SkyTran's
super energy efficiency
Time for some basic
aerodynamic, physics and math lessons!
The chart shown here should give you some basic insight into the
importance of using optimized streamlined shapes in transportation vehicles.
AERODYNAMIC DRAG
D = Cd X A X q Aerodynamic
Drag
Force
(pounds)Aerodynamic Drag Coefficient (dimensionless) Projected Frontal Area (square feet) Dynamic Pressure (pounds per square foot)
THE SHAPE EFFECT
(a measure of how streamlined a body shape is)THE SIZE EFFECT
HOW SPEED (V) AND DENSITY(ρ) ARE TAKEN INTO ACCOUNT
EQUAL DRAG BODIESCUBE Cd = 1.05 CdA = 1.05 ft2
Flat plate "B" has 56% of the drag of flat plate "A".
"C" only has 25% the drag of "A".
"D" only has 6% of the drag of "A".
q=1/2ρV2 =(VMPH)2/391 (at sea level, 590F) Speed Dynamic Pressure 0 mph 0 10 mph .25 lb/ft2 20 mph 1.02 lb/ft2 30 mph 2.30 lb/ft2 40 mph 4.09 lb/ft2 50 mph 6.39 lb/ft2 60 mph 9.20 lb/ft2 70 mph 12.53 lb/ft2 80 mph 16.37 lb/ft2 90 mph 20.72 lb/ft2 100 mph 25.58 lb/ft2 150 mph 57.54 lb/ft2
A =1.0 ft2 SPHERE Cd = .47 CdA = 1.05 ft2 A =2.13 ft2 CHOPPED TEAR DROP Cd = .10 CdA = 1.05 ft2 A =10.5 ft2 TEAR DROP Cd = .05 CdA = 1.05 ft2 A =21 ft2 The product CdA
is called the EFFECTIVE FRONTAL AREA.This next section shows some of the output from our Power Consumed calculation spreadsheet. It properly accounts for aerodynamic drag, magnetic drag and linear motor efficiency loss effects. This small section of the spreadsheet shows the calculated costs of electrical energy to move a fully loaded SkyTran vehicle a distance of 100 miles (at 100 mph no less!). The spreadsheet then compares this efficiency to a 20 mile per gallon car using $2.30 per gallon gasoline. You can download our Excel spreadsheet here for free and do the "what ifs" using your own car's MPG efficiency, local gasoline prices & electrical rates. Obviously, the calculated SkyTran EQUIVALENT MPG figure will come out different every time. Final results will very much depend on whether you own a Hummer, a Prius Hybrid or something in between.
If the industrial electricity rate for power = 8 cents per kilowatt-hour Energy cost to travel 100 miles by SkyTran = $ 0.71 Compare this to your car that gets 20 MPG (miles per gallon) of gasoline costing $ 2.30 per gallon Energy cost to travel 100 miles by your car = $ 11.50 Thus, a 20 MPG car costs 16.2 times what SkyTran does for energy
CLICK HERE
to DOWNLOAD this Excel Spreadsheet
so you can do your own power required calculations
plus predictions for EQUIVALENT Miles Per Gallon.
Why are the SkyTran vehicles so compact?
Why did you seat the SkyTran passengers in tandem
instead of the more logical side-by-side position?At first glance many people think we should make our SkyTran vehicles larger to carry more passengers. They don't realize that even changing passenger seating from tandem to side-by-side involves significant energy efficiency penalties. The following table gives you numbers to ponder. Don't forget that the cost of the structure for building any guideway will be directly related to the weight carried. Envision the difference between one structure designed to carry legal 80,000 pound gross weight trucks and another designed to carry 700 pound gross weight vehicles!
Possible SkyTran/UniModal Configurations Prone - Solo
Absolute minimum teardropSingle Seater
Sports car like
reclined seatingTwo Passenger
TandemTwo Passenger
Side by SideFour Passenger
Two Front,
Two Rear
Performance Comparisons of Possible SkyTran/UniModal Configurations Prone - Solo Single Seater Two Passenger Two Passenger Four Passenger Absolute minimum teardrop Comfortable
with
20 lbs luggageTandem Side by Side Two Front,
Two RearPod Weight (lbs) 100 150 200 270 350 Max People Wt (lbs) 200 200 500 500 1000 Total weight (lbs) 300 350 700 770 1350 Frontal Area (sq ft) 0.88 6.067 6.067 12.2 12.2 Drag Coefficient 0.12 0.168 0.168 0.22 0.22 CdA product (sq ft) 0.1056 1.018 1.018 2.684 2.684 Air Drag Horsepower @ 100 MPH 3.38 6.94 6.94 18.298 18.298 MagLev Horsepower @ 100 MPH 1.60 1.87 3.73 4.10 7.19 Total Horsepower @ 100 MPH 4.98 8.81 10.68 22.40 25.49 kW power to track @ 100 MPH 4.13 7.30 8.85 18.56 21.12 Energy Cost per 100 miles $0.33 $0.58 $0.71 $1.48 $1.69 Equivalent MPG 697 394 325 155 136 Relative Efficiency 214% 121% 100% 48% 42% Acceleration Power req'd (kW) 20.6 36.5 44.3 92.8 105.6 Assumes: 20 MPG car & $2.30/gallon gas = $11.50/100 miles; Electricity (industrial) @ $.08 per kW-hr; SkyTran @ 100 MPH. Don't forget there is all kinds of research is currently being done to improve the fuel efficiency of automobiles. Hybrids, fuel cells, direct natural gas or hydrogen burning, etc. One has to ask oneself what happens to congestion even if an affordable 500 MPG automobile is invented? If it is a standard 4 or 5 passenger size it will unfortunately take up the same space on today's roads and will do nothing to eliminate congestion. Even something as advanced as the Rocky Mountain Institute's four passenger, 100 MPG, HyperCar concept is a futile effort when it comes to alleviating congestion.
Unless you build personal sized vehicles that use offline stations operating on an elevated 3D grid (in order to eliminate the average speed killing stopping and starting of any form of group transit and all red light type 2D intersection stopping) you cannot do anything significant at any reasonable cost to reduce daily commuting congestion hassles.
To maintain car culture heaven, the cities need to build 10 times the current number of freeways. Imagine what would happen to congestion if the government could afford to build 6 lane freeways crisscrossing everywhere. Especially if each intersecting node had non-stop cloverleaf exit and merging ramps. SkyTran offers exactly that at affordable costs!
