If iam not wrong Pak- China J-11 is a copy of Su27/30. correect me if iam wrong...
i dont know how people take "copy"
here is a neutral article hope it will help you
Shenyang J-11B
by Dr Carlo Kopp
Text © 2008 Carlo Kopp
Line Artwork © 2008 Carlo Kopp
Background
The controversial J-11B is an unauthorised derivative of the Sukhoi J-11A/Su-27SK, built by Shenyang in China. The aircraft has been the subject of an ongoing dispute between Beijing and Moscow which has caused the suspension of production of the second batch on indigenously manufactured legally licenced J-11A/Su-27SK.
The J-11B is not an exact clone of the Su-27SK, despite the commonly held view this is so. The airframe and engines can be considered to be 'cloned' but the systems are mostly unique to this variant.
Known differences include:
A Chinese IRST set located in the centreline position as with the OLS-27 in early Su-27S.
A planar array multimode radar which resembles the Phazotron Zhuk-27 series. It includes an IFF interrogator array.
An Onboard Oxygen Generator System (OBOGS). Only the most recent Russian variants have an OBOGS.
A unique glass cockpit design, with an asymmetric layout quite different from the Su-30MKK/MK2 and Su-27SMK.
An optical MAWS system claimed to operate in the UV band.
Dielectric panels on the stabilators not seen on any Russian variant.
The differences between the J-11B, Su-27SK and Su-27SMK are sufficiently great that this must be considered a unique offshoot of the Flanker family of fighters, not a subtype of the baseline Su-27SK/J-11A.
Shenyang J-11B Sino-Flanker