Not A Bird & Not A Plane: A Quick Guide To Super Alternative Military Aircraft

When is a plane, not a plane? This question is similar to "When does a pond become a lake." While everyone will agree that an A320 or F-22 Raptor is an airplane, disagreement and confusion arise around the margins. Even the Wright Brothers were far from the first men to 'fly.' The first man to fly was a Frenchman in 1783 in a balloon. Before 1903, men had already achieved powered flight (airships) and heavier than air flight (with gliders). The Wright brothers achieved a very qualified world-first "sustained flight by a manned heavier-than-air powered and controlled aircraft" - aka the first flight in an airplane.

Ekranoplans/Ground effect vehicles

While (despite the name), flying boats are considered airplanes, ekranoplans are somewhat confusing. Ekranoplans (or ground-effect vehicles) are something like hovercrafts but resemble aircraft a lot more. They work by flying over and skimming the surface of the water, where they can make use of the ground effect to provide increased lift. Ekranoplans are not always limited to water and can fly over any flat area.

Ekranoplans occupy a strange position between ships and airplanes. One small ferry ekranoplan, the AirFish 8, is registered as a ship in the Singapore Registry of Ships. The famous ekranoplans of the USSR were developed as ships, with the Lun-class ekranoplan (Project 903) being the only operational ground effect warship to enter operational service (on the Caspian Sea).

But the DARPA's Liberty Lifter (currently under development) would make one bizarre ship. The vehicle is planned to be able to fly both in and out of ground effect and climb as high as 10,000 feet above mean sea level.

Rocket planes

Rocket planes are another odd flying machine that sits at the conjuncture between aircraft and spacecraft. They use rocket engines and have achieved hypersonic speeds. Reflecting their weird position, most rocket planes have been built as experimental and research vehicles to develop interceptor fighter jets and space aircraft.

One of the most famous rocket planes produced was the North American X-15. It was a hypersonic rocket-powered aircraft operated by the US Air Force and NASA. In the 1960s, it set records at the edge of outer space that have never been broken. In October 1967, the X-15 flew at Mach 6.7, setting an unbroken record for a crewed, powered aircraft. It also set the unofficial altitude record flying at 354,000 feet - five miles above the proposed boundary between Earth's atmosphere and outer space).

The X-15 could not take off on its own and had to be carried into the atmosphere by a mothership (a modified Boeing 747). The X-15 flew at such high altitudes that the very first full-pressure protection 'spacesuits' were developed for it.

The 5 Air Force pilots who flew the X-15 qualified for military astronaut wings immediately, while three other civilian pilots were later given NASA astronaut wings in 2005. One of the military pilot-astronauts was Neil Armstrong.

Bell Boeing V-22 Osprey

The Encyclopedia Britannica defines an airplane as "any of a class of fixed-wing aircraft that is heavier than air, propelled by a screw propeller or a high-velocity jet, and supported by the dynamic reaction of the air against its wings."

So, this definition excludes gliders - including those of World War II. Strangely, the large military gliders used on D-Day and in Operation Market Garden (aka a Bridge to Far) would not be considered "airplanes." Additionally, helicopters (a rotary wing) and airships (lighter than air) are excluded by this definition. But how flexible can one be with what counts as a rotary wing?

The Bell Boeing V-22 Osprey is a multi-mission tiltrotor aircraft that combines vertical takeoff and landing (VTOL) and short takeoff and landing (STOL) capabilities. It essentially can operate as both a helicopter and an airplane. It can use its propellers as rotors to take off like a helicopter but then use them as a prop-aircraft and use its wings for lift.

Drones

According to the Encyclopedia Britannica definition of 'airplane,' there is no reason why fixed-wing drones are not 'airplanes.' But it is curious that while some unmanned aircraft can be considered airplanes, many are more like unmanned helicopters (like quadcopter drones).

Also, while most drones are designed to be unmanned platforms - some are manned aircraft retrofitted to be drones. Examples include the Aeroprakt A-22 Foxbat drone modified from a sports aircraft Ukraine uses for deep strikes in Russia and the US Air Force's QF-16 Full Scale Aerial Targets. The QF-16s are made by retrofitting retired F-16 Fighting Falcons to be operated remotely for testing new systems and training pilots. Additionally, there is discussion that the British may develop the BAE Tempest sixth-generation manned fighter to be optionally manned.