J-8 is not an enlarged J-7, anymore than every airliner in the world are copies or enlarged or smaller versions of each other. You cannot use basic aerodynamic configuration as a basis to think one is a copy of the other, otherwise, there is some build relationship between the Delta Daggers and Darts to the Mirage III. The J-8 does not share the same wing aspect as the J-7 or the MiG-21, and the fuselage proportions to the wings are quite different as well. The plane is twin engined, which means a major structural change and a different intake tunnel design. The current radars of the J-8II are domestic; the Zhuk was a demo for an export model and was never used by the PLAAF for its own. The engines were improved copies from those of the MiG-21MF, the engines of which is actually different from that of the original J-7, however, later copies of the J-8II are using an all new indigenous engine code named Kunlun.
J-10 has the same aerodynamic configuration as the Lavi, but the lines are different if you put the two aircraft over each other on both side views and plan views. Not only is the J-10 longer, but every part of the airframe and wings are non interchangeable between the two along with different sweeps and aspect ratios for the wings and canards, all critical areas in aerodynamics and flight behavior. This one can be verified with actual photos and models of the two aircraft. No matter what people want to believe, the direct evidence of the physicality of the two planes are there and undeniable. This does not mean that the J-10 may have benefited from Israeli and Russian aerodynamic research however.
Arjun uses 120mm rifle. Every tank in the world that uses this gun and caliber has licensed that from Germany.
