Horace T. Pentecost and the Hoppi-Copter
I’d completely forgotten about this little piece of family history until my brother Wade reminded me of it. In the 1940s, our great Uncle Penny invented a backpack helicopter called the Hoppi-Copter, and one of his prototypes is in the Smithsonian.
Horace T. Pentecost’s first attempt, the HX-1, never actually flew as intended, but that’s the model I see most often in pictures of Uncle Penny. It’s also the model that’s in the Smithsonian (and which is currently on loan to the Pima Air & Space Museum in Tucson.) Evidently, the initial version of the Hoppi-Copter was doomed by the fact that landing on one’s feet and keeping one’s balance might be difficult while wearing a contraption made of spinning blades that could easily splinter if they struck the ground. The placard near the Hoppi-Copter at the Pima Air & Space Museum reads:
“The Hoppi-Copter is part of the long quest for a truly low cost personal flying machine. It was designed by Horace Pentecost of Seattle, Washington during World War II. He marketed it to the U.S. military as a replacement for the parachutes used by paratroops. The design consists of a small 20 horsepower motor powering two counter-rotating set of rotor blades, strapped to the back of the pilot. The greatest weakness of the design was its use of the pilot’s legs as landing gear. If he stumbled during landing or take-off the blades would quickly turn into thousands of potentially lethal splinters as they pounded themselves into the ground. This was, quite correctly, seen as ridiculously hazardous and the idea was quickly abandoned.
“Built by Horace Pentecost in 1945 and briefly tested by the U.S. military. It made about 20 flights with the pilot tethered by safety cable to prevent him from falling down. It was donated to the National Air & Space Museum in 1951 and was placed on loan to the Pima Air & Space Museum in 1996.”
The next model of the Hoppi-Copter featured a seat and wheels.
Version 2 also merited a mention in the April 7, 1947 issue of Time magazine:
“Ever since Icarus, and in spite of what happened to him, men have dreamed of strapping wings on themselves and taking off like the birds. Airplanes have never completely satisfied this desire. The plane itself does the flying; the man only rides and steers. Gliders are only half the ticket.
“Last week the ancient dream showed headline-hitting signs of coming true. At a Philadelphia meeting of the American Helicopter Society, Horace T. Pentecost told about the “Hoppi-copter” (see cut), which he has been developing in Seattle. It is a helicopter stripped to essentials: little more than a seat, landing wheels and two horizontal rotors revolving in opposite directions. The power source is a 35 h.p. engine with two opposed cylinders like an outboard motor. According to Mr. Pentecost, ‘the required blade adjustments to render typical three dimensional helicopter flight have been coordinated into a single control handle placed conveniently in front of the operator.’
“Total weight (not counting Mr. Pentecost): 173 lbs. The Hoppi-copter should ‘retail for little more than the better modern motorcycle.’ Helicopter experts would be more enthusiastic if they had seen it flying, but no performance records have been made available.
“But the designers have incorporated one important safety feature. Icarus made the mistake of flying too near the sun, which melted the wax that held his wings together. The Hoppicopter’s announced ceiling is a modest 12,000 ft.”
The third version of the Hoppi-Copter put the engine under the pilot’s seat and became the subject of an article in the January, 1951 issue of Mechanix Illustrated (along with some rather fanciful illustrations.)
According to the Smithsonian, after ultimately failing to get any interest from the military, Pentecost later tried to market the Hoppi-Copter as “sport aircraft,” and that “just as the company was ready to place the Hoppi-Copter into production, Pentecost’s ex-wife forced him out of the company when she managed to become a majority shareholder.” Tim McAdams’ AOPA blog says that Pentecost’s ex-wife (aka my great Aunt Charlotte) owned 45% of the company (per her divorce settlement with Horace) and became a majority shareholder by teaming up with Uncle Penny’s lawyer, who owned 10%.
After that, nothing much happened until 1956, when investors tried to revive the company, but that didn’t work out either, and the Hoppi-Copter seems to have faded into ancient family history and an exhibit that the Smithsonian loans out to other museums. I have no idea what happened to Uncle Penny or the later incarnations of his machine. Wish I knew more.