On April 12, 1961, something amazing happened: Yuri Gagarin, a Soviet cosmonaut, became the first human to fly into space in a massive 2,400-kilogram spacecraft. Just a week later, Bell Aerosystems introduced another exciting invention: the gas-powered rocket pack. This rocket pack could fly 35 meters in just 13 seconds, which was thrilling to see. But the engineers who built it weren’t as impressed. They knew that this short flight was all the rocket pack could do, despite years of hard work.
So, why was it easier to send a huge spacecraft into space than to fly a single person with a jetpack? It all comes down to physics, specifically Newton’s laws of motion. To fly, you need a strong upward force to counteract gravity pulling you down. You might think that lighter objects would be easier to lift, but there’s a twist. Modern jet engines, which are our main tools for flying, actually work better when they’re bigger.
Jet engines operate by pulling in a lot of air and then pushing it out quickly. Most of this air doesn’t go through the engine’s core but still helps create thrust. The air that does enter the core gets compressed by tightly packed blades. This compressed air is then mixed with jet fuel and ignited in the combustion chamber. The heat causes the air to expand rapidly, shooting out of the exhaust and pushing the engine forward.
As the air exits, it spins a turbine in the exhaust nozzle. This turbine powers the fan and compressor blades, keeping the engine running as long as there’s fuel. The more air an engine can take in and push out, the more thrust it generates. On a modern jet, the front fan is bigger than a truck, and even at low speeds, these engines produce enough thrust to keep a passenger plane flying.
Smaller engines, however, can’t take in as much air. For a long time, engineers couldn’t make an engine small and light enough for a person to wear, yet powerful enough to lift both the pilot and the fuel. Early designs could only fly for 30 seconds, and controlling the powerful thrust was tricky and dangerous.
In the 2000s, new materials, manufacturing techniques, and computing technology improved jet engines’ fuel efficiency and power-to-weight ratio. By 2016, tiny engines the size of a coffee can and weighing less than 2 kg could produce 220 Newtons of force. This was when Richard Browning, an English engineer, saw a chance to create a new kind of jetpack.
His invention, the Jet Suit, used a single engine on the back and two micro-engines on each arm to balance the thrust. This setup provided three points of stability, making it feel like leaning on crutches while someone supports your back. It might seem hard to control all these engines, but many pilots learn to do it in less than a day, thanks to their brains’ advanced computing power.
Our brains and sensory systems help us balance and move smoothly, allowing pilots to control their flights with small arm movements. They can increase or decrease lift, turn in mid-air, or glide forward for up to 5 minutes. This technology is still new, and without big improvements in fuel efficiency and engine tech, we won’t all have jetpacks soon. But with how far we’ve come, who knows where we’ll fly next?
Use household materials to create a simple model of a jet engine. This activity will help you understand how air compression and thrust work. Gather materials like a plastic bottle, a balloon, and straws. Follow instructions to assemble your model and observe how air pressure can create movement. Discuss with your classmates how this relates to the principles of jet engine operation.
Conduct experiments to explore Newton’s laws of motion. Use a skateboard or a small cart to demonstrate how forces affect motion. Try pushing the cart with different amounts of force and observe the effects. Record your observations and explain how these principles apply to the challenges of creating a functional jetpack.
Work in groups to design your own jetpack using craft materials. Consider the challenges discussed in the article, such as balancing thrust and weight. Present your design to the class, explaining how it addresses these challenges. Use your creativity and knowledge of physics to propose innovative solutions.
Research recent advancements in jetpack technology. Create a presentation to share your findings with the class. Highlight key innovations, such as new materials or engine designs, and discuss their potential impact on the future of personal flight. Use visuals and examples to make your presentation engaging.
Use an online flight simulator to experience the challenges of controlling a jetpack. Practice maneuvering and balancing in a virtual environment. Reflect on the experience and write a short essay about the skills and technologies needed to operate a real jetpack successfully.
On April 12, 1961, Soviet cosmonaut Yuri Gagarin piloted a 2,400-kilogram spacecraft in humanity’s first manned space flight. One week later, Bell Aerosystems debuted another advancement in aviation: the gas-powered rocket pack. Capable of flying 35 meters in just 13 seconds, the rocket pack thrilled onlookers. However, the device’s engineers were less enthused. Despite years of cutting-edge work, they knew this short flight was all the rocket pack could manage.
So why was a massive spacecraft easier to send flying than a single pilot? According to Newton’s laws of motion, the physics behind flight are actually quite simple. All you need is a powerful enough upward force to counteract the downward force of gravity. Since objects with more mass experience stronger gravitational forces, lighter objects should be easier to get off the ground. However, modern jet engines, our primary tool for flight, actually become more efficient the larger they are.
Jet engines work by sucking in large volumes of air and then expelling that air as quickly as possible. While most of this air bypasses the inner machinery, it still contributes significantly to the engine’s thrust. The air that enters the engine’s core gets compressed by a series of tightly packed blades. This compressed air then enters the combustion chamber, where it is injected with jet fuel and ignited. The heat causes the compressed air to rapidly expand, bursting out of the exhaust and propelling the engine forward.
As air leaves the engine, it also turns a turbine embedded in the exhaust nozzle. This turbine powers the fan and the compressor blades, creating a cycle that maintains thrust for as long as there’s fuel to burn. The more air an engine can intake and expel, the more thrust it can produce. On a modern jet, the diameter of a frontal fan is larger than a truck. Even spinning at relatively low speeds, these engines produce more than enough thrust to maintain the necessary speed for flying a passenger aircraft.
However, smaller engines simply can’t take in as much air. For most of the 20th century, engineers couldn’t produce an engine small and light enough for an individual to wear, yet powerful enough to lift itself alongside its pilot and fuel. Designs could only carry enough fuel for 30 seconds of flight, and when airborne, the powerful thrust in a single direction made jetpacks difficult and dangerous to control.
The new millennium brought advances in materials, manufacturing, and computing technology, including systems that could manage fuel injection with incredible precision. Together, these dramatically improved fuel efficiency and power-to-weight ratio of jet engines. By 2016, micro-engines the size of a coffee can and weighing less than 2 kg could achieve 220 Newtons of force. This was when an English engineer named Richard Browning saw the opportunity to create a new kind of lightweight jetpack.
In addition to a single engine strapped to the back, this so-called Jet Suit involved a pair of micro-engines on each arm to split and balance the thrust. Working with the back engine, these provided three points of stability, which some pilots describe as being akin to comfortably leaning on crutches while a friend supports your back. It may seem complicated to manage all these engines at once, but many pilots master it in less than a day with the help of another advanced computer system—their brain.
Various brain regions and multiple sensory systems perfectly calibrate our sense of balance and spatial orientation, helping pilots smoothly direct their flights. Slight movements of the arms allow operators to increase and decrease lift, quickly turn in mid-air, or glide forward for up to 5 minutes. This technology is still fairly new, and without major advances in fuel efficiency and engine technology, don’t expect to have a jetpack of your own any time soon. But if reaching for the sky has already brought us this far, who knows where we’ll fly next?
Jetpack – A device worn on the back which propels a person through the air using jets of gas or liquid. – The engineer tested the new jetpack to see how high it could lift a person off the ground.
Physics – The branch of science concerned with the nature and properties of matter and energy. – In physics class, we learned about the laws of motion and how they apply to everyday objects.
Thrust – The force that moves an object forward, often used in the context of engines and rockets. – The rocket’s engines produced enough thrust to escape Earth’s gravity.
Gravity – The force that attracts a body toward the center of the earth, or toward any other physical body having mass. – Gravity is the reason why we stay grounded and why objects fall when dropped.
Engine – A machine designed to convert energy into useful mechanical motion. – The car’s engine was powerful enough to drive up steep hills without slowing down.
Flight – The action or process of flying through the air. – The physics of flight involves understanding how lift, thrust, and drag work together.
Air – The invisible gaseous substance surrounding the earth, a mixture mainly of oxygen and nitrogen. – Air resistance is a force that acts against the motion of an object moving through the atmosphere.
Technology – The application of scientific knowledge for practical purposes, especially in industry. – Advances in technology have made it possible to build more efficient and environmentally friendly engines.
Materials – The matter from which a thing is or can be made, often used in the context of engineering and construction. – Engineers must choose the right materials to ensure that a bridge is strong and durable.
Motion – The action or process of moving or being moved. – Newton’s laws of motion help us understand how forces affect the movement of objects.
