Okay then, it's no surprise that new technology is constantly evolving and none more than in aviation. It's also no surprise that to save costs of building aircraft to accommodate the latest of the latest, companies resolve to customizing older aircraft to try the new stuff out, saving themselves and the government millions.
But it does make for some very unusual looking aircraft, some of them even looking mutated. With bulges and blisters on their otherwise smooth metal fuselages and wings.
The British Aerospace Nimrod Maritime patrol aircraft was based on the famous De Havilland DH-106 Comet Airliner, so when the airborne warning version of the Nimrod was being developed, the people at British Aerospace aviation deemed that it made perfect sense to use a surplus Comet Airframe to test out the elaborate radar equipment on.
This North American "Sabreliner" private Jet was used to test out F16 avionics and they were stored in an actual F16 nose.
This Douglas DC3 Dakota of the Canadian Airforce was used to test out avionics meant for the Canadian built version of the Lockheed F104 Starfighter, again, they just bolted a nose from a Starfighter to the aircraft.
I guess the name on the fuselage says enough.
But by far the strangest was this modified Convair C 131 cargo plane that was used to test out flight simulator technology IN FLIGHT. (Go figure) and so they just jammed the entire cockpit section into the nose of that plane.
