Author: Martin Su
Date: 05-19-12 15:55
I view the J-20 Mighty Dragon as a large F-22. It has greater range and a similar payload. Two side-bays for short-range air-to-air missiles and a main weapon bay to carry medium-range air-to-air missiles.
J-20 combat range: 1,243 miles (see http://en.wikipedia.org/wiki/Chengdu_J-20#Specifications).
F-22 combat range: 471 miles (see http://en.wikipedia.org/wiki/Lockheed_Martin_F-22_Raptor#Specifications).
How about a physics argument?
China's J-20 is indisputably larger than the F-22. Therefore, it can carry a larger volume of fuel. Hence, China's J-20 indisputably has a larger combat radius than the F-22. The conclusion is the same.
The F-22 Raptor combat radius of 471 miles was determined from flight test data (see http://www.f22-raptor.com/technology/data.html).
The larger Russian T-50/Pak-Fa has been reported to have a combat radius of 1,500 km or 900 miles (see http://www.flightglobal.com/news/articles/aero-india-roadmap-revealed-for-medium-combat-aircraft-353034/).
It is perfectly reasonable to expect the physically larger Chinese J-20 to have a far greater combat radius than the F-22.
THE CUBE ROOT OF 3
In an earlier post, I made the claim that the J-20 Mighty Dragon has a far greater combat radius (e.g. 1,243 miles) than the F-22 (e.g. 471 miles).
Obviously, it is indisputable the J-20 has significantly longer range than the F-22. Your eyes can easily note the larger physical size of the J-20 in a photographic comparison (with the pictures normalized to match the sizes of the pilots' helmets and airplane wheels).
Anyway, we're moving onward to a mathematical analysis. For a J-20 to have three times the range of a F-22, it needs to carry three times the fuel. Volume is determined by three dimensions (e.g. length, width, and height).
To carry three times the fuel of a F-22, the J-20 must have a fuel tank that is three times larger. The cube root of three will indicate how much larger the J-20 fuel tank must be in physical dimensions.
The cube root of 3 = 1.44
Thus, if the J-20 fuel tank is 1.44 times longer, 1.44 times wider, and 1.44 times taller than the F-22 then the J-20 has three times the fuel load of the F-22.
Anyway, I don't have the schematics for the J-20 and F-22. However, it is entirely plausible that the J-20 fuel tank is 1.44 times larger than the F-22 in all three dimensions. Therefore, it is credible the J-20 has three times the combat radius of the F-22. The US Air Force screwed up in building an air superiority fighter with such a short range.
China can easily bomb (with ballistic, cruise, or MLRS missiles) any potential airfields that may serve as a base of operations for the F-22. Without a base to resupply fuel and ammunition, the F-22 is out of action in the Chinese theater of operation.
[Note: I am aware the J-20 will weigh a little more than the F-22 and it will have to carry a little more than three times the fuel load. However, this is offset by more lift from the canards and the calculations are meant to be approximate to illustrate a point.]