Listening to ASTM member Bill Bertelsen describe the hovercraft
invented by his father, William Bertelsen, M.D., brings to mind
the flying cars on the Jetsons.
Dr. Bertelsens Aeromobile-2000 has a hover-ring, instead of tires,
and flies inches above ground on a cushion of air. One wonders
if advanced models will be parked in home hoverports of the future,
nixing the problem of snowbound roads.
British hovercraft have ferried aircraft, cars, and passengers
across the English channel since the 1960s. Typically, gas-fueled
hovercraft move 35 mph (56 km/h) above ice, calm water or flat
land. Hills, headwinds, and rough surfaces challenge land travel,
but a proliferation of Web-connected manufacturers and enthusiasts
continue to expand their capabilities.
An aeronautical and astronautical engineer, Bill Bertelsen provides
occasional technical assistance to Dr. Bertelsen and his company,
Aeromobile, Inc., Rock Island, Ill. (www.aeromobile.com). Dads
patented tilting Gimbal fans offer superior maneuverability,
he says. Each unit provides both lift air and 360&Mac251; directional thrust. My Dads control system makes this one different
than some of the other air cushion vehicles that have been used
over the years. We think were on the threshold now of something
that will have a lot of utility.
Bertelsen is vice chairman of ASTM Subcommittee D30.09 on Sandwich
Construction. He invented the Hydromat panel test system used
in new ASTM D 6416, Standard Test Method for Two-Dimensional Flexural
Properties of Simply Supported Sandwich Composites, and developed
the standard with ASTM Committee D30 on Composite Materials. My
Dad and I think the ASTM test method will play a role in air cushion
development. Sandwich construction offers the possibility of weight
savings on the hull for air cushion vehicles as well as boat hulls.
The prototype is basically a steel tube and aluminum structure
but we could save a lot of weight with composite.
In the 1870s, Sir John Thornycroft birthed the idea of early hovercraft
and hydroplanes with experiments on his aunts lily pond. Air
car theories surfaced, but Sir Christopher Cockerell is credited
with the first unmanned working models in the 1950s. As Cockerell
designed hovercraft in England, Bill Bertelsen watched his father
invent air cushion vehicles in Illinois: I can recall helping
Dad measure base pressures when I was just seven or eight years
old. Id mark the manometers when hed fire up one of his machines.
Wed first test the machine inside the workshop and then take
it over to the high school football field.
A general practitioner, Dr. Bertelsen sought alternative travel
when impassible rural areas slowed his housecalls. He flew his
first man-carrying hovercraft in 1958, eight months earlier than
Cockerell. Dad is an air cushion vehicle pioneer, says Bertelsen.
He was the first one to fly a man-carrying air cushion vehicle.
It was developed more or less simultaneously in England by Sir
Christopher Cockerell and my Dad over here. In fact, one of my
Dads early machines is in storage at the Smithsonian. There were
some independent efforts going on in different countries. Nobody
knew about the work going on, so there was some overlap.
Bill assisted with several of his Dads 18 modelsgood practice
for his present position as chief test engineer with Gougeon Brothers,
Inc., Bay City, Mich., an epoxy-resin formulator of general purpose
laminating products. In materials testing 17 years, he creates
methods and equipment to test epoxy and its composites.
Dr. Bertelsen never flew to housecalls, but his vision may be
similarly realized; the U.S. Coast Guard is considering the A-2000
for ice patrol and rescue. Dad will celebrate his 80th birthday
in May, says Bill. He is working part-time as an emergency room
physician and continues to refine the Gimbal fan. It is anticipated
that the A-2000 will generate interest and income for another
of Dr. Bertelsens innovations, a high-speed shuttle Aeroduct
transportation system. It will open up a lot of possibilities
for efficient surface travel, he continues. I hope to be involved
with that at some point. //