The TAI KAAN – Turkiye’s 5th Gen Fighter – How does it stack up?
First of all, a little digression. How come Turkiye is developing, and flying a prototype 5th Gen Fighter? This is a valid question, given that the US, while they would probably claim to have the only true 5th Gen combat aircraft, appears up to this point only to have competition in this field from the Russians and the Chinese, along with an experimental demonstrator from Japan. The Europeans have largely met their current needs with the very capable, but not Low Observable (LO), Rafale and Typhoon, and are debating how to jump to a Gen 6 product in competing international project proposals.
Meanwhile, Turkiye has been embarked on a decades-long quest to develop a national aerospace industry capable of developing and integrating high technology combat aircraft, remotely piloted and autonomous systems, weapons, and the necessary sensors and systems, and able to integrate these into a significant locally developed and produced Defence capability.
This growing industrial base had positioned Turkiye to contribute significantly to the US F-35 program, with the expectation that this would become a key component of Turkiye’s air combat capability. However, the separate decision by Turkiye to procure the Russian S-400 surface-to-air missile for its its Ground-based Air Defence system, has resulted in Turkiye being barred from the F-35 program. This, in turn, has spurred the development of the Turkish TFX fighter program, which has moved from initiation in 2018 to first flight of the TAI KAAN prototype in 2024.
Comparative Analysis
Hush-Kit asked me to look at KAAN and the F-22, and consider such questions as how these aircraft compared in sustained turn rate, instantaneous turn rate, maximum speed and so on. These aspects are important for an aircraft which is expected to deliver air superiority, where the likelihood of being surprised over hostile territory is perhaps greater, and where there may be a need for within visual range (WVR) combat, or extreme manoeuvres to survive a missile attack. The F-22, for example, is clearly intended to succeed in both WVR and beyond visual range (BVR) engagements, and, as a result needs to have both long-range, powerful sensors, extreme manoeuvrability, and a mix of long and short-range missile systems and a gun. Are all these things necessary in a LO platform? Perhaps not, if the primary role is air defence over home territory and deterrence of attack by others. But perhaps they are required if, like the US, you are going for global air dominance.
With no F-35, and with no likelihood of other weapons systems being supplied by the US, it may be that Turkiye has been forced into a re-think of the key roles for KAAN. Comparison of what we know about the aircraft may be helpful, but a word of caution is necessary on looking at the available data. Firstly, it won’t tell the whole story – frequently aspects such as weight and signature are just unavailable, and publicly available performance data will not be linked to mission, configuration or load. Nevertheless, the table below provides some critical data for the F-22 and KAAN.
| Critical data | F-22 | Kaan |
| Wing area | 78 m^2 | 60m^2 |
| Aspect Ratio | 2.36 | 3.2 |
| Leading Edge Sweep | 42 deg | |
| Span | 13.56 m | 14 m |
| Length | 18.92 m | 21 m |
| Height | 5.08 m | 6 m |
| Thrust in afterburner A/B | 2 x 156 kN A/B F119 + Thrust vectoring | 2 x F110 131 kN |
| Empty Weight | 19.7 t | 14.15 t |
| Fuel Weight | 8.2 t | 8 t (est) |
| Weapons fit | 2 AIM-9X, 6 AMRAAM, Gun +strike weapons | MRAAM, SRAAM, Meteor +strike weapons |
| Gross Weight | 29.4 t | 27.2 t |
| Combat weight (with weapons, pilot, 50% internal fuel) | 25.2 t | 23.2 t |
| G limit | +9 | +9 -3.5 |
| Service ceiling | Service Ceiling 65,000+ ft | 55,000 ft |
| Sensors etc | AESA radar, IFF, Datalink, JTIDS | AESA, EO, IRST |
| Max Mach | 1.82 supercruise, max 2.25 | 1.8 |
Before deriving some figures from the data, a few notes are important. Looking at, for example Wikipedia data, there are often inconsistencies or undefined figures. While figures like empty weight are often firm, it is necessary to consider what ‘Gross Weight’ and ‘Max Take-off weight’ might represent. For the F-22, I estimated the gross weight for an air combat configuration as empty weight, plus full fuel, plus 6 x AMRAAM, 2 x AIM9X, and an estimated allowance for pilot plus his equipment, missile launcher adaptors, and gun ammunition, and the result was within ½% of the gross weight quoted in Wikipedia, the difference probably being expendables (chaff and flares). Few figures are available for KAAN, but I found an empty weight along with consistent figures for the quoted gross weight. Max TO weight is not relevant for manoeuvre performance evaluation, as this will generally represent a max ferry range, non-combat, configuration. The combat weight quoted above is the Gross weight – 50% internal fuel.
It is also important to note that the prototype KAAN is unlikely to represent the final production aircraft. Firstly, there is likely to be weight growth during development, as more systems are integrated on the aircraft, and secondly, given the history, Turkiye are likely to require a locally produced rather than US engine for the aircraft, with consequential impacts on weight, thrust, and perhaps configuration.
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Derived data
Aircraft performance depends on a number of factors, some of which may be derived from the data table above. Here are some figures that may help in comparing performance, along with some other comparisons:
| F-22 | Kaan | ||
| Thrust/Combat Weight | 1.26 | 1.15 | |
| Wing loading (Combat weight/Wing Area) | 323 kg/m^2 | 387 kg/m^2 | |
| MRAAM | AIM-120 | Meteor, Gokdogan | |
| SRAAM | AIM-9X | Bozdogan | |
| Signature | VLO | Reduced | |
| Thrust vectoring | YES | NO | |
Looking at these figures, we can make some observations about platform point performance.
Climb rate is determined by Specific Excess Power, otherwise expressed as (Thrust-Drag)/Weight, and we can see that the F-22 has a thrust to weight advantage over KAAN, suggesting initial climb rate will be greater for the F-22. The KAAN does have a longer airframe than the F-22, suggesting that it may have lower wave drag, at least partly offsetting its thrust disadvantage in transonic and supersonic flight.
Sustained turn rate (STR) is the maximum turn rate achievable without losing height or speed. It represents a condition where the drag of the turning aircraft is equal to the maximum thrust available. This varies across the aircraft flight envelope. For much of the envelope, the aircraft will be limited, not by available lift and thrust, but by the structural g limit of around 9 g, which essentially arises because of pilot limitations. It is an important measure in sustained WVR combat – an increasingly rare situation due to the lethality of modern SRAAM weapons.
STR increases with increased thrust, and reduces with increased drag, of which there are three principal components, the Zero Lift Drag, Cd0, which depends on shape and surface area; the wave drag, which depends on Mach number, area distribution and lift; and the induced drag, which depends on lift coefficient and aspect ratio. The F-22 has a shorter fuselage and lower aspect ratio wing than the KAAN, which may increase Cd0, wave drag and induced drag, but it also has a higher thrust to weight ratio, and greater wing area. Overall, I would expect there to be little difference in STR performance.
Instantaneous turn rate (ITR) is the turn rate obtained when the aircraft is pulled to its maximum lift coefficient while in full thrust. In practice, like STR, structural and pilot considerations will limit this for at least a substantial part of the flight envelope. It can be important in a WVR turning combat in order to create a missile or gun firing opportunity. While this may seem unlikely, this situation might occur in a combat where longer-range and off-boresight missiles have been expended, or when unexpected air combat occurs.
ITR increases with increased thrust, and with increased available lift (through increased wing area, vortex lift or increased structural margin), and with thrust-vectoring, which provides largely lift-independent pitch rate. On all these grounds except structural limits, F-22 should deliver a higher ITR than KAAN.
The F-22 has a higher maximum speed than KAAN – however, as noted earlier, I would expect KAAN to adopt different engines in the future, assuming that there continues to be a desire to avoid dependence on the US.
I’ve assessed KAAN as not achieving the VLO characteristics of the F-22, at least at this stage. While Turkiye has developed the capability to manufacture the structure appropriate to the LO F-35, and, indeed, KAAN, more is required to achieve the VLO of F-22. This is, however, mostly physics, and there seems no reason why Turkiye would not incorporate the necessary coatings, treatments and devices that are present on the F-22 and F-35. However, the prototype KAAN shows no evidence of these details being applied – one would expect to see a gold-flashed cockpit, treatment of edges and panel junctions and so on.
There is clearly a desire to optimise the weapons carriage capability for non-US weapons, and this may be one reason for the longer fuselage of the aircraft, which could be useful in enabling a greater variety of weapons to be deployed, and, perhaps, a higher fuel volume to be carried.
What is the requirement?
Given the history outlined above, one might think that the primary aim for Turkiye would be to replace the F-35, now that is no longer available. However, much depends on how Turkiye was planning to use the F-35. Was it to be primarily a strike platform, supported by other systems which deliver air superiority? Was the Turkish F-35 to be an Air Defence fighter with strike capability? Or an Air Superiority fighter in its own right? Different Nations appear to have adopted differing concepts of operation, as is reasonable, given each Nation’s individual geography and military aspirations.
So, Turkiye perhaps started from a position of using S-400 for area ground-based air defence, backed up by F-35 as a supplementary air defence asset, and a strike asset, with a view to deterring any regional air threats, and striking land and maritime targets if required. The move by the US to bar the acquisition of F-35 seems, at least at this point, to have increased the criticality of the KAAN program, and, perhaps, broadened its scope, with KAAN looking to provide greater air-to-air and air-to-surface weapons capability, with a larger weapons bay and generally more F-22-like stores carriage capability.
However, to become a really effective BVR fighter and capable strike platform, much platform and system development will be needed. Tasks ahead will include realising the LO potential of the airframe, incorporation of the onboard systems and sensors required to detect, localise and attack air and surface targets, as well as the integration of the necessary weapons and links to offboard systems. The capability of a LO BVR air combat platform depends less on its innate performance characteristics, and more on its ability to operate in an integrated air combat system, with other aircraft, autonomous and semi-autonomous assets, AEW&C and ground-based sensors and air defence systems.
Jim Smith
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