A man wearing a Hoppi-Coptor, a personal helicopter device developed by Horace Pentecost, c. 1950. (Photo: General Subjects Photograph Collection, 1845-2005, Washington State Archives, Digital Archives)

Have you ever fantasized about the day when you can strap on a backpack, pull a cord, and launch into the air, with a propeller above your head like a real-life Inspector Gadget?

Then let us introduce you to the Hoppi-Copter, the one-man helicopter that some believed would revolutionize personal travel and warfare.

In December of 1945, Horace T. Pentecost created his Seattle company, Pentecost, based on a single alluring idea: that humans would be better off if they could fly easily and cheaply, preferably by using a helicopter that strapped to their backs. An almost alarming number of test pilots and investors agreed.

“It looks something like the futuristic ‘jumping belt’ of the Buck Rogers comic strip,” raved Life Magazine in 1947. Pentecost always intended for his invention to be an affordable mode of transit; later that year, Time reported that it might cost “little more than the better modern motorcycle.” Hobbyists, too, could take to the sky with reckless abandon.

According to the National Air and Space Museum, which has a dismantled Hoppi-Copter in storage, Pentecost’s first attempt at marketing to the U.S. Army didn’t pan out, not least of all because operating these machines were unwieldy and dangerous. Excitement grew for the new technology though, and one-man helicopters became the new weapon to romanticize in war.

The body of the Hoppi-Copter was made from metal tubes, which came together out of a sturdy backpack that the hypothetical brave soldier would strap on in lieu of a parachute in combat situations. A bulbous, two-stroke engine powered the flying device, and two separate propellers would saw above the wearer’s head as they moved in opposite directions to generate the necessary lift. The wearer was completely open to the elements. The writers at Popular Mechanics in 1966 joked, “There’s no lack of fresh air for the operator of this one-man helicopter.”

A 1947 volume of Aviation Week even gave some attention to the Hoppi-Copter engine, saying the prototype was created by piecing engine parts from four different companies together, with plans to design a dedicated Hoppi-Copter engine with private investor money.

The Pentecost HX-1 Hoppi-Copter, a functional backpack helicopter. (Photo: Public Domain/WikiCommons)

The first Hoppi-Copter prototype had other drawbacks, particularly that it lacked landing gear. Despite the obvious safety risks, Pentecost gathered hype around his idea, and, after a few years, renamed his company Hoppi-Copters, Inc. He first marketed it to the U.S. military as an alternative or replacement for parachuting troops, and generated excitement when he presented it to the British Ministry of Supply, who requested two models for testing purposes.

The Hoppy-Copter Model 102 added some rational improvements: a small seat and wheeled landing gear in a tripod style. Unfortunately, the motors and propellers were still located right near the wearer’s head, which must have been both dangerous and deafening.

Though these new developments seemed like a logical progression, Pentecost never gave up on the strap-on model. An issue of Flight from 1952 shoves a mention and photo of the Hoppi-Copter amid announcements of new jet planes, noting that not only had Hoppi-Copter, Inc. returned to the strap-on model, but that it was “under development for strictly military, or naval, purposes.”

A modern-day gyrocopter in action. (Photo: Dave Warley/flickr)

This one-person helicopter idea wasn’t completely unique. Across the ocean in Copenhagen, another backpack helicopter was created by Vincent Seremet, an inventor who made all kinds of one-person-only flying machines. Called the ryghelikopter, Seremet’s model used a parachute harness, a throttle, and the power of the operator’s own weight to steer, says the Danish Technical museum. Between 1958 and 1968 he also made a flex wing, an auto-gyro, and a motorized injection seat, but like the Hoppi-Copter, his ryghelikopter didn’t exactly catch on.

Indeed, just nine years after the idea of a helicopter backpack was first floated, Hoppi-Copter, Inc. failed, in 1954. Pentecost, however, was not deterred from his dream. He became president of Capital Helicopter Corporation, where he continued to work on ideas for similar helicopters, including another strap-on helicopter called the Capital Copter C-1. 

Even today, machines similar to the original Hoppi-Copter are still being invented. In recent years, a one-man helicopter known as the GEN H-4 debuted in Japan. Weighing just 154 pounds, it looks remarkably like the later Hoppi-Copter models, with its small seat and a tripod style landing stand. It has now been certified by the Guinness Book of World Records as the world’s smallest helicopter. 

To be fair, among weird WWII-related weapons like bat-bombs, the midcentury Hoppi-Copter seems almost tame. And of course, the future of flight attacks ended up going the completely unmanned route with drones. If you’re still looking for an aerial cruise around town in a backpack helicopter, though, the possibility is out there; there are more than a few ambitious inventors who can back you up.