How to fly as simply and ecologically as possible? Who hasn't dreamed of it one day? From Icarus's wings of wax and feathers to the technologies that now allow man to leave dry land, considerable progress has been made. Unfortunately, as enthusiasts of the subject know, these technologies are often energy-intensive and therefore not very ecological.

This is one of the issues that Christophe Martz has addressed to create the disruptive Dragonfly paramotors, equipped with 2 counter-rotating electric motors. This configuration improves machine efficiency, reduces CO90 emissions by more than 2% and offers many other comfort and safety benefits.

Discover Dragonfly Paramotor, the best electric paramotor in the world in terms of energy efficiency.

Dragonfly: the origin of this disruptive and original project

In 2016, Christophe, paraglider and paramotor pilot since 2012, goes to the Icarus Cup, a global air sports event that takes place every year near Grenoble for a few days. There he discovered a project for an electric paramotor with 4 propellers in a cage that announced very, too, promising figures. Unfortunately, the verification calculations he carried out in the following weeks actually revealed the lack of feasibility of this project.

But Christophe is an engineer and is pugnacious, and, in the middle of theoretical calculations, he wonders if it was possible to find a more energy-efficient configuration. The Dragonfly project was launched!

We will have to wait another 5 years to arrive at the first test flights, carried out at the end of 2021. 5 years was the time needed to find the batteries, the motorization and the accessories (like the throttle) adapted and efficient enough to meet the strict specifications defined by Christophe. It was out of the question to arrive at a twin-engine machine which did not present a significant improvement in performance while not doing no compromise on security. It was also obviously necessary to make a chassis that was strong enough and light enough.

All of this has been rigorously tested for hundreds of hours on test benches or during ground tests before the very first flight. Aeronautical design is one of the fields the most rigorous of engineering.

To learn more about the origin of Dragonfly, you can read on the official website the full history of the project on the Dragonfly website

But how does a Dragonfly paramotor work and what are the advantages?

First, let's review together the overall operation of a paramotor. If you are familiar with the world ofULM (Ultra Light Motorized) you can skip this paragraph which only covers a few basic concepts.

Composed ofa paraglider type wing, also sometimes called Sheer, the paramotor is distinguished from the paraglider by the presence of a motor which allows it to take off directly from the ground and gain altitude thanks to the thrust of its engine and possibly thanks to thermals as in paragliding. The wing is connected to the pilot's harness by hangers, these are the "strings" that can be seen between the pilot and the wing. The wing is piloted using 2 control handles, also called brakes, which are connected to the trailing edge of the wing and which deform it to initiate a turn. A paramotor is said to have 2 axes because the roll and yaw are linked. A frame connects the engine, harness and wing. It also protects the latter from the motorized elements and the rapidly rotating propeller.

The paramotor is the lightest, simplest, most easily transportable and storable and most economically accessible motorized aircraft.

Now let's see what characterizes a Dragonfly paramotor. A paramotor can be motorized in 2 different ways:

• With a thermal engine that consumes gasoline (paramotors Thermal)
• With an electric motor that uses energy stored in batteries (paramotors Power)

Thermal paramotors create air pollution and CO2 emissions and other constraints linked to thermal engines (noise, odor, starting problems, maintenance, etc.)

Electric paramotors eliminate some of these constraints and direct air pollution but are not not performing well enough at present to be able to compete with thermal paramotors on certain critical points for pilots: machine weight and autonomy.

The goal of Dragonfly is to provide a high-performance electric paramotor while eliminating the constraints of thermal engines. To better understand the ecological impacts of using paramotors, you can read this article specifically dedicated to carbon footprint of a microlight paramotor.

The configuration of the Dragonfly is based on a series of calculations aimed at giving it better aeronautical and propulsive efficiency. This determines the device's ability to fly for a long time without increasing its energy consumption. Good propulsive efficiency also improves take-off speed. Thus, the Dragonfly was designed to operate with two propellers rather than one, and therefore with two motors. We are talking about systems. twin rotors or twin-engine

The great technical specificity of Dragonfly is the lateral offset of the propellers ! On a classic paramotor, the single propeller is located behind the harness and the protective cage. During flight, the pilot is then in the path of the air passing through the propeller, which considerably increases the disturbances of the air arriving in the plane of the propeller. As a result, the efficiency of the propeller is degraded: the engine needs more power to provide the same thrust and energy consumption increases.

On the Dragonfly, the two propellers are offset laterally, they are therefore not, or much less, obstructed in flight and disturbed by this phenomenon.

This little aeronautics course on propulsive efficiency allows you to quickly understand why a twin engine is always more efficient than single engine.

Also, the two propellers of a Dragonfly paramotor are said "counter-rotating". Which means each propeller turns in a different direction. This configuration avoids certain drawbacks inherent in single-engine aircraft, in particular the engine couple.

Advantages of a twin-engine Dragonfly in video

This short video summarizes the advantages of a twin-engine paramotor in less than a minute:

What are torque effects and gyroscopic effects?

On a classic paramotor, equipped with a single propeller, when it turns, it causes what is called a torque effect. That is to say that the paramotor will tend to want to pivot therefore turn in the opposite direction to that of the propeller. This effect is of course not desirable in flight because it will degrade the performance of the machine and especially on a paramotor, because it is a very light machine. On single-propeller paramotors, the torque effect is generally attenuated (but never removed) using various technical means such as, for example, an asymmetry of the attachment points to the wing.

On a Dragonfly, there is no torque effect so no torque effect worries! In fact, as the two propellers turn in opposite directions, the torque effects caused cancel each other out. Thus, the paramotor turns both right and left, which provides additional flight comfort and safety. The absence of torque allows for faster take-off as you can see in this video of a Dragonfly take-off:

The gyroscopic effect is the effect that aims to maintain in position the axis of rotation of a rapidly rotating mechanical part. Without the gyroscopic effect, bicycles and motorcycles would not be able to maintain balance. For them it is an advantage, in the air it is rather a disadvantage.

On an aircraft, the gyroscopic effect of the single "engine-propeller" will reduce the maneuverability of the aircraft: that is to say its ability to change direction (quickly) and the gyroscopic precession will cause involuntary movements for the pilot.

We understand it perfectly in this explanatory video:

In some cases the gyroscopic effect can be an advantage: for example, when flying in a straight line your single-engine aircraft can be less sensitive to turbulence and the precession can be used to improve the handling of certain trajectories, it can be exploited by pilots in aerobatics for example.

But on a paramotor, with a flexible wing and above all offset several meters from the axis of the gyroscope, the Gyroscopic effects have only disadvantages because the gyroscopic effects will apply mainly to the harness.

As a paramotor is very light and its wing is flexibly mounted on the wing then the gyroscopic precession cannot be attenuated by the wings or by pilot action on the rigid wings of an aircraft. The gyroscopic precession will therefore create involuntary movements on the paramotor chassis independently of the wing (or almost). It can create movements that can be dangerous via a moment perpendicular to the axis of rotation of the propeller. And this moment can discharge the tension applied to the wing and cause a loss of lift which can lead to a crash.

This video explains these two effects on a paramotor in more concrete terms, going as far as a crash as in the first seconds of the video:

Gyroscopic and gyroscopic precession effects are greatly attenuated with the twin-engine contra-rotating configuration of a Dragonfly paramotor. Explanations…

Gyroscopic and precession effects on a counter-rotating twin-engine aircraft attenuated

1. Gyroscopic effects : Each rotating propeller creates a gyroscopic pendulum. In a system with counter-rotating propellers, the gyroscopic moments of the two propellers rotating in opposite directions can partially compensate each other, thus reducing the overall effect on the aircraft.
2. Gyroscopic precession : Gyroscopic precession is the phenomenon by which a gyroscope (such as a rotating propeller) responds to a force applied to its axis of rotation by moving perpendicular to the direction of that force and its axis of rotation. In a system with counter-rotating propellers, the Precession forces generated by each propeller can also partially offset each other, reducing the overall effect of precession on the aircraft.

Although contra-rotating propellers can reduce gyroscopic and precession effects, they do not completely cancel them out. The specific configuration and design of the aircraft, as well as the position and orientation of the propellers, play a crucial role in managing these effects. Designers must take these factors into account to optimize the stability, handling and safety of the device.

In summary, non-coaxial counter-rotating propellers can reduce gyroscopic and gyroscopic precession effects, but do not eliminate them entirely. Aircraft design must be carefully considered to optimally manage these effects. Which seems to be the case for Dragonfly paramotors.. To learn more you can read this more detailed article on torque and gyroscopic effects in aeronautics.

What are the advantages of a Dragonfly paramotor?

In summary, the advantages of a counter-rotating twin-engine configuration on a paramotor or other aircraft are as follows:

• a better propulsive efficiency and therefore a best machine performance and lower consumption
• Lower consumption allows the use of smaller batteries, therefore lighter (one of the 3 prototypes weighs only 24 kg, which is an electric feat. It can fly for around 30 minutes)
  
• As the batteries are smaller, the total weight of the machine is reduced for the same autonomy. Note: Current electric cars have not been optimized for machine efficiency, we have simply changed the energy chain without making a dedicated design. Electric cars are therefore generally heavier than thermal cars.
• absence oftorque effect et reduced gyroscopic effects
• improvement of safety and comfort during take-off and in flight : shorter takeoffs and 100% symmetrical handling
  
• active safety by flight controller and dedicated firmware : Dragonfly detects falls, abnormal angles and accelerations and possible engine failures or propeller damage.
• smart phone app which improves rider comfort and safety
• folding machine plus easily transportable and storable (see details below)
• aeronautical lighting (red and green)

What are the advantages of electric (aeronautical) propulsion in general?

The use of electricity also allows other advantages not specific to twin-engine (both types of advantages are cumulative on a Dragonfly):

• No gasoline to carry, no mixing to be done (thermal paramotors overwhelmingly use 2-strokes)
• No odors during transport, storage or use
• No risk of hydrocarbon pollution floors (full, crash, etc.)
• Reduction of direct pollution:
  • 95% CO2 reduction (emissions less than 20g/km for the Dragonfly)
  • no smoke and unburned matter (fine particles)
  • reduced noise level: An electric paramotor is less noisy especially for others over 150m.
• Solar charging or renewable source of batteries
• Less vibration  : improved comfort and reduced rider fatigue
• Reduced maintenance compared to thermal systems: the only wearing part is the battery.
• Extended life of electric motors which wear out less than 2-stroke thermal engines
• Hourly energy cost divided by 10 (see below)

A cost per flight hour divided by at least 10

A classic thermal paramotor will consume on average 5 to 10 € of fuel per hour of flight (this can go up to 15 to 20 € for very powerful engines and two-seaters), while a Dragonfly electric paramotor will consume less than 0,5 € of electricity per hour. You will find more figures and data on the page of the technical comparison of the Dragonfly VS thermal paramotor VS electric paramotor

Dragonfly, the fastest and easiest to transport foldable ULM in the world

This is another major advantage of the Dragonfly: it is a fully foldable paramotor that is easy to transport.

Dragonfly was designed specifically to be able to be fully folded and disassembled in just a few minutes (less than 3 minutes once the technique is mastered). This feat is made possible by the integration of multiple pin systems when designing the chassis.

Pins are small safety elements that allow the assembly and maintenance of different parts between them. They do not require the use of tools during assembly or disassembly, which makes them particularly effective for easily transporting the Dragonfly. On the other hand, When folded and lying down, the device easily fits into the trunk of a station wagon.. And if the latter is rather large, it is even possible to bring in two simultaneously, which quickly proves useful to be able to fly several Dragonflies. It's always more fun to send yourself into the air with several people!

The video below shows the assembly and disassembly of a Dragonfly in just a few minutes.

Key Features

After all these technical explanations, a summary of the main characteristics of the current Dragonfly prototypes:

• Energy efficiency 40 to 50% higher to that of single-engine electric models, 40% is a considerable improvement in the field of aeronautics
• A machine zero torque with effects reduced gyros
• Several batteries allowing respectively a capacity of 1.6 or 3.0, 3.2 or 6.0 kWh
• A respective weight of 24, 28kg and 41kg depending on the battery model chosen. The 41 kg model is recommended for trolley use rather than foot take-off
• Folding machine easily transportable and storable

Un detailed comparison of the different prototypes is available on the project website. This comparison is evolving.

Dragonfly invited to the Paris 2024 Olympic Games with the FFPLUM

Dragonfly is already showing itself to the general public and has had the honour of representing, alongside the French ULM Federation (FFPLUM), theiULM innovation at Club France theirs 2024 Paris Olympics.

Marketing and sales price?

The final sales price has not yet been defined, nor the marketing date. Despite the excellent performance compared to the competition, the public tariff should be in the same order of magnitude than the premium single-engine electric or even thermal paramotors on the market. With Dragonfly you will fly with the equivalent of a TESLA at the price of... a GOLF!

Nevertheless, the obstacles to overcome There are still many gaps between prototypes and the development of a marketable machine. Particularly in administrative level, Christophe clearly noted the The dichotomy between media and political discourse and the harsh reality on the ground is important.…and it’s quite sad for innovation and low-carbon flight in France!

Christophe expected difficulties when he embarked on this (slightly crazy) project, but he didn't think he would encounter so many non-technical difficulties. Indeed, if he was able to overcome all (or almost all) of the technical and aeronautical difficulties, other difficulties gradually appeared as the project progressed. But Christophe is resilient and the performances are too good to abandon the project so quickly.

Dragonfly notably received, at the beginning of 2025, a first certification from the DGAC and the Ministry of Transport.

To go further and above all faster, Dragonfly would need new means, sponsorship or assistance from an industrialist or an SME.

2024 recap in video

Are you interested in Dragonfly?

If you are interested in Dragonfly, please feel free to follow on social networks or visit the following pages:

• On the official Dragonfly paramotor website
• Watch videos from the Dragonfly YouTube channel (it is notably possible to watch flights with a Dragonfly)
• On the Dragonfly Facebook page
• On LinkedIn

You can also contribute materially, immaterially or financially to the project. Don't hesitate to contact Christophe directly via the contact form, you'll see he's nice! I promise!