Cost effective ultra-efficient VTOL aircraft Genesys X-2

Introduction

Recent advances in aircraft propulsion indicate a direction of development geared towards partial (hybrid) or total electrification. Over the past two decades, several key technologies for power systems and drive systems have matured to the extent that power and energy density have become suitable for a big part of aerospace applications and missions. The power density and reliability of the electric motors and drive electronics have become viable, leading to the industry's interest in aerospace propulsion systems.

Moreover, there is a need for a multi-purpose general aviation aircraft with the ability to take-off and land vertically. In particular, the passengers and freights transport would benefit tremendously from the ability to pick up from otherwise inaccessible locations, thus helping people of worldwide to reach quickly their destination.

Unfortunately, the development and production costs for VTOL aircraft are very high. An obvious way to reduce these costs is to use components from the existent aircraft. Reusing a larger and highly complex component induces lower costs of development and production.

?A big part of the current electric VTOL concepts seems to be very inefficient, making an unsatisfactory compromise between the two mode of operation, respectively the vertical flight and the forward flight.?This induces an increased size of the energy source, reducing the range and the payload.??

?The new VTOL aircraft concept GENESYS X-2 with Distributed Electric Propulsion

?Our company Skynet Project is developing a new concept, respectively an ultra-efficient VTOL aircraft GENESYS X-2 which has a published patent application.

Distributed electric propulsion (DEP) is an emerging set of technologies which enable new vehicle configurations by allowing the efficient distribution of many thrust producing elements around the airframe. One pathway to achieving this is by placing many electric motors and propellers along the leading or along the trailing edge of the wing, an arrangement referred to as a DEP blown wing. This arrangement increases the effective lift of the wing through interaction of the propeller slipstream with the wing and with the trailing edge flap.

Previous blown wing concepts, based on large propellers or turbine engines, were mechanically complex and adopted only for specialized applications. A DEP blown wing offers a simpler and potentially more efficient way to enhance the high-lift capability of wing.

Several different systems have previously been developed where power added to a wing-flap system significantly increases the effective lift coefficient. In the existing literature such systems are generically termed "powered-lift" configurations, although the meaning of that term has evolved; currently it describes any aircraft with VTOL capability that is also capable of wing-borne flight.

Lift-enhancing powered-lift systems can be broadly divided into two categories.

The first uses interactions between the wing and a tractor propeller slipstream to augment the lift of the wing. These systems are commonly called blown lift, blown wing, or deflected slipstream vehicles.

The second category uses the interaction of a pusher propeller with aerodynamic surfaces to provide the lift enhancement. These systems can be referred to as augmenter wings, or blown flaps.

The present concept GENESYS X-2 combines efficiently the blown lift with augmenter wings, optimizing the propeller-wing interaction to improve high-lift system performance.

GENESYS X-2 is a practical solution which uses a set of eight propellers, four of them being located in front of the aircraft center of gravity and below the wing and four of them being located behind the center of gravity of the aircraft and above the wing as is shown in figure 1.

Fig. 1

Four propellers are of tractor type and four propellers are of pusher type. The pusher propellers have articulated blades. Four propellers are located along the leading edge of the wing and four propellers are located along the trailing edge of the wing. The left propellers are sustained by a simple left frame and similarly, the right propellers are sustained by a right frame. Both left and right frames are rigidly mounted with a shaft which is suspended inside the fuselage, being located preferably in the center of gravity of the aircraft. The shaft is acted by at least an actuator controlled by a computer. The wings present at them external sides two winglets operating as jet limiters for the air flow which blows the wings. GENESYS X-2 may have preferably a standard fuselage obtained from an existent fuselage of a conventional take-off and landing -CTOL aircraft, which comes also with its retractable landing gear. This reduces enormously the development costs and speed up the certification process.

In operation, GENESYS X-2 tilts the entire propulsion system around the center of gravity to manage different flying phases. The wings are blown by the air flow favorable accelerated by the propellers over the entire dimension of the wing span.

In take-off and landing position the propellers are slightly tilted forward as is shown in figure 1. After take-off the landing gear is retracted inside the fuselage as is shown in figure 2.?

Fig. 2

In the transition phase, which is the costliest in terms of energy consumption, the propellers are all tilted to the front as is shown in the figure 3.?

Fig. 3

In this position the lift increases significantly due to propeller-wing interaction. The front propellers produce a substantial increased pressure under the wings and the rear propellers produce an increased suction over the wings, even at low horizontally speed. So the size of the embarked energy source can be reduced substantially.

In forward flight operation the propellers reach an almost vertically position as is shown in figure 4.

Fig. 4

At the cruising speed the aircraft must maximize its efficiency and consequently the four pusher propellers are deactivated as is shown in figure 5.

Fig. 5

In this case the blades of each pusher propellers are forced by the strong air flow to align with the electric motor axis and this reduces drag.

The aircraft can use different control surfaces as flaps to improve the control.

The redundancy level of a VTOL vehicle with eight propellers is obvious, so is not necessary to be explained. But GENESYS X-2 has a supplementary feature because in emergency cases the vehicle ca land as conventional aircraft using the landing gear.??

Moreover, a variant of GENESYS X-2, with diminished power requirements (around 50%), can be used as ultra-short take-off and landing-USTOL aircraft. In this case the certification process is much shorter.

The energy source of GENESYS X-2, transporting 7-8 passengers, can be a battery package, but in this case the speed (250 km/h) and the range are limited (around 400 km), depending on the energy density of the batteries.

A first alternative is a hybrid energy source with fuel cell, turbine engine or internal combustion engine. All of these sources can be operated with carbon neutral fuels like hydrogen or ammonia. The choice of energy source is based on its availability, power density level and specific fuel consumption. The fuel tanks and the batteries can be optimally located in the wings which are “liberated” by the components of the propulsion system and can be structurally integrated.

Using a hybrid energy source associated with a buffer battery package, the speed can increase to around 350 km/h and the range to around 1400 km. This range is absolutely convenient for most of the European countries but also with the travel between neighboring countries.

In another variant GENESYS X-2 can be supplied with electricity in motion from an infrastructure developed on the ground. This is a so called dynamic charging. The electric power flow is variable depending on the conditions, including also possible phases with power flowing from the on-board energy storage and the grid to the on-board traction system. The vehicle might travel at a variable speed while power transfer level would be real-time responsive to vehicle power demand or the condition of the electric grid/distribution system, within the constraints of the system capability or other fixed parameters. Charging commences automatically (or with pilot-confirmation for the manned vehicles) from within the vehicle as soon as the vehicle enters a charging zone on the infrastructure.

In the underside of the vehicle is unrolled a kind of telescopic pantograph, integrated in the vehicle aerodynamics when the vehicle flies outside of the infrastructure. The pantograph is extended when the vehicles is approaching on the infrastructure. In the next phase the pantograph is coupled with the infrastructure and the vehicle begins to use the external source of energy instead of its internal resources and concomitantly recharges its batteries. as is shown in figure 6.

Fig. 6

The infrastructure contains mainly two polarities isolated electrically between them and is suspended from the ground with some pillars to keep the environment in a clean state.

In principle, dynamic charging solution allows power to be continuously supplied to the vehicle from an external source, thus enabling a significant reduction of the on-board battery size and, at the same time, reducing virtually to zero the time the vehicle needs to stop for the recharging operations and the related range anxiety.

The reduction in battery size allows a lighter vehicle to be realized in comparison to other electric aircraft. A reduction is therefore expected in terms of energy required for thrusters and related CO2 emissions. In addition, CO2 emissions related to the energy required for the production of the battery should also benefit from a reduction of the size of the on-board pack.

On the other hand, the infrastructure cost of high speed train as TGV is between US $5 bn and $7 bn/100 km. Other emerging concepts as Hyperloop are highly more expensive. All these transport systems suffer from flexibility and the passengers must combine different means of transport to reach their destination.

In our case the cost is a fraction of TGV infrastructure cost and the system is environmentally friendly. With this transport system in place, the electric aircraft can fly as long as the infrastructure is extended. The destination can be reached with a single transport means, saving time and money.

The table below (fig. 7) shows the performance estimation for a 7-8 passenger GENESYS X-2 with an available hybrid propulsion (internal combustion engine range extender) and with dynamic charging.

GENESYS X-2 is a scalable concept and can be achieved in a size of a small drone, but also as a large aircraft.

The traditional way of determining the efficiency of vertical flight and hovering is to consider the power loading of the vehicle. This is a simple ratio between the weight of the vehicle and the available power. Another method of measuring hover efficiency is disc loading, i.e., Weight of vehicle / Area of thrust producing structure. A VTOL aircraft with high power loading and low disc loading is the most efficient at hovering, which is the case for GENESYS X-2, as is shown in Figure 8.

?Fig. 8

GENESYS X-2's new architecture combined with the use of existing standard components induces several advantages for the general aviation:

o Reduced development cost with around 50%

o Reduced manufacturing cost with around 40%

o Reduced complexity and consequently reduced maintenance costs

o Multi-mission capability because the same aircraft can operate as VTOL, USTOL or CTOL

o High efficiency in hover and transition due to blown wings

o High efficiency in forward flight due to blown wings and propeller deactivation

o Improved redundancy

o Increased efficiency due to hybridization (with 30% said NASA)

o Need much less power to take off and land, determining improved disk loading and hover efficiency compared with existent VTOL solutions

o Scalability of the design from drones to large aircraft

Market opportunities

o Vertiport to vertiport ?transportation

o Fast deliveries for commercial and medical purposes

o Medical emergency services

o Re-supply of offshore oil and gas platforms

o Inaccessible regions delivery

o Aerial fire-fighting

o Spreading substances in agriculture

o Rapid deployment of troops and cargo from remote locations all over the world including from naval locations

o Pollution and traffic monitoring

Contact info:

E-mail: [email protected] ?[email protected]