Bell has revealed part of its vision for
a future high-speed vertical takeoff and
landing or VTOL aircraft. A type of
platform that u.s special operations
command has recently been taking a
particular interest in.
The company's initial stole concepts aim
to combine the hover capability of a
helicopter with the speed, range, and
survivability features of a fighter
aircraft, according to the company.
These designs could potentially lead to
a replacement for the air force's cv-22
biosphere tilt-rotor aircraft as well as
other types. three different but similar stole
concepts were unveiled by bell today, one
of which is apparently unmanned.
All of
them utilize a propulsion concept in
which wingtip rotors are used for
vertical lift, then these rotors fold
away to reduce drag while turbofans
provide thrust for the high speed, forward flight. the same concept is something that we
have seen before in earlier bell patents
for a new generation converter plane.
Future convertible engines could
eventually provide their fill designs with
a power plant that can switch between
turboshaft and turbofan modes, eliminating the need for separate lift
and cruise engines.
With no air intakes visible on the
wingtip nacelles, this could also suggest
some form of hybrid-electric propulsion
for the rotors as well which would use
the main jet power plant to provide gobs
of electrical power to drive the rotors
during terminal flight modes.
The first two aircraft in bell's concept
artwork appear to be manned with cockpit
transparencies and access doors into the
main cabin, while the last seems to be
unmanned.
While they all seem to share the same
propulsion concept, the three bell
designs otherwise differ in more minor
details including engine intake
arrangement and tail fins.
In addition, the airframes all look to
incorporate basic low observable
features, suggesting that they are
designed to offer some degree of stealth
at least when their rotors are folded
away.
Bells have dull technology is a step-change improvement in rotorcraft
capabilities, said Jason Hurst, vice
president of bell's innovation division.
Our technology investments have reduced
risk and prepared us for rapid
development of still in a digital
engineering environment, leveraging
experience from a robust past of
technology exploration and close
partnerships with the department of
defense and research laboratories."
Exactly how the aircraft are expected to
work from a propulsion point of view has
not been revealed, but Bell does mention
emerging propulsion technologies which
could well be a reference to convertible
engines.
In addition, the company has detailed
aspects of the broader capabilities of
its hostile design concepts. these will include the ability to hover
while producing limited downwash, unlike
the CV-22b for example jet light crew
speeds of over 400 knots, runway
independence and hover endurance and
scalability to suit a range of missions
from unmanned personnel recovery to
tactical mobility.
Finally, bell says that it VTOL aircraft are planned to have gross
weights ranging from 4.000 pounds to
over 100.000 pounds, suggesting that
there are other similar designs in the
works in addition to these three. by way of contrast, the C-22b tilt rotor
has a gross weight of 60 500 pounds.
The first design on the left appears
larger than the osprey while the second
looks similar in size. the third unmanned concept looks smaller
still which makes sense. so this is clearly a highly scalable
concept.
It is interesting to note that bell's
concept art shows the larger of the
two-man designs wearing a tail flash of
the kind that airlifters as well as
aerial refueling tankers, assigned to air
mobility command typically wear.
The smaller of the manned concepts has
sharp mouth nose art and features a
sensor turret under the fuselage and
looks overall to be more of an assault
transport in the vein of the CV-22b. The unmanned type looks like it could
have the ability to carry weapons and
could be envisioned as operating in an
escort role accompanying the larger
stools to a target area, among other
mission sets.
In its press release bell also mentioned
its particular pedigree in the
high-speed vertical lift aircraft
technology, pointing to a wide range of
previous VTOL configurations such as the X-14, X-22
15-3, and 15-15
which the company developed variously
for NASA, the DOT army and the air
force.
Today of course bell together with
Boeing is responsible for the V-22
Osprey tilt-rotor.
In april this year, Bell received a 950
000 contract from the Air Force Research Laboratory (AFRL) to research its VTOL concept. A month later air force Colonel Ken
Kubler special operations command's
program executive officer for fixed-wing confirmed that the bell design was among
those the command was looking at to meet
the emerging stole requirement.
In addition to bell which is perhaps the
established high-speed VTOL player, the
air force special operations command and
the afworks technology incubator are
also looking at smaller companies who
might be able to contribute
groundbreaking ideas to the stole.
The afworks challenge submissions for
which closed last month have been for
other concepts that could offer optimal
agility in austere environments. There are other designs too, dating back
as far as the early 1980s that reveals
just how long the department of defense
has been looking at exotic vertical lift
platforms including stealthy ones and
high-speed ones.
The war zone has looked in detail at
some of these in the two-part feature
series linked here. while a short takeoff and landing VTOL, rather than a VTOL concept the air
force's speed agile concept demonstrator
or SACD similarly to achieve high speed featured a four-engine configuration
and was also intended to move larger and
heavier payloads.
Some of these earlier concepts have been
unmanned too like the initial bells toll
concepts. Lockheed Martin's VTOL advanced
reconnaissance insertion organic
unmanned system various is one example
of this line of thinking. then there is DARPA's VTOL plane, another program seeking to exploit the
advantages of fixed-wing and rotary-wing
concepts, albeit with a plan top
sustained flight speed of 300 to 400
knots.
That same program yielded the 15-24 lightning strike, another unmanned VTOL
concept developed for the defense
advanced research projects agency (DARPA) by aurora flight sciences now part of
Boeing together with Rolls-Royce and
Honeywell but later canceled.
While a high-speed VTOL design would
offer more rapid deployment and enhanced
survivability, the freedom from
conventional runways and infrastructure
also aligns with the pentagon's
increasing focus on so-called
distributed operations, especially the
kinds of campaigns that might be
expected in a peer conflict in the
Asia-pacific region.
It may not be entirely coincidental, therefore china too is looking at
similar kinds of concepts including an
exotic looking model of an apparent
hybrid gas turbine electric manned
combat rotorcraft appearing earlier this
year.
As in the bell concept, at least some of
the prop rotors on the Chinese design
incorporate a folding mechanism to
reduce drag while in forwarding flight.
Undoubtedly actually realizing the
promise of true high-speed VTOL flight
will involve considerable technological
challenges ahead. However, it's becoming increasingly clear
that this is a goal that a growing
number of branches of the military in
the united states and elsewhere are now
intent on achieving.
