Aircraft

Video: Wave Engine's UAV test flight brings pulsejet into 21st century

Video: Wave Engine's UAV test flight brings pulsejet into 21st century
Wave Engine Corp's first product - the J-1 engine - has no moving parts, and has launched in style, powering a demonstrator UAV through a successful test flight
Wave Engine Corp's first product - the J-1 engine - has no moving parts, and has launched in style, powering a demonstrator UAV through a successful test flight
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Wave Engine Corp's first product - the J-1 engine - has no moving parts, and has launched in style, powering a demonstrator UAV through a successful test flight
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Wave Engine Corp's first product - the J-1 engine - has no moving parts, and has launched in style, powering a demonstrator UAV through a successful test flight
The J-1 engine powered the Scitor-D UAV through take-off, climb/cruise and landing
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The J-1 engine powered the Scitor-D UAV through take-off, climb/cruise and landing
"This technological development signals major improvements for the cost and rapid-producibility of future jet powered aircraft," said Wave Engine Corp
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"This technological development signals major improvements for the cost and rapid-producibility of future jet powered aircraft," said Wave Engine Corp
Wave Engine Corp demonstrated a prototype engine mounted atop a glider in 2020
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Wave Engine Corp demonstrated a prototype engine mounted atop a glider in 2020
Graphic showing the Wave Engine's repeating cycle
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Graphic showing the Wave Engine's repeating cycle
The J-1 engine is rated for high-speed UAVs weighing up to 200 lb, and Wave Engine Corp is also working on a larger K-1 variant (pictured) for aircraft up to 1,000 lb gross weight
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The J-1 engine is rated for high-speed UAVs weighing up to 200 lb, and Wave Engine Corp is also working on a larger K-1 variant (pictured) for aircraft up to 1,000 lb gross weight
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Wave Engine Corp has aced a demonstration flight of a simple jet engine with no moving parts. A modern version of a pulsejet, the J-1 engine powered a UAV through take-off and several mid-air stop/starts before the aircraft nailed the landing.

The Wave Engine is an evolution of the pulsejet engine, a simple jet propulsion device where air is fed into a chamber and fuel introduced. This is ignited to produce a fireball that forces high-pressure heated gasses down a tube and out of the tailpipe, creating thrust. As this happens, the pressure inside the engine drops and creates a partial vacuum which draws fresh air in, and another burst of fuel is ignited to repeat the process.

This is not new technology of course. The pulsejet has been around in one form or another for more than a hundred years, most notably during WWII when it powered the so-called buzz bombs – an early cruise missile with a fairly limited range that caused daily mayhem and destruction throughout London from mid-1944.

The advent of online video platforms has become fertile ground for backyard inventors to test their pulsejet mettle, with "crazy rocketman" Robert Maddox regularly breathing fire on motorcycles, karts, trikes, skateboards and dragsters. But it's the ever-charismatic Colin Furze we've selected to highlight the essence of these ear-splitting madcap builds, with his now 10-year-old jetbike test video.

The JET Bicycle - The most dangerous unsafe bike EVER

Wave Engine has spent the last few years tweaking the formula, and now reckons that its "proprietary technology enables high speeds and allows for an order-of-magnitude reduction in the cost and complexity of jet propulsion."

Where some designs utilize mechanical valves, the digitally controlled Wave Engine uses a short intake tube as its valve. The combustion chamber sits in front of this and then curves into the tailpipe. When the air/fuel is ignited, the explosion – or more correctly deflagration – sends the hot gasses out of both tubes to generate thrust. Air is sucked in by the resulting vacuum inside, and the process starts afresh with a new ignition.

Graphic showing the Wave Engine's repeating cycle
Graphic showing the Wave Engine's repeating cycle

The first full-scale prototypes were developed and tested at the University of Maryland in 2016. An initial seed round in 2018 raised US$1.45 million, followed by development funding from DARPA to the tune of $3 million. The company then took to the air with the first manned aircraft demonstrator in 2020 – where the prototype engine was reportedly engaged mid-flight. The US Air Force Armament Directorate added a cool million to the development pot in 2021, and a second seed round in 2022 brought in another $3.5 million from the private sector.

Wave Engine Corp demonstrated a prototype engine mounted atop a glider in 2020
Wave Engine Corp demonstrated a prototype engine mounted atop a glider in 2020

Now Wave Engine's first product has been launched in the shape of the 55-lbf-thrust (245-N) J-1, which has been used as the sole powerplant for a 100-lb (45-kg) Conventional Take-Off and Landing unmanned aerial vehicle (UAV) dubbed the Scitor-D. This time the test flight included remote start using liquid fuel, self-powered take-off, climb-cruise, mid-air engine stops and landing. Ear protectors at the ready for the video below!

Wave Engine Corp. Flight Video

The J-1 engine measures 5.5 x 12.5 x 64 in (14 x 32 x 163 cm) and tips the scales at 18 lb (8.2 kg). It's reported capable of running on gas (87 Octane), ethanol-based biofuel (E85), and kerosene-based fuel (Jet-A/JP-8), and is said to have demonstrated fuel efficiency to rival turbine-based engines (at under 2 lb/lbf-hr), though development continues and performance is expected to improve.

"We continue to push the performance and flight envelope," said Daanish Maqbool, CEO of Wave Engine Corporation. "We have worked for years to harness the power of sound and fire, and we believe it is going to change the industry."

Pricing has not been revealed, but Wave Engine told us that its technology "is a general purpose one that is suitable for military and the commercial sectors. At present, we are mainly seeing interest from military customers and partners in utilizing this technology for attritable aircraft. Ultimately, we believe this technology will also enable new classes of aircraft for civil markets." A 220-lbf (978.6 N) K-1 engine designed for aircraft up to 1,000 lb (450 kg) is also in the works.

Source: North American Wave Engine Corporation

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7 comments
7 comments
TechGazer
Even without weapons, sending these drones over enemy troops might ruin their day with noise, and use up ammo firing at the pesky things.

Please don't allow these engines to be used near populated areas, or even in nice quiet wilderness areas.
Global
Sounds very similar to a prop engine, but how is the thrust control?
Uncle Anonymous
Interesting.

Considering the noise a pulse jet makes, only the military would be interested in these units. I just can't see these in use for general aviation.

As for the video with Colin Furze, there's an old axiom: "Continually doing things where there is a slim chance of disaster will, compounded over time, inevitably result inn a disaster. Why? Because the universe doesn't care about how much fun you are having."
dandandan
It’s like a V1 with modern avionics! I hope they don’t fly them near nursing homes in the south of England!
martinwinlow
Yup... Not going to do anything to improve the image of GA in the context of noise, is it?
GdB
Ukraine needs this tech ASAP
GdB
I seems like airframe integrated performance could be improved enormously with a fairing and simple moving/rotating intake/exhaust mode device at each port to optimize flow energy and minimize drag.