+++ DISCLAIMER +++
Nothing you see here is real, even though the conversion or the presented background story might be based on historical facts. BEWARE!
During the 1950s, Hindustan Aircraft Limited (HAL) had developed and produced several types of trainer aircraft, such as the HAL HT-2. However, elements within the firm were eager to expand into the then-new realm of supersonic fighter aircraft. Around the same time, the Indian government was in the process of formulating a new Air Staff Requirement for a Mach 2-capable combat aircraft to equip the Indian Air Force (IAF). However, as HAL lacked the necessary experience in both developing and manufacturing frontline combat fighters, it was clear that external guidance would be invaluable; this assistance was embodied by Kurt Tank.
In 1956, HAL formally began design work on the supersonic fighter project. The Indian government, led by Jawaharlal Nehru, authorized the development of the aircraft, stating that it would aid in the development of a modern aircraft industry in India. The first phase of the project sought to develop an airframe suitable for travelling at supersonic speeds, and able to effectively perform combat missions as a fighter aircraft, while the second phase sought to domestically design and produce an engine capable of propelling the aircraft. Early on, there was an explicit adherence to satisfying the IAF’s requirements for a capable fighter bomber; attributes such as a twin-engine configuration and a speed of Mach 1.4 to 1.5 were quickly emphasized, and this led to the HF-24 Marut.
On 24 June 1961, the first prototype Marut conducted its maiden flight. It was powered by the same Bristol Siddeley Orpheus 703 turbojets that had powered the Folland Gnat, also being manufactured by HAL at that time. On 1 April 1967, the first production Marut was delivered to the IAF. While originally intended only as an interim measure during testing, HAL decided to power production Maruts with a pair of unreheated Orpheus 703s, meaning the aircraft could not attain supersonic speed. Although originally conceived to operate around Mach 2 the Marut in fact was barely capable of reaching Mach 1 due to the lack of suitably powerful engines.
The IAF were reluctant to procure a fighter aircraft only marginally superior to its existing fleet of British-built Hawker Hunters. However, in 1961, the Indian Government decided to procure the Marut, nevertheless, but only 147 aircraft, including 18 two-seat trainers, were completed out of a planned 214. Just after the decision to build the lukewarm Marut, the development of a more advanced aircraft with the desired supersonic performance was initiated.
This enterprise started star-crossed, though: after the Indian Government conducted its first nuclear tests at Pokhran, international pressure prevented the import of better engines of Western origin, or at times, even spares for the Orpheus engines, so that the Marut never realized its full potential due to insufficient power, and it was relatively obsolescent by the time it reached production.
Due to these restrictions India looked for other sources for supersonic aircraft and eventually settled upon the MiG-21 F-13 from the Soviet Union, which entered service in 1964. While fast and agile, the Fishbed was only a short-range daylight interceptor. It lacked proper range for escort missions and air space patrols, and it had no radar that enabled it to conduct all-weather interceptions. To fill this operational gap, the new indigenous HF-26 project was launched around the same time.
For the nascent Indian aircraft industry, HF-26 had a demanding requirements specification: the aircraft was to achieve Mach 2 top speed at high altitude and carry a radar with a guided missile armament that allowed interceptions in any weather, day and night. The powerplant question was left open, but it was clear from the start that a Soviet engine would be needed, since an indigenous development of a suitable powerplant would take much too long and block vital resources, and western alternatives were out of reach. The mission profile and the performance requirements quickly defined the planned aircraft’s layout: To fit a radar, the air intakes with movable ramps to feed the engines were placed on the fuselage flanks. To make sure the aircraft would fulfill its high-performance demands, it was right from the outset powered by two engines, and it was decided to give it delta wings, a popular design among high-speed aircraft of the time – exemplified by the highly successful Dassault Mirage III (which was to be delivered to Pakistan in 1967). With two engines, the HF-26 would be a heavier aircraft than the Mirage III, though, and it was planned to operate the aircraft from semi-prepared airfields, so that it would receive a robust landing gear with low-pressure tires and a brake parachute.
In 1962 India was able to negotiate the delivery of Tumansky RD-9 turbojet engines from the Soviet Union, even though no afterburner was part of the deal – this had to be indigenously developed by Hindustan Aeronautics Limited (HAL). However, this meant that the afterburner could be tailored to the HF-26, and this task would provide HAL with valuable engineering experience, too.
Now knowing the powerplant, HAL created a single-seater airframe around it, a rather robust design that superficially reminded of the French Mirage III, but there were fundamental differences. The HF-26 had boxy air intakes with movable ramps to control the airflow to the two engines and a relatively wide fuselage to hold them and most of the fuel in tanks between the air ducts behind the cockpit. The aircraft had a single swept fin and a rather small mid-positioned delta-wing with a 60° sweep. The pilot sat under a tight canopy that offered – similar to the Mirage III – only limited all-round vision.
The HF-26’s conical nose radome covered an antenna for a ‘Garud’ interception radar – which was in fact a downgraded Soviet ‘Oryol’ (Eagle; NATO reporting name ‘Skip Spin’) system that guided the HF-26’s main armament, a pair of semi-active radar homing (SARH) ‚Saanp’ missiles.
The Saanp missile was developed specifically for the HF-26 in India but used many components of Soviet origin, too, so that they were compatible with the radar. In performance, the Saanp was comparable with the French Matra R.530 air-to-air missile, even though the aerodynamic layout was reversed, with steering fins at the front end, right behind the SARH seaker head – overall the missile reminded of an enlarged AIM-4 Falcon. The missile weighed 180 kg and had a length of 3.5 m. Power came from a two-stage solid rocket that offered a maximum thrust of 80 kN for 2.7 s during the launch phase plus 6.5 s cruise. Maximum speed was Mach 2.7 and operational range was 1.5 to 20 km (0.9 to 12.5 miles). Two of these missiles could be carried on the main wing hardpoints in front of the landing gear wells. Alternatively, infrared-guided R-3 (AA-2 ‘Atoll’) short-range AAMs could be carried by the HF-26, too, and typically two of these were carried on the outer underwing hardpoints, which were plumbed to accept drop tanks (typically supersonic PTB-490s that were carried by the IAF’s MiG-21s, too) . Initially, no internal gun was envisioned, as the HF-26 was supposed to be a pure high-speed/high-altitude interceptor that would not engage in dogfights. Two more hardpoints under the fuselage were plumbed, too, for a total of six external stations.
Due to its wing planform, the HF-26 was soon aptly called “Teer” (= Arrow), and with Soviet help the first prototype was rolled out in early 1964 and presented to the public. The first flight, however, would take place almost a year later in January 1965, due to many technical problems, and these were soon complemented by aerodynamic problems. The original delta-winged HF-26 had poor take-off and landing characteristics, and directional stability was weak, too. While a second prototype was under construction in April 1965 the first aircraft was lost after it had entered a spin from which the pilot could not escape – the aircraft crashed and its pilot was killed during the attempt to eject.
After this loss HAL investigated an enlarged fin and a modified wing design with deeper wingtips with lower sweep, which increased wing area and improved low speed handling, too. Furthermore, the fuselage shape had to be modified, too, to reduce supersonic drag, and a more pronounced area ruling was introduced. The indigenous afterburner for the RD-9 engines was unstable and troublesome, too.
It took until 1968 and three more flying prototypes (plus two static airframes) to refine the Teer for serial production service introduction. In this highly modified form, the aircraft was re-designated HF-26M and the first machines were delivered to IAF No. 3 Squadron in late 1969. However, it would take several months until a fully operational status could be achieved. By that time, it was already clear that the Teer, much like the HF-24 Marut before, could not live up to its expectations and was at the brink of becoming obsolete as it entered service. The RD-9 was not a modern engine anymore, and despite its indigenous afterburner – which turned out not only to be chronically unreliable but also to be very thirsty when engaged – the Teer had a disappointing performance: The fighter only achieved a top speed of Mach 1.6 at full power, and with full external load it hardly broke the wall of sound in level flight. Its main armament, the Saanp AAM, also turned out to be unreliable even under ideal conditions.
However, the HF-26M came just in time to take part in the Indo-Pakistani War of 1971 and was, despite its weaknesses, extensively used – even though not necessarily in its intended role. High-flying slow bombers were not fielded during the conflict, and the Teer remained, despite its on-board radar, heavily dependent on ground control interception (GCI) to vector its pilot onto targets coming in at medium and even low altitude. The HF-26M had no capability against low-flying aircraft either, so that pilots had to engage incoming, low-flying enemy aircraft after visual identification – a task the IAF’s nimble MiG-21s were much better suited for. Escorts and air cover missions for fighter-bombers were flown, too, but the HF-26M’s limited range only made it a suitable companion for the equally short-legged Su-7s. The IAF Canberras were frequently deployed on longer range missions, but the HF-26Ms simply could not follow them all the time; for a sufficient range the Teer had to carry four drop tanks, what increased drag and only left the outer pair of underwing hardpoints (which were not plumbed) free for a pair of AA-2 missiles. With the imminent danger of aerial close range combat, though, During the conflict with Pakistan, most HF-26M’s were retrofitted with rear-view mirrors in their canopies to improve the pilot’s field of view, and a passive IR sensor was added in a small fairing under the nose to improve the aircraft’s all-weather capabilities and avoid active radar emissions that would warn potential prey too early.
The lack of an internal gun turned out to be another great weakness of the Teer, and this was only lightly mended through the use of external gun pods. Two of these cigar-shaped pods that resembled the Soviet UPK-23 pod could be carried on the two ventral pylons, and each contained a 23 mm Gryazev-Shipunov GSh-23L autocannon of Soviet origin with 200 rounds. Technically these pods were very similar to the conformal GP-9 pods carried by the IAF MiG-21FLs. While the gun pods considerably improved the HF-26M’s firepower and versatility, the pods were draggy, blocked valuable hardpoints (from extra fuel) and their recoil tended to damage the pylons as well as the underlying aircraft structure, so that they were only commissioned to be used in an emergency.
However, beyond air-to-air weapons, the HF-26M could also carry ordnance of up to 1.000 kg (2.207 lb) on the ventral and inner wing hardpoints and up to 500 kg (1.100 lb) on the other pair of wing hardpoints, including iron bombs and/or unguided missile pods. However, the limited field of view from the cockpit over the radome as well as the relatively high wing loading did not recommend the aircraft for ground attack missions – even though these frequently happened during the conflict with Pakistan. For these tactical missions, many HF-26Ms lost their original overall natural metal finish and instead received camouflage paint schemes on squadron level, resulting in individual and sometimes even spectacular liveries. Most notable examples were the Teer fighters of No. 1 Squadron (The Tigers), which sported various camouflage adaptations of the unit’s eponym.
Despite its many deficiencies, the HF-26M became heavily involved in the Indo-Pakistan conflict. As the Indian Army tightened its grip in East Pakistan, the Indian Air Force continued with its attacks against Pakistan as the campaign developed into a series of daylight anti-airfield, anti-radar, and close-support attacks by fighter jets, with night attacks against airfields and strategic targets by Canberras and An-12s, while Pakistan responded with similar night attacks with its B-57s and C-130s.
The PAF deployed its F-6s mainly on defensive combat air patrol missions over their own bases, leaving the PAF unable to conduct effective offensive operations. Sporadic raids by the IAF continued against PAF forward air bases in Pakistan until the end of the war, and interdiction and close-support operations were maintained. One of the most successful air raids by India into West Pakistan happened on 8 December 1971, when Indian Hunter aircraft from the Pathankot-based 20 Squadron, attacked the Pakistani base in Murid and destroyed 5 F-86 aircraft on the ground.
The PAF played a more limited role in the operations, even though they were reinforced by Mirages from an unidentified Middle Eastern ally (whose identity remains unknown). The IAF was able to conduct a wide range of missions – troop support; air combat; deep penetration strikes; para-dropping behind enemy lines; feints to draw enemy fighters away from the actual target; bombing and reconnaissance. India flew 1,978 sorties in the East and about 4,000 in Pakistan, while the PAF flew about 30 and 2,840 at the respective fronts. More than 80 percent of IAF sorties were close-support and interdiction and about 45 IAF aircraft were lost, including three HF-26Ms. Pakistan lost 60 to 75 aircraft, not including any F-86s, Mirage IIIs, or the six Jordanian F-104s which failed to return to their donors. The imbalance in air losses was explained by the IAF’s considerably higher sortie rate and its emphasis on ground-attack missions. The PAF, which was solely focused on air combat, was reluctant to oppose these massive attacks and rather took refuge at Iranian air bases or in concrete bunkers, refusing to offer fights and respective losses.
After the war, the HF-26M was officially regarded as outdated, and as license production of the improved MiG-21FL (designated HAL Type 77 and nicknamed “Trishul” = Trident) and later of the MiG-21M (HAL Type 88) was organized in India, the aircraft were quickly retired from frontline units. They kept on serving into the Eighties, though, but now restricted to their original interceptor role. Beyond the upgrades from the Indo-Pakistani War, only a few upgrades were made. For instance, the new R-60 AAM was introduced to the HF-26M and around 1978 small (but fixed) canards were retrofitted to the air intakes behind the cockpit that improved the Teer’s poor slow speed control and high landing speed as well as the aircraft’s overall maneuverability.
A radar upgrade, together with the introduction of better air-to-ai missiles with a higher range and look down/shoot down capability was considered but never carried out. Furthermore, the idea of a true HF-26 2nd generation variant, powered by a pair of Tumansky R-11F-300 afterburner jet engines (from the license-built MiG-21FLs), was dropped, too – even though this powerplant eventually promised to fulfill the Teer’s design promise of Mach 2 top speed. A total of only 82 HF-26s (including thirteen two-seat trainers with a lengthened fuselage and reduced fuel capacity, plus eight prototypes) were built. The last aircraft were retired from IAF service in 1988 and replaced with Mirage 2000 fighters procured from France that were armed with the Matra Super 530 AAM.
Length: 14.97 m (49 ft ½ in)
Wingspan: 9.43 m (30 ft 11 in)
Height: 4.03 m (13 ft 2½ in)
Wing area: 30.6 m² (285 sq ft)
Empty weight: 7,000 kg (15,432 lb)
Gross weight: 10,954 kg (24,149 lb) with full internal fuel
Max takeoff weight: 15,700 kg (34,613 lb) with external stores
2× Tumansky RD-9 afterburning turbojet engines; 29 kN (6,600 lbf) dry thrust each
and 36.78 kN (8,270 lbf) with afterburner
Maximum speed: 1,700 km/h (1,056 mph; 917 kn; Mach 1.6) at 11,000 m (36,000 ft)
1,350 km/h (840 mph, 730 kn; Mach 1.1) at sea level
Combat range: 725 km (450 mi, 391 nmi) with internal fuel only
Ferry range: 1,700 km (1,100 mi, 920 nmi) with four drop tanks
Service ceiling: 18,100 m (59,400 ft)
g limits: +6.5
Time to altitude: 9,145 m (30,003 ft) in 1 minute 30 seconds
Wing loading: 555 kg/m² (114 lb/sq ft)
6× hardpoints (four underwing and two under the fuselage) for a total of 2.500 kg (5.500 lb);
Typical interceptor payload:
– two IR-guided R-3 or R-60 air-to-air-missiles or
two PTB-490 drop tanks on the outer underwing stations
– two semi-active radar-guided ‚Saanp’ air-to-air missiles or two more R-3 or R-60 AAMs
on inner underwing stations
– two 500 l drop tanks or two gun pods with a 23 mm GSh-23L autocannon and 200 RPG
each under the fuselage
The kit and its assembly:
This whiffy delta-wing fighter was inspired when I recently sliced up a PM Model Su-15 kit for my side-by-side-engine BAC Lightning build. At an early stage of the conversion, I held the Su-15 fuselage with its molded delta wings in my hand and wondered if a shortened tail section (as well as a shorter overall fuselage to keep proportions balanced) could make a delta-wing jet fighter from the Flagon base? Only a hardware experiment could yield an answer, and since the Su-15’s overall outlines look a bit retro I settled at an early stage on India as potential designer and operator, as “the thing the HF-24 Marut never was”.
True to the initial idea, work started on the tail, and I chopped off the fuselage behind the wings’ trailing edge. Some PSR was necessary to blend the separate exhaust section into the fuselage, which had to be reduced in depth through wedges that I cut out under the wings trailing edge, plus some good amount of glue and sheer force the bend the section a bit upwards. The PM Model’s jet exhausts were drilled open, and I added afterburner dummies inside – anything would look better than the bleak vertical walls inside after only 2-3 mm! The original fin was omitted, because it was a bit too large for the new, smaller aircraft and its shape reminded a lot of the Suchoj heavy fighter family. It was replaced with a Mirage III/V fin, left over from a (crappy!) Pioneer 2 IAI Nesher kit.
Once the rear section was complete, I had to adjust the front end – and here the kitbashing started. First, I chopped off the cockpit section in front of the molded air intake – the Su-15’s long radome and the cockpit on top of the fuselage did not work anymore. As a remedy I remembered another Su-15 conversion I did a (long) while ago: I created a model of a planned ground attack derivative, the T-58Sh, and, as a part of the extensive body work, I transplanted the slanted nose from an academy MiG-27 between the air intakes – a stunt that was relatively easy and which appreciably lowered the cockpit position. For the HF-26M I did something similar, I just transplanted a cockpit from a Hasegawa/Academy MiG-23 with its ogival radome that size-wise better matched with the rest of the leftover Su-15 airframe.
The MiG-23 cockpit matched perfectly with the Su-15’s front end, just the spinal area behind the cockpit had to be raised/re-sculpted to blend the parts smoothly together. For a different look from the Su-15 ancestry I also transplanted the front sections of the MiG-23 air intakes with their shorter ramps. Some mods had to be made to the Su-15 intake stubs, but the MiG-23 intakes were an almost perfect fit in size and shape and easy to integrate into the modified front hill. The result looks very natural!
However, when the fuselage was complete, I found that the nose appeared to be a bit too long, leaving the whole new hull with the wings somewhat off balance. As a remedy I decided at a rather late stage to shorten the nose and took out a 6 mm section in front of the cockpit – a stunt I had not planned, but sometimes you can judge things only after certain work stages. Some serious PSR was necessary to re-adjust the conical nose shape, which now looked more Mirage III-ish than planned!
The cockpit was taken mostly OOB, I just replaced the ejection seat and gave it a trigger handle made from thin wire. With the basic airframe complete it was time for details. The PM Model Su-15s massive and rather crude main landing gear was replaced with something more delicate from the scrap box, even though I retained the main wheels. The front landing gear was taken wholesale from the MiG-23, but had to be shortened for a proper stance.
A display holder adapter was integrated into the belly for the flight scenes, hidden well between the ventral ordnance.
The hardpoints, including missile launch rails, came from the MiG-23; the pylons had to be adjusted to match the Su-15’s wing profile shape, the Anab missiles lost their tail sections to create the fictional Indian ‘Saanp’ AAMs. The R-3s on the outer stations were left over from a MP MiG-21. The ventral pylons belong to Academy MiG-23/27s, one came from the donor kit, the other was found in the spares box. The PTB-490 drop tanks also came from a KP MiG-21 (or one of its many reincarnations, not certain).
Painting and markings:
The paint scheme for this fictional aircraft was largely inspired by a picture of a whiffy and very attractive Saab 37 Viggen (an 1:72 Airfix kit) in IAF colors, apparently a model from a contest. BTW, India actually considered buying the Viggen for its Air Force!
IAF aircraft were and are known for their exotic and sometimes gawdy paint schemes, and with IAF MiG-21 “C 992” there’s even a very popular (yet obscure) aircraft that sported literal tiger stripes. The IAF Viggen model was surely inspired by this real aircraft, and I adopted something similar for my HF-26M.
IAF 1 Squadron was therefore settled, and for the paint scheme I opted for a "stripish" scheme, but not as "tigeresque" as "C 992". I found a suitable benchmark in a recent Libyian MiG-21, which carried a very disruptive two-tone grey scheme. I adapted this pattern to the HA-26M airframe and replaced its colors, similar to the IAF Viggen model, which became a greenish sand tone (a mix of Humbrol 121 with some 159; I later found out that I could have used Humbrol 83 from the beginning, though…) and a very dark olive drab (Humbrol 66, which looks like a dull dark brown in contrast with the sand tone), with bluish grey (Humbrol 247) undersides. With the large delta wings, this turned out to look very good and even effective!
For that special "Indian touch" I gave the aircraft a high-contrast fin in a design that I had seen on a real camouflaged IAF MiG-21bis: an overall dark green base with a broad, red vertical stripe which was also the shield for the fin flash and the aircraft’s tactical code (on the original bare metal). The fin was first painted in green (Humbrol 2), the red stripe was created with orange-red decal sheet material. Similar material was also used to create the bare metal field for the tactical code, the yellow bars on the splitter plates and for the thin white canopy sealing.
After basic painting was done the model received an overall black ink washing, post-panel shading and extensive dry-brushing with aluminum and iron for a rather worn look.
The missiles became classic white, while the drop tanks, as a contrast to the camouflaged belly, were left in bare metal.
Decals/markings came primarily from a Begemot MiG-25 kit, the tactical codes on the fin and under the wings originally belong to an RAF post-WWII Spitfire, just the first serial letter was omitted. Stencils are few and they came from various sources. A compromise is the unit badge on the fin: I needed a tiger motif, and the only suitable option I found was the tiger head emblem on a white disc from RAF No. 74 Squadron, from the Matchbox BAC Lightning F.6&F.2A kit. It fits stylistically well, though. 😉
Finally, the model was sealed with matt acrylic varnish (except for the black radome, which became a bit glossy) and finally assembled.
A spontaneous build, and the last one that I completed in 2022. However, despite a vague design plan the model evolved as it grew. Bashing the primitive PM Model Su-15 with the Academy MiG-23 parts was easier than expected, though, and the resulting fictional aircraft looks sturdy but quite believable – even though it appears to me like the unexpected child of a Mirage III/F-4 Phantom II intercourse, or like a juvenile CF-105 Arrow, just with mid-wings? Nevertheless, the disruptive paint scheme suits the delta wing fighter well, and the green/red fin is a striking contrast – it’s a colorful model, but not garish.
Posted by Dizzyfugu on 2023-01-18 10:16:54