Originally Posted by
ORAC
We get back to the fact that even the 737 airframe is to big and a business jet would be more suitable.
But is it? If processing is on board (and there are LOTS of arguments against off-board processing) then besides the processor operators, it also makes sense to put the decision makers on board. That generally requires more volume than most biz jets provide. Further, once you go over about 1000 FH/yr, airliners are actually cheaper to operate than biz jets. So any cost advantage of a biz jet goes out the window if you actually fly the airplane.
But the really big issue is power generation. Biz jet engines and accessory gear box systems just are not designed to generate lots of power, and with active jamming, laser defense, laser offense, high power sensors, big on board processing systems, a robust comms suite, etc etc, the host aircraft needs to be able to generate LOTS of power. And finally, mission sets tend to creep upward, not downward. A bizjet based aircraft will likely not have a lot of growth margin. That's not to say that biz jets never make sense. Depending on the mission set and implementation, a biz jet may be ideal. But for the mission set of the current AWACS, you just couldn't cram all of the capability of that aircraft into a biz jet sized platform.
To put all this in perspective consider that the P-8 is based on the longer -800 airframe, not the shorter -700 airframe. And that's because the extra volume is needed. And the engines and nacelles of the P-8 have been modified with 180KVA generators. 360 kilowatts is a LOT of power. And when (not if) directed energy weapons start being fielded, they'll likely need to triple that power and get in the megawatt range.