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NASA Unveils Plans For Electric-Powered Plane (techcrunch.com)
An anonymous reader quotes a report from New York Times: A new experimental airplane being built by NASA could help push electric-powered aviation from a technical curiosity and pipe dream into something that might become commercially viable for small aircraft. At a conference on Friday of the American Institute of Aeronautics and Astronautics in Washington, Charles F. Bolden Jr., the NASA administrator, announced plans for an all-electric airplane (Warning: source may be paywalled) designated as X-57 and nicknamed "Maxwell," part of the agency's efforts to make aviation more efficient and less of a polluter. "The X-57 will take the first giant step in opening a new era of aviation," Mr. Bolden declared. Maxwell is equipped with 14 electric propeller-turning motors located along the wings, which will all be used to create sufficient thrust during take-off and landing. Only two large motors on the tips of the wings will be used once it's up in the air. The plane is a result of NASA's "New Aviation Horizons" initiative: a 10-year program to create a new generation of X-planes that will make use of greener energy, use half as much fuel, and be half as loud as commercial aircraft in use today.
The issues with electric planes have been beat to death here, this NASA plane appears to have no solution for any of them.
In two days .
You know that first A in NASA is Air, right? You're a fucking idiot. This is their fucking job. Now, I'm pretty sure that their plan is to throw money at contractors and hope magic happens, but aircraft are most certainly in their charter.
"Sec. 103. As used in this Act--
(1) the term "aeronautical and space activities" means(A) research into, and the solution of, problems of flight within and outside the earth's atmosphere, (B) the development, construction, testing, and operation for research purposes of aeronautical and space vehicles, and (C) such other activities as may be required for the exploration of space; and
(2) the term "aeronautical and space vehicles" means aircraft, missiles, satellites, and other space vehicles, manned and unmanned, together with related equipment, devices, components, and parts."
triggering the Beatles: http://www.azlyrics.com/lyrics...
let us hope nasa will waste lost of money trying out all the inefficient ways of making electric planes.
then hopefully russians will create cheap and effective electric planes that everyone (even the usa military ) can borrow, as they do with human space travel (again even usa military use russian rockets now ) .
meanwhile eion musk will blow lots of hype trying get his cronies in usa government to give him money to make electric planes too(especially ones that fly on social media to give his fanboys much needed orgasms). as with all his projects this will be a subsidy worthy cause, even without crony capitalism.
12 engines as deadweight and dragging props, that doesnt seem very efficient ? Even with foldable props, they will induce a significant drag. I am sure NASA can come up with a better solution for extra power needed for takeoff.
So they have 12 extra motors/props just for takeoff, that add both weight and drag? Why don't they just use one motor and drive one of the wheels against the ground?
You're forgetting that with the extra props across the wing, you need a much much smaller wing, and can have a wing with much higher aspect ratio*. The reduction in wing area and increased aspect ratio more than offsets any drag from the multiple (folded) props during cruise.
*Those props aren't there for thrust, they are for increasing flow velocity over the wings.
"There are a dozen opinions on a matter until you know the truth. Then there is only one." - CS Lewis (paraprhase)
GP also ignorantly fails to understand that props efficient in high speed flight are inefficient at low airspeed and vice versa, so stowing climb props is a very good choice for an electric airplane.
Space exploration? You make it sound like we have to send people up a few hundred miles in order to take pictures of things light-years away?
RTFA. Max speed is 175KT, not exactly "high speed". NASA also admits this won't be viable for commercial service, basically a hobbyist plan for short flights with very little payload.
Bottom line though is that NASA is and has always been a PR machine. An all electric plane is a warm fuzzy story for people to read.
Indeed, research is a bit part of what NASA does - and IMHO, it should be bigger. I agree with Buzz Aldrin that NASA should revert to the earlier NACA model.
Monkeywrench Ex Machina.
"Conventional" aviation supplies a product for market demand: high-speed, low-cost transportation. Low-mass, high-energy fuels make it possible: primarily kerosene, with some use of high-octane gasoline. Right now, electrical power will never replace hydrocarbon fuels because the energy density
energy unit / mass unit
is too low. Even worse, the
cost / energy unit
for batteries exceeds the hydrocarbon
cost / energy unit
"price density". Yes, battery aviation now exists - with government subsidies, and yes, battery aviation fans will howl that government subsidizes hydrocarbons, etc. etc. etc. Hydrocarbon subsidies should end. This does not change the fact that battery energy density will never exceed hydrocarbon energy density.
Now, maybe steam has potential:
https://www.youtube.com/watch?v=nw6NFmcnW-8
Take an electrified Amtrak train from DC to Boston. The cars are passive, all the pulling is done by the engine(s) up front.
The distributed motors are a feature, not a bug. With current designs, manufacturers can't go with more smaller engines due to efficiency losses. The engines installed on aircraft now are used to provide thrust and the resulting wind across the airfoil from that forward movement is what provides lift.
This design is different because the smaller motors have higher efficiencies and are able to direct air over the airfoil directly instead of relying solely on forward thrust to provide the same wind. That adds to lift, which reduces takeoff distance, which reduces friction losses from the wheels.
Sig not found.
Lots of tradeoffs. Airflow over the wings helps takeoff performance, but the disrupted airflow from the props in cruise is likely top reduce efficiency. Generally for low speed aircraft you want as few total propeller blades as you can use in order to reduce the losses from blade tip vortices. (practical effects like prop diameter will often force you to more props and more blades).
The article states that the Maxwell X plane is a hybrid and goes on to detail it is electric propulsion and battery powered. That doesn't sound like a hybrid to me. I can only guess they either used the term in error or were think of future concepts.
Interesting I would guess pure electric aircraft make up the majority if you include hobby quadcopters in that definition. I mention that as I think the takeaway from the article is that electric aircraft are practical in some niche areas and NASA's work will widen those niches. The changes need for EV cars to replace ICE are evolutions in batteries and is already close to the tipping point, but It is going to take some truly impressive breakthrough in battery technology before your will see traditional commercial jets like the A320, 737, 767 or A380 replaced. My guess we are are years, not decades, away from cars going all electric but for aircraft we are probably still talking decades.
My guess is the props on the takeoff motors fold in when cruising to reduce drag. Even if they do I would still worry about the remaining drag and the extra weight.
But then again it is an X plane. That is why you build them, to see how good or bad the ideas are in the real world.
hah, even better, look up "climb prop" and "cruise prop" and realize there's a huge difference between the optimal pitch for 80 kts and 130 kts. (climb speed v.s. cruise speed). Considering that tip speed is close to 540 kts at max RPM, that's an 8% difference in speed which is significant.
> GP also ignorantly fails to understand that props efficient in
> high speed flight are inefficient at low airspeed and vice versa,
> so stowing climb props is a very good choice for an electric airplane.
Howsabout variable pitch propellors??? They've been around since the 1920's, and have been in practical use since the 1930's https://en.wikipedia.org/wiki/...
Rev up 2 or 4 engines (admittedly a bit inefficient) for takeoff, and then back off to more efficient speed for cruising. 2 or 4 larger engines are cheaper and more efficient than 14 smaller ones. A bonus feature is that many "variable pitch propellors" can change pitch to *REVERSE* thrust. This is useful for backing up out of a hangar, as well as providing braking during landing on short airstrips.
I'm not repeating myself
I'm an X window user; I'm an ex-Windows user