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.
