eye of the eagle

DrJorus · April 21, 2025, 1:49pm

Would you like to see the Red Slope module in-game?

Yes
No (please explain)

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Machbet “Red Slope”: An eye on the sky

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History

The Machbet project started back in 1993, when the IAF commisioned the Israeli company IAI (Israeli Aerospace Industries) to upgrade and modernise the now obsolete M163 VADS.
The main features of the project were: upgraded firepower with the addition of a Stinger missile pod, modern FCS with digital technology, day/night and all weather capabilities thanks to FLIR imaging and GPS navigation and tracking systems.
The first prototype was presented in 1995 and after a period of testing and bug fixing, the Machbet entered service in 1997.

The first models of the new AA system were using a very specific thermal imaging system: Rafael’s “Red Slope” (מדרון אדום - Midrom Adon). This can even be seen on the official Machbet brochure. More specifically, Red Slope is a thermal imaging technology, which was based on Prof. Kidron’s work (an Israeli scientist and professor, the father of microelectronics in Israel). In the early 1970s the US and Israel agreed that both countries should develop a common infrared module (called “CM”) to make it easier and cheaper to manufacture. This first intention was actually stopped by Texas Instrument, who refused to sell their advanced technology to a foreign country.
This decision had the consequence of starting a national program to develop indigenous electo-optics and thermal imagers. Initially, Israel’s MOD assigned this responsibility to EL-OP, which resulted in the production of the first CMT modules. Later, Rafael refined this technology into a better module: the Red Slope (which was still based on the original CMT module, therefore Prof. Kidron’s original designs and work). The first generation of Red Slope were sold in 1000+ units, while the second generation went on the be even installed on FCS for vehicles and tanks. Considering its compact nature, it was also issued to infantry alongside other devices like TAS-6. The actual manufacturing process took place in OPGAL, a subsidiary of Rafael. This is why the commercial designation of this device is TD-92, but it still referred to as “Red Slope” by the IDF and even Rafael.

RAFAEL - From the laboratory to the battlefield

It was also used for long range surveillance with several combinations of supports and additional electronic equipment, like on the “LORROS” and Rafael’s Stalker system.

LORROS

Rafael's STALKER

IDF base surveillance

“Red Slope” Specifications

The TD-92 is “a ruggedized FLIR designed for passive day and night long range surveillance, incorporating state-of-the-art features, such as closed cycle cooling, signal processing and pseudo DC restoration. This stand-alone thermal imaging system provides high resolution, real time TV pictures under conditions of smoke, haze, dust, light camouflage, searchlights, direct sunlight and darkness.”
It was available in 3 different versions: 6" dual FOV telescope, 6" triple FOV telescope and 9" triple FOV telescope.

TD-92 official specification sheet

td-92 stats

Using available sources, it is possible to ascertain the exact model used on the Machbet.
Sadly, the official web page of the TD-92 is an archived version, missing the images. Therefore I have used Jane’s Electro-Optic Systems 1999-2000 purely as a visual reference, so that it can be established that the model name corresponds to the actual device.

Considering that OPGAL offered 3 versions of the TD-92, it first necessary to discover the size of the lens mounted on the Machbet.

Knowing the size of the body of the imager, it is possible to determine that the lens assembly is actually slightly bigger than the width/height of the imager itself. A 9" lens equals to 22.86cm, while the imager is 24cm. Looking at the photos provided, it is clear that the lens mounted is 9", if it were 6" (15.24cm), it would have been significantly smaller than the body of the imager.

The last detail that needs to be determined is the the amount of FOVs available. The source of this information is found in the magazine “Air Force Journal” no. 210 of June 1996 (דן פישל, ‏חבטת פתיחה, בטאון חיל האוויר 210, יוני 1996), pages 50-52.

Article

“Lower the barrels”, commands Lieutenant Yoav, and Sergeant Amnon traverses the turret up and down, and begins to search in his night optics for the target in the air. “Medium field”, calls in the communications device Lieutenant Yoav, and Sergeant Gabriel changes the night vision system from wide FoV to medium FoV, closer to the target. On the control unit screen appear two black stains, which move towards us at rapid speed. “Narrow field” calls Lieutenant Yoav, and the two unidentified stains are revealed all of a sudden as two (AH-1) Cobra helicopters, still at a great distance from us.

The article mentions 3 FOVs: narrow, medium and wide.

Therefore, it has been established that the Machbet uses the TD-92 thermal imaging camera (visual analisys). The diameter of the lens is 9" (size estimate) and it features 3 FOVs (mentioned in the article). The following table, taken from the official manufacturer’s website, provides the specifications of this model.

Thanks to @Rastmust it is possible to get a better understanding of what the Red Slope can do. Comparing Red Slope’s performance with the American AH-64 Apache thermal imager, it is possbile to estimate a magnification of up to 70x zoom on Red Slope. With electronic magnification, that number could go up to 140x magnification. Of course, this kind of magnification would be useful in real life, but in War Thunder we can look for something more practical. My suggestion for the maximun zoom level would be 24x, which would make target identification easy (especially useful in simulator battles and to spot launched ordnance). My recommendation for the minimum level of zoom would be 3x, which would allow for a magnificent wide field of view, incredibly useful to spot a flying target while scanning the skies.

Sources for calculations

MIL-HDBK-799(AR) - Fire Control Systems - General - 1996

Where would it sit and why should it be added?

Currently the Machbet uses a very anemic FLIR system, with a fixed 6x zoom and FOV. This makes looking for targets quite inefficient and at times annoying since, at certain distances, the resolution is so low that a helicopter looks just like a white pixel and the player might miss it. The Red Slope system would greatly increase the efficiency in looking for aerial targets, making the whole platform more effective at keeping an eye on the skies. Being a modification, the player can still choose to keep the standard FLIR system, should he prefer that for ground confrontations (yes, the Vulcan cannon can still hurt even against ground targets).
Here is my idea of how the current modifications could be reworked to leave space for the Red Slope module: