1:72 Tbilisi Aircraft Manufacturing TAM-1 „გველგესლას (Gvelgeslas/Viper)“, aircraft „Blue 07“ of the Georgian Aviation and Air Defence Command of the Defence Forces; Alekseevka air base (Tbilisi), 2021 (What-if/modified Hobbycraft kit)
+++ DISCLAIMER +++
Nothing you see here is real, even though the model, the conversion or the presented background story might be based historical facts. BEWARE!
Some background:
The Georgian Air Force and Air Defense Division (თავდაცვის ძალების ავიაციისა და საჰაერო თავდაცვის სარდლობა; tavdatsvis dzalebis aviatsiisa da sahaero tavdatsvis sardloba) was established on January 1, 1992, and in September the Georgian Air Force conducted its first combat flight during the separatist war in Abkhazia. On August 18, 1998, the two divisions were unified in a joint command structure and renamed the Georgian Air Force.
In 2010, the Georgian Air Force was abolished as a separate branch and incorporated into the Georgian Land Forces as Air and Air Defense sections. By that time, the equipment – primarily consisting of Eastern Bloc aircraft inherited from the Soviet Union after the country’s dissolution – was totally outdated, the most potent aircraft were a dozen Suchoj Su-25 attack aircraft and a handful of MiG-21U trainers.
In order to rejuvenate the air arm, Tbilisi Aircraft Manufacturing (TAM), also known as JSC Tbilaviamsheni and formerly known as 31st aviation factory, started a modernization program for the Su-25, for the domestic forces but also for export customers. TAM had a long tradition of aircraft production within the Soviet Union. In the 1950s the factory started the production of Mikoyan’s MiG-15 and later, the MiG-17 fighter aircraft. In 1957 Tbilisi Aircraft State Association built the MiG-21 two-seater fighter-trainer aircraft and its various derivative aircraft, continuing the MiG-21 production for about 25 years. At the same time the company was manufacturing the K-10 air-to-surface guided missile. Furthermore, the first Sukhoi Su-25 (known in the West as the "Frogfoot") close support aircraft took its maiden voyage from the runway of 31st aviation factory. Since then, more than 800 SU-25s had been delivered to customers worldwide. From the first SU-25 to the 1990s, JSC Tbilaviamsheni was the only manufacturer of this aircraft, and even after the fall of the Soviet Union the production lines were still intact and spares for more than fifty complete aircraft available. Along with the SU-25 aircraft 31st aviation factory also launched large-scale production of air-to-air R-60 and R-73 IR guided missiles, a production effort that built over 6,000 missiles a year and that lasted until the early 1990s. From 1996 to 1998 the factory also produced Su-25U two-seaters.
In 2001 the factory started, in partnership with Elbit Systems of Israel, upgrading basic Su-25 airframes to the Su-25KM “Scorpion” variant. This was just a technical update, however, intended for former Su-25 export customers who would upgrade their less potent Su-25K export aircraft with modern avionics. The prototype aircraft made its maiden flight on 18 April 2001 at Tbilisi in full Georgian Air Force markings. The aircraft used a standard Su-25 airframe, enhanced with advanced avionics including a glass cockpit, digital map generator, helmet-mounted display, computerized weapons system, complete mission pre-plan capability, and fully redundant backup modes. Performance enhancements included a highly accurate navigation system, pinpoint weapon delivery systems, all-weather and day/night performance, NATO compatibility, state-of-the art safety and survivability features, and advanced onboard debriefing capabilities complying with international requirements. The Su-25KM had the ability to use NATO-standard Mark 82 and Mark 83 laser-guided bombs and new air-to-air missiles, the short-range Vympel R-73. This upgrade extended service life of the Su-25 airframes for another decade.
There were, however, not many customers. Manufacturing was eventually stopped at the end of 2010, after Georgian air forces have been permanently dismissed and abolished. By that time, approximately 12 Scorpions had been produced, but the Georgian Air Force still used the basic models of Su-25 because of high cost of Su-25KM and because it was destined mainly for export. According to unofficial sources several Scorpions had been transferred to Turkmenistan as part of a trade deal.
In the meantime, another, more ambitious project took shape at Tbilisi Aircraft Manufacturing, too: With the help of Israel Aircraft Industries (IAI) the company started the development of a completely new attack aircraft, the TAM-1 “Gvelgeslas” (გველგესლას, Viper). It heavily relied on the year-long experience gathered with Su-25 production at Tblisi and on the tools at hand, but it was eventually a completely new aircraft – looking like a crossbreed between the Su-25 and the American A-10 with a T-tail.
This new layout had become necessary because the aircraft was to be powered by more modern, less noisy and more fuel-efficient Rolls Royce AE 3012 turbofan engines – which were originally intended to power the stillborn Yakovlev Yak-77 twin-engine business jet for up to 32 passengers, a slightly derated variant of the GMA 3012 with a 44 in diameter (112 cm) fan and procured via IAI from the United States through the company’s connection with Gulfstream Aerospace. Their larger diameter (the Su-25’s original Soyuz/Tumansky R-195 turbojets had a diameter of 109,5 cm/43.1 in) precluded the use of the former integral engine nacelles along the fuselage. To keep good ground clearance against FOD and to protect them from small arms fire, the engine layout was completely re-arranged. The fuselage was streamlined, and its internal structure was totally changed. The wings moved into a low position. The wings’ planform was almost identical to the Su-25’s, together with the characteristic tip-mounted “crocodile” air brakes. Just the leading edge inside of the “dogteeth” and the wing roots were re-designed, the latter because of the missing former engine nacelles. This resulted in a slightly increased net area, the original wingspan was retained. The bigger turbofans were then mounted in separate pods on short pylons along the rear fuselage, partly protected from below by the wings. Due to the jet efflux and the engines’ proximity to the stabilizers, these were re-located to the top of a deeper, reinforced fin for a T-tail arrangement.
Since the Su-25’s engine bays were now gone, the main landing gear had to be completely re-designed. Retracting them into the fuselage or into the relatively thin wings was not possible, TAM engineers settled upon a design that was very similar to the A-10: the aircraft received streamlined fairings, attached to the wings’ main spar, and positioned under the wings’ leading edges. The main legs were only semi-retractable; in flight, the wheels partly protruded from the fairings, but that hardly mattered from an aerodynamic point of view at the TAM-1’s subsonic operational speed. As a bonus they could still be used while retracted during emergency landings, improving the aircraft’s crash survivability.
Most flight and weapon avionics were procured from or via Elbit, including the Su-25KT’s modernized “glass cockpit”, and the TAM-1’s NATO compatibility was enhanced to appeal to a wider international export market. Beyond a total of eleven hardpoints under the wings and the fuselage for an external ordnance of up to 4.500 kg (9.900 lb), the TAM-1 was furthermore armed with an internal gun. Due to procurement issues, however, the Su-25’s original twin-barrel GSh-30-2 was replaced with an Oerlikon KDA 35mm cannon – a modern variant of the same cannon used in the German Gepard anti-aircraft tank, adapted to the use in an aircraft with a light-weight gun carriage. The KDA gun fired with a muzzle velocity of 1,440 m/s (4,700 ft/s) and a range of 5.500m, its rate of fire was typically 550 RPM. For the TAM-1, a unique feature from the SPAAG installation was adopted: the gun had two magazines, one with space for 200 rounds and another, smaller one for 50. The magazines could be filled with different types of ammunition, and the pilot was able select between them with a simple switch, adapting to the combat situation. Typical ammunition types were armor-piercing FAPDS rounds against hardened ground targets like tanks, and high explosive shells against soft ground targets and aircraft or helicopters, in a 3:1 ratio. Other ammunition types were available, too, and only 200 rounds were typically carried for balance reasons.
The TAM-1’s avionics included a SAGEM ULISS 81 INS, a Thomson-CSF VE-110 HUD, a TMV630 laser rangefinder in a modified nose and a TRT AHV 9 radio altimeter, with all avionics linked through a digital MIL-STD-1553B data bus and a modern “glass cockpit”. A HUD was standard, but an Elbit Systems DASH III HMD could be used by the pilot, too. The DASH GEN III was a wholly embedded design, closely integrated with the aircraft’s weapon system, where the complete optical and position sensing coil package was built within the helmet (either the USAF standard HGU-55/P or the Israeli standard HGU-22/P), using a spherical visor to provide a collimated image to the pilot. A quick-disconnect wire powered the display and carried video drive signals to the helmet’s Cathode Ray Tube (CRT).
The TAM-1’s development was long and protracted, though, primarily due to lack of resources and the fact that the Georgian air force was in an almost comatose state for several years, so that the potential prime customer for the TAM-1 was not officially available. However, the first TAM-1 prototype eventually made its maiden flight in September 2017. This was just in time, because the Georgian Air Force had formally been re-established in 2016, with plans for a major modernization and procurement program. Under the leadership of Georgian Minister of Defense Irakli Garibashvili the Air Force was re-prioritized and aircraft owned by the Georgian Air Force were being modernized and re-serviced after they were left abandoned for 4 years. This program lasted until 2020. In order to become more independent from foreign sources and support its domestic aircraft industry, the Georgian Air Force eventually ordered eight TAM-1s as Su-25K replacements, which would operate alongside a handful of modernized Su-25KMs from national stock. In the meantime, the new type also attained interest from abroad, e. g. from Bulgaria, the Congo and Cyprus. The IDF thoroughly tested two early production TAM-1s of the Georgian Air Force in 2018, too.
General characteristics:
Crew: 1
Length: 15.53 m (50 ft 11 in), including pitot
Wingspan: 14.36 m (47 ft 1 in)
Height: 4.8 m (15 ft 9 in)
Wing area: 35.2 m² (378 sq ft)
Empty weight: 9,800 kg (21,605 lb)
Gross weight: 14,440 kg (31,835 lb)
Max takeoff weight: 19,300 kg (42,549 lb)
Powerplant:
2× Rolls-Royce AE 3012 turbofans with 44.1 kN (9,920 lbf) thrust each
Performance:
Maximum speed: 975 km/h (606 mph, 526 kn, Mach 0.79)
Range: 1.000 km (620 mi, 540 nmi) with internal fuel, clean
Combat range: 750 km (470 mi, 400 nmi) at sea level with 4.500 kg (9,911 lb) of ordnance,
incl. two external fuel tanks
Service ceiling: 7.800 m (25,550 ft)
g limits: +6.5
Rate of climb: 58 m/s (11,400 ft/min)
Armament:
1× 35 mm (1.38 in) Oerlikon KDA cannon with 200 rds in two magazines
under the lower forward fuselage, offset to port side.
11× hardpoints with a capacity of up to 4.500 kg (9,911 lb) of external stores
The kit and its assembly:
This rather rigorous conversion had been on my project list for many years, and with the “Gunships” group build at whatifmodellers.com in late 2021 I eventually gathered my mojo to tackle it. The ingredients had already been procured long ago, but there are ideas that make you think twice before you take action…
This build was somewhat inspired by a CG rendition of a modified Su-25 that I came across while doing online search for potential ideas, running under the moniker “Su-125”, apparently created by someone called “Bispro” and published at DeviantArt in 2010; check this: (www.deviantart.com/bispro/art/Sukhoi-Su-125-Foghorn-15043…). The rendition shows a Su-25 with its engines re-located to the rear fuselage in separate nacelles, much like an A-10, plus a T-tail. However, as many photoshopped aircraft, the shown concept had IMHO some flaws. Where would a landing gear go, as the Su-125 still had shoulder wings? The engines’ position and size also looked fishy to me, quite small/narrow and very far high and back – I had doubts concerning the center of gravity. Nevertheless, I liked the idea, and the idea of an “A-10-esque remix” of the classic Frogfoot was born.
This idea was fueled even further when I found out that the Hobbycraft kit lends itself to such a conversion. The kit itself is not a brilliant Su-25 rendition, there are certainly better models of the aircraft in 1:72. However, what spoke for the kit as whiffing fodder was/is the fact that it is quite cheap (righteously so!) and AFAIK the only offering that comes with separate engine nacelles. These are attached to a completely independent central fuselage, and this avoids massive bodywork that would be necessary (if possible at all) with more conventional kits of this aircraft.
Another beneficial design feature is that the wing roots are an integral part of the original engine nacelles, forming their top side up to the fuselage spine. Through this, the original wingspan could be retained even without the nacelles, no wing extension would be necessary to retain the original proportions.
Work started with the central fuselage and the cockpit tub, which received a different (better) armored ejection seat and a pilot figure; the canopy remained unmodified and closed, because representing the model with an open cockpit would have required additional major body work on the spinal area behind the canopy. Inside, a new dashboard (from an Italeri BAe Hawk) was added, too – the original instrument panel is just a flat front bulkhead, there’s no space for the pilot to place the legs underneath the dashboard!
In parallel, the fin underwent major surgery. I initially considered an A-10-ish twin tail, but the Su-25’s high “tail stinger” prevented its implementation: the jet efflux would come very close to the tail surfaces. So, I went for something similar to the “Su-125” layout.
Mounting the OOB stabilizers to the fin was challenging, though. The fin lost its di-electric tip fairing, and it was cut into two sections, so that the tip would become long enough to match the stabilizers. A lucky find in the scrap box was a leftover tail tip from a Matchbox Blackburn Buccaneer, already shortened from a former, stillborn project: it had now the perfect length to take the Su-25 stabilizers! To make it fit on the fin, an 8mm deep section was inserted, in the form of a simple 1.5mm styrene sheet strip. Once dry, the surface was re-built with several PSR layers. Since it would sit further back on the new aircraft’s tail, the stinger with a RHAWS sensor was shortened.
On the fuselage, the attachment points for the wings and the engine nacelles were PSRed away and the front section filled with lots of lead beads, hoping that it would be enough to keep the model’s nose down.
Even though the wings had a proper span for a re-location into a low position, they still needed some attention: at the roots, there’s a ~1cm wide section without sweep (the area which would normally cover the original engine nacelles’ tops). This was mended through triangular 1.5 mm styrene wedges that extended the leading-edge sweep, roughly cut into shape once attached and later PSRed into the wings’ surfaces
The next construction site were the new landing gear attachment points. This had caused some serious headaches – where do you place and stow it? With new, low wings settled, the wings were the only logical place. But the wings were too thin to suitably take the retracted wheels, and, following the idea of a retrofitted existing design, I decided to adopt the A-10’s solution of nacelles into which the landing gear retracts forward, with the wheels still partly showing. This layout option appears quite plausible, since it would be a “graft-on” solution, and it also has the benefit of leaving lots of space for underwing stores, since the hardpoints’ position had to be modified now, too.
I was lucky to have a pair of A-10 landing gear nacelles at hand, left over from a wrecked Matchbox model from childhood time (the parts are probably 35 years old!). They were simply cut out, glued to the Su-25 wings and PSRed into shape. The result looked really good!
At this point I had to decide the model’s overall layout – where to place the wings, the tail and the new engine nacelles. The latter were not 1:72 A-10 transplants. I had some spare engine pods from the aforementioned Matchbox wreck, but these looked too rough and toylike for my taste. They were furthermore too bulky for the Su-25, which is markedly smaller than an A-10, so I had to look elsewhere. As a neat alternative for this project, I had already procured many moons ago a set of 1:144 resin PS-90A engines from a Russian company called “A.M.U.R. Reaver”, originally intended for a Tu-204 airliner or an Il-76 transport aircraft. These turbofan nacelles not only look very much like A-10 nacelles, just a bit smaller and more elegant, they are among the best resin aftermarket parts I have ever encountered: almost no flash, crisp molding, no bubbles, and perfect fit of the parts – WOW!
With these three elements at hand I was able to define the wings’ position, based on the tail, and from that the nacelles’ location, relative to the wings and the fin.
The next challenge: how to attach the new engines to the fuselage? The PS-90A engines came without pylons, so I had to improvise. I eventually found suitable pylons in the form of parts from F-14A underwing missile pylons, left over from an Italeri kit. Some major tailoring was necessary to find a proper position on the nacelles and on the fuselage, and PSRing these parts turned out to be quite difficult because of the tight and labyrinthine space.
When the engines were in place, work shifted towards the model’s underside. The landing gear was fully replaced. I initially wanted to retain the front wheel leg and the main wheels but found that the low wings would not allow a good ground clearance for underwing stores and re-arming the aircraft, a slightly taller solution was necessary. I eventually found a complete landing gear set in the scrap box, even though I am not certain to which aircraft it once belonged? I guess that the front wheel came from a Hasegawa RA-5C Vigilante, while the main gear and the wheels once belonged to an Italeri F-14A, alle struts were slightly shortened. The resulting stance is still a bit stalky, but an A-10 is also quite tall – this is just not so obvious because of the aircraft’s sheer size.
Due to the low wings and the landing gear pods, the Su-25’s hardpoints had to be re-arranged, and this eventually led to a layout very similar to the A-10. I gave the aircraft a pair of pylons inside of the pods, plus three hardpoints under the fuselage, even though all of these would only be used when slim ordnance was carried. I just fitted the outer pair. Outside of the landing gear fairings there would have been enough space for the Frogfoot’s original four outer for pylons, but I found this to be a little too much. So I gave it “just” three, with more space between them.
The respective ordnance is a mix for a CAS mission with dedicated and occasional targets. It consists of:
– Drop tanks under the inner wings (left over from a Bilek Su-17/22 kit)
– A pair of B-8M1 FFAR pods under the fuselage (from a vintage Mastercraft USSR weapon set)
– Two MERs with four 200 kg bombs each, mounted on the pylons outside of the landing gear (the odd MERs came from a Special Hobby IDF SMB-2 Super Mystère kit, the bombs are actually 1:100 USAF 750 lb bombs from a Tamiya F-105 Thunderchief in that scale)
– Four CBU-100 Rockeye Mk. II cluster bombs on the outer stations (from two Italeri USA/NATO weapon sets, each only offers a pair of these)
Yes, it’s a mix of Russian and NATO ordnance – but, like the real Georgian Su-25KM “Scorpion” upgrade, the TAM-1 would certainly be able to carry the same or even a wider mix, thanks to modified bomb racks and wirings. Esp. “dumb” weapons, which do not call for special targeting and guidance avionics, are qualified.
The gun under the nose was replaced with a piece from a hollow steel needle.
Painting and markings:
Nothing unusual here. I considered some more “exotic” options, but eventually settled for a “conservative” Soviet/Russian-style four-tone tactical camouflage, something that “normal” Su-25s would carry, too.
The disruptive pattern was adapted from a Macedonian Frogfoot but underwent some changes due to the T-tail and the engine nacelles. The basic tones were Humbrol 119 (RAF Light Earth), 150 (Forest Green), 195 (Chrome Oxide Green, RAL 6020) and 98 (Chocolate) on the upper surfaces and RLM78 from (Modelmaster #2087) from below, with a relatively low waterline, due to the low-set wings.
As usual, the model received a light black ink washing and some post-shading – especially on the hull and on the fin, where many details had either disappeared under PSR or were simply not there at all.
The landing gear and the lower areas of the cockpit were painted in light grey (Humbrol 64), while the upper cockpit sections were painted with bright turquoise (Modelmaster #2135). The wheel hubs were painted in bright green (Humbrol 101), while some di-electric fairings received a slightly less intense tone (Humbrol 2). A few of these flat fairings on the hull were furthermore created with green decal sheet material (from TL Modellbau) to avoid masking and corrections with paint.
The tactical markings became minimal, matching the look of late Georgian Su-25s. The roundels came from a Balkan Models Frogfoot sheet. The “07” was taken from a Blue Rider decal sheet, it actually belongs to a Lithuanian An-2. Some white stencils from generic MiG-21 and Mi-8 Begemot sheets were added, too, and some small markings were just painted onto the hull with yellow.
Some soot stains around the jet nozzles and the gun were added with graphite, and finally the kit was sealed with a coat of matt acrylic varnish.
A major bodywork project – and it’s weird that this is basically just a conversion of a stock kit and no kitbashing. A true Frogfoot remix! The new engines were the biggest “outsourced” addition, the A-10 landing gear fairings were a lucky find in the scrap box, and the rest is quite generic and could have looked differently. The result is impressive and balanced, though, the fictional TAM-1 looks quite plausible. The landing gear turned out to be a bit tall and stalky, though, making the aircraft look smaller on the ground than it actually is – but I left it that way.
Posted by Dizzyfugu on 2021-12-13 18:23:36
Tagged: , 1:72 , tam-1 , viper , Tbilisi , Aircraft , Manufacturing , გველგესლას , Gvelgeslas , 07 , Georgia , Aviation , Air , Defence , Command , Forces , Alekseevka , base , 2021 , What-if , whif , Hobbycraft , model , kit , modellbau , conversion , su-25 , frogfoot , gunship , fictional , suchoj , tactical , attack , plane , a-10 , warthog , sukhoj , suchoi , fake , foghorn
