When people hear about jetpacks, they usually think about their appearances in SciFi or the big screen. Jetpacks are famous from the Mandilorian or Spy Kids, but they are real devices that have been around since the 1950s. These jetpacks are exciting and amazing machines; with demonstrations of these devices being an awesome spectacle. These Rocket Belts developed in the 50s used two nozzles that blasted high pressure steam generated by hydrogen peroxide to create thrust, which was quite loud and dangerous but created quite the show[1]. However, these demonstrations also illustrate the main problem with these jetpacks, they aren’t very useful for much else. The hydrogen peroxide jetpacks could only fly for around 20 seconds, severely limiting their use cases. Despite being developed by the military, their best use case was probably being used as a finale to Michael Jackson’s concerts during his Dangerous tour.
Newer jetpacks use diesel fueled jet engines that have pushed their endurance to ten minutes[2] and have given rise to discussion of possible use cases for paramedics, the military and civilian use. Despite these improvements, there are still numerous problems facing the still emerging jetpack industry, most importantly safety but also efficiency and flight control. Despite these problems, solutions could be just around the corner.
The Status Quo
How microturbines power the modern jetpack, despite their problems
Modern jetpacks are powered by small, heavy-fuel burning microturbine engines. These engines are relatively light yet produce a powerful thrust, enough to lift a person plus all of the jetpack equipment. Despite these impressive qualities, they still have some major problems. As a result jetpacks haven’t been embraced by the wider aviation community.
One of the most important flaws that is the Achilles heel of the modern jetpack is their fuel consumption. The engines used Jetpack Aviation’s JB-10 use a combined 4.75L[3] of fuel per minute, meaning pilots need to carry a large amount of fuel on their back for a 10 minute endurance. This limits range but also use cases in general, not to mention the environmental impact of burning gallons of diesel for such a short flight.
Another downside of the turbines is their “lag”. An immediate increase in throttle doesn’t mean an immediate increase in thrust[4]. This makes flight control very difficult for pilots and flying requires substantial training and skill. Flight control is mostly done by the pilot leaning their body, which isn’t the most precise. As you can see, while modern jetpacks are an improvement on the old, they still have many problems to overcome.
Safety, or Lack Thereof
Flying is inherently dangerous, but jetpacks raise additional concerns
The use of microturbines make jetpacks able to fly, but they weren’t designed for human flight. They originate from the remote control plane hobby and are therefore not built to the rigorous safety standards of aviation engines designed to carry humans. Engine failure is especially dangerous for jetpacks as they don’t have the ability to glide like a plane or helicopter. All of the lift is generated by the microturbines.
This is why jetpack flight has been limited to flying over water or very close to the ground, with the hope any accident would be more akin to a jetski or motorcycle crash, again limiting where jetpacks can be used. While there has been discussion of adding rocket powered ballistic parachutes to jetpacks, this would still expose the pilot to a “danger zone” in which they would be high enough above the ground that a crash could be deadly but low enough that the parachute would not have time to properly deploy and arrest the pilot’s fall[5].
In the event of a crash, the pilot also has to keep in mind they may be carrying many gallons of unburnt fuel. While the heavy fuels microturbines use are not that flammable compared to other hydrocarbons, the quite dangerous and hot jet exhaust from the microturbines could ignite the fuel. These safety issues have raised concerns, but they have yet to stop their development.
Use cases
Despite their problems, jetpacks may have some niche use cases
Many have questioned the usefulness of the jetpack, but they have seen some interest from professional organizations. The Great North Air Ambulance service in the UK which primarily uses helicopters have trialed Gravity Industries’ jetpacks[6]. Jetpacks offer the ability to land in places where helicopters can’t and would be difficult to reach by foot, offering rapid response paramedics in austere areas. This is especially useful in the mountainous highlands. While these trials did show some promise, the jetpacks can only transport a paramedic, not an injured patient needing care at a hospital, again highlighting their limitations.
Another source of interest has been militaries, US DoD responsible for the funding of the Rocket Belt after all. Their versatility and their ability to land basically anywhere is quite the advantage over typical military helicopters. The UK’s military has trialed jetpacks to board ships, however no military has officially adopted jetpacks. However at least one unnamed military has purchased jetpacks[7].
While it seems paramedics and the military are understandably not so convinced about the utility of jetpacks, they have seen a lot more success as a form of entertainment[8]. Demonstrations and shows of jetpacks have been popular since their inception and jetpacks companies are now offering flight experiences, although with the Jetpack tethered to the ground. There have been talks about jetpack racing as well. While it may seem like jetpacks are going to remain expensive toys to show off, solutions to these problems have been researched.
The Future
Jetpacks have many problems, but they could be solved with new breakthroughs
Despite the above mentioned problems, there have been some developments that would make a future jetpack pilot excited. One is the Martin Jetpack, which used an internal combustion engine that powered ducted fans for lift instead of microturbines. This made the jetpack much more efficient than its contemporaries, burning a respectable 1.5L[5] of fuel a minute and allowing it to fly for more than 20 minutes. Despite these impressive stats, the jetpack was more akin to an ultralight helicopter than a jetpack, weighing 300lbs due to the weight of the engine and fans, plus the company is now defunct. While this may seem like a failure, it could be the ancestor to a jetpack with a lighter more powerful engine that could be worn on the pilot’s back, especially due to new developments in power dense internal combustion engines[9].
A surprising amount of studies have also been conducted on computerized flight control for microturbine jetpacks, making them easier to operate[10], [11], [12], [13]. These studies have shown that it is possible to have an autopilot to assist the pilot, especially if more novel techniques like thrust vectoring is used. The jetpack industry has also shown a lot of parallels to the unmanned aircraft industry, and this could lead to developments in new more efficient engines and systems for jetpacks. While the current jetpacks are a far cry from the devices seen in science fiction, they have shown promise even in their current state. Future developments could pave the way for a future where jetpacks are a useful tool.
[7] M. Dirago, “Raising the Bar: The Future of Individual Lift Devices in Warfare”.
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