Aerial Urban Mobility Rankings (2020 Update)

A version of this article first appeared in our free newsletter, to subscribe click here

I will start this article with an explanation of how the rankings are generated, then show the results of the rankings.

At the end I will give some advice based on my experience of working in the field for a number of years. 

Here we go…

Preamble
The rankings are based on a weighted score system that I have developed to represent the best of my knowledge and experience regarding technical, certification and commercial (market) risks.

This method has my own bias baked into it (despite my best efforts) and I welcome any challenge or disagreement. 

The aim of this effort is not to make people feel bad or harm any project. However, there are certain unavoidable realities regarding the certification process, the cost of developing and producing complex air vehicles and the unusual nature of the market regarding aircraft purchases and the flying public.

There are always winners and losers, and, in aerospace development there are no participation trophies. The failure of a program represents the loss of most, or all, of the value of the investment in that failed program. 

The purpose of these rankings is not to identify those who will fail. I do not claim to be able to tell the future. The rankings are all relative so all the programs may fail or all of them may succeed. However, the rankings represent my best guess at the relative risk of failure of all of the programs considered.

You are welcome to address any comments to me directly at rabbott@abbottaerospace.com

And a final word: I work with many of the eVTOL programs in this list. I have done paid work, pro bono and informal advising and technical work for many programs. It is a privilege to work with all of these programs. They are all doing their best to push the industry forward and develop new forms of transportation. I have done my best to avoid my relationships to any of these programs influencing my assessment.

The Assessment
The assessment is based on a modified set of weighted factors based on the white paper I authored in 2018: https://www.abbottaerospace.com/wpdm-package/aa-wp-2018-001/

I have updated the weighting and the method. If you are interested in the method please contact me for more information.
The assessment is broken down into the sub categories on the vertical flight society website. These are: Vectored Thrust, Lift + Cruise, Wingless Multicopter, Hoverbikes and Electric Rotorcraft.

These categories are all scored against the same metrics and so vehicles in these separate categories can be compared against each other.

A good number of the vehicles included in this assessment are pure technology demonstrators or early prototypes. For these immature designs, the outcome of my analysis and final placing is unkind and these projects are included for interest only.

The assessments are based on the state of current technology and the current regulations and interpretation. These rankings are not a criticism of the inherent value of the idea, it is my assessment of the likelihood of the design being brought to market and achieving commercial success in the current environment.

Categorical Comparative Assessment
All of the assessments are shown in a 2 dimensional space plotting a derived certification quotient (encompassing technical and regulatory risk – level of difficulty to develop and certify) and a similarly derived market quotient (encompassing all aspects of commercial risk – what is the likely market demand for the aircraft)

The 2D plots are all in the form shown below:

The top right corner of the graph represents a high score for both certification and and market quotients, the lower left hand corner of the graph represents a low score for both certification and market quotients

The comparative assessments within the separate categories are shown below:

Vectored Thrust

Lift + Cruise

Wingless Multicopter

Hover Bikes

Electric Rotorcraft

Summary and Combinations

The different types of VTOL aircraft when combined on the same graph give the following result:

And this is the same graph showing the projects with labels:

All projects considered and their scores are shown below in score order:

PositionScoreProject
10.662Transcend Air Vy 400
20.655Dufour aEro2
30.624Flexcraft
40.612DeLorean Aerospace DR-7
50.560Samad Aerospace Starling Jet
60.554Pegasus Universal Aerospace Vertical Business Jet
70.481Cartivator SkyDrive
80.466Ascendance Flight Technologies Atea
90.457Lazzarini Hover Coupé
100.454XTI Aircraft Trifan 600
110.407Alaka’i Technologies Skai
120.388Gizio EJ420 ElectroJet
130.386Vertical Aerospace (unmanned)
140.378EHang 184
150.371Beta Technologies (prototype)
160.368Lazzarini FD-One
170.365Moller Skycar M200
180.359EHang 216
190.354Horus Hoverbike
200.345EAC Whisper
210.335Voyzon e-VOTO
220.333AeroMobil 5.0
230.330Frogs 282
240.327Airbus Helicopters CityAirbus
250.318Astro Elroy (“Passenger Drone”)
260.314Imaginactive Ambular
270.304Avioneo Robotics Avioneo 2345
280.300Davies “Tesla Concept Model V”
290.290Alauda Airspeeder
300.290AirCar
310.283Moog SureFly
320.283Moog SureFly
330.280Tier One Modified Robinson R44
340.267China Helicopter Research and Development Institute Electric Helicopter (CHRDI AVIC)
350.266Kármán XK-1
360.263Airflight
370.263Assen A1
380.261Zuri
390.260Bay Zoltán Flike
400.260SkyDrive SD-XX
410.257ALI Technologies Xturismo
420.244Piasecki PA-890
430.234HoverSurf Scorpion
440.213Flyter PAC VTOL 720-200
450.210ALI Technologies Hover Bike
460.210AirspaceX MOBi
470.205Eco’Trip
480.204Edea 22/1 Jay
490.201Jetson Aero Speeder
500.197Air Transportation Technology Catapult One – I, II
510.195Ambular 2.0
520.187UAVOS SumoAir
530.174Assen Aeronautics A2 Avenger
540.174Wisk
550.172Heitech Cruiser
560.170Baykar Cezeri
570.166Baaz Concept Design
580.165SkyDrive SD-02
590.164Aerodyne Vector
600.164Gizio DDRH/DDVL
610.162Ray Research VTOL Aircraft
620.162Removed
630.159Leap Vantage – I
640.156Pop.Up Next
650.156Malloy Aeronautics Hoverbike
660.147Heitech Air F1
670.141Archer
680.136Davinci ZeroG
690.134Zenith Altitude EOPA
700.133Hemanth Sudhakaran AVEM
710.132Aquinea ENAC Volta
720.131PDRL AeroHans 2S
730.131Kovacs Flike
740.125Kronstadt Air Taxi
750.124EVA Valkyr
760.122Flyt Aerospace FlytCycle
770.112Digi Robotics DroFire
780.103Rolls-Royce EVTOL
790.101Lazzarini Linux
800.098Applied VTOL Concepts Epiphany™ FLYING CARpet
810.093Deep Blue Aviation MX 18 Silhouette M
820.092PAL-V International Liberty
830.085Flexcraft Test Bench RPV
840.084Lazzarini I.F.O.
850.084Aston Martin Volante
860.083Ambular 3.0
870.080Overair (Karem) Butterfly
880.079Joby Aviation S4
890.078Gravity X Koncepto Millenya
900.074Zeva Zero
910.072Beta Technologies ALIA
920.071Aurora Flight Sciences PAV
930.070Neo Aeronautics Crimson S8
940.069Vinati F-Helix
950.066EVA X01
960.065Hyundai S-A1
970.064OVER LLC
980.062Skyworks Global eGyro
990.061CAPS
1000.060Samad Aerospace HUMA
1010.058NFT ASKA
1020.057Embraer Pulse Concept
1030.052AirisOne
1040.050Robathan Range Rover eVTOL
1050.047CHRDI AVIC Sylan
1060.045AutoGyro eCavalon
1070.043MyDraco
1080.041Flutr Motors Flutr
1090.037Fraundorfer Aeronautics Tensor
1100.036DragonAir Airboard 1 & 2 – II
1110.030Varon V210
1120.023Moscow Team AI Kamchatka
1130.021SKYLYS Aircraft AO
1140.020VerdeGo Aero PAT200
1150.017SkyCab
1160.015Georgia Tech HummingBuzz – I
1170.012Micor Technologies Variable Geometry VTOL aircraft (VAGEV)
1180.007FanFlyer
1190.006Avianovations Hepard
1200.003Trek Aerospace FlyKart 2 – I, II
121-0.004Grug Group Business eVTOL Jet
122-0.006Uber Elevate eCRM-001
123-0.009Athena Aero
124-0.012Aufeer Design Flying Taxi
125-0.014Tecnalia
126-0.015Moller Skycar M400
127-0.020Prime Design Consultancy Services Haricopter X1-B
128-0.021Flyter PAC VTOL 420-120
129-0.023Embraer DreamMaker
130-0.023ElectraFly ElectraFlyer
131-0.026Manta Aircraft ANN1
132-0.026Heitech Magic Cloud
133-0.034Leap Aeronautics
134-0.043Colugo Systems
135-0.044Macchina Volontis Flying Car
136-0.051Terrafugia TF-X
137-0.051PFV Personal Flying Vehicle #1
138-0.052PteroDynamics Transwing
139-0.053Aliptera ADR-1 Dragon Rider
140-0.054Napoleon Aero VTOL
141-0.056Edea 22/2 Squid – II
142-0.062COMAC eVTOL
143-0.064CycloTech Compound Helicopter
144-0.065Micor Technologies Advanced Individual VTOL Aircraft (AIVA)
145-0.066KARI PAV
146-0.067Swallow VTOL
147-0.080aeroG Aviation aG-4 Liberty
148-0.080Opener BlackFly V3
149-0.081Vickers WAVE eVTOL
150-0.082Ryerson Helium – II, III
151-0.087Esprit Aeronautics Lancer ePAV
152-0.088Skyworks Vertijet
153-0.096Carter Aviation Air Taxi/Jaunt
154-0.097Detroit Flying Cars WD-1
155-0.098LIFT Hexa
156-0.099Doroni Carbon One
157-0.100rFlight rWing
158-0.104Stuttgart Aerospace Apollo
159-0.110Happy Takeoff Prism
160-0.110Jetoptera J2000
161-0.122VRCO NeoXCraft
162-0.124JAXA Hornisse 2B
163-0.125Gizio CellCraft G150
164-0.127AutoFlightX V600
165-0.128Aeroxo ERA Aviabike – I, II
166-0.130VOX Aircraft M400
167-0.132Ray Research Dart Flyer
168-0.134Neva Aerospace AirQuadOne
169-0.140Innowings Aerospace PKOK
170-0.143Horizon AutoCopters Auto-Copter
171-0.145Jaunt Air Mobility Journey
172-0.153Kitty Hawk Heaviside
173-0.161GroundAero Sport Utility Aircraft
174-0.163Electric Jet Aircraft EJ-1S
175-0.174VTOL Aviation Abhiyaan
176-0.175Gizio CellCraft G450
177-0.182SkyBoom eVTOL Automobiles
178-0.183Raven – III
179-0.184B-Technology Beccarii
180-0.184Collaborative Mini-Bee
181-0.185Bell Nexus
182-0.186VTOL Aviation India Abhigyaan NX
183-0.197Lilium Jet
184-0.203Industry Network Cocooon X-1
185-0.204Bell Nexus 6HX
186-0.205EXA Air Car
187-0.212Terrafugia TF-2 Tiltrotor
188-0.216Autonomous Flight Y6S
189-0.228KineticCo Aerospace and Advanced Technologies
190-0.234CFC AirCAR
191-0.235NEAE-GSI eVTOL-BUS
192-0.235Prime Design Consultancy Services Haricopter X1-Q
193-0.238Scoop Pegasus 1 – I
194-0.239HoverSurf Formula
195-0.242chAIR Multicopter
196-0.243Hirobo Bit
197-0.250Urban Aeronautics CityHawk
198-0.251Paragon VTOL Aerospace T21 Raptor
199-0.254Grug Group Ghost X V1
200-0.254Grug Group Ghost X V1
201-0.257Grug Group Ghost X V3
202-0.264AMSL Aero Vertiia
203-0.271Aliptera APV-1
204-0.271GyroBike
205-0.276A³ Vahana
206-0.279Hoversurf Formula (No wing)
207-0.282ACS Aviation
208-0.299Aeronext Flying Gondola
209-0.302Gizio EJ11 ElectroJet
210-0.302CycloTech Passenger Demonstrator
211-0.338Imaginactive Transvolution
212-0.345Bartini Flying Car
213-0.354Sharifzadeh Zero G eCruzer
214-0.358Neoptera eOpter
215-0.374Vertiia
216-0.385HoverSurf Drone Taxi R-1
217-0.417Vision VTOL
218-0.467Advanced System Engineering – FIPSI WX4
219-0.507Advanced System Engineering – FIPSI BX4
220-0.536HopFlyt Venturi

The spread of scores were assessed to determine if the distribution included any anomalies that would indicate an error in the application of the scoring algorithm:

It appears that the application of the scoring method is free of obvious errors.

Summary of Results and ‘Awards’
The top scoring projects are unchanged from the initial assessment made in 2018. The top five eVTOL projects that exhibit the most favourable characteristics for certification and commercial success are:

PositionScoreProject
10.662Transcend Air Vy 400
20.655Dufour aEro2
30.624Flexcraft
40.612DeLorean Aerospace DR-7
50.560Samad Aerospace Starling Jet

Below are high scoring projects in some of the categories that I use for the assessment

Most Beautiful (In no particular order and according to my taste)

Davies “Tesla Concept Model V”

DeLorean Aerospace DR-7

Lazzarini Hover Coupé 

ALI Technologies Xturismo

Most Unusual

Industry Network Cocoon X-1

Robathan Range Rover eVTOL

Volerian

Zeva Zero

Avianovations Hepard

Advice

This is where I sound off on what I think may help improve a project’s chances of getting to market and being successful once you get there.

This section is as populated with my personal bias as the rest of this article, these opinions are all my own. 

  1.  Gatekeepers: You have to get through the certification process. The award of a type certificate depends on a succession of findings of compliance for each paragraph of the regulations. Achieving a finding of compliance relies on the person awarding that finding. Develop your relationships with those individuals. Inspire confidence and over achieve with presenting good quality data in all circumstances. Management of the perception of risk is paramount.
     
  2.  Money: The total cost of development is directly related to the time spent in development and certification. Keep your team small (minimize your $ per hour), expedite your certification program (minimize the total number of hours), reduce risks (minimize the chance of the number of hours increasing). Do not expand your team beyond the minimum size until you have a frozen detailed product specification and an approved certification plan. It is very easy to get into certification, very difficult to get out of it.
     
  3. Batteries: Assumptions of future battery energy density are unwise. Overestimation of present battery energy density is unwise. 250Kwh/Kg may be presently theoretically achievable. For the installed system it never is. Battery charge times and battery lifetimes have to be practically addressed. Thermal failure modes of Li-Po batteries have to be addressed and mitigated. Current installed battery/electrical drive systems are approximately 14 times less weight efficient than a turboprop system burning JetA. 
     
  4. Hydrogen: Great energy density, lousy density. Expensive. No infrastructure. Hydrogen is a form of displaced NIMBY carbon dioxide generation. Your aircraft may be carbon neutral, the supply chain for your fuel is not.
     
  5. Mistakes: Everyone makes mistakes. It is very cost effective to learn from other people’s mistakes, it is very expensive to learn from your own. 

In general, the air vehicle market has proven to be historically very conservative. It is very risk averse. In part this is because of the cost of insuring aircraft and in part because of the flying public’s general low threshold of perceived personal risk.

Just as you have to manage the perception of risk in the mind of the regulator you have to do the same for the insurance market and the minds of your future customers and users. We engineers find innovation very attractive and exciting. Other institutions and individuals do not feel the same way we do. There is some good data on the fear of flying and anxiety regarding flying here: Fear of Flying Statistics (2020 Data)

There is a trade off between promoting the new and exciting and reinforcing the dependable and reliable.

I fear that most eVTOL programs concentrate on the former and ignore the latter and this will harm them both in the certification process and with the customers.

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Aerial Urban Mobility Rankings (2020 Update)

A version of this article first appeared in our free newsletter, to subscribe click here

I will start this article with an explanation of how the rankings are generated, then show the results of the rankings.

At the end I will give some advice based on my experience of working in the field for a number of years. 

Here we go…

Preamble
The rankings are based on a weighted score system that I have developed to represent the best of my knowledge and experience regarding technical, certification and commercial (market) risks.

This method has my own bias baked into it (despite my best efforts) and I welcome any challenge or disagreement. 

The aim of this effort is not to make people feel bad or harm any project. However, there are certain unavoidable realities regarding the certification process, the cost of developing and producing complex air vehicles and the unusual nature of the market regarding aircraft purchases and the flying public.

There are always winners and losers, and, in aerospace development there are no participation trophies. The failure of a program represents the loss of most, or all, of the value of the investment in that failed program. 

The purpose of these rankings is not to identify those who will fail. I do not claim to be able to tell the future. The rankings are all relative so all the programs may fail or all of them may succeed. However, the rankings represent my best guess at the relative risk of failure of all of the programs considered.

You are welcome to address any comments to me directly at rabbott@abbottaerospace.com

And a final word: I work with many of the eVTOL programs in this list. I have done paid work, pro bono and informal advising and technical work for many programs. It is a privilege to work with all of these programs. They are all doing their best to push the industry forward and develop new forms of transportation. I have done my best to avoid my relationships to any of these programs influencing my assessment.

The Assessment
The assessment is based on a modified set of weighted factors based on the white paper I authored in 2018: https://www.abbottaerospace.com/wpdm-package/aa-wp-2018-001/

I have updated the weighting and the method. If you are interested in the method please contact me for more information.
The assessment is broken down into the sub categories on the vertical flight society website. These are: Vectored Thrust, Lift + Cruise, Wingless Multicopter, Hoverbikes and Electric Rotorcraft.

These categories are all scored against the same metrics and so vehicles in these separate categories can be compared against each other.

A good number of the vehicles included in this assessment are pure technology demonstrators or early prototypes. For these immature designs, the outcome of my analysis and final placing is unkind and these projects are included for interest only.

The assessments are based on the state of current technology and the current regulations and interpretation. These rankings are not a criticism of the inherent value of the idea, it is my assessment of the likelihood of the design being brought to market and achieving commercial success in the current environment.

Categorical Comparative Assessment
All of the assessments are shown in a 2 dimensional space plotting a derived certification quotient (encompassing technical and regulatory risk – level of difficulty to develop and certify) and a similarly derived market quotient (encompassing all aspects of commercial risk – what is the likely market demand for the aircraft)

The 2D plots are all in the form shown below:

The top right corner of the graph represents a high score for both certification and and market quotients, the lower left hand corner of the graph represents a low score for both certification and market quotients

The comparative assessments within the separate categories are shown below:

Vectored Thrust

Lift + Cruise

Wingless Multicopter

Hover Bikes

Electric Rotorcraft

Summary and Combinations

The different types of VTOL aircraft when combined on the same graph give the following result:

And this is the same graph showing the projects with labels:

All projects considered and their scores are shown below in score order:

PositionScoreProject
10.662Transcend Air Vy 400
20.655Dufour aEro2
30.624Flexcraft
40.612DeLorean Aerospace DR-7
50.560Samad Aerospace Starling Jet
60.554Pegasus Universal Aerospace Vertical Business Jet
70.481Cartivator SkyDrive
80.466Ascendance Flight Technologies Atea
90.457Lazzarini Hover Coupé
100.454XTI Aircraft Trifan 600
110.407Alaka’i Technologies Skai
120.388Gizio EJ420 ElectroJet
130.386Vertical Aerospace (unmanned)
140.378EHang 184
150.371Beta Technologies (prototype)
160.368Lazzarini FD-One
170.365Moller Skycar M200
180.359EHang 216
190.354Horus Hoverbike
200.345EAC Whisper
210.335Voyzon e-VOTO
220.333AeroMobil 5.0
230.330Frogs 282
240.327Airbus Helicopters CityAirbus
250.318Astro Elroy (“Passenger Drone”)
260.314Imaginactive Ambular
270.304Avioneo Robotics Avioneo 2345
280.300Davies “Tesla Concept Model V”
290.290Alauda Airspeeder
300.290AirCar
310.283Moog SureFly
320.283Moog SureFly
330.280Tier One Modified Robinson R44
340.267China Helicopter Research and Development Institute Electric Helicopter (CHRDI AVIC)
350.266Kármán XK-1
360.263Airflight
370.263Assen A1
380.261Zuri
390.260Bay Zoltán Flike
400.260SkyDrive SD-XX
410.257ALI Technologies Xturismo
420.244Piasecki PA-890
430.234HoverSurf Scorpion
440.213Flyter PAC VTOL 720-200
450.210ALI Technologies Hover Bike
460.210AirspaceX MOBi
470.205Eco’Trip
480.204Edea 22/1 Jay
490.201Jetson Aero Speeder
500.197Air Transportation Technology Catapult One – I, II
510.195Ambular 2.0
520.187UAVOS SumoAir
530.174Assen Aeronautics A2 Avenger
540.174Wisk
550.172Heitech Cruiser
560.170Baykar Cezeri
570.166Baaz Concept Design
580.165SkyDrive SD-02
590.164Aerodyne Vector
600.164Gizio DDRH/DDVL
610.162Ray Research VTOL Aircraft
620.162Removed
630.159Leap Vantage – I
640.156Pop.Up Next
650.156Malloy Aeronautics Hoverbike
660.147Heitech Air F1
670.141Archer
680.136Davinci ZeroG
690.134Zenith Altitude EOPA
700.133Hemanth Sudhakaran AVEM
710.132Aquinea ENAC Volta
720.131PDRL AeroHans 2S
730.131Kovacs Flike
740.125Kronstadt Air Taxi
750.124EVA Valkyr
760.122Flyt Aerospace FlytCycle
770.112Digi Robotics DroFire
780.103Rolls-Royce EVTOL
790.101Lazzarini Linux
800.098Applied VTOL Concepts Epiphany™ FLYING CARpet
810.093Deep Blue Aviation MX 18 Silhouette M
820.092PAL-V International Liberty
830.085Flexcraft Test Bench RPV
840.084Lazzarini I.F.O.
850.084Aston Martin Volante
860.083Ambular 3.0
870.080Overair (Karem) Butterfly
880.079Joby Aviation S4
890.078Gravity X Koncepto Millenya
900.074Zeva Zero
910.072Beta Technologies ALIA
920.071Aurora Flight Sciences PAV
930.070Neo Aeronautics Crimson S8
940.069Vinati F-Helix
950.066EVA X01
960.065Hyundai S-A1
970.064OVER LLC
980.062Skyworks Global eGyro
990.061CAPS
1000.060Samad Aerospace HUMA
1010.058NFT ASKA
1020.057Embraer Pulse Concept
1030.052AirisOne
1040.050Robathan Range Rover eVTOL
1050.047CHRDI AVIC Sylan
1060.045AutoGyro eCavalon
1070.043MyDraco
1080.041Flutr Motors Flutr
1090.037Fraundorfer Aeronautics Tensor
1100.036DragonAir Airboard 1 & 2 – II
1110.030Varon V210
1120.023Moscow Team AI Kamchatka
1130.021SKYLYS Aircraft AO
1140.020VerdeGo Aero PAT200
1150.017SkyCab
1160.015Georgia Tech HummingBuzz – I
1170.012Micor Technologies Variable Geometry VTOL aircraft (VAGEV)
1180.007FanFlyer
1190.006Avianovations Hepard
1200.003Trek Aerospace FlyKart 2 – I, II
121-0.004Grug Group Business eVTOL Jet
122-0.006Uber Elevate eCRM-001
123-0.009Athena Aero
124-0.012Aufeer Design Flying Taxi
125-0.014Tecnalia
126-0.015Moller Skycar M400
127-0.020Prime Design Consultancy Services Haricopter X1-B
128-0.021Flyter PAC VTOL 420-120
129-0.023Embraer DreamMaker
130-0.023ElectraFly ElectraFlyer
131-0.026Manta Aircraft ANN1
132-0.026Heitech Magic Cloud
133-0.034Leap Aeronautics
134-0.043Colugo Systems
135-0.044Macchina Volontis Flying Car
136-0.051Terrafugia TF-X
137-0.051PFV Personal Flying Vehicle #1
138-0.052PteroDynamics Transwing
139-0.053Aliptera ADR-1 Dragon Rider
140-0.054Napoleon Aero VTOL
141-0.056Edea 22/2 Squid – II
142-0.062COMAC eVTOL
143-0.064CycloTech Compound Helicopter
144-0.065Micor Technologies Advanced Individual VTOL Aircraft (AIVA)
145-0.066KARI PAV
146-0.067Swallow VTOL
147-0.080aeroG Aviation aG-4 Liberty
148-0.080Opener BlackFly V3
149-0.081Vickers WAVE eVTOL
150-0.082Ryerson Helium – II, III
151-0.087Esprit Aeronautics Lancer ePAV
152-0.088Skyworks Vertijet
153-0.096Carter Aviation Air Taxi/Jaunt
154-0.097Detroit Flying Cars WD-1
155-0.098LIFT Hexa
156-0.099Doroni Carbon One
157-0.100rFlight rWing
158-0.104Stuttgart Aerospace Apollo
159-0.110Happy Takeoff Prism
160-0.110Jetoptera J2000
161-0.122VRCO NeoXCraft
162-0.124JAXA Hornisse 2B
163-0.125Gizio CellCraft G150
164-0.127AutoFlightX V600
165-0.128Aeroxo ERA Aviabike – I, II
166-0.130VOX Aircraft M400
167-0.132Ray Research Dart Flyer
168-0.134Neva Aerospace AirQuadOne
169-0.140Innowings Aerospace PKOK
170-0.143Horizon AutoCopters Auto-Copter
171-0.145Jaunt Air Mobility Journey
172-0.153Kitty Hawk Heaviside
173-0.161GroundAero Sport Utility Aircraft
174-0.163Electric Jet Aircraft EJ-1S
175-0.174VTOL Aviation Abhiyaan
176-0.175Gizio CellCraft G450
177-0.182SkyBoom eVTOL Automobiles
178-0.183Raven – III
179-0.184B-Technology Beccarii
180-0.184Collaborative Mini-Bee
181-0.185Bell Nexus
182-0.186VTOL Aviation India Abhigyaan NX
183-0.197Lilium Jet
184-0.203Industry Network Cocooon X-1
185-0.204Bell Nexus 6HX
186-0.205EXA Air Car
187-0.212Terrafugia TF-2 Tiltrotor
188-0.216Autonomous Flight Y6S
189-0.228KineticCo Aerospace and Advanced Technologies
190-0.234CFC AirCAR
191-0.235NEAE-GSI eVTOL-BUS
192-0.235Prime Design Consultancy Services Haricopter X1-Q
193-0.238Scoop Pegasus 1 – I
194-0.239HoverSurf Formula
195-0.242chAIR Multicopter
196-0.243Hirobo Bit
197-0.250Urban Aeronautics CityHawk
198-0.251Paragon VTOL Aerospace T21 Raptor
199-0.254Grug Group Ghost X V1
200-0.254Grug Group Ghost X V1
201-0.257Grug Group Ghost X V3
202-0.264AMSL Aero Vertiia
203-0.271Aliptera APV-1
204-0.271GyroBike
205-0.276A³ Vahana
206-0.279Hoversurf Formula (No wing)
207-0.282ACS Aviation
208-0.299Aeronext Flying Gondola
209-0.302Gizio EJ11 ElectroJet
210-0.302CycloTech Passenger Demonstrator
211-0.338Imaginactive Transvolution
212-0.345Bartini Flying Car
213-0.354Sharifzadeh Zero G eCruzer
214-0.358Neoptera eOpter
215-0.374Vertiia
216-0.385HoverSurf Drone Taxi R-1
217-0.417Vision VTOL
218-0.467Advanced System Engineering – FIPSI WX4
219-0.507Advanced System Engineering – FIPSI BX4
220-0.536HopFlyt Venturi

The spread of scores were assessed to determine if the distribution included any anomalies that would indicate an error in the application of the scoring algorithm:

It appears that the application of the scoring method is free of obvious errors.

Summary of Results and ‘Awards’
The top scoring projects are unchanged from the initial assessment made in 2018. The top five eVTOL projects that exhibit the most favourable characteristics for certification and commercial success are:

PositionScoreProject
10.662Transcend Air Vy 400
20.655Dufour aEro2
30.624Flexcraft
40.612DeLorean Aerospace DR-7
50.560Samad Aerospace Starling Jet

Below are high scoring projects in some of the categories that I use for the assessment

Most Beautiful (In no particular order and according to my taste)

Davies “Tesla Concept Model V”

DeLorean Aerospace DR-7

Lazzarini Hover Coupé 

ALI Technologies Xturismo

Most Unusual

Industry Network Cocoon X-1

Robathan Range Rover eVTOL

Volerian

Zeva Zero

Avianovations Hepard

Advice

This is where I sound off on what I think may help improve a project’s chances of getting to market and being successful once you get there.

This section is as populated with my personal bias as the rest of this article, these opinions are all my own. 

  1.  Gatekeepers: You have to get through the certification process. The award of a type certificate depends on a succession of findings of compliance for each paragraph of the regulations. Achieving a finding of compliance relies on the person awarding that finding. Develop your relationships with those individuals. Inspire confidence and over achieve with presenting good quality data in all circumstances. Management of the perception of risk is paramount.
     
  2.  Money: The total cost of development is directly related to the time spent in development and certification. Keep your team small (minimize your $ per hour), expedite your certification program (minimize the total number of hours), reduce risks (minimize the chance of the number of hours increasing). Do not expand your team beyond the minimum size until you have a frozen detailed product specification and an approved certification plan. It is very easy to get into certification, very difficult to get out of it.
     
  3. Batteries: Assumptions of future battery energy density are unwise. Overestimation of present battery energy density is unwise. 250Kwh/Kg may be presently theoretically achievable. For the installed system it never is. Battery charge times and battery lifetimes have to be practically addressed. Thermal failure modes of Li-Po batteries have to be addressed and mitigated. Current installed battery/electrical drive systems are approximately 14 times less weight efficient than a turboprop system burning JetA. 
     
  4. Hydrogen: Great energy density, lousy density. Expensive. No infrastructure. Hydrogen is a form of displaced NIMBY carbon dioxide generation. Your aircraft may be carbon neutral, the supply chain for your fuel is not.
     
  5. Mistakes: Everyone makes mistakes. It is very cost effective to learn from other people’s mistakes, it is very expensive to learn from your own. 

In general, the air vehicle market has proven to be historically very conservative. It is very risk averse. In part this is because of the cost of insuring aircraft and in part because of the flying public’s general low threshold of perceived personal risk.

Just as you have to manage the perception of risk in the mind of the regulator you have to do the same for the insurance market and the minds of your future customers and users. We engineers find innovation very attractive and exciting. Other institutions and individuals do not feel the same way we do. There is some good data on the fear of flying and anxiety regarding flying here: Fear of Flying Statistics (2020 Data)

There is a trade off between promoting the new and exciting and reinforcing the dependable and reliable.

I fear that most eVTOL programs concentrate on the former and ignore the latter and this will harm them both in the certification process and with the customers.

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