They're the same shape they'd be if they had to fly on a 20-hp lawn tractor engine. Like a motorglider. Nothing new here at all, like you say.With our current understanding of aerodynamics, this indicates that battery powered airplanes should all have long skinny wings and egg shaped fuselages, and amazingly... that's what they look like. In contrast with all the Unobtanium wannabee tech stuff we see every day, all of the common sense and data on energy density perfectly support the current (glider-looking) electric airplane designs, and the actual flight results on these airplanes prove out that they work to a modest degree.
The electric motor is called a "motor" because it converts energy into motion. An ICE is called an "engine" because it has to make that energy by chemically converting fuel into heat. Now we run into some inconvenient facts that have been addressed before:The electric propulsion has 2 characteristics that might be really valuable, besides 'green craze':
- high power to weight ratio for the electric motor: this means that for a short 'hop' the propulsion system might be lighter than conventional ICE. Think case that the aircraft needs to fly only 20 - 30 minutes ( e.g. commuting to work)
Ya we know all that.The electric motor is called a "motor" because it converts energy into motion. An ICE is called an "engine" because it has to make that energy by chemically converting fuel into heat. Now we run into some inconvenient facts that have been addressed before:
Storing electricity costs weight, and has safety issues for some battery types. Electricity storage is a lot heavier than chemical (gasoline/diesel) storage and it's much slower to "refuel." Electricity generation, which has to happen somewhere before you can charge those batteries, has a whole bunch of efficiency losses between generation and its conversion into motion, so the electric is not innocent of wastage.
That is not quite true: a gasoline ICE engine uses about 15 pounds of air for every pound of gasoline burned. Luckily the air is not needed to be stored on board the aircraft. Current batteries store all the reactants inside.Electricity storage is a lot heavier than chemical (gasoline/diesel) storage ...
It is much more effective to produce electricity at a coal power plant - efficiency about 60%; transmission, conversion, charging batteries, discharging, conversion for the motor, everything is close to 90% - than to use an ICE and burn gasoline at 30% efficiency. This assuming electricity is produced by coal only. Also the gasoline needs to be refined and transported to the pump, and transporting fuel is much less efficient than transporting electricity.Electricity generation, which has to happen somewhere before you can charge those batteries, has a whole bunch of efficiency losses between generation and its conversion into motion, so the electric is not innocent of wastage.
It isn't that easy to take a pure sailplane and add an engine for efficient flight. Sailplanes are generally heavy per seat and adding an engine, prop and three wheels makes it far heavier. To climb at a high rate you need significant hp. That's why tow planes have big engines. We don't see many large motor gliders for high speed cruising. Too rough and the wife will not go a second time.My last sailplane (1980's technology) had a 45-1 L/D with the long wingtips on it. The airplane carried 40 gallons of water ballast, which would equal the weight of a pretty large battery. At 1102 pounds gross weight, that means less than 25 pounds of thrust would fly it in that condition, at about 60 knots. One of you genius-level guys can estimate how big of a battery/motor combination it would need to take off, climb to a thousand meters, and then cruise at that max efficiency for X miles. I'm guessing that 250 pounds of battery and 60 pounds of motor and prop would deliver a lot of range.
That coal has to be mined and transported. It has to be moved into the plant, and the coke removed. That's plenty of loss right there. The spent steam has to be cooled to condensation for pumping back into the boilers. More lost energy. Besides that, when you take 90% of something that's 90% efficient, you end up with 81%. Do that a few more times, representing each stage of power delivery and conversion, and you don't have much left. So everything involved has to be very efficient, and that costs lots of money.It is much more effective to produce electricity at a coal power plant - efficiency about 60%; transmission, conversion, charging batteries, discharging, conversion for the motor, everything is close to 90% - than to use an ICE and burn gasoline at 30% efficiency. This assuming electricity is produced by coal only. Also the gasoline needs to be refined and transported to the pump, and transporting fuel is much less efficient than transporting electricity.
It does not make me happy. The stuff you are citing is from sources that have suspect motives. We have already addressed the limits of battery technology, limits that will take some fantastic new technology to resolve, and fantastic new technologies are not known for being inexpensive or for their immediate availability. This is not the digital world, where Moore's Law says that the tech doubles every two years or something. Your computer doesn't have to fly. Nor does your cellphone. Flying demands LOTS of energy, not a 3 GB processor.And electric I planes are an inevitability.
Check the date ,2021.The battery problems are
bieng addressed apace.Good news every day.
Hope that makes you happy.
OK, a short aside. I spent a lot of time in Bethesda Naval Hospital (Cancer). Bethesda is the main hospital for military amputees treatment and recovery among other things.I remember the big hoopla 20 years ago about "it" coming and changing the way we moved around. "Bigger than the internet," they said. The Segway. And how big did that go over? Finally died last year. I'm either living in some remote part of the world, or there were never many takers for it. Other than in videos, I've seen them used exactly once, a group of four or five being rented by tourists.
Hoopla. Hype. We all fall for it until we get old and experienced enough to spot baseless claims and start being skeptical. At least most of us reach that point. Some can be fooled endlessly.
Actually ICE does still have plenty of room for improvement, they've just been complacent because they had a highly profitable business with little competition. Opposed piston engines are one interesting category for further R&D. And there's a company called Alfadan that's working on a new 4 cylinder inline with higher displacement than has been possible thus far, due to a dynamic balancing issue caused by asymmetry of the up and down strokes of the cylinders with simple connecting rods to the crankshaft. The youtube channel "driving 4 answers" has a good video on it.ICE got nothing more to give,just going to get more expensive,more regulated,less popular,
an industry with huge wealth and power left
facing its own inevitable replacement without
the good grace to help the sucession of societies energy needs along.
Political pressure from climate change activists. They demand an end to fossil fuels right now, not understanding the devastation of such a move. For one thing, it would leave a country with a badly disabled military, and guess what comes of that? The UK is committed to all electric military stuff ASAP. Tanks, planes, everything. Tell me how that makes sense....why do we see governament step by step making life of "normal" car owners difficult? This has nothing to do with logic or ecology.