Electrofluidsystems presents their vision for futuristic hyperfast flying wing package drones and air taxis with hydrogen (H2) fuel cells, plasma flow control and bionic Stingray geometry. The idea for a Stingray-shaped electric vertical take-off and landing (eVTOL) flying wing arose last summer and was convincing enough to get the company an invitation as one of 200 startups worldwide to take part at the Teknofest - Takeoff International Startup Summit held September 16 - 19, 2019 at Atatürk Airport Istanbul. At that time the project was still in the very early stages and thus not selected for support in Turkey. Electrofluidsystems now reveals the first details of the more advanced concept which has great potential for a series of new UAV systems (UAS) with the first product on target to enter the market in end of 2021.

Electrofluidsystems originally planned to reveal the first details and eVTOL prototypes with a 1.11 m span width at the UAS Innovation Hub at the Berlin Air Show ILA 2020. However the event was cancelled because of the threat of the novel coronavirus.

The near-term vision for 2021 - 2022 is to have two mini UAS products with a 1.11 m wingspan: 1. PlasmaFalcon 1.11 with 6 - 11 kg maximum take-off weight (MTOW) and 2. PlasmaRay 1.11 with 11 - 18 kg MTOW. There are two types: H2PlasmaRay uses a hydrogen (H2) fuel cell module to demonstrate the technology as a proof of concept, whereby PlasmaRay uses Lithium-Polymer (LiPo) batteries only. For the 1.11 m H2PlasmaRay 1.11 with a 300 - 379 bar internal tank (1 kg) the 0.8-liter volume and 16.5 grams of gaseous hydrogen mass is quite small. The overall specific energy is 110 Wh/kg and thus is lower than that of LiPos with 150 - 200 Wh/kg. 

Nevertheless, the fuel cell technology gets more interesting with the bigger 2.22 m scale model. The specific energy with gaseous hydrogen storage goes beyond values of 300 Wh/kg. Furthermore, there are amazing developments from MetaVista in South Korea and the USA regarding how to use liquid hydrogen for future drone applications. In 2019, MetaVista broke the multi rotor UAV Flight Time World Record by demonstrating a flight duration of 12 hours, 7 minutes and 5 seconds. The multicopter was powered by an 800 W Intelligent Energy Fuel Cell Module and 390 grams of hydrogen stored in a 6-liter liquid hydrogen cylinder for up to 6500 Wh of electrical energy. 

Package Drones H2PlasmaRay 1.11 and PlasmaRay 1.11

The H2PlasmaRay 1.11 is a 1:6 scale model and technology demonstrator for a future air taxi with a 6.66 m wingspan. It is produced with laser sintering and will use an 800 W fuel cell module from Intelligent Energy and a 0.8-liter 300 bar pressure tank with 16.5 grams of gaseous hydrogen as described before. The electrical energy is 275 Wh in gaseous form and 867 Wh in the liquid hydrogen case.

But why do we need hydrogen powered flight vehicles? Today, the aviation industry produces about 115 grams of CO2 per passenger kilometer. This equals about 859 million tons of CO2 emission per year. The contribution to global CO2 emissions is just 2% but it is expected to double by 2030, and we really don’t know the future impact of huge manned rockets for intercontinental and even interplanetary flights such as those promoted by SpaceX. We also don’t know the future impact of rocket-powered suborbital spacecraft as promoted by companies like Virgin Galactic for the growing near-space to space tourism industry. So we need to look for disruptive technologies to replace our present jet engines and chemical rockets, even with efforts that are just step by step. Fuel cell technology is one way to reduce CO2 emissions. It is a technology which presently provides more specific energy than average LiPo-batteries with 150 - 200 Wh/kg.

Also, more powerful solid-state batteries are already on the way: Samsung recently unveiled new solid-state lithium metal batteries with an estimated specific energy of 360 Wh/kg. Other companies like TeraWatt Technology even announced a record-breaking specific energy of 432 Wh/kg (1122 Wh/l). Sion Power even talks about 650 Wh/kg. These new batteries will be commercially available in a few years from now and then they will help companies like Lilium to meet their goals which may be challenging  today, but will certainly be possible in the near future. Just imagine, the limitations we may face today can change tomorrow as our ideas evolve based on new innovations such as the next generation fuel cells with 960 Wh/kg from HyPoint. Today, we are just now on the path to build electric drones which can fly 300 km at 300 km/h speed with a useful payload of 300 kg. Joby Aviation and Lilium might already cover two of those three parameters that we all dream of. To cover all three, we combine a drag reduced flying wing design with a state-of-the-art hydrogen fuel cell technology from Intelligent Energy with at least 350 - 450 Wh/kg. 

With the use of liquid hydrogen tanks those “dream“ parameters can be even extended from 300 to 1000 km and beyond to cover longer business routes like Munich and London. We will see further details on this later in the discussion of the H2PlasmaRay 6.66. On the way to developing hyperfast air taxis we plan to use all scale-models from 1:6 (11 - 18 kg MTOW), 1:4     (25 - 40 kg MTOW), 1:3 (70 kg MTOW) to 1:2 (210 kg MTOW) as commercial package drones.

Wingcopter for instance is the fastest fixed-wing mini drone with a Guinness World Record of 240 km/h. It is presently also the drone with the best weight-to-payload ratio among fixed-wing VTOLs on the market. The PlasmaRay 1.11 (18 kg MTOW) and the bigger PlasmaRay 1.66 (25 - 40 kg MTOW) have the potential to exceed all those numbers, setting new records.

All types will have optional NVIDIA based Artificial Intelligent (AI) swarm controllers with six fisheye cameras to safely fly 6-13 flying wings (Swarm Flyer) in half-diamond and full-diamond formations to reduce the overall drag by up to 65%. More details about our bionic swarm technology will be discussed at the Revolution.Aero Europe 2020 meeting in London.

Today, it is not widely known that even birds use drag-induced electrostatic fields to control V-formation. Other insects like bumblebees apply electrokinetic effects to increase  dynamic viscosity. It is still difficult to understand why they can fly at amazing Himalayan altitudes beyond 7,600 meters (25,000 feet). Here on this topic, our company Electrofluidsystems is truly inspired by nature.

Our motto is: We Make Dreams Fly. For now, the PlasmaFalcon and PlasmaRay UAS do not use electroviscous effects on the micro or nano-scale. But all of our present models already use dynamic corona discharge to control separated air flow at high angles of attack (alpha). Similar critical situations can be also induced at horizontal flight when strong crosswinds start to blow from underneath or come from sideways to induce dangerous flow separation at the outer wings. These are the most critical situations for flying wings. Plasma helps to stabilize.

There are different plasma flow control techniques which are discussed in our scientific papers to reduce drag and increase crosswind stability by 60% and more. Pulsed plasma actuators, for instance, can cause lift enhancement by 25-75 % and drag reduction by 10-20 %. Pulsed electric wind induces rolling cylinder vortices which run over the wings and keep the air attached even at very high angles of attack. At normal cruise conditions there is still some lift enhancement by 10-15 % and drag reduction by 5-10 %. 

These are all techniques which, when necessary, would enable our Plasma Flyers to glide at very high altitudes just by “flapping“ the fields. Special nanosecond pulsed plasma actuators would then be used for anti- and de-icing means. Plasma control techniques will also be used later on PlasmaFalcon propellers and PlasmaRay lift-fans to make them more efficient and operative at high altitudes which now are usually only reachable by MALE or HALE type UAVs.

The mid-term vision for 2023-2025 is to have UAS products with 1.66 m, 2.22m, 3.33 m and 6.66 m span width as 1:4, 1:3, 1:2 and 1:1 technology demonstrators for future hyperfast air taxis H2PlasmaRay 6.66, H2PlasmaRay 8.88, H2PlasmaRay 11.1 and H2PlasmaRay 13.3 Strato. 

Passenger Drones (Air Taxis) H2PlasmaRay 6.66 to H2PlasmaRay 19.9

H2PlasmaRay 6.66 is an electric vertical take-off and landing (eVTOL) air taxi with a maximum take-off-weight (MTOW) of 900 kg. It has a bionic Stingray-shaped flying wing design with two separate propulsion units for VTOL and cruise. A distributed propulsion of 10 Schübeler electric ducted fan (EDF) jets, each 195 mm in diameter,  used for horizontal flight. 38 EDF jets of the same type are used for vertical take-off and landing (VTOL). These jets can generate 950 kg of static thrust in continous mode or 1050 kg for a short period of time. The H2PlasmaRay will have similar landing gears like the new Rhaegal drone of Sabrewing to enable alternative starts from runways and emergency landings on highways. The avionics is inspired by Thales FlytX and will use several touchscreens and a central joystick for optional pilot control.

Future cargo versions will alternatively use six plasma flow controlled lift-fans for eVTOL-mode in a similar way as shown by Valkyrie Systems Aerospace for the Eagle Hoverjet.

Lilium previously worked on a 2-seater with about a 6 m wingspan. Beside you can find estimated parameters of the Lilium prototype compared with our 2-seater H2PlasmaRay 6.66. 

The next bigger H2PlasmaRay 8.8 will be a 5-seater with an 8.8m wingspan and 1,850kg MTOW as a direct competitor to fast flyers like Joby Aircraft S4 and Lilium Jet. A cargo version could easily carry 1,000 lbs (454 kg) and would be a short to mid range competitor to Rhaegal RG-1. H2PlasmaRay 11.1 would have a MTOW of 3,000 kg, H2PlasmaRay 13.3 of 5,700 kg, LH2PlasmaRay 18.0 Strato of 10,500 kg and LH2PlasmaRay 19.9 Strato of 13,500 kg with a cargo volume of up to 4.5 tons when used as long range transport drone. 

The specific energy is 378 Wh/kg with gaseous and +1,000 Wh/kg with liquid hydrogen. H2PlasmaRay 6.66 – 250 / 300 could store about 12 / 18 kg of liquid hydrogen which would provide about 200 / 300 kWh of electrical energy. So, a LH2PlasmaRay 6.66 - 250 / 300 would have an amazing range of 1,000 / 1,300 km. Just imagine the range of a LH2PlasmaRay 19.9.

‘Water will be the coal of the future.‘ Jules Verne, The Mysterious Island , 1874.

About Electrofluidsystems

Berkant Göksel is an innovator, entrepreneur and futurist with over 20 years of expertise in cutting-edge aerospace, energy and plasma engineering. He has a MSc. equivalent Diploma in Aerospace Engineering from Berlin Technical University and will complete his Doctoral Study in Energy Process Engineering from Berlin Technical University in summer 2020. Berkant previously worked as research scientist at Berlin Technical University.