X Prize Clean Aviation: $10 million

[mheslep]

No, I had a legitimate gripe. 50 miles is what a car is used for, and this is what NASA said this vehicle would not compete against.

Why not? The range is 50 miles in 20 minutes, parking lot to parking lot just like for the car. The car takes an hour, maybe two if you are behind the traffic in one of the photos.

 

[Cyrus]

Why not? The range is 50 miles in 20 minutes, parking lot to parking lot just like for the car. The car takes an hour, maybe two if you are behind the traffic in one of the photos.

Just think about it, having people fly around in an automated highway in the sky "grid" for anything less than 50 miles is a nightmare. All you have done is take the cars and congestion and put it slightly higher in the sky. The airways are already designed for aircraft, so if you are going to suddenly introduce car like airways, they are going to have to be well defined, probably flying overhead existing roads. So you can't just reroute cars anywhere you like it some sort of an optimizer that figure out where to direct each car to minimize travel time for the entire system.

Even for something between 50-400 miles, I don't see why this vehicle works. Take a Cessna, not only is it quick, I can take 4 people along with me.

For more than 400 miles, fly commercial.

 

[mheslep]

Just think about it, having people fly around in an automated highway in the sky "grid" for anything less than 50 miles is a nightmare.

Different topic. You asked why not take a car, not what would happen if all short distance transportation moved into the air.

Even for something between 50-400 miles, I don't see why this vehicle works. Take a Cessna, not only is it quick, I can take 4 people along with me.

Because you can't fly the Cessna out of your back yard. Most people in the US will require at least 40 minutes to get their light traffic airport to reach that Cessna, in which case one might as well drive ( or helo)

 

[Cyrus]

Different topic. You asked why not take a car, not what would happen if all short distance transportation moved into the air.

Because you can't fly the Cessna out of your back yard. Most people in the US will require at least 40 minutes to get their light traffic airport to reach that Cessna, in which case one might as well drive ( or helo)

Watch the video over again, they take off from a heli-port, not peoples back yards, and for good reason. But, let's assume you do fly it from your back yard. This vehicle is a single seater, this is very different from a vehicle you can put more than one person and payload in for an extended range. At that point, you're now talking about larger levels of noise, and inherently large disk loadings. Which means this thing will be shooting rocks and dirt below it at dangerous speeds to people, houses, fences, etc.

The V-22 suffers from this problem too.

-nS-C-xuH-g[/youtube]

 

[mheslep]

Economist article on burgeoning electric aircraft

High voltage
Transport: As electric cars make steady progress on land, battery- powered aircraft of various kinds are quietly taking to the air
http://www.economist.com/node/16295620

 

[mheslep]

Add to that list: Cessna along with Bye Energy are coming out with an electric Cessna Skyhawk 172. Aviation week and mfn sources say the aircraft will

o carry enough batteries on board for two hours of flight,
o have solar panels built into the wings to augment range,
o have a cost per mile flown 'several multiples' cheaper than the same distance flown with aviation fuel.
​

[URL]http://www.byeenergy.com/Pages/assets/images/banners/banner-cessna-iso.jpg[/URL]
http://www.byeenergy.com/Pages/FAQ.html
http://www.cessna.com/NewReleases/New/NewReleaseNum-1192324720455.html

 

[mheslep]

NASA just http://www.nasa.gov/topics/technology/centennial/gfc_final.html" for an (effectively) electric aircraft competition: $1.35 million.

The winning aircraft had to fly 200 miles in less than two hours and use less than one gallon of fuel per occupant, or the equivalent in electricity. The first and second place teams, which were both electric-powered, achieved twice the fuel efficiency requirement of the competition, meaning they flew 200 miles using just over a half-gallon of fuel equivalent per passenger.

Or 400 mpg effective for the winners. By comparison, according to NASA, typical general aviation aircraft achieve 5-50 mpg.Energy per gallon of gasoline is ~34 kWh, so the winners achieved 200 miles/17 kWh. At 150 Wh per kg of Li-ion battery: 113 kg of battery aboard (Edit: reserve of 30 mins required, or +25%; total minimum on board charge/wgt: 21.3 kWh/ 142kg)
More rules:
http://www.nasa.gov/pdf/590567main_NASA Green Flight Challenge_revised.pdf

Performance Required:
Range: 200 statute miles, with 30 min. reserve, day VFR at ≥ 4000’ MSL over nonmountainous, sparsely-populated coastal terrain
Efficiency: ≥ 200 Passenger-MPGe energy equivalency
Speed: ≥ 100 mph average on each of two 200 mile flights
Minimum Speed: ≤ 52 mph in level flight without stall, power and flaps allowed
Takeoff Distance: ≤ 2000 feet from brake release to clear a 50 foot obstacle
Community Noise: ≤ 78 dBA at full power takeoff, measured 250 feet sideways to takeoff brake release
Handling Qualities: Acceptable on all 7 basic handling qualities.

Features Required:
Passengers: Upright seats with adequate volume for a 6-foot tall, 200 pound (lb) adult.
Wingspan: Must fit inside 44-foot wide hangar for weighing (wingfold is acceptable). Height, length and landing gear footprint limits are defined in the Green Flight Challenge Team Agreement.
Vehicle Weights: ≤ 6500 lb. with ≤ 4500 lb. on main gear and ≤ 2000 lb. on nosewheel or tail-wheel
Field of View: Acceptable to FAA licensing authorities and FAA AC25.773-1
Control System: Must provide dual controls if two or more seats
Payload Carried: 200 lbs per seat. Dual pilots if two or more seats. 200 lbs per seat sandbag ballast in all seats not occupied by pilot/co-pilot
Seating Configuration: Tandem seating is allowed, but vehicles with 3 or more seats must place at least 2 seats directly side-by-side. Rapid exit required for all seats.
Fuel/Energy Use: Energy consumed: 1 gallon of 87 octane unleaded auto gasoline = 115,000 BTU. [...]
Fuels/Energy Allowed: Avgas 100 low-lead (LL), Jet-A, diesel, unleaded auto gasoline, bio-fuels, H2, synthetics, electricity.
ePower Measurement: Electric-powered aircraft will use a CAFE-provided power meter to accurately determine energy used during the competition
Flightworthiness: Valid US FAA Airworthiness Certificate for unrestricted day VFR flight in the Continental United States, proof of structural limit

https://www.youtube.com/watch?v=ujeJB8dlie8