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Overview
The TS-11 Iskra (spark) bis is a Polish jet trainer/ light multirole aircraft. Poland’s first indigenous jet aircraft, it was developed from 1957, first flew in 1960, and entered service in 1964. The Iskra bis DF featured an improved SO-3W engine and mounted a trio of AFA-39 cameras for reconnaissance. Like the Iskra D before it, the DF saw limited export success with 16 purchased by India. 38 also served in the Polish Air Force.
History
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Development
Poland’s first jets were a trio of Yak-17s and 11 Yak-17UTI trainers purchased in 1950. As the Siły Powietrzne (Air Force, from here on abbreviated SP) acquired more jet aircraft (Yak-23s in 1951, production of MiG-15s in 1952) the need for a new basic jet trainer arose. In 1956, project requirements for the new TS-11 (named for lead designer Tadeusz Sołtyk) were laid out- the aircraft was to be of all-metal construction with a low, straight, thin wing, a top speed of Mach 0.8 and a conventional tandem cockpit layout with the student in the front and the instructor behind. The TS-11 was to be armed with a 23mm cannon for gunnery training or to allow the aircraft to operate as a fighter should global war break out.
A full-scale wooden mockup was built in late 1957. This was followed by a static test airframe in March 1959 and three proper flying prototypes from December 1959, all mounting the British Viper 8, acquired from Yugoslavia. The TS-11 made it first flight on 5th February 1960, being publicly debuted on 11th September 1960 in Łódź. The three prototypes underwent extensive testing late 1960 through 1961, proving easy to fly, agile, stable, reliable, and simple to maintain- in short, exactly what you’d want in a training aircraft.
Iskras A B C
Production of the TS-11 Iskra bis A began in 1964. Production aircraft were fitted with the HO-10, a copy of the Viper 8 with slight improvements that boosted its continuous power to 7.84kN. 47 would enter service between 1964 and 1967.
In 1966, TS-11 Iskra bis B began development with four underwing hardpoints for carrying ordinance, for training or combat. This aircraft had the SO-1 engine initially, later replaced by the more reliable but equally powerful SO-3. The Iskra bis B entered service in 1968, gradually replacing the Iskra As, with a total of 155 produced. The TS-11 Bs were gradually upgraded to D standard.
The Iskra B was followed in 1971 by the Iskra C. The first non-trainer model of the TS-11, it was designed for photoreconnaissance and artillery spotting and had the rear controls removed and replaced with a recon suite. Five Iskra Bs were modified on the assembly lines in 1972 to the Iskra C standard. These aircraft served until 1983, when they were refitted into standard Iskra DF trainers.
Refining the Spark- the Iskra D
The Iskra B had proved itself to be an excellent aircraft but it still had room to grow. So in 1972 development of the Iskra D began. All avionics were replaced by more modern models, and the SO-3 engine was replaced by an improved, more powerful SO-3B. The Iskra D was the first model to see export interest- in 1972, Iran evaluated the aircraft, and in 1973 Peru and India did as well. Of these countries, India would be the only one to actually purchase the TS-11. In 1975, 50 Iskra Ds were purchased; these aircraft as well as a later second order of 10 would serve in the IAF from 1976 until 2004. Poland would receive the Iskra D the same year. The existing inventory of Iskra Bs would gradually be converted to Iskra D standard.
Return of the Photo-Spark: the Iskra DF
While the Iskra C had been unsuccessful, the idea of using the Iskra as a reconnaissance aircraft still had a great appeal. So in 1974 the Iskra bis DF was developed, with the same trio fo cameras found on the Iskra C and a navigator’s desk in the rear cockpit. However, unlike the C, the rear controls were not removed, allowing the aircraft to still act as a trainer. It also featured the final engine development, the SO-3W. The SO-3W was a further refinement of the SO-3B, with a longer service life and slightly higher thrust. The Iskra DF model entered production in 1977 and service in 1978. India purchased 16 of these aircraft at some point in the late 70s, bringing their total to 76 Iskra D/DFs. The Polish Air Force operated 46 DFs, for 62 total produced.
Almost Immortal Spark
The TS-11 had an extremely long service life, the longest for any armed single-engine jet in service of the country of origin. Simply, nothing could replace it. The first attempt to build a successor came with the TS-16 Grot of 1963, a supersonic aircraft (only the second supersonic trainer aircraft design in the world, preceded only by the T-38). This aircraft never saw production due to ballooning costs. The next attempt to replace the TS-11 came in 1976 with the I-22 Iryda. The Iryda was a subsonic twin-engine aircraft comparable to the Alpha Jet. This aircraft was actually produced and even entered service, and proved reliable, agile, and easy to fly just like the Iskra, while having substantially improved performance. However, the end of the Cold War and subsequent budget cuts killed the I-22 program in 1999 after only 28 built and 5 years of service. The I-22 would be the last indigenous Polish combat aircraft design. The next attempt to replace the TS-11 came in 2010, with the SP looking to purchase and license-produce the L-159 Albatros 2. This purchase was not pursued. The TS-11 would only begin being replaced in 2017, with the controversial purchase of the M-346 Bielik. While originally offered the M-346LCA, a modified version the the M-346FT, Poland instead opted for an unarmed version of the aircraft. This meant that many pilots were being deployed to their operational units without any actual weapons training, a significant issue only resolved in 2023 with the purchase of the FA-50GF. The final TS-11s were retired in 2021, 64 years after their first introduction.
Further Developments
The Iskra DF was the final new-build TS-11 model. The only subsequent TS-11 model was the Iskra bis R, a naval reconnaissance version with 6 DFs converted to the standard in 1992.
Specifications
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Airframe
Length: 11.25m
Span: 10.60m
Height: 3.50m
Empty Mass: 2,560kg
Loaded mass: 3,734kg
Wing Area: 17.50m^2
Crew: 2
Propulsion
1x SO-3W turbojet
Max thrust: 10.79kN
Internal Fuel: 1,200L across 4 self-sealing tanks
Flight Performance
Max Speed: 790km/h (Mach 0.64)
Climb Rate: 19.4m/s
Armament
1x NS-23 23mm cannon
23x115mm
115 rounds
600 RPM
720m/s
or, interchangeably (can be swapped out in <30 minutes)
1x NR-23
23x115mm
150 rounds
900 RPM
720m/s
I’d have the NS-23 stock and NR-23 as a Rank I/II modification
Underwing hardpoints x4:
1x OFAB-100 100kg bomb
1x Mars-2 launcher (4x S-5)
1x Mars-4 launcher (8x S-5)
1x Zeus-1 gun pod
Pretty much every source mentions the Zeus-1 gunpod. However, the only information on the pod is that it has a calibre of 7.62mm.
Systems
RW-UM radar altimeter
Engine fire suppression system
KAP-3 ejection seats
The Iskra bis DF in-game
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The TS-11 has pretty poor performance for an aircraft of its time because of its role as a trainer. However, it performs decently compared to first-gen jets. The Iskra would be a central part of a Polish air tree, helping to bridge the gap between wartime western equipment and post-cold-war western equipment. Compared to the preceding Iskra D, the Iskra DF is nearly identical. The SO-3W provides slightly improved thrust, but not enough to significantly impact performance. Additionally, while the specified weights of the D and DF are the same these are rounded numbers and the DF is probably a couple dozen kilos heavier, again not enough to significantly impact performance.
Pros:
- Agile
- Decently fast
- Moderately powerful engine
- Decent rocket load for CAS
Cons:
- Mediocre climb rate
- Limited armament- NR-23 is an effective cannon but only a single cannon is rather poor
- Insufficient suspended armament for base bombing
Placement in a hypothetical Polish air tree
Gallery
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TS-11 DFs were typically mostly bare metal with coloured noses and tails to indicate operating unit
However they have also sported a number of other liveries, in Polish service, museums, private collections, and civilian service
There’s also the lovely livery of the Red-White Sparks aerobatic team. They operated the special TS-11 MR, based on the TS-11 B but upgraded with more powerful engines as they became available. I believe this is justification enough for this skin for the B, D, and DF
The SO-3W that powers the Iskra DF, a refined development of the SO-3B
Iskra Ds during a live-fire exercise
The TS-11 can be armed with Mars-2 or Mars-4 rocket pods, both shown here on a BR 200
Inside the front and rear cockpits. Avionics saw frequent upgrades so these should only be taken as a general layout
The elusive Zues-1 pod
The TS-11 DF was also exported to India
Sources
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Polskie Skrzydła- Polish Wings 36 TS-11 Iskra- Dariusz Karnas and Artur Juszczak
PZL TS-11 Iskra. 2008. - Polot
PZL TS-11 Iskra. 2009. - Polot
PZL TS-11 Iskra. 2010. - Polot
PZL TS-11 Iskra. 2011. - Polot
PZL-Mielec TS-11 Iskra two-seat low-wing jet trainer
Also check out the other members of the TS-11 family!
Iskra A
Iskra B
Iskra C
Iskra D
Iskra R
Iskra BR 200