17
votes
Could the static charge build up during flight be sufficient to power aircraft systems?
Here's a very back of the envelope calculation for precipitation static:
The wetted area of a 787 is around $1800~\rm m^2$
The most triboelectric materials are around $.2~\rm nC/g$
The density of ...
- 12k
9
votes
Accepted
Why don’t ionocrafts (ionic propelled aircrafts) use ducted ionic thrusters instead of open air thrusters?
A problem of ionic thrusters is that they only generate a gram of thrust for every watt, which is really inneficient.
The Wikipedia article says that about the early versions. I don't think it ...
- 56.2k
8
votes
Why don’t ionocrafts (ionic propelled aircrafts) use ducted ionic thrusters instead of open air thrusters?
This is Ethan Krauss. My VTOL Ion Propelled Vehicles have onboard power. Rather than a wire mesh, they have streamline wing shaped collectors made of concentric hexagons. Those surfaces are currently ...
- 81
6
votes
Why don’t ionocrafts (ionic propelled aircrafts) use ducted ionic thrusters instead of open air thrusters?
Is it correct to ask about "inonocrafts" (the plural?) Are there any other examples besides the 5lb MIT one?
The theoretical thrust gain from a duct would have to overcome the additional ...
- 7,568
5
votes
Accepted
Why ionocrafts (ionic propelld aircrafts) don't use electromagnetism to improve performance?
An ionocraft does use an electromagnetic accelerator. It works by generating an electric field that accelerates the ions between two plates and taking advantage of the interaction between the ions and ...
- 12k
5
votes
Accepted
Are there any aircrafts that use the same "ballooning effect" of spiders to fly?
No.
Phenomena that we observe of objects in the miniature realm do not scale up to our size. Small insects are capable of many things that humans are not, as in this example: Water Strider
Asking if ...
- 24.8k
5
votes
Instead of battery why we don't use some perpetual energy source? Atomic Energy?
Because there is no such thing as a perpetual energy source. Atomic energy eventually runs out and all reactors have to be refueled. Stars all run out of fuel as well and flame out in some interesting,...
- 12.6k
5
votes
Accepted
Why was the Sikorsky Firefly built but never flown?
The director of Sikorsky Innovations Chris Van Buiten called it a
technology demonstrator and research platform that will let us explore the technology, partnerships and technical collaboration...
...
- 10.6k
4
votes
Performance metrics of a propulsion system - optimising a propulsive fan system
Well, if all you care about is the fan performance by itself, then you've pretty much got it. Maximize the component cycle efficiency and maximize the propulsive efficiency and that's it. But if you ...
- 5,508
4
votes
Accepted
Any idea what this Ampaire plane is?
It's called the Ampaire Tailwind, and as this article explains, it only exists in scale models and renderings at the moment.
- 3,751
4
votes
Accepted
Where is the battery location of Eviation's new electric aircraft Alice?
According to FlightGlobal the batteries of the original prototype were located in the fuselage, under the floor structure:
He [engineer Jonathan Johnson] got out of his seat and went to the battery ...
- 27.1k
4
votes
Accepted
Use of Fuses in modern Aircraft Systems
Yes you will find fuses sometimes used where you need instantaneous protection of a circuit from overcurrent, where a circuit breaker, which must heat up to work like the fuse does but needs more time ...
- 126k
4
votes
Accepted
Do EA-6B Electronic Countermeasure Officers focus on one task at a time?
Prowler ECMOs rotate seats, and while sitting in the front right seat they function as a copilot. There is no second set of controls as some aircraft have, but they are responsible for operation of ...
- 24.8k
3
votes
Comparison: e-aircraft vs. ground EV modes (car, coach, rail)
Train wins, every single time. Zero induced drag.
Thanks to the magic of Timken roller bearings (in truth, plain bearings worked even better when rolling fast enough for the hydrodynamic layer to ...
3
votes
Will the electric motor work well in ultralight aircraft?
It might. This answer shows two graphs from a now dead link, from am article that concluded that a 20 hp electric motor does a better job at powering a hydraulic pump than a 50 hp combustion motor.
...
- 61.3k
3
votes
Will the electric motor work well in ultralight aircraft?
What you need to do converting from gas to electric is to look at peak rpm for a given prop, and endurance.
HP comparisons may be meaningless because gas motors have much lower max rpm, and most ...
3
votes
Is it possible to build an ultralight helicopter with electric motors as its main engines?
From a quick Google search, you can find that Sikorsky Firefly and Tier One R44 are two examples of eHelos, conventional helicopters converted to electric propulsion. They both fly around 20-30 ...
- 1,179
2
votes
Are any flight schools or clubs in Canada using Pipistrel's Alpha Electro or Velis Electro?
The University of Waterloo has imported Canada's first Pipistrel Velis Electro. This one is for testing, but hopefully it leads to certification and flight schools like our partner Waterloo Wellington ...
- 21
2
votes
Accepted
Are any flight schools or clubs in Canada using Pipistrel's Alpha Electro or Velis Electro?
The only Pipistrel Electro registered in Canada is an Alpha, C-IZAP, registered to a private owner in British Columbia. So the answer is for now, no.
Pipistrels, including the Electros, are licenced ...
- 126k
2
votes
What's prohibiting the use of large batteries for electric aircraft?
Jet fuel is around 43 MJ/kg while battery is 0.9MJ/kg
Fossil fuel airplanes is already taking off with 1/3 total weight being fuel 1/3 weight being payload (B737-300, 62t MTOW, 18t fuel, 16t payload)....
- 2,900
2
votes
How to find the battery mass fraction for electrical VTOL aircraft/drone
I'm a bit late here but... have you seriously calculated the battery mass fraction?
The "weight fractions" method is a quick & dirty method to evaluate how much fuel is burned during ...
- 9,489
2
votes
Comparison: e-aircraft vs. ground EV modes (car, coach, rail)
For airplanes and cars, one approach might be to break it down to wattage per seat mile for each conveyance. Cars only need about 20-30 HP to cruise on the highway; say 22 kW. An airplane needs about ...
- 126k
1
vote
To what extent is it viable to launch manned gliders vertically using unmanned drones rather than tow planes?
Making a glider gain altitude by lifting it up vertically using a drone or a crane does not make much sense. It's a bit like denying the fact that the glider has wings.
To make an analogy with the ...
- 4,454
1
vote
To what extent is it viable to launch manned gliders vertically using unmanned drones rather than tow planes?
Boeing experimented with a strategy to launch a parachute via rocket, and then use that as a winch point in the sky. A rope would connect the falling parachute to a glider on the ground on one end, ...
- 4,893
1
vote
To what extent is it viable to launch manned gliders vertically using unmanned drones rather than tow planes?
With a cheap source of electricity the concept might be viable, if only for tourist flights.
Another approach might be with a balloon. Here the lift is free and great heights are possible.
Or, ...
1
vote
Who is the manufacturer of the power inverter used by Ampaire electric aircraft?
It's probably a device from Cascadia, Unitek, Sevcon, or Emsiso.
The motor looks like an Emrax axial flux motor. At one point, Emrax's user guide said their motors are compatible with controllers from ...
- 1,058
1
vote
How to find the battery mass fraction for electrical VTOL aircraft/drone
It would seem quite reasonable to assume that for a vtol drone (or any other vtol acft) takeoff can be considered to be insignificantly different from climb segment. Only difference would be the short ...
- 27.1k
1
vote
Relation between lift force and torque produced in propeller used for vertical take-off and landing aircrafts
What you are looking for is Blade Element Theory:
The expression for the torque of the whole propeller is therefore
$$ Q = \frac{1}{2} \rho V^2 B \int_0^RQ_c \, dr $$
Q - total torque required by ...
- 805
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