Dual gyro instruction in an RAF 2000 turns out to be an eye-opener
My wife and I were playing golf one Saturday morning with her coworkers, and I was asked what was new with my fob.
“Oh, I’m learning to fly a gyroplane for a story for KITPLANES,” I answered.
“Wow! Those helicopter-like machines they used to advertise in the back of Popular Mechanics!” was the rejoinder.
“I was going to build one of those, keep it in the backyard, and fly it from the street!”
“Can you really teach yourself to fly one of those things?”
“Yeah, but you can kill yourself doing it. Here’s why…”
They listened intently while my wife grimaced as another beautiful Saturday degenerated into shop talk.
Legality vs. Practicality
The legal answer to “What does it take?” is simple: FAR 61.113 requires an applicant for the private pilot gyroplane certificate to possess a Class 3 medical certificate, a passing grade on the written exam, 20 hours flight instruction from a certified gyroplane flight instructor (15 of which must be in a gyroplane) and 20 hours of solo practice (10 must be in a gyroplane.)
Of the instruction required, 3 hours must be in cross-country flying, 3 hours and 10 takeoffs and landings in night flying (for night-flying privileges) and 3 hours in preparation for the flight test. Of the gyroplane solo experience, 3 hours must be in cross-country flight and three takeoffs and landings must be done at an airport with a control tower.
For the rated private pilot seeking an add-on rating, only an additional 10 hours of solo experience in gyro planes is required, after receiving instruction up to solo. Those are the bare, legal minimums. But after my first encounter with the gyro plane, I was convinced that 50 hours of dual would be required in my case.
“I see now why people can get killed teaching themselves to fly these things,” was my stock response to “How’s the gyro training going?” for the next three weeks. The gyrocopter instructor, of course, said it would take 15 hours to get “comfortable” with the machine.
Lesson 1: What, You’ve Never Done This Before?
I met instructor Jim Mayfield at Phoenix-Goodyear Airport in early October last year. Mayfield owns Arizona Rotors, a two-man flight school and dealership for the Rotary Air Force RAF 1000 and 2000 kit gyro planes. He’s also an FAA-designated examiner.
We would be training in the two-place RAF 2000, equipped with a Subaru Legacy EJ22 of 130 hp and an FAA waiver for use in flight instruction. There isn’t much preparation an aspiring gyrocopter pilot can do before going out to the airport. According to Mayfield, there is no good basic gyroplane text, but he presented me with an outline of material to be covered. Rotary Air Force’s flight manual offered no clues to the new pilot (but then, neither would a Cessna flight manual to a fixed-wing pilot.)
Yes, I would have to learn from the rich tradition of oral history: the rotor craft culture’s colorful creation myths of blade-flapping and shattered rotors. To reinforce my learning, I bought a new Pilot Logbook and Journal from Flywrite Systems, which has plenty of room for notes and drawings; my plan was to take notes during pre- and postflight briefings, and review them each night before a new lesson.
We met at 7 a.m. for the introductory lesson; the bumps and gusts of a typical Arizona day make for frustrating lessons, said Mayfield, so it’s best to start early. Also, because the RAF 2000 was designed and originally flown in Canada, late morning and afternoon launches resulted in uncomfortable engine temperatures and severely decreased performance. (It could have been worse; students learning during the sweltering summer months report at 3:30 a.m. for briefings and sunrise launches.)
After a good hour of describing gyrocopter basics with a plastic helicopter model, we squeezed into the RAF 2000 gyroplane for a short session of takeoffs and landings, medium turns and avoidance and recovery from the gyroplane’s weak point: pilot-induced oscillations.
The pilot and passenger (in this case, the instructor) sit side by side on top of a molded plastic fuel tank that doubles as a seat. Four-point restraint systems attach to the main airframe and the mast engine pylon. Until the first pilot boards the machine, its tailwheel rests on the ground. Adding weight causes the RAF 2000 to rock forward on its main wheels until the direct-link steerable nosewheel contacts the ground.
The cyclic control looks like and serves pretty much the same purpose as a helicopter’s, or a fixed-wing aircraft’s control stick. Because of the cramped nature of the enclosed cockpit, I was concerned that my legs would interfere with proper side-to-side movement of the cyclic. No problem, I would discover, due to the minuscule movement required to control the gyroplane.
The two throttle handles are mounted on a torque tube that runs along the front edge of the seats, just to the left of each pilot’s left thigh. Rudder pedals are linked directly to the rudder and the nosewheel, but differential braking is controlled by two handles resembling a twin’s throttles; I began to wonder if Mayfield wasn’t joking when he said I’d need three hands to fly this.
Fortunately, there’s not much call for heavy braking after landing a gyroplane. Ignition is solid-state, so startup is a matter of pumping the throttle once, flip ping on the battery and alternator switches, and holding the starter switch up for a half second. The Subaru engine and four-blade Warp Drive composite propeller are smooth and quiet.
No doors were installed on this RAF 2000, so the lengthy taxi to the departure end of Goodyear’s Runway 03 was drafty. The rotor blades slowly bob up, down and around, even with the control and rotor locks set. It felt like I was driving some sort of a weird go-kart in a parade.
The fun began at the runup area. There’s no need to check magnetos or perform a “ignition” runup with the Subaru engine, so it’s a deceptively simple matter of releasing the control and rotor locks, then engaging the pre-rotator. A gyro plane does not have a powered rotor, but requires the rotor to spin—in our case to about 300 rpm—to generate lift.
The rotor spins as a result of airflow passing up and through the rotor disc. Somehow, the rotor must be made to accelerate to flight speed before liftoff, and the pre-rotator starts the process. There’s a bicycle-brake-like handle on the RAF 2000’s left cyclic that engages a clutch. An eternity of careful slipping is required to get the blades to 80 rpm, at which point it can be fully engaged.
Initially, the gyrocopter’s cyclic will want to jab twice per revolution as the blade traveling into the wind lifts, so the pilot finds himself simultaneously squeezing the clutch and trying very hard to keep the cyclic centered. At 100 rpm, the cyclic is moved halfway to the rear stop, while still holding the clutch in. At 125 rpm, the cyclic is moved all the way to the rear stop. When rpm is at 150 rpm, it’s time to call for clearance and move out to the runway.
When starting the takeoff roll, power is added gradually until the rotor speed reaches 200 rpm. Any slower and the rotor blades can’t accept the airflow and will begin to flap, causing damage. The cyclic is held full back during the takeoff roll, and if you don’t pay attention, the craft will rock back onto its tailwheel or even leap into the air, only to mush back onto the runway.
Mayfield would pretty much be taking off and landing for the next few lessons. It is overwhelming at first.
Like a fixed-wing aircraft during a soft-field takeoff, the gyroplane is allowed to lift off at a slow airspeed— about 50 mph for the RAF 2000—and to accelerate in ground effect until climb airspeed is reached.
In a gyroplane, this magic number is minimum power required speed (MPRS); MPRS is similar to best lift-to-drag airspeed, which is most efficient and also allows best rate of climb. For ease of training (and less wear and tear on the gyro-plane), we used this airspeed for everything: takeoff, landing, maneuvering and cruise.
But the climb attitude is nearly level; the gyroplane is a level-attitude flying machine, Mayfield said, and it’s hard for a fixed-wing pilot to overcome the tendency to pull the stick to climb, and even harder to stop oneself from pushing the nose lower to accelerate in ground effect.
Once the machine reaches MPRS in the level attitude, it will begin to climb. It’s a simple matter then to maintain a level attitude and climb to your desired altitude. This may sound easy and simple, but it was frustrating because I was overcontrolling, and the sequence of events happens quickly. No one could possibly teach himself to fly this without wrecking it, I decided.
Episode 2: Writer-Induced Oscillations
Mayfield had warned me that he would frequently take the controls throughout training, sometimes to save the machine when I screwed up and sometimes to give me a rest. I was following through on the controls during the first takeoff and Mayfield noticed that I had a death grip on the stick and my entire body was tense. “OK, I’ve got it,” he announced. “You need to loosen up and relax.”
There was no need for rudder during climbout, but I was pushing both like brake pedals. When I realized this, I dropped my feet to the floor, and I may have even taken my left hand off the throttle. It was the first of three times during this lesson that he took the controls to give me a break because of the tension he could sense.
I was simply over controlling the gyroplane, no matter how small my control inputs were, and tension in my arms and shoulders aggravated the situation. The gyrocopter, Mayfield explained, requires control pres-sure, not movement. Oddly enough, it flies straight and level until the pilot knocks it out of that state.
How much control movement is really needed then, I asked? “Just enough. No more, no less,” he said. “When you get 15 hours in this, you’ll wonder how anyone can overcontrol a Cessna 150.” I guess that’s what I’m going to learn from this trial, I thought: precise control.
We flew to a nearby practice area and I began to practice pilot-induced oscillations. Because the gyroplane is inherently stable, there’s nothing to straight-and-level flight other than trimming and leaving it alone.
Of course, my feelings of self-worth as a pilot were not being validated by the gyroplane, so I subconsciously made not-so-itty-bitty stick movements to maintain my self esteem, resulting in pitch excursions that grew in severity when I overcorrected.
“OK, that’s enough,” said Mayfield as he took control. Pilot-induced oscillations (PIOs) are a real danger in gyroplanes. If allowed to go unchecked, the tailboom may eventually rise into the rotor disc, damaging one or both. By pitching too far nose down and applying power, the pilot could actually unload the rotor disc, resulting in catastrophic rotor stall.
This is the dreaded phenomenon called going negative, meaning that the normal upward flow through the rotor disc is reversed and may cause rotor breakup. It is often fatal at any altitude.
PIOs are best described by comparing the rotorcraft airframe to a bobweight at the end of a pendulum that is attached to the center of the rotor disc. Once something disturbs it from equilibrium, it rocks back and forth until stopped. You don’t stop a swinging pendulum by pushing it at the top of its swing, and for the same reason you don’t push the stick forward as the gyroplane’s nose reaches the top of the oscillation.
You simply stop the descent of the nose when it reaches the horizon, like catching the bob weight at the bottom of the pendulum’s arc. This made sense, but for the next six lessons I continued starting and having to stop these annoyances that I couldn’t blame on anyone but myself. Although it helped to look at the horizon and hold the cyclic lightly between thumb and pointer finger, it wasn’t until 7 hours of flight time that I adjusted to it.
Because of the dangers of letting the PlOs go uncorrected, and the distressing and distracting nature of the phenomenon (how could you ever line up with the runway or stabilize an approach if this was going on?), I decided that gyroplanes should never be considered toys, and wondered if I would ever feel safe flying them. And that was before we got into the landings.
Lesson 3: Getting It Down
The landing is the only segment of gyroplane flight that is not performed in a level attitude. The nose is lowered simultaneously as power is reduced. After being told never to “unload the disc” by abruptly pushing the stick for ward, I was nervous.
Initially, I inadvertently changed pitch throughout the approaches, finding that I was pulling back at around 250-300 feet AGL when the runway appeared to be rushing up. This was particularly a problem during engine-off approaches, with a 4:1 glide ratio.
I had noticed my tendency to do this in fixed-wing aircraft before, but it wasn’t critical. In the case of the gyro plane, however, it resulted in quite a few go-arounds; below 100 feet, pitch changes should not be made because loss of rotor rpm is hard to recover from. It took conscious effort to maintain pitch on down to 20-40 feet above the run way, where it was time to flare.
It was all too easy to overcontrol when flaring, resulting in the gyroplane arresting its descent 10-20 feet in the air. Control input should be so gradual, according to Mayfield, that you can’t see the stick move. When I got the hang of that, I found myself continuing the gradual back pressure when I’d reached level attitude. It seemed as if the machine was continuing the pitch change—like a pendulum—unless I stopped it.
Our target level-off altitude was a foot off the runway, at which point I was to hold it off until we had zero forward speed. Airspeed dissipates rapidly once leveled off, and suddenly greater amounts of back pressure were needed to keep it off. Once the wheels touch, power is reduced to idle and the cyclic should be full back.
It’s an odd feeling for a fixed-wing pilot: You expect to be roll down the runway after touchdown at 30 mph, but in the gyroplane, you’ve stopped and can even be rolling backward. For a brief moment, the machine hovers and then settles gently to the pavement—assuming you’ve leveled off an inch or two off the runway.
For a running landing—or touch and go—the nosewheel is gently lowered, cyclic still full back and partial power brought in until rotor rpm is increasing and is above 200 rpm to prevent blade flapping. For a full-stop landing, the cyclic is eased forward to unload the rotor disc. The manual calls for braking as necessary after touchdown, but there should be zero forward speed. Not that the gear can’t handle it, but the pilot doesn’t have enough hands for throttle, cyclic and brake handles.
As the weekly lessons progressed, approaches and landings replaced pitch control as the most difficult and frustrating aspects of flying the gyrocopter. Reviewing my notes from the previous lessons was helpful for sequence of actions on takeoff and landing, but gentle, subtle control pressure eluded me. And the concentration required to correctly flare and hold the machine off the ground made me forget to straighten out; I was looking over the nose of the side-by-side seat enclosure, not straight ahead.
About the time I got the hang of it — the seventh flight and just over 6 hours — a new twist was added: power-off autorotation and landing. Up until now, power and pitch reductions were simultaneous and gentle. Because of my fear of depitching and unloading the rotor disc, I hesitated and gently lowered the nose after the sudden power reduction. Not quick enough, as airspeed rapidly dissipated into the yellow arc and the machine yawed sharply to the right (the rudder is mounted at an angle for cruise flight).
The importance of immediate reaction was driven home and Mayfield took control and used nearly all the altitude remaining to maintain rotor rpm and increase airspeed to MPRS. After doing so well and screwing up so bad the next minute, I felt like I’d taken six or seven steps back.
The next few attempts were better, but I found myself not catching the yaw problem in time, using too much rudder, then letting pitch wander. And as my frustration level increased, I tensed up and my performance worsened. May field recognized this and ended that day’s lesson by taking the controls and demonstrating. We agreed that I’d reached a learning plateau and needed to come back refreshed and relaxed.
This could take forever, I thought, as I left the airport that day. Mayfield was going to be out of town for more than three weeks, and I felt that all my gains would have evaporated by the time he returned. Although I was happy to return to my glider training during the break, I wondered if my new soaring skills would have atrophied as well. Can there be much cross-over in proficiency between flying a Schweizer 2-33 and an RAF 2000?
The answer is yes. Two short flights after my two-month break from gliders found my instructor pronouncing me ready to solo, and I did.
And the three week break from gyro planes? I did surprisingly well when Mayfield and I met again. With a total of nearly 7 hours of gyro instruction and a three-week respite, I returned and flew with no PIOs, passable running landings, and increasingly better power-off landings, including curved approaches. Maybe it was the rest, maybe it was the glider time, but I finally felt comfort able with the gyroplane.
Mayfield, who’d told me my goal for the mission was to fly without his having to nag or correct me, had to open his mouth only once or twice. The bottom line? At first I found that learning to fly an autogyro precisely can be discouraging. But with a good gyroplane and excellent instruction such as Jim provides, you’ll catch on eventually, and gyro flying turns out to be a heck of a lot of fun. In addition, my logbook now contains a brand new endorsement to fly gyroplanes solo.
Sounds really hard but I would like like to try it sometime.