The Dream Of Gyrocopter Flight

N40KB Ken Brock GyrocopterMike Blier samples Ken Brock's own is McCulloch-powered KB-2 gyroplane for the first time. Blier found Brock's machine considerably more powerful than his own VW-powered KB-2. (4)

The life and times of the homebuilt rotorcraft comes of age, courtesy of Brock Manufacturing.

According to the FAA, the most numerous type of homebuilt aircraft registered in the U.S. is . . . the gyroplane. More than 800 of these little rotorcraft are on the FAA’s latest registry of homebuilt experimental planes – gyrocopter flight is popular!

A lot of pilots are not even acquainted with the term “gyroplane,” which is the generic name for what most of us think of as a gyrocopter. “Gyrocopter” is the trade name for Bensen Aircraft’s gyroplane.

Igor Bensen of Raleigh-Durham, North Carolina, engineered and successfully marketed the first amateur-built gyroplane in the early 1950s as a towed glider. Adding an engine, he sold the plans and kits for building the Bensen Gyrocopter.

For many years Bensen Aircraft was the only United States company producing amateur-built gyroplane products, so the trade name Gyrocopter became for gyroplanes what Scotch (a 3M trade name) became for cellophane tape. The gyroplane is a very simple device which, at least theoretically, has several advantages over conventional aircraft.

The rotor cannot stall, because it is always in autorotation; air continually moves up through the blades, automatically maintaining proper rotor speed. Takeoff run is short compared to airplanes, and landing rollout, with or without the engine running, can be zero, with proper technique.

Because of their simplicity, gyroplanes are relatively easy and inexpensive to build. All these factors no doubt account for the popularity of the breed. Many non-pilots built and learned to fly them successfully, with or without the benefit of training by an experienced gyroplane pilot.

During the ’60s and 70s, dozens of gyroplanes, mostly Bensen Gyrocopters, showed up at the experimental aircraft fly-ins. But not all pilots did well. For awhile, gyroplanes developed a poor safety reputation. Some builders used improper materials or building processes, resulting in fatal structural failures.

Other pilots killed themselves through improper flying techniques, such as those that might cause negative-G flight, a no-no in a gyroplane. Some simply flew their machines into the ground or into hills or wires. As in almost all homebuilt aircraft accidents, builders or pilots – errors accounted for most accidents.

Some Bensen dealers operated ground-towed, two-place gyrogliders for training. But many gyroplane pilots simply taught themselves to fly with the help of instructions supplied with the Bensen plans and kits.

My introduction to the Bensen flying machines became a cover story in Popular Mechanics in the very early 1950s. The cover painting showed a gyroplane glider flying in a stiff breeze while tethered to a fence post. The article caught the imagination of thousands of would-be pilots who sent for plans.

A summer trip to North Carolina in 1958 rekindled my interest in the Bensen craft; I got a flight with Igor Bensen himself in his two-place, car-towed demonstrator at the Raleigh-Durham Airport.

I ordered a set of the glider plans, but found the kit and component prices beyond the reach of someone who was saving money to finish college. I recall that a section of the manual was devoted to teaching oneself to fly in easy stages. The mid-’60s provided an opportunity to finish and fly a nearly completed Bensen gyro glider.

My two partners and I found the machine easy to fly, even with its overhead bicycle-style cyclic, which had to be moved opposite from the way a control stick would move. (Left cyclic tilted the rotor disc right.)

Of the three of us, I was the only licensed pilot; I was flying sailplanes. Interestingly, the reversed control on the gyro glider never caused a problem-probably because of its bicycle handlebar configuration.

My partners and I planned to fly the glider for a while and then convert it to a powered gyrocopter. We even bought a new McCullough 72-hp drone engine. But the project came to naught due to pilot error: mine. I failed to replace the makeshift tow release on our machine with the proper Schweizer tow release that’s called for in the Bensen plans.

On the day of the crunch I was being towed at about 40 feet of altitude when the hitch failed. It turned out that even a slight side load would cause the homemade tow hitch to open under tension.

At the time, I had neither the airspeed nor the altitude to cushion the descent much, and gyro glider parts spread away from me as the rotor came apart on impact. The result: no injury, but considerable damage to flying machine and pride.

The gyrocopter flight lesson has stuck with me: make sure critical aircraft parts meet or exceed the designer’s specifications. Until recently, my time in gyroplanes was limited to that brief experience. Ken Brock changed that.

Ken Brock teaching gyrocopter flight

A strong right arm, Ken Brock’s right arm in this case — serves as the gyroplane’s pre-rotator. After prestation, with the cyclic (control stick) held full-aft and the gyroplane facing even a slight breeze, the rotor will accelerate slowly to flight speed.

Ken started a small machine shop in 1957. He was interested in flying, which led him to build and fly a Bensen Gyrocopter. He liked the machine so well that he became a West Coast Bensen dealer and sold gyrocopters for the next 17 years.

In his machine shop, he made and sold accessories for the gyroplanes, most notably a plastic combination seat/fuel tank. Although Brock is not an engineer, he fabricated some subtle changes in the Bensen design, and in the mid-1970s he stopped being a Bensen dealer and began manufacturing his own gyroplane kits.

Flying Bensen Gyrocopters first, and later his own gyroplanes, Ken flew hundreds of airshow demonstrations. For the thousands of spectators who see a gyroplane fly for the first time, his act continues to be an eye-opener.

Included are high- and low-speed passes, wingovers (rotorovers?) of more than 90° of bank and a deadstick no-rollout spot landing to show center. In 1971 Ken flew one of his gyros 3400 miles across the country in 10 days to demonstrate the safety and reliability of the gyroplane. He reported not one problem with the aircraft.

Ken calls his gyroplane the KB-2. It features an all-metal rotor system and either VW or McCulloch power. The gyro glider can be built first and later it can be converted to a powered gyroplane. Plans are available for $75 (1984 prices). A total of nine kits make up the KB-2.

Many builders start with the airframe materials kit, which costs $525, and go from there as time, money and inclination permit. The kit includes a $2900, 1835 cc VW engine, and complete, the KB-2 will cost about $6500. Machined parts in most of the KB-2 kits are finished.

Tubes are cut to length, bent and jig-drilled at the factory. There’s enough work left for the kitbuilder to qualify his aircraft for an experimental home-built certificate, but most of the hard work has been done already by Brock Manufacturing.

Brock’s spotless 10,000-square-foot machine shop in the Los Angeles suburb of Stanton is heavily involved in aerospace projects. He recently made the landing gear for the Rutan Voyager, the airplane intended to fly unrefueled around the world.

Brock manufactures parts for the Dragonfly, the KR-series planes, the Thorp T-18, the Marquart Charger, the VariEze and Long-EZ, the Solitaire sailplane and others. There’s plenty of work for the company’s 23 employees.

Most impressive among Brock’s extensive metal working equipment is a $130,000, computer-controlled electrical discharge machine that cuts precision steel dies. The dies are used to turn out large quantities of aircraft and parts.

Following a tour of the machine shop, Ken and I drove north of the Los Angeles basin to his airstrip near El Mirage Dry Lake. The dry lake is well known to dirt bikers, glider pilots, gyroplane enthusiasts, land sailors and assorted other weekend desert people.

The reason for all this activity is that the lakebed is hard and flat . . . and nearly seven miles long! (About once every ten years enough rain water collects to submerge the lakebed for a few days, helping to smooth the surfaces disrupted by years of recreational use.) Ken Brock’s desert retreat is perfect for all kinds of flying activity.

From time to time his large steel hangar houses his various aircraft, including a Brantly helicopter, a completely restored Stinson, a Cessna 210, a Thorp T-18 and other airplanes. The 2600-foot airstrip lies alongside. Ken’s cabin, moved to the site by the previous owner, was originally the El Mirage post office.

Gyro engine heaven

Now it serves the Brocks and their desert guests as headquarters for whatever activity is planned. The activity we planned was to checkout Brock’s two-place towed gyroplane; it was strikingly similar to the Igor Bensen trainer that I’d sampled long ago.

Brock employee Mike Blier drove the tow car, taking hand signals from Ken Brock during the training. Blier, who flies his own VW-powered Brock gyroplane, is a former U.S. Navy chief whom I’d known in the Western Pacific aboard the cruiser Long Beach.

Another of those “small world” get-togethers. Ken first explained that, like a helicopter, a gyroplane must be controlled from the moment the rotor starts to spin until it has come to a complete stop at the end of a flight.

Unlike a helicopter, the gyrocopter’s rotor is spun first by hand. If there’s any wind, the craft faces the breeze and, with the stick held fully back to tilt the rotor aft, the blades begin to accelerate.

In the absence of a wind, the gyroplane is towed or taxis slowly to allow the rotor to accelerate. Too much wind through the rotor at this point will slow the blades; a slow acceleration of about a 30-second duration is what’s needed.

Lateral stability provided by tow-rope tension eliminates the need for rudder input in the gyro glider. Speeding up to about 45 mph, we flew about 20 feet high at the end of a rather short cable.

Ken demonstrated the slight amount of stick movement it takes to maneuver the gyro or to keep it in a precise position behind the car. I soon got my chance to practice, and found the gyroglider to be very responsive. Smooth inputs of pressure, rather than discernible control movement, is what the gyro requires.

Like everybody else, I tended to overcontrol at first. But within five minutes, the gyro settled behind the car into whatever position I wanted. We moved up and to one side of the dust thrown up by the tow car. The drill was easy.

Next I practiced speed changes as Ken directed Mike (using hand signals I couldn’t see) to speed up or slow down without warning. The objective was to sense quickly the loss of power and set up a constant rate of descent for a landing, but to hold off the touchdown until the proper slow-airspeed attitude was achieved.

Not all the gyrocopter flight landings were beautiful, but they improved until we were ready to progress to the next phase of training. “Do whatever’s needed to keep it flying right,” Ken shouted. I wondered what he had in mind, but didn’t have to wait long to find out.

He threw his body as far to the right as he could, causing me to use full left stick to maintain a level attitude. (Rotorcraft are especially sensitive to e.g. location.) Next he leaned far forward, which required instant back-stick response.

Finally, all of these gyrations were combined with the power-loss landing drill. Correcting just before landing for the considerable displacement of Ken’s bulk sometimes required more than full control deflection; I found myself leaning far left to compensate for his lunge to the right.

The exercise was a confidence-builder for both of us. It simulated automatic reaction to a heavy gust or other unexpected occurrence. By this time we’d all had a long day, and sunset was about 25 minutes away. But the adventure wasn’t over.

Ken had used his black-and-chrome show machine to demonstrate hands-off stability gyrocopter flight and provide me with some pictures before our training session began. Ken now started the engine, and I climbed into the tow car with Mike for a closeup look at some gyroplane peculiarities.

Taxiing alongside us, Ken set his power at about one-third and took his hand off the throttle. With the stick near neutral, he accelerated quickly and climbed to five feet. Then, still leaving the throttle untouched, he began easing the stick aft. Instead of climbing, the gyro began a deceleration that was so rapid that Blier had to brake heavily to keep the car alongside.

VW powered Brock gyrocopter

Ken Brock (right) helps Mike Blier as he prepares to fly Brock’s KB-2 gyroplane. No newcomer to gyroplanes, Blier flies his own VW-powered, Brock machine.

Ken repeated the drill at a higher throttle setting, again showing the tremendous drag the rotor disc provides when it’s tilted farther aft. He also was reminding me of the proper touchdown attitude. After one last demonstration, he rolled to a stop. With engine still running and rotor spinning, Ken held the stick back and motioned for me to approach from the front.

I soon found myself strapped into Ken’s chrome-plated gyroplane. “Don’t climb higher than five feet,” he advised. A last-gasp headwind from the west provided us both with a surprise: I got airborne (to maybe six inches) as soon as I applied a bit of throttle. (I’m lighter than Ken.)

A bit of forward stick set me back down gently. Approaching the task cautiously, I used a very low throttle setting at first, but found that forward-stick unloaded the disc and accelerated me to maybe 40 mph. A tiny bit of back pressure had me flying a gyroplane for the first time. Ken was alongside in the car and gave an approving “thumbs up.”

Yaw control with rudder was easy; I didn’t have to think about keeping the nose pointed in the right direction. The remaining time before sunset was used to experiment with slightly higher power settings, to practice landings and generally to enjoy myself.

At one point I signaled Ken that I was going to take a left turn around some bikers on the lakebed; it was my only real excuse for a turn during my several flights down the dry lake. On the last run I relaxed enough to fly with just thumb and index finger. . . and to look around quite a bit while flying my five-foot pattern.

Sunset signaled the end of the flying day and my very limited exposure to gyroplane flying. On the way back to Brock’s cabin, Mike Blier pointed out that I’d never used more than one-third throttie. Equipped with a 90-hp McCulloch engine, the Brock KB-2 has plenty of power.

For what it’s worth, here are my impressions as a just-soloed gyroplane beginner: First, the hour or so flying with Ken in the two-place gyroglider was invaluable. He charges $375 (1984) for this course, and I’d advise any prospective gyroplane pilot to invest in a checkout gyrocopter flight like this before setting foot in a powered gyroplane.

The lack of a good local gyroplane instructor with a two-place glider (or of a seven-mile dry lakebed on which to practice) might convince me to add an airline ticket and a night or two in a motel to this “insurance bill;” I’d schedule myself to fly with Ken himself.

Second, flying the gyro feels more like flying a helicopter than I had imagined, because of its responsiveness and the resulting need for smooth, tiny movements. (I lack a helo rating, but have flown them enough to have a feel for the type.)

Brock finds that anyone with the desire and the right attitude can learn to fly the gyro trainer. So the lack of airplane-type control feel is insignificant. He claims all of his students have flown the two-place gyroglider successfully. Third, the gyro is so much fun that I can understand how some pilots become overconfident (as a few do in all types of aircraft).

Anyone with a strong desire to hotdog in the air by gyrocopter flight, however, should have a serious talk with himself or herself before flying a gyroplane. My guess is that those with self-discipline will survive to savor the gyrocopter flight experience. As for myself, I’m looking forward to more gyroplane flying.

Brock Gyroplane KB-2G And KB-2
Empty weight (KB-2G) 120lb
Empty weight (KB-2) 240lb
Gross weight 600lb
Disc loading, max. (KB-2G) 1.58 lb./sq. ft.
Height (KB-2G) 6 ft. 8 in.
Width (KB-2G) 5 ft. 8 in.
Rotor diameter 22 ft.
Rotor blade chord (KB-2G) 7 in.
Maximum speed (KB-2) 85-90 mph
Cruise speed (KB-2) 60-70 mph
Minimum level speed (KB-2) 25 mph
Range, maximum (KB-2) 150 miles (2.5 hr.)
Rate of climb (KB-2) 1200 fpm
Fuel capacity (KB-2) 8.9 gal.
Takeoff distance (KB-2) 300 ft.
Landing roll (KB-2) 0-20 ft
Service ceiling (KB-2) 10,000 +
Engine The KB-2 is powered with a 90-hp, four-cylinder, two-stroke McCulloch engine.
Manufacturer Ken Brock Mfg.
The Dream Of Gyrocopter Flight
Article Name
The Dream Of Gyrocopter Flight
David Martin examines the gyrocopters of 1984. With the likes of Ken Brock and Igor Bensen offering various forms of gyrocopter flight with their different gyroplane designs.

Be the first to comment on "The Dream Of Gyrocopter Flight"

Leave a comment

Your email address will not be published.