Introducing this bug-eyed monstrosity; The Ch-37C was a huge, heavy-lift helicopter, that experienced its first-ever flight in 1956, it was also one of the last helicopters to use a piston engine, which was even bigger, heavier, and sadly less powerful than the turboshaft engines. It wasn’t all bad though, as the helicopter did help to recover spy satellite film capsules that dropped from space via parachute.
It did provide some decent services but it was terribly strange-looking, which, as it might come as a surprise, is of somewhat importance, even for NASA.
EL/M-2075 Phalcon
According to FAS, the EL/M was the most advanced airborne early warning and control system. Had it not been for the clown-style nose of the EL/M, it would just appear to be a regular 707 Boeing. The chief objective of the plane was to serve as an intelligence provider to maintain air control and conduct surveillance.
The EL/M-2075 is a solid-state conformal array radar system for use on a 707 Boeing. While it was super-advanced, design-wise, people had an issue with the strange-looking nose making the Phalcon looking very strange. You can't win it all.
Piasecki H21
It should be no surprise that this flying machine also got the nickname, "the flying banana," this multi-purpose helicopter used wheels, floats, and skis and even had a winterization feature that allowed it to function at ridiculously low temperatures ( -65 Fahrenheit.)
Piasecki produced the H21 as an Arctic rescue helicopter, which makes sense considering its fantastic cold-proof functionality. But even with all those capabilities as well as the fact that it was equipped for 12 infantrymen or 12 stretchers, and two medical attendants, the helicopter only was in operation between 1952 until 1959. Did it have to do with the ridiculous shape? It's possible.
LTV XC-142
Another experimental gem we have here. The XC-142 was a tri-service tilt-wing aircraft created to investigate the operational suitability of vertical/short takeoff and landing transports. After the first transitional flight with vertical take-off that took place in January 1965, there was some hesitation over whether or not to continue.
The vertical take-off that resulted in the helicopter being changed to forward flight and ultimately land vertically was perhaps a little too complicated. Five models were manufactured, as a large, boxy fuselage with a tilted rear area featuring a loading ramp. The wingspan was 67 feet and 58 feet long overall. After the five models, they ceased to produce it.
Avro Canada VZ-9AV Avrocar
It's pretty tempting to get behind the wheel of a flying saucer! But, when it came to this UFO, inspired flying machine, the cost was just too much, estimated at $10 million apiece, according to Aviation CV. Not only were the costs exorbitant, but the other problem with the project was that the designers and engineers grappled to get the Avrocar more than a few feet off the ground without facing major problems.
After some tweaks, production commenced in 1958, but the engineers built only two models in two years. Throughout testing, the Avrocar had unresolved thrust and stability problems that limited it to a low-performance flight envelope. And so the Avro Canada VZ-9AV Avrocar was no more.