Custom Planes
Pages 46-47




The Amazing
One-Man Helicopter


I FIRST SAW the Gen H-4, the world's smallest single-place heli­copter, two years ago at EAA AirVenture in Oshkosh, Wisconsin, and I saw it again last year. But each time I saw it, it was sitting firm­ly on the ground. I kept coming back and asking the people at its booth, "When are you going to fly it?" I always got the same answer: "Not today. It's too windy."
     Too windy? It looked calm enough to me; even butterflies were doing touch and goes on the dandelions growing on the runway! I eventually got tired

The Gen H4, the world's smallest helicopter, was flown many times during the Copperstate Fly-in 2000. INSET PHOTO: A similar one-man helicopter, called the Hoppi Copter, was tried and abandoned by the militaty in the early 1950s.
of asking and walked away thinking, "There's no way that little hoptycopter (as I called it) can actually take off and fly." Then I promptly forgot all about it. At that time, the Gen H-4 was being promoted by ESCO Engmeermig Systems Co., Ltd., Matsumoto, Japan, the company that designed and built the kit.
    The idea for the design of a small, one-man helicopter isn't exactly new. During World War II, a number of prototypes were designed and developed at the request of the Army and Navy. Many of the dozen or so that were actually built were tested, but non ever made the grade. It's interesting to note that one of the prototypes tested during the 1950s bears a remarkable resemblance to the Gen H-4.
     The idea behind the World War II project development of the one-man helicopter was an attempt by the military to find a way to get troops back from behind enemy lines under their own power. (Another such project resulted in Goodyear's design of the inflatable aircraft made of rubberized fabric. It proved to be more successful, but none of these devices ever went into production either.) The major stumbling block was that, during that era, there were no suitable lightweight engines small enough to fit the design, yet powerful enough to pick up the helicopter and remain sufficiently reliable to safely power both the vehicle and its human cargo.
     In 1999 I came across a copy of a standalone photo of the Gen H-4-one I'd taken at AirVenture-and it was published in CUSTOM PLANES. Dozens of readers wrote to us with questions about it. Some asked if I'd ever seen it fly. Others wanted to know if I'd actually flown it myself. Many asked how uch it cost and where they could buy one. Inquiries about the little “hoptycopter” kept coming.
It is powered by two twin-cylinder twostroke engines of approximately 40 horsepower combined.
     Well, I hadn't even chosen the photo to be published; our art director used the photo to fill a blank spot in the magazine because he thought the aircraft was "cute." I guess he was right. And all those readers who wrote in evidently agreed with him. Eventually, we all got so busy, we almost forgot about the little helicopter.
     Then, when the CUSTOM PLANES staff covered the latest EAA Copperstate Fly-In, there was the little Gen H-4 again. This time I decided to get answers to the questions readers had sent to us. I had a long talk with the folks working the company's booth. They told me that yes, it did run; yes, it was flown at least once a day. My hat goes off to the young pilot (the son of the importer) who mastered the device.
     After witnessing one of the flights of the little Gen H-4, I spoke at length with the U.S. dealer, a gentleman from Ace Craft USA in Platte City, Missouri. As you can see, I took photos of the little one-man 
helicopter in flight, but from what I considered a safe distance with my longest telephoto lens. I was asked if I'd like to strap on the little aircraft and take it up for a flight, but I politely and firmly declined the offer.
     I learned later that the design had, at some point in the past, been turned over to a knowledgeable engineer (one familiar with autogyro and helicopter design) to ensure that the little helicopter was safe and as easy as possible to fly. The helicopter is exceedingly well built. It's powered by what looked like four Zenoah G-62 two-stroke engines, the same kind of engine modelers install in their large-scale RC models. As an avid modeler of giant-scale RC airplanes, I've used them myself, and I've found this type of engine to be a reliable source of power for lightweight applications.
     In the Gen H-4, each of the engines is hitched up to one of the two rotors, with a clutch, so that each rotor has two engines for power. Because each engine puts out about 10 horsepower, the helicopter has a total of 40 horsepower. 
The pilot was Jon Plummer, the son of the importer, Ace Craft of Missouri.
The electronics for the engines are located in a pod behind the pilot's seat.
Theoretically, in the unlikely event that one of the engines might fail on takeoff, the little helicopter would probably just sink back onto the ground. If that happened in flight, there would still be enough power for the pilot to make a controlled landing.
     The Gen H-4 helicopter weighs 155 pounds empty and can operate at a 400-pound gross weight. It has two 13.1-foot, counterrotating, fixed-pitch blades. Altitude control is achieved by controlling the engines' rpm. A yoke hangs down in front of the pilot, and it's used to aim the rotor head in the direction the pilot chooses. 
     I was among the hundreds of Copperstate spectators who gathered around to see the young man fly the Gen H-4 daily at noon. I was watching his flight through my camera's telephoto lens, and he certainly 
looked like he knew what he was doing. He started with his feet on the ground, and as the rotors came up to speed, he found the sweet spot, picked up his feet, then placed them on the footrest.
     His hands were quite busy with the controls, but he did fly it, and it was under complete control. I also saw him perform a series of flight maneuvers: some wide turns, backing up, going forward and several more.
     Yes, I finally saw the little one-man Gen H-4 helicopter fly. However, I don't think it's quite ready for an ordinary person (even your average pilot) to jump into it and, for example, use it to fly over a traffic jam on the interstate.
     The company's one-page brochure says that the Gen H-4 can be assembled in about 40 hours. When I asked about the price of the Gen H-4 kit at Copperstate, I was told it was $30,000. 

For More Information
Ace Craft USA
Dept. CP
P.O. Box 474
Platte City, MO
(816) 858-3694

Copyright March 2001 All Rights Reserved