U-2 "Dragon Lady" vs. RQ-4 Global Hawk

This has rarely been discussed as far as I’m aware, but I think it’s interesting to debate.

The U-2 is notorious for being the most famous spyplane of the Cold War, and even today it still provides an unmatched capability for high-altitude reconaissance and surveillance. It has a wide variety of sensors from standard cameras to satellite uplinks to SAR to just about everything else. It has two wing hardpoints for superpods as well as E and Q bays for various types of equipment. The top of the fuselage can also carry a sattellite uplink pod. The U-2S model has been upgraded with a brand-new cockpit layout which includes large (and I mean large) MFD’s and other such displays. The engine has been changed to the same F118 that powers the B-2. This engine is lighter and more powerful than the J-75 is replaced. The U-2 has a very long range of over 4,000 miles, and some missions can last as long as six or seven hours.

The RQ-4 is the ultimate in UAV technology at the moment. It is the largest, fastest, and highest flying UAV. It has a wide range of sensors ranging from SAR to infrared equipment to just about everything else. It’s not quite as fast as the U-2 with max speed of about 450 mph (compared to a max of just over 500 for the U-2), and it can’t quite get as high (65,000 foot max altitude compared to 90,000 for the U-2…although the Dragon Lady usually flies misisons at 70,000 feet), it’s certainly got much more endurance and range.

Neither the RQ-4 or U-2 can be refuelled in flight to my knowledge.

There’s talk that the U-2 might be retired by 2011……personally I hope this doesn’t happen and I guess I’m wondering if the RQ-4 can completely replace it. Can it do everything the U-2 does as well as the U-2 does it? Does the U-2 still have a place in today’s skies? It seems to me that while th RQ-4 is a great aircraft, it just seems weird if the U-2 is no longer flying. What do you guys think? Any experts that can narrow down the pros and cons of the U-2 and RQ-4?