It had
to be the lightest aircraft at Oshkosh AirVenture 1999. And it was no mere
novelty because it flew several times before large crowds that cheered
the pilot and the design.
With a grin, the Japanese-speaking designer
of the GEN H-4 called the ultralight helicopter Inspector Gadget, after
the popular movie about a man with a helicopter that comes out of his head.
An exceedingly absurd image, it is nonetheless amazingly on point for the
H-4.
More down to earth, the 155-pound, one-man
helicopter is a counterrotating design done as simply as the imagination
allows. With four tiny engines and an overhead-style joystick, the machine
actually looks plausible and flyable by mortal humans.
When it was demonstrated over several days
at AirVenture, the improbable aircraft coaxed onlookers to regard it seriously. |
| Designer Gennai Yanagisawa and pilot Jon Plummer stand
under the GEN H-4 fitted with its ballistic parachute in the disk-shaped
pod above the top rotor blade. The emergency parachute can be deployed
in the event that all four engines fail. |
|
GEN H-4 Helicopter
For those unfamiliar with rotorcraft, two
broad categories can be identified:
Gyroplanes do not drive the rotor blades; helicopters do. The H-4 is
a true helicopter in that it can achieve and has demonstrated no- wind
vertical takeoffs and hovering flight.
We've seen counterrotating blades before but
never on anything so tiny as the GEN H-4. Such a design allows elimination
of a tailrotor, cutting many pounds and shrinking the size. You could stand
two GEN H-4s in the bed of a full-size American pickup track (given a little
creative packing).
Credit for the intense miniaturization goes
to Gennai Yanagisawa, a former auto designer who founded a high-tech machinery
company. In the 1980s he created the tiny 6.2-pound, 10-hp GEN125 engine
used in quadruplicate on the GEN H-4.
The four engines provide a total of 40 hp,
a figure that will rise to 60 when four 15-hp engines are added later to
address heavier American pilots. In the meantime, Yanagisawa's company,
Engineering System Co. Ltd. (ESCO), employs very lightweight pilots to
test the vehicle. |
| Weight is also saved in the unique wheel system. Now in
its fourth generation, the H-4 has knuckle wheels on all four corners.
A series of bearing rollers mounted to an axle, they permit motion in all
directions much like a castering wheel. Representatives rolled the H-4
into position on Oshkosh's ultralight runway proving the tiny wheels work
even on turf.
What Cockpit?
To many, one of the best features of ultralights
is an open cockpit. The GEN H-4 has arguably the most open cockpit of any
flying machine at AirVenture.
With three gear legs and four wheel points (the
front leg forms a T), the pilot sits in a seat attached to the fuel tank.
Securely four-point fastened, the operator moves a control yoke that hangs
down in front of him like the old Bensen gyros or early Rotec Rally ultralights.
On the control are two grips, a right-hand spring-loaded throttle lever
and four electric starter buttons. A left-thumb button activates the electrical
yaw control. A light above each starter button confirms the engine is operating
and one digital tach measures engine speeds.
When the pilot moves the yoke fore and aft
or side to side, he moves the entire arrangement above his head. The engines
are radially arranged, feeding a central reduction gear drive, and they
have a doughnut-shaped muffler surrounding them. Fixed-pitch rotors and
engines are set atop a gimbal system using curved guides that tend to center
the control in the absence of pilot input.
At one point, the pilot removed his left hand
and waved at the crowd while in low hover, something you don't typically
see from a chopper pilot. (His right hand remained active as he had to
keep power applied via the spring-loaded throttle.) |
| The GEN H-4 flew at AirVenture 99 and proved to be
a crowd pleaser. Many who were unsure the tiny chopper could get off the
ground were amazed and delighted. |
| The flight control yoke moves fluidly fore and aft
and side to side and has starter controls and lights at bottom, throttle
on the right, yaw control on the left, a digital tach sampling one engine,
and kill switches. |
|
| Looking over Plummer's shoulder, you get some idea
of the simple controls used for flight. The pilot's left thumb is ready
to activate the electrical yaw control to maintain direction. |
|
If the whole thing still sounds
difficult to master, consider this: Neither operator testing the GEN H-4
is a licensed pilot and neither has any rotor experience. The controls
are therefore a testament to intuitive feel. Most helicopters require extensive
training.
Second Coming
Americans first saw the GEN H-4 fly at the
1998 EAA convention. Since then the ultralight helicopter has logged some
25 hours, according to company representatives.
At this year's gathering, the little machine flew
several times, although always in calm winds and with no one else operating
on the ultralight runway. Even though these were closely regulated flights,
they were legitimate freeflying demonstrations with no tethers. In all
cases, the pilots appeared to have full and easy control. They were able
to hover up to about 10 feet. It didn't look particularly challenging,
and I found myself envisioning flight in the H-4.
Rotary wing skeptics wondered about any helicopter
that cannot autorotate to a landing. This technique allows engine-out touchdowns
in conventional choppers, but that won't work on the GEN H-4. |
To address this safety concern, Yanagisawa
designed redundancy into his ultralight helicopter. "If one engine fails,
the remaining three permit normal flight," he said. "If two engines fail,
the H-4 can still be landed safely." He feels the failure of three or all
four engines would be extremely unlikely. However, should fuel contamination
seize all powerplants, Yanagisawa has designed a ballistic parachute setup.
In a disk-shaped pod above the top rotor blade,
a rocket-deployed parachute will be installed. Capable of saves from very
low altitudes, this addition may permit flying at altitude and over some
distances. However, the parachute manufacturer says it demanded use only
on unmanned aircraft until further testing is done.
Not Ready for Sale... Yet
Even if you can swallow a $30,000 price tag
for such a miniature marvel, you can't buy one yet. Further testing is
planned, and the larger engines have not been fitted. Yet given nearly
a decade of development, ESCO appears committed to bringing the ultralight
helicopter to market. A kit is being developed that is said to require
30-40 hours of assembly.
The first generation of this machine was called
the BDH-1 for Boy's Dream Helicopter. Though Yanagisawa's fantasy may have
originated in Japan, the appeal of such a small vertical launching aircraft
is global. One need only be convinced that the thing can actually fly safely.
Several well-orchestrated flights at Oshkosh 1999 proved the concept works.
The company is seeking U.S. dealers. Are you ready?
PHOTOS: DAN JOHNSON
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|
Engineering
System's GEN H-4
Price:
Standard kit.............................$30,000 (est.)
Specifications:
Rotor diameter................................... 13.1 ft.
(dual counterrotating)
Rotor speed.............................800-850 rpm
Height..................................................7.5 ft.
Weights and loading:
Empty weight (without fuel)....................155 lb.
Gross weight.......................................485 lb.
Pilot weight.......................................185 lb.*
Fuel capacity.........................................5 gal.
Engines:
4 GEN125, radially arranged.
Total power, 40 hp.
Performance:
Maximum cruise speed.......................60 mph
Never exceed speed........................120 mph
Service ceiling (calculated)...............10,000 ft.
Fuel consumption..............................5 gph**
Manufacturer:
Engineering System Co. Ltd.,
5652-83 Sasaga Matsumoto,
Nagano-ken
JAPAN 399-0033
phone 011-81-263-26-1212
fax 011-81-263-26-1213
e-mail: [email protected];
www.engineeringsystem.co.jp
*with 40 hp; 60 hp planned for greater pilot weight
** depends on pilot weight; less with lighter pilot |
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Copyright
November 1999 All Rights Reserved
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