
Claims were made from insiders that if the FC-31 is navalized, it'd be enlarged at the very least to improve its take-off performance from carrier landing strips.
See the changes from YF-17 to F-18 Hornet. Carrier aviation requires shorter take-off distances, which means an enlarged wing, and also requires weight increases.
The FC-31 to begin with is roughly a 17.3 x 11.5m fighter, putting it as clearly larger than the F-35. The YF-17 to F-18 Hornet transition saw the addition of about 0.2m in length and 2m in wingspan. The J-15 it's likely going to replace is 21.9 x 14.7m, which is about 25% larger in length and span, or 56% larger in total volume.
The Super Hornet adds about 1.2 meters to length and 1 meter to wingspan, as a comparison point.
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My taste in carrier aircraft, anyways, tends toward heavyweights like the F-14 or J-15, as opposed to mediumweights like the F-18A or F-35. A carrier, after all, is an extremely expensive mobile airfield, and when you're paying so much for the airfield, you want the best fighters you can get for the airfield.