Updated: February 25, 2016
JET PACK PHOTO GALLERY #02
The world got its first look at personal jetpacks in the 1960s when Wendell Moore,
an engineer at Bell Aerospace, designed the Bell Rocket Belt. Partially, funded
into the air for what amounted to a 20-second hop, instead of actual sustained
flight. The rocket belt and its test pilot, Bill Suitor, became very famous in
the late 1960s touring the world, and even made an appearance in a movie. When
Moore died in 1969, Bell Aerospace scrapped plans for the personal rocket belt.
Photo courtesy U.S. Patent and Trademark Office Wendell Moore filed a patent for
this propulsion unit in June 1960. This illustration is from patent number 3,021,095.
In 1995, the technology used to build the Bell Rocket Belt was revived by a group of
Texas engineers who designed a slightly enhanced version called the RB 2000 Rocket Belt.
The redesigned belt was able to travel 50 percent farther than the Bell Rocket Belt,
enabling users to stay airborne for 30 seconds instead of 20.
Rocket packs contain three substances that make up a chemical reaction that produces
High-pressure nitrogen gas
Samarium-nitrate-coated silver (which acts as a catalyst)
Two metal tanks mounted on the rocket pack are filled with a total of about 6 gallons
(23 liters) of hydrogen-peroxide propellant. When the operator opens the throttle,
the high-pressure nitrogen gas is released, forcing the hydrogen peroxide into a
catalyst chamber. Once inside the catalyst chamber, the hydrogen peroxide reacts
with the silver material, which turns the hydrogen peroxide into a high-pressure,
superheated steam that measures 1,370 degrees Fahrenheit (743 degrees Celsius).
The steam shoots out through two bent tubes that run from the top of the tank down
the side, just behind the operator's arms. The tubes are wrapped in insulation so
that no heat is lost. Because of the heat, the operator must wear a heat-resistant
suit to prevent burns. Water and vapor exiting from the two nozzles at the end of
the exhaust tubes produce more than 300 pounds of thrust, which is more than enough
to propel a person into the air for a short rocket flight.
Rocket packs are unlikely to become commercially marketed products due to their drawbacks.
While they have been tested at speeds of over 100 mph (161 kph), they lack the agility
displayed by Millennium Jet's XFV. Also, a rocket pack uses up its 6 gallons of fue
in just 30 seconds of flight, whereas the XFV can travel for more than three hours on
10 gallons of gasoline. No company is currently working on a rocket-pack design, and
the RB 2000 has not been tested since 1995 due to legal battles among its designers.
The Exo-Skeletor Vehicle can fly to 10,000 feet and travel at up to 80 mph.
The personal flying vehicle closest to entering the commercial market does not
look like any flying vehicle we've seen before. The SoloTrek Exo-Skeletor
Flying Vehicle (XFV) being developed by Millennium Jet works something like the
Harrier jet, lifting off vertically. But instead of jet propulsion, the XFV uses
propellers to lift the aviator off the ground.
Once strapped into the vehicle, which has also been called an air scooter, the engines
will turn the overhead duct fans at 3,500 to 4,000 revolutions per minute (rpm) to
provide adequate thrust to propel you into the air. The device is 7.5 feet (2.3 meters)
high, and operators are required to be between 5 foot 4 inches and 6 foot 6 inches
(163 to 198 cm) tall and weigh between 115 and 275 pounds (52 to 125 kg) for maximum
maneuverability and safety.
Once airborne, you can zip over tree tops at a top speed of 80 mph (129 kph) for 150 miles
(241 km) on a 10.5-gallon tank of gas before refueling. Average cruising speeds are
between 46 and 69 mph (74 and 111 kph). Because it can climb as high as 10,000 feet
(3,048 meters), there's the possibility that the XFV would share its air space with
other small aircraft. The compact size of the XFV will allow it to land on any space
larger than a kitchen table.
While the company has not said when they will market the vehicle, it reports that there
are applications for private use. Initially, it's likely to be used by paratroopers,
who would use the XFV to fly into battle. There are four major components of the XFV
that will enable it to fly us to work someday:
130-horsepower gasoline engine
Drivetrain that drives the ducted fan blades
Counter-rotating ducted fans (two)
At the heart of the patented XFV is a 350-pound (130-kg), 130-horsepower, four-cylinder
engine that uses everyday 87-octane gasoline, the same gas that you put in your car.
Like your car, the XFV has a piston engine. But while an automobile engine and many
aircraft engines operate on a four-cycle regime, the XFV engine operates on two cycles.
In a four-cycle engine, there are a lot of moving parts that are prone to catastrophic
failure, including intake and exhaust valves, pushrods, valve lifters, camshafts, timing
belts and oil pumps. The two-cycle engine has fewer moving parts, although it still
includes some, such as crankshafts (see How Two-stroke Engines Work for details).
The engine is connected to a system of drive shafts, universal joints and gear boxes,
which drive the counter-rotating ducted fans. The ducted fan blades have a fixed pitch,
meaning they are rigidly fixed to the central rotating fan hub at a set angle. The
fixed-pitch (as opposed to variable-pitch) fan further reduces the number of moving
parts at work on the XFV. However, the downside of fixed-pitch blades is that they
cannot be adjusted during flight.
In normal operation, users would control the XFV through the use of two hand-control
grips and control arms, and by shifting their weight from side to side. The aircraft
has three-axis control: forward and backward, left and right, and up and down. By
twisting the left-hand grip, you can increase the rpm of the ducted fans to accelerate the speed of the aircraft. The right-hand grip allows you to adjust the tilt of the
fans for forward or backward flight or make the XFV spin on its vertical axis.
Shifting your weight will allow you to make turns. Like a helicopter, the XFV can
also hover in a stationary position for up to three hours. In the case of any
catastrophic failure, the aircraft would automatically deploy a parachute to safely
bring the craft down.
Millennium Jet received $5 million in funding from the Defense Advanced Research
Projects Agency (DARPA), which is the research arm of the U.S. military. The XFV
has completed nearly 400 wind-tunnel tests at the NASA-Ames Research Center.
Millennium Jet is analyzing how to market the aircraft, but hasn't said when it might be available to the public. The price is projected to be comparable to that
of a high-performance sports car.