Why can't Turkey just buy double the number of Typhoons?
In order for Turkey To keep up, it will either need to make unauthorized upgrades of its F-16s Or build a medium weight replacement for the F-16. Any other option will leave it vulnerable to foreign sanctions, even if it claims it is using weapons in self defense, similar to what happened to them with the leopard tanks and Germany. The T-FX will take sometime and an interim program may not be a bad idea, similar to south Korea’s non-stealthy KFX before its final Stealthy K-FX is ready. Even for the Turks, the costs would be at least $10-15 Billion to just replace half their fleet with a semi-stealthy fighter if they can keep per unit costs at $50-60 million. Considering their experience and sunk costs in making fuselage parts for the F-35, their industry would love some orders to cover the lost revenue from the F-35 program.
The goal of any interim fighter would have to be to keep it “simple” but modern. A program that can go from the drawing board to first flight in about a year, and production in a few years after that. If Turkey doesn’t either switch to an all T-FX fleet or build some interim fighters, it will remain dependent on foreign suppliers and be vulnerable to foreign sanctions. Turkey could go back and build one of the single engine designs it had tested for the T-FX program. Considering Turkey experience build part of the F-35 Fuselage, it maybe better off building a similar semi-Stealthy conventional layout platform. It will be the best platform to integrate all the sub-Systems under development for the T-FX as well as a lower cost but very modern platform for export to countries like Pakistan looking to replace its Mirage fleet, looking for ToT, and Access to European weapons and sub-systems without buying a European platform but sharing the cost due to economies of scale. Especially if both nations could commit to 150 planes each, the costs would come down and it would help build up both defense industries to modern standards.
Turkey just build the Hurjet, so this would be a natural evolution, and a good stepping stone to the T-FX program. Pakistan too will ultimately need to replace its oldest F-16s and Mirages, before you know it, and a Turkish interim jet maybe the most cost effective option. This would be especially true if Pakistan is blocked from getting any upgrade on its F-16s in a reasonable timeframe.
operating the same jet would also allow Turkey and Pakistan to help each other in the event of war imposed on either nation. From loaning jets to actually sending pilots and planes, Pakistan and Turkey have the potential to become interoperable if they operate a common platform that is sanction-proof.
Also of the conventional design below, if the rail were changed from a “four poster”: twin vertical and twin horizontal at the rear, to a Pelikan tail, it would help in the development of that technology as well per the design recently revealed for project Azm.