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Cities

Travel time

The quality of a city depends on things like
*) The average travel time
*) The amount of residential and yard space per person
*) The amount of public park space

Most cities are poorly designed in this regard and hence new cities may emerge that are built from scratch. These cities will take advantage of possibilities offered by electric driverless cars prefabricated housing, and factories where you can manufacture things for yourself.

          Population  Population  Area  Travel  Travel
           density    (millions)  (km2)  time   means
          (people/ha)                   (mins)

Manila         430     1.65      38.6     30    Taxi
Delhi          255    11.0      431       30    Bus
Paris          215     2.27     105       30    Subway
Seoul          130    10.4      605       30    Subway
New York City  104     8.18     784       30    Subway
San Francisco   67      .81     121       30    Subway
Boston          51      .65     125       30    Subway
Isla Vista      48      .023      4.8      5    Walk, bike
Pasadena        24      .140     59.5     10    Car
Beverly Hills   23      .347     14.8     10    Car
Iowa City       10      .068     64.8     10    Walk, bike
Electic cars outperform public transportation for travel time and energy use. New York City is a catastrophic case that illustrates the weaknesses of public transportation. To get anywhere you have to:
*) Take the elevator from whatevery floor you're on to the ground floor.
*) Walk to the subway
*) Wait for the subway
*) Ride the subway
*) Transfer subways
*) Wait for the subway
*) Ride the subway
*) Walk from the subway station to the destination skyscraper
*) Take the elevator from the ground floor to the destination floor

This often takes more than 30 minutes, plus the subway routes are awkwardly designed.

Consider two constrating city designes
Design 1) Everyone has a yard adjacent to a park and no upstairs neighbors. The house has a garage with an electric car.
Design 2) Everyone lives in skycrapers

Being able to drive an electric car right up to your residence dramatically reduces travel time.

Lawns and parks are good for social interaction, especially for families with children. Skyscrapers are poor in this regard.

A high population density can be achieved even if everyone has a yard. For example, suppose a citizen has on average:
*) A residence of 30 square meters.
*) A yard of 20 square meters.
*) The residence is adjacent to a park with 30 square meters per person.
*) Road space of 20 square meters per person.

These residences are larger than typical New York City apartments and they achieve a respectable population density of 10000 people/km2.


Travel time

A city with sensible traffic flow can achieve a large population and a small travel time. For example,

City radius             =  R       =     3 km
Average travel speed    =  V       =    15 meters/second
Average travel time     =  T = R/V =   3.3 minutes
City population density =  D       = 10000 people/km2  =  1 person every 10 meters2
City population         =  P = πDR2=280000 people
It helps to centralize. 4 points of focus of a city are the college, the pub district, the shopping district, and the K-12 school. These can be placed in the city center and the residences and businesses radiate out from the center.
Electric cars

Tesla Model S

Electric cars outperform gasoline cars in all aspects except range. They're simpler, more powerful, quieter, and more flexible, plus in time the cost of batteries will decrease and the range problem will be solved.

The range of an electric car depends on the battery price and is typically .03 kilometers per battery dollar. The value for battery energy/$ increases with time and in the future range won't be a problem. The battery tends to be around 1/3 the cost of the car. For a typical car,

Battery energy/mass =  em           =  .60 MJoules/kg
Battery energy/$    =  e$           =.0070 MJoules/$
Battery mass        =  Mb           =  100 kg
Battery energy      =  E  =  Mb em  =   60 MJoules
Battery cost        =  P  =  E /e$  = 8570 $
Range               =  X            =  273 km            At a city speed of 17 m/s
Range/$             =  X$ =  X/P    = .032 km/$

The range is limited by air drag and rolling drag. Rolling drag dominates at low speed and air drag dominates at high speed, and at the critical "drag speed" Vd they are equal, typically around 17 m/s. For a typical car,

Car mass                   =  M           = 1200 kg
Gravity constant           =  g           =  9.8 m/s2
Tire rolling drag coeff    =  Cr          =.0075
Rolling drag force         =  Fr = Cr M g =   88 Newtons

Air drag coefficient       =  Ca          =  .25
Air density                =  D           = 1.22 kg/meter3
Air drag cross-section     =  A           =  2.0 m2
Car velocity               =  V           =   17 m/s      (City speed. 38 mph)
Air drag force             =  Fa = ½CaADV2 =  88 Newtons

Total drag force           =  F  = Fr + Fa = 176 Newtons
Drag speed                 =  Vd           =  17 m/s     Speed for which air drag equals rolling drag
Car electrical efficiency  =  Q            = .80
Battery energy             =  E            =  60 MJoules
Work done from drag        =  EQ = F X     =  Cr M g [1 + (V/Vd)2] X
Range                      =  X  = EQ/(CrMg)/[1+(V/Vd)2] =  272 km
The range is determined by equating the work from drag with the energy delivered by the battery.   E Q = F X.

The drag speed Vd is determined by setting Fr = Fa.

Drag speed  =  Vd  =  [Cr M g / (½ Ca D A)]½  =  4.01 [Cr M /(Ca A)]½  =  17.0 meters/second

Electric car batteries

Mitsubishi i-MiEV
Nissan Leaf

The battery is the dominant cost in an electric car.

                  Engine  Battery  Battery  Battery  Battery  Battery  Battery  Battery  Car    Car   Car
                  power    power   energy    mass                       cost             mass  range  cost
                  kWatt    kWatt   MJoule     kg      MJ/kg    kW/kg      $      MJ/$    kg     km     $

Tesla S P85D         568    397     306       540     .57      .74     44000    .0070    2239   426  115000
Ford Focus Electric  107     92      82.8     295     .281     .31     12000    .0069    1674   122   22495
Nissan Leaf           80     80      76.7     218     .35      .37      5500    .0139    1493   172   22360
Mitsubishi i-MiEV     47     47      58       201     .288     .23                       1080   100   16345

Electric car vs. electric aircraft

An electric aircraft uses 7 times more energy than an electric car in terms of energy/distance/mass. Electric aircraft have a cruising speed of 50 m/s and electric cars in cities move at around 15 m/s.

Typical values for electric aircraft and cars are:

Electric aircraft speed                     =  50 m/s
Electric aircraft power/mass                =  50 Watts/kg
Electric aircraft energy/distance/mass=  eair= 1.0 Joules/m/kg
Electric aircraft flying time         =  T  =3600 seconds
Electric aircraft range               =  X  = 180 km
Gravity constant                      =  g  = 9.8 m/s2
Electric car mass                     =  M
Electric car rolling drag coefficient =  Cr = .0075
Electric car rolling drag             =  Fr =  Cr M g
Electric car total drag               =  F  =  2 Fr        (Assume rolling drag = air drag)
Electric car energy/distance/mass     =  ecar=  2 Cr g  =  .147 Joules/m/kg
Aircraft energy / Car energy          =  eair / ecar  =  6.8

Energy source

Tesla Roadster

The performance of a car depends on its power source. Lithium batteries have a substantially lower value for energy/mass than gasoline.

                         Energy/Mass   Power/mass  Energy/$   Recharge    Max
                          MJoule/kg     kWatt/kg   MJoule/$   time       charges

Diesel fuel                   48          -        41          -
Lithium battery                 .60        .75       .007     hour       104
Lithium-ion supercapacitor      .054     15                   seconds    105
Supercapacitor                  .016      8          .00005   seconds    106
Aluminum electrolyte capacitor  .010     10          .0001    seconds     ∞
Electric motors can reach a power/mass of 10 kWatts/kg.
Supercapacitors are a rapidly-improving technology and lithium batteries are a mature technology.
Motors

Electric motors and gasoline motors have a similar power/mass.

                        MJ/kg  kWatt/kg  kWatts  kg

Supercapacitor, Li-ion    .054  15
Electric motor, maximum   -     10       200     19.9    EMRAX268 Brushless AC
Turbofan jet engine       -     10.0      83.2    8.32   GE90-115B Brayton
Electric motor, DC        -      7.8       1.04    .133  ElectriFly GPMG5220 brushless DC
Gasoline engine (BMW)            7.5     690             BMV V10 3L P84/5 2005
Model aircraft engine     -      2.8
Battery, lithium-ion      .75    1.5
Fuel cell, Honda          -      1.0
Typical diesel V8 turbo   -       .65
Solar cell, space station -       .077

Rolling drag

Typical car tires have a rolling drag coefficient of .01 and specialized tires can achieve lower values.

Mass of car              =  M
Gravity coefficient      =  g  =  9.8 meters/second2
Car downward force       =  Fg =  M g
Rolling drag coefficient =  Cr
Rolling drag             =  Fr =  C Fg
The tires with the lowest rolling drag coefficient are:
Tire                  Rolling drag coefficient

Bridgestone B381          .00615
Michelin Symmetry         .00650
Michelin Tiger Paw        .00683
Bridgestone Dueller       .00700
BFGoodrich Rugged Trail   .00709
Michelin LTX              .00754
Goodyear Integrity        .00758

Railroad                  .00035       Steel wheels on steel rails
Racing bicycle tires      .0025        8 bars of pressure
Typical bicycle tires     .004
18-wheeler truck tires    .005
Typical car tire          .01
Data
Transport energy cost

The cost of transport depends on the drag force per person.

Drag force              =  F
Distance traveled       =  X
Energy expended         =  E  =  F X
Number of people        =  N
Energy/distance/person  =  Z  =  E/X/N  =  F/N
Drag speed              =  Vd         (Speed for which rolling drag = air drag)
For typical vehicles,
                            Mass   Cr    Area    Cd  Drag speed   People   Force/person  Force/person
                             kg            m2           m/s                 at 15 m/s      at 30 m/s

Electric bike                  20  .003      .7   1.0     2.6      1          99         387
Electric scooter              120  .005     1.0   1.0     4.0      1         147         550
Electric car, lightweight     600  .0075    2.0    .20   14.3      1         105         269
Electric car, middleweight   1200  .0075    2.5    .25   15.7      1         180         437
Electric car, heavyweight    1800  .0075    3.0    .3    15.9      1         262         632
Bus                         10000  .005     8.0    .6    15.7     60          23.1        56.0
Subway car                  34000  .00035  10.0    .6     6.3    100           9.7        34.4
18-wheel truck              36000  .005     8.0    .6    24.6      1        2422        4397
Aircraft, 747              220128   -        -     -       -     480                     625
The force/person for the 747 aircraft is for a cruising speed of Mach .9 and an altitude of 12 km.

We assume that each person adds 80 kg to the mass of the vehicle.

Buses use 5 times less energy as cars but only if they are full

Within cities, cars have faster travel times than buses, especially if parking is abundant or the cars are self-driving. Buses are more suited to inter-city transport.

Trains use 2 times less energy than buses but they are highly inflexible.


Acceleration

Acceleration depends on the size of the battery, and supercapacitors can add an extra boost. For a typical car that accelerates from 0 to 100 km/h (37.8 m/s) in 8 seconds, the size of the battery required is:

Car mass          =  M             =  1200 kg
Target speed      =  V             =  27.8 m/s           (100 km/h. Speed at end of acceleration)
Kinetic energy    =  E  =  ½ M V2  =  464000 Joules
Time              =  T             =     8 seconds   (Time to accelerate from rest to speed V)
Engine efficiency =  Q             =    .8
Power             =  P  =  E/T     = 58000 Watts
Battey power/mass =  p             =   750 Watts/kg
Battery mass      =  MB =  P / (Q p)   =   112 kg
Battery cost/mass =  c             =    86 $/kg
Battery cost      =  C             =  9600 $

Recovering breaking energy

Supercapacitors are ideal for recovering breaking energy because they can be charged/discharged more times than batteries. To capture the energy from breaking from freeway speed, on order of 27 kg of supercapacotors are required.

Car mass                   =  M   =  1200 kg
Car velocity               =  V   =  27.8 m/s
Car kinetic energy         =  E   =464000 Joules
Supercapacitor energy/mass =  e   = 16000 Joules/kg
Supercapacitor mass        =  E/e =    29 kg

Flying cars

Fantrainer
Fantrainer
Terra Fugia

Optica
Ducted fan

The principal challenge for flying cars is noise. There is no such thing as a quiet flying car.

Fixed wing flight is at least 6 times more efficient than helicopter flight.

The larger the propeller the less noise. The sound power of a propeller scales as the 5th power of tip speed. A flying car should have a propeller as large as possible. A single large propeller is better than multiple small propellers.

A ducted (shielded) propeller is substantially quieter than an unshielded propeller, and is more efficient in producing thrust.

Electric aircraft are substantially simpler and safer than gasoline aircraft.

Nominal configuration for a quiet flying car:

A single large ducted fan mounted on the rear
50 kWatt engine
Gyrofans and gyroscopes for stability
Wings that fold for driving
Telescoping wing section within the main wing (wings should be as long as possible)
A cockpit with a low cross-section, like a velobike. The passengers sit behind the pilot
Thin tires for a low cross section
A 10 kg vehicle parachute for emergency landing
2 kg parachutes for passengers
A total mass in the range of 500 kg


Prefabricated homes

Prefabricated homes cost in the range from 20 to 100 $/foot2. A 400 foot2 minimalistic home costs on order 8000 $.


Shipping containers

Prefabricated homes can be made from shipping containers, which are abundant, cheap, and easily delivered.


                               $   Length  Width  Height  Mass
                                     ft     ft      ft     kg

10-foot shipping container   1000    10      8     8.5    1300
20-foot shipping container   1200    20      8     8.5    2200
40-foot shipping container   1500    40      8     8.5    3800
Typical mobile home                  90     18

Prefabricated bamboo house

For a 1-level prefabricated square bamboo house,

Side length       =    8 meters
Wall height       =    3 meters
Floor area        =   64 meters2
Wall area         =   24 meters2
Interior walls    =   24 meters2
Total wall area   =  248 meters2       Floor, ceiling, 4 walls, and interior walls
Wall thickness    =  .05 meters
Wall volume       = 12.4 meters3
Bamboo density    =  350 kg/meter2
Bamboo mass       =  4.3 tons
Carbon mass       =  2.2 tons
Bamboo carbon frac=   .5
House mass        =  7.0 tons
A helicopter can carry 12 tons. A prefabricated house can be placed anywhere in the wilderness and multiple modules can be assembled on site.
Wilderness

Prefabricated houses can be helicoptered to wilderness locations and flying cars can be used to reach them.


Sky cranes

CH-47 Chinook
S-64 Aircrane
Karman K-MAX
CH-47 Chinook

              Mass   Payload  Power  Speed  Range  Climb  Rotor  Ceiling  Power/Mass
             (tons)  (tons)   (MW)   (m/s)  (km)   (m/s)   (m)    (km)     kWatt/kg

S-64 Aircrane   8.72   9.07   7.11     56    370   6.75   21.95             815
CH-47 Chinook  11.15  12.7    7.03     88    741   7.73   18.3    6.1       630
Karman K-MAX    2.33   2.72   1.34     51    495          14.71             575   85 gallons/hr

Helicopter drones

The flight time of a drone is determined by:
*) The battery energy/mass.
*) The power/mass required to hover.
*) The ratio of the battery mass to the drone mass.

Typical parameters for a drone are:

Drone mass         =  M          =  1.0 kg
Battery mass       =  Mbat        =  .5 kg           (The battery is the most vital component)
Battery energy     =  E          =  .38 MJoules
Battery energy/mass=  ebat= E/Mbat=  .75 MJoules/kg   (Upper range for lithium batteries)
Drone energy/mass  =  e  =  E/M  =  .38 MJoules/kg
Drone power/mass   =  p  =  P/M  =   60 Watts/kg    (Practical minimum to hover. Independent of mass)
Drone power        =  P  =  p M  =   60 Watts       (Power required to hover)
Flight time        =  T  =  E/P  = 6250 seconds  =  104 minutes
The flight time in terms of component parameters is
T  =  (ebat/p) * (Mbat/M)


                Drone  Battery  Drone  Battery  Battery  Drone  Drone  Flight  Price  Wireless
                mass   energy           mass             power          time           range
                 kg    MJoule   MJ/kg    kg      MJ/kg   Watt    W/kg  minutes   $      km

Mota Jetjat Nano .011    .00160  .145                     3.3    303      8      40    .02
ByRobot Fighter  .030    .0040   .133                     6.7    222     10     120    .1
Blade mQX        .0751   .0067   .089                    11.2    149     10     115
XDrone Zepto     .082    .0067   .081                     4.6     56     24      40    .05
Walkera QR Y100  .146    .0213   .146   .0413    .52     17.8    122     20     100    .1
MJX Bugs 3       .485    .0480   .099                    44.4     92     18     100    .5
DJI Mavic Pro    .725    .157    .217   .24      .65    109      150     24    1000   7.0
XK Detect X380C 1.18     .216    .183                   120      102     30     522   1.0
Xiaomi Mi       1.376    .319    .214                   197      143     27     380   1.0
DJI Phantom 4   1.38     .293    .212   .426     .69    174      126     28    1000   5.0
XK X500         1.8      .288    .160                   160       89     30     303   1.0
JYU Spider X    2.1      .360    .171   .812     .44    200       95     30     155   4.0
MD4-1000        2.65    1.039    .392                   197       74     88    2000    .5
DJI Inspire     2.935    .360    .123   .67      .54    333      114     18    2000   7.0
Altura Zenith   3.5     1.327    .379                   491      140     45    2000   1.0
Walkera QR X800 3.9      .799    .205  1.134     .70    222       57     60    2700   2.0
AEE F100        6.0     1.598    .266                   380       63     70   58000  10.0
Chaos HL48      6.8     1.758    .259                   651       96     45   20000  20.0
MD4-3000       10.4     2.80     .269                  1037      100     45           4.0
Ehang 184     200      51.8      .259                 37500      188     23  300000   3.5
Airbus EFan                                              60
The minimum power requirement for quadcopter flight is of order 60 Watts/kg.
1 MJ = 1 MJoule = 106 Joules

Electric power outperformes gasoline power in all categories except energy density. Electric motors are lighter, simpler, cheaper, more flexible, and more reliable than combustion motors.


Fixed-wing drones
            Drone  Battery  Drone  Drone  Drone  Flight  Cost  Wireless  Wing  Wing  Cruise   Max   Flight
            mass   energy    E/M   power          time          range    area  span  speed   speed  range
             kg    MJoule   MJ/kg  Watts  W/kg   minutes  $       km      m2    m     m/s     m/s    km

Sky Hawk       .355  .0346  .097    19.2  54.1     30     400    1.0           1.0
Chaipirinha    .62   .088   .142                          154                   .85
AgDrone       2.25   .639   .284   161    71.7     66            4.5            .124  46.7     82    50
Trimble UX5   2.5    .320   .128   107    42.7     50   10000    2.5     .34    .10   80             60
Airbus E-Fan 450  104.4     .232 29000    64.4     60                          9.5    44.4     61.1 160
Sun Flyer   1225

Hover efficiency

The goal of a propeller is to maximize the power/mass ratio.

A propeller test consists of measuring the lift force, the power, and the tip speed (F,P,V), and this can be used to determine the rotor quality parameters (Q,q,W).

Mass             =  M
Rotor radius     =  R
Rotor lift/drag  =  Q  =  F / Fd
Air density      =  D  =  1.22 kg/meter3
Rotor lift param =  W  =  F D-1 R-2 V-2
Rotor tip speed  =  V
Rotor lift force =  F  =  D W R2 V2
Rotor drag force =  Fd
Rotor power      =  P   =  Fd V  =  F V / Q
Rotor quality    =  q   =  Q W½ D½
                        =  F3/2 P-1 R-1
Rotor force/power=  Z   =  F / P
                        =  Q / V
                        =  D½ W½ Q R F
                        =  q R F


Rotor           Radius    Z    Force   Power  Rotors  Blades  Freq   V     q    W     Q
                  m      N/W     N       W            /rotor   Hz   m/s

10 inch           .127   .078     2.94    37.5  1       2     72    57.5  1.06  .045  4.48
10 inch           .127   .056     9.8    176    1       2    131   104.5  1.37  .046  5.85
 9x47SF           .114   .129     1.06     8    1       2     50    35.8  1.17  .052  4.62
 9x47SF           .114   .0427   11.5    269    1       2    166.7 119.4  1.27  .051  5.10
10x47SF           .127   .186      .696    4    1       2     33.3  26.6  1.22  .050  4.95
10x47SF           .127   .0405   16.8    414    1       2    166.7 133.0  1.31  .048  5.39
11x47SF           .140   .161      .960    6    1       2     33.3  29.3  1.13  .047  4.72
11x47SF           .140   .0381   23.1    607    1       2    166.7 146.6  1.45  .045  5.59
12x38SF           .152   .160     1.20     7    1       2     33.3  31.8  1.15  .042  5.09
12x38SF           .152   .0381   28.4    745    1       2    166.7 159.2  1.34  .040  6.07
13 inch           .165   .081     5.81    72    1       2                 1.18
Walkera QR X800   .193   .172     9.56    55.5  4       2                 2.76
Chaos HL48        .203   .102     8.33    81.4  8       3                 1.45
Ehang             .80    .052   245     4688    8       2                 1.02
Phurba           1.6     .115  1200    10435    4       2                 1.4
For drones, the force and power are for one propeller.
Propeller data
#1 #2
Propellers
    Radius   Mass
      m      grams

     .12     11
     .127     6.5
     .171    39.7
     .193    40

Power

For a typical drone,

Drone mass             =  M
Battery mass           =  Mbat
Payload mass           =  Mpay
Climbing speed         =  Vcli
Max horizontal speed   =  Vmax
Hover constant         =  H            =  60 Watts/kg       Power/mass required to hover
Hover power            =  Phov=  H M
Hover power for payload=  Ppay=  H Mpay
Gravity constant       =  g            =  9.8 m/s
Power to climb         =  Pcli=  M g V
Drag coefficient       =  C
Air density            =  D            = 1.22 kg/meter3
Drone cross-section    =  A
Drag power             =  Pdrag= ½ C D A V3
If the climbing power is equal to the hover power,
V = H / g  =  6 meters/second
If the climbing power is equal to the drag power,
M g V = ½ C D A V3

V  =  [2Mg/(CDA)]½  =  4.0 [M/(CA)]½ meters/second
              Drone  Battery  Load   Hover  Load  Climb   Power   P/M  Climb Speed  Thrust
               kg      kg      kg    Watt   Watt  Watt    Watt    W/kg  m/s   m/s   Newtons

Nihui NH-010     .0168  .0047    -       6.7                 6.7  1426   -     -
Walkera QR Y100  .146   .0413    -      17.8         35.5   53.3  1291   -     -
DJI Mavic Pro    .725   .24      -     109                 109     454   5    18
DJI Phantom 4   1.38    .426     .462  174    58     81    232     545   6    20
JYU Spider X    2.1     .812    2.3    200   219    103    419     516   5     8
MD4-1000        2.65            1.2    197    89    195    286           7.5  12     118
DJI Inspire 1   2.935   .67     1.7    333   193    144    526     785   5    22
AEE F100        6.0             2.5    300                 380                28
Chaos HL48      6.8             6.8    651   651          1302
MD4-3000       10.4             4.6   1037         1019   1496          10           280
Ehang         200             100    37500                                    28

Drone   kg     Drone mass without payload
Battery kg     Battery mass
Load    kg     Maximum payload for hovering
Hover   Watt   Power required to hover without payload
Load    Watt   Power used for the payload only
Climb   Watt   Climbing power  =  Mass * ClimbVelocity * Gravityconstant
Power   Watt   Total power  =  Hover power + Load power
P/M     W/kg   Power/Mass for the battery
Climb   m/s    Maximum climbing speed
Speed   m/s    Maximum horizontal speed
Thrust  Newton Maximum thrust
The JYU Spider X has the largest value for (payload mass) / (drone mass). The battery power/mass is
Battery power/mass  =  Phov ⋅ (M + Mpay) / M / Mbat  =  516 Watts/kg

Noise

Noise power is proportional to the rotor tip speed to the fifth power. The more rotors and the more blades per rotor, the less noise produced.


Flying electric car

We give a sample design for a flying electric car based on current technological capabilities. We choose a design with 4 rotors mounted on a cross above the car, with a forward, aft, left, and right rotor. The forward-aft rotor distance is larger than the left-right rotor distance. The left-right cross section is a wing, and it has an interior telescoping sections that extend the length of the wing when flying. The elements of a 1-person flying car are:

                    kg

Passenger
Cabin
Battery
Motors
Rotors
Cross structure
Wing
Car axels
Wheels

Battery energy/mass =  e        =  .8 MJoules/kg
Battery power/mass  =  p        =  2000 Watts/kg
Rotor quality       =  q        =  1.25
Mass                =  M        =  400 kg
Gravity constant    =  g
Force               =  F  = Mg  =  4000 Newtons
Number of rotors    =  N
Rotor radius        =  R        =  1.5 meters
Hover force/power   =  Z  =qR(F/N)=  .0593
Hover power         =  P        =  67450 Watts
Hover power/mass    =  p        =  169 Watts/kg
Rotors         =    4
Blades/Rotor   =    3
Rotor radius   =  1.6 meters
Payload        =  100 kg             One person plus luggage
Fuselage mass  =  125 kg
Battery mass   =   75 kg
Total mass     =  300 kg
Hover          =  100 Watts/kg
Hover power    =30000 Watts
Total power    =60000 Watts
Battery        =  800 Watts/kg
Battery mass   =   75 kg

Beam strength

The maximum force on a beam is:

Beam length     =  L
Beam height     =  H
Beam width      =  W
Shear strength  =  S
Density         =  D
Mass            =  M
Breaking force  =  F  =  (2/3) W H2 S / X





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