One of the F-35's key selling points is its internal weapon storage. This not only allows it to remain stealthy, but it "cleans" up the aerodynamics of the aircraft. That is Lockheed's claim, anyway; and it is true to a point.
During the recent "CF-35 Webinar"(available here), Lockheed test pilot Billie Flynn often implies that, because the F-35 carries its weapons and fuel inside, it is more aerodynamic and stealthy than traditional aircraft. This is true... To a point.
A traditional fighter aircraft loaded up with missiles, bombs, and external fuel tanks will indeed handle much differently than one that is unencumbered. Extra weight, extra drag, and changes to the aircraft's center of gravity will make it slower and clumsier, no doubt about that. An aircraft capable of mach 2 "clean" may be reduced to subsonic speeds at best. Since the F-35 carries it all inside, that means an "loaded" F-35 must perform better than a "loaded" 4th generation fighter... Right?
|This (assuming 2 BVR and 2 WVR missiles)...|
The F-35 carries a maximum of 5000lbs worth of ordnance internally. That is divided up amongst 4 hardpoints. Two of those hardpoints are restricted to AMRAAM storage only. That means, for an air to air role, an F-35 is restricted to a maximum of 4 missiles, two of which must be AMRAAMs, while the other two may be either AMRAAMs or ASRAAMs. The F-35 does have the option of storing additional weapons on pylons, but this throws the F-35's stealth and aerodynamic advantage out the window.
To compare, a 4th generation fighter like the Gripen stores all of its missiles and extra gas externally. However, if you compare the actual payloads, you will see that adding four missiles and some fuel (as in the middle picture) doesn't really add a whole lot of bulk. As an added bonus, as fuel is used and missiles are fired, the Gripen in the (above in the middle) will only become lighter and more sleek, especially if the drop tank is jettisoned.
|"Fully loaded" F-35.|
|Fully loaded Typhoon.|
|Fully loaded Gripen.|
Again, as the Typhoon and Gripen release their weapons, their aerodynamics will improve substantially. Once they release all but their air-to-air weaponry, they will be capable of supercruise, as well as being able to fulfill an air-superiority role with 6 missiles.
The F-35 in the above example, however, will now be at a disadvantage. It only has 4 air-to-air missiles, and its most vaunted feature, stealth, will be severely compromised by the addition of the external pylons. It could still be stealthier than the other two, but it is still slower and less well armed.
The F-35 does have a much better range than the legacy CF-18 without external tanks, but so do the Gripen E, Super Hornet, and Typhoon. So again, comparisons must be based on range. It is important to note that aircraft burn through fuel at different rates. For example, 450 gallons of fuel will go further in the smaller, single engined Gripen than the bigger, twin-engined Typhoon.
|Okay... This might be a little much.|
It is important when comparing these fighter aircraft to do so with similar missions and payloads in mind. Comparing one fighter with a light load of air-to-air missiles against another with heavy bombs and fuel tanks is disingenuous.