Flying Platforms: Aeronautical Engineering’s Evolutionary Dead End?

Despite being portrayed as the “most fearsome must have military vehicle” in 1960s era comic books, are flying platforms really nothing more than aeronautical engineering’s evolutionary dead end? 

By: Ringo Bones 

Despite giving the impression to those who should have known better that it is the ultimate must-have logistical transport vehicle with unlimited potential military applications and ever since film documentaries made about them in the 1970s and 1980s about the US Army’s barmy equipment acquisition programs during the latter half of the 1950s, policymakers who should have known better often hailed them that if the US Army had them during the Vietnam War, or during former US President George “Dubya” Bush’s Operation Iraqi Freedom, America’s overseas military intervention campaigns could have had a different – supposedly better – outcome. And despite being portrayed in 1960s era comic books as high-tech airborne Segway transports for both superheroes and super-villains alike, are flying platforms nothing more than a representation of the Cold War era aeronautical engineering’s research-and-development’s evolutionary dead end? 

In the world of aeronautical engineering research-and-development, flying platforms are a subclass of rotary-wing aircraft. Like helicopters and convertible aircraft, they are supported in hovering flight by the jet-momentum reaction produced by constantly accelerating a portion of the surrounding air downwards. Flying platforms are unlike helicopters in that the rotors used to produce the supporting jets are relatively small and unlike convertible aircraft in that no winglike appendages are provided for high-speed level flight. Flying platforms are unlike ground-effect machines, hovercrafts, or Ekranoplan-type craft, in that the flying platforms are capable of rising to higher altitudes in comparison to their maximum dimension. Thus, the flying platform is a rotary-wing aircraft whose aerodynamic characteristics have been “compromised” by reducing the size of the lifting-rotor system relative to the central body. 

Flying platforms have been envisioned as military personnel carriers for short-range operations at moderate speeds over terrain which is impassable to surface vehicles. The comparatively small size of the lifting rotors is dictated by the necessity of reducing the overall-dimensions of the vehicle for the purposes of storage and concealment.    

The first free flight of a flying platform was made on February 4, 1955. Manufactured by the Hiller Aircraft Corporation, the “platform” was 6 feet in diameter and was powered by two Nelson aircraft engines driving the rotors through V-belts. 

If you think “pervertiplanes” – i.e. convertiplane / convertible aircraft are aerodynamically perverted products of aeronautical engineering, flying platforms could be well-described as the “super-freaks” of Cold War era products of aeronautical engineering. There are three serious problems in the operation of flying platforms and these are directly attributable to the small size of the lifting rotors. 

One of the problems is that the small size of the lifting rotors leads to high lifting-jet velocities which cause trouble directly by creating a serious erosion and dust problem. The high lifting-jet velocities also cause trouble indirectly, since the continuous dissipation of the kinetic energy of the lifting jet leads to high rotor-power consumption that result in much higher fuel consumption in comparison to a conventional helicopter. A second problem affecting flying platforms is that the small size of the lifting rotor leads to catastrophic rates of descent in the event of power plant failure. Unlike the helicopter, which can make an autorotative descent with a wind-milling rotor, or a fixed-wing aircraft, which can glide, the flying platform falls like a rock in the event of a complete power plant failure. This problem is commonly solved by providing two or more independent power plants, so that the machine may descend at a safe rate if one power plant fails. The third serious problem is that the small size of the rotors relative to the rest of the vehicle leads to serious interference-flow effects between the hull of the vehicle and its rotors, particularly in forward flight. These interference effects lead to poor stability and control properties of flying platforms. Thus, this is the very reason why no flying platform type armored personnel carriers and VIP transport vehicles are deployed during the prosecution of former US President George “Dubya” Bush’s Operation Enduring Freedom and Operation Iraqi Freedom.