JetQuad: Quad-Turbine VTOL Drone

Introducing the world's first smallest and most powerful jet-drone with vertical take-off and landing capabilities: AB4 JetQuad

AB4 JetQuad Drone Features
AB4 JetQuad Drone Top-View

Propulsion

Four identical Microturbines (small jet-engines) power the JetQuad. Each turbine generates 25 Horsepower and is about the size of a large soda can. The total power output of the drone at full throttle is 100 Horsepower. This is a significant amount of power considering the fact the drone is just under 2-feet in diameter and is about 2-feet tall. These turbines consume ordinary Diesel fuel and once ignited produce very consistent amounts of power for prolonged periods of time.

 

JetQuad Propulsion - Four Microturbine Jet-Engines

Control

The drone utilizes four proprietary Thrust Vector Systems (TVS). A centralized Flight Control Computer fuses data from a multitude of sensors which include GPS, Lasers, Gyroscopes, Accelerometers, and Cameras. Advanced algorithms built-in to the computer control the four TVS and four engines. A companion-computer provides Guidance and Obstacle Avoidance.

 

Payload

The JetQuad can lift payloads up to 30lb in weight. The user may mount the payload in a variety of locations: on-top, beneath, on the side, or in front of the drone. Furthermore, the payload can contain additional fuel tanks, robotics arms, sensor kits, or delivery packages. The microturbines of the drone generate a total of 100 Watts of power. The payload system has access to this power and can use it throughout the entire flight.

 

Performance

With a 30lb payload, the drone has an endurance of 8 minutes. However, the jet-engines allow the drone to reach a top-speed of 300mph at an altitude of 500ft (FAA Regulations). Consequently, in 8-minutes, the drone can easily cover a maximum 40-mile distance. Further development of engines and prototype will greatly increase this performance. In addition, the lack of wings, air-foils, and control surfaces means the drone is very stable in adverse weather conditions. Finally, the drone can operate at very high altitudes (up to 2-miles) thanks to the high compression of the turbines.

Airframe

The JetQuad is designed to be both light and very tough. Made from a combination of Carbon Fiber and Aluminum, we created a truly industrial drone that can withstand the harsh environments encountered across the world. There are no wings, air-foils nor blades exposed on the exterior of the drone. This means that the drone has higher resistance to impacts and adverse weather conditions.

FanQuad - JetQuad Electrical Simulator

When we throttle up a turbine, we encounter a phenomenon called "turbo-lag". This is the amount of time it takes the turbine to spin-up to whatever RPM value we demand. Consequently, this greatly diminishes the response time of the engine. As a result, it is very difficult to program an adequate control system to allow for stable flight. The control system must consider the slow response of the turbines and the high-response of the Thrust Vector Systems. Before doing any tests with the jet-powered drone, we built an Electrical Simulator (called FanQuad). It is a small-scale version of the JetQuad, and instead of Jet-Engines, it is powered by Electrical Ducted Fans (EDF). The FanQuad has greatly helped us tackle the control system issues. Regard the video below for a field-test of the FanQuad Electrical Simulator.

How does the JetQuad outperform conventional electrical drones?

To answer this question, let us familiarize the reader with two important physical concepts - Energy Density and Power-to-Weight Ratio. Thanks to the use of Diesel, as opposed to Lithium-based batteries, JetQuad has a higher Energy Density when compared to an electrical Multicopter of similar weight. Furthermore, the JetQuad has a very high power-to-weight ratio because the jet-engines are turbine-based.

Energy Density

The energy density measures Energy storage in a unit mass. It has units of MJ/kg. JetQuad uses Diesel fuel which has Energy density of 40MJ/kg. Electrical drones use solid Lithium-based batteries which at most, have an energy density of 1MJ/kg. This means that for the same on-board mass of fuel (or battery) storage, the JetQuad stores 40 times more energy than the equivalent electrical Drone. Of course, jet-engines are heavier then electrical motors. However, they have much higher power-to-weight ratio, so this penalty is insignificant. The US Department of Energy (DOE) has recently initiated a 5-year research to develop the next-generation battery technology. DOE targets to achieve energy density of 3MJ/kg energy density. This is still 1/10 of the energy-density of Diesel. As a result, the JetQuad will remain competitive for many years to come.

Power-to-Weight Ratio

The power-to-weight ratio determines how much power a given engine outputs for a given mass of that engine. Electrical drones have a large penalty in this regard. The Brushless electrical motor, on its own, has a very large Power-to-weight ratio. But, when added with the weight of propeller, Electronic Speed Controllers, and Batteries, this ratio is greatly decreased. Turbine-based engines, like jet-engines, do not suffer from this problem. More specifically, the JetQuad uses Microturbines - small jet-engines that can run at 150,000RPM. This is an ultra-high rotation rate and leads to vast amounts of power produced from a small engine. In addition, electrical drones must limit current flow to prevent overheating of electronics that support smooth motor operation. In contrast, fuel flow-rate is the limiting factor for turbine-based engines. It gives, jet-engine designers the flexibility to extract much more power from smaller motors.

Potential Applications

The JetQuad drone has the potential to revolutionize a variety of industries. The key markets that could greatly benefit from the advantages of the JetQuad are: Medical, Maritime, and Construction.

Medical

JetQuad can provide ultra fast transportation of medicine or organs between hospitals in a metropolitan area, roof-top to roof-top. The drone can easily re-use the existing infrastructure of helicopter landing-pads.

Maritime

It is imperative to protect large ocean-crossing container vessels against shallow waters, adverse weather conditions and piracy. A JetQuad drone can be permanently stationed on the ship and provide 24-7 automated surveillance of the surroundings areas.

Construction

Need to lift a heavy bucket of cement to the top floor of a sky-scraper? Renting out a crane or a helicopter may be simply out of questions. A heavy-lift JetQuad may be easily leased for an hour, delivered on a back of a pick-up truck to get the job done.