Last I checked Beta is doing flight tests with the VTOL engines and props folded. They are working on fixed wing aspects first. From what i have read previously, some (or one) of the engineers at Beta felt the fixed wing portion of flight is harder to get correct and requires more testing, and the FAA has the same position. The VTOL portion is more a matter of brute force and failure modes, so it will be done after what they believe will be a confirming prototype for the fixed wing design.Nice content of the Martine Rothblatt flight, though it's interesting that they carefully avoided including any video of the takeoff or landing. Obviously it's capable of CTOL in addition to VTOL, which is a good thing.
2nd law of Thermodynamics says otherwise. You can't "pay back" the costs, let alone more than pay back the costs. Otherwise you have a perpetual motion machine.Wrong.It is counterintuitive.The "cost" is more than paid back in reduced resistance and therefor heat,which is proof of increased overall efficiency.
Pick up your game.
Strike two.2nd law of Thermodynamics says otherwise. You can't "pay back" the costs, let along more than pay back the costs. Otherwise you have a perpetual motion machine.
And there's no need to get snarky
ok so you choose to retain the snark. Noted. You might not like what that brings.Strike two.
Its not a heat engine.
Its a non linear chemical reaction that is
counter-intuitive in that there is specific temp
(higher than ambiant),where resistence is lower,current is lower,therfore total heat generated in the charge and discharge cycles
Back to school baby.
Your lucky to get snarky,some of the best here
will manage to assign remedial reading without
ever quite acknowleging your existance.
Wow.ok so you choose to retain the snark. Noted. You might not like what that brings.
Just because you are talking about an electric motor doesn't relieve you of the 2nd law, (ie.e Entropy) because YOU wrote [emphasis mine - and I retained your typos] :
"One counterintuitive aproach to battery temp management is to HEAT the battery....reduced the resistance,therefore current, and therefor heat."
YOU are talking about heat. Therefore whatever that addition of heat does to battery efficiency cannot do it with 100% efficiency. Neither can you generate and transmit the heat with 100% efficiency.
Can you? No you can't.
2nd law. Entropy.
Losses. And then whatever efficiency gain you get from heating a battery cannot give you MORE than what you expended to get it: Entropy.
The thing is you have to treat all of it as one system - you cannot just look at an efficiency increase in one aspect and ignore the losses you incurred to get that.
And I'm skeptical about that - usually resistance goes down when you chill something, not heat something - but I don't know about your 'application". And since you mention that you are "going from memory here"
...and didn't provide a reference to the paper but said only " ,but recent work published this year."......
I can't really speak to it. But I'm skeptical about that.
So go ahead with your snark. But this comment of yours:
Its not a heat engine.
...tells me that you might not understand basic physics.
When you argued with the sentence, which was my first comment:Wow.
A battery is not nor was it ever a heat engine.
Irrelevant. As has been explained.
And your atempt to somehow hijack the point
Too bad you think that pointing out a problem with your "view" is a hijack.
That's the sort of response I expect from a teenager.
"....and blather on about the second law is disingenious or a go to knee jerk reaction to
a PERCIEVED voilation of the first principal,
that energy can not be created or destroyed."
My point has nothing to do with energy being created nor destroyed. That's the First Law of Thermo. My point has to do with the second. So this snarky attempt to say something relevant fails.
Also, Entropy has a say in realms outside of Thermodynamics as well. That's why I introduced the term.
You clearly do not, can not, or refuse to, think about this.
So the idea is to raise the temp of the battery to the sweet spot and hold it there,allowing for
a faster and deeper charge and discharge cycle.
You can repeat this all you want but it doesn't address my point.
As I wrote I cannot comment on whether or not heating a battery helps it's efficiency in some regime. You didn't supply a reference to the paper you claim this all came from. It sounds odd to me but as I said until I read something authoritative I won't claim that the counterintuitive notion of heating an electrical system makes it more efficient is wrong.
But of course that has nothing to do with my point either.
And the strategic use of partial out of context quotes is bad mannered and gets you snark.
Nope. You are snarky because you think it makes you cool or you think it lends weight to what you say, or something. Whatever the reason it's childish.
Especially since what tripped your hysterical reaction was this one sentence:
"Which [i.e. your heating up the battery] takes energy and therefore must be added to the "cost"/energy utilization etc."
Which is pretty innocuous and merely states that you cannot ignore the cost of generating the heat to heat the battery.
Picking and choosing quotes is done to focus you on the part of your comments that are faulty. All the rest of the garbage you write is still there in your post and not hidden. Long posts get to the TLDR stage quickly so selecting the pertinent phrases or sections is done for efficiency.
You should know that when I reply to a post my reply is aimed at everyone - not just the person I'm replying to. So TLDR matters there too.
You are now trying to attack my method of reply and NOT what I'm saying. That plus you keep repeating that heating the battery speeds up recharge are the clearest indicators you don't know what my point is and/or understand it. It makes me think you are more evangelical than engineer.
That dealership is just across the street from my home airport. Anyone who wants to come look at the hydrogen car mentioned above, you can fly in to KWHP and I'll cheerfully drive you across the street to see the car. There's even a pretty good Mexican restaurant that just opened catty-corner across the street the other way... if you like good Ceviche !Those interested in experimenting with hydrogen fuel based here is 161hp for less than $20k.
2019 Hyundai NEXO Blue KM8J74A6XKU001139 | KARPLUS WAREHOUSE INC. Pacoima, CA (888karplus.com)
Backed by the government. Why does that inspire absolutely no confidence in me whatsoever? Oh, that's right. I worked for the government, or government contractors, for about 30 years, and worked with a lobbying group for a while. I've come to the firm conclusion the only thing government does well is break things and kill people, and sometimes they also screw that up, usually due to some political crap.Hydrogen backed by the government.
Moreover, Landsvirkjun, the National Power Company of Iceland, and the Port of Rotterdam have completed a pre-feasability study about exporting green hydrogen from Iceland to Rotterdam and the Swedish Energy Agency has allocated €30 million to Project Air, an industrial concept to produce...www.pv-magazine.com
Myself being an 'old guy' having enough experience and a masters degree in engineering, I agree with a lot that was said, but I think that electric propulsion makes a small VTOL aircraft viable for the following reasons:This, boys and girls, is from 1967. And it's just one silly little example of why we old guys are so skeptical of the current marketing hype around electric airplanes or VTOLs or hydrogen fuel cells or almost anything else these days.
View attachment 112486
It was posted over on Pilots of America. Some interesting comments about stuff like this. Hindsight is a wonderful thing, since it makes your baloney detector much more sensitive. Young people don't have hindsight yet. They have to be repeatedly fooled by stuff like this before it develops. Or they need a good degree in physics; that alone will smarten them up.
"A Sucker Is Born Every Minute" Dept.
Your take is an interesting departure from any I have heard so far.Myself being an 'old guy' having enough experience and a masters degree in engineering, I agree with a lot that was said, but I think that electric propulsion makes a small VTOL aircraft viable for the following reasons:
- it has high efficiency regardless of power setting - it has 90%+ efficiency when providing happily for a short time 150% of rated power for hovering, or cruising at 30% 'throttle' setting for effective cruise
- simpler design for distributed propulsion
- electric motors have high specific power
For these reasons I believe a personal VTOL aircraft can be built successfully today, and if sized for short flight - e.g. for under 30 minutes, fun flying or commuting - the propulsion system could be even lighter than equivalent piston ICE, even using the low specific energy batteries we have right now.
That being said, I don't agree with current VTOL configurations. Designing an effective VTOL is hard, the aerodynamics is a compromise, the rotors are too small for effective hover, but too large to provide efficiently high speed cruise thrust, or if stopped - are a source of extra drag, compromising the cruise performance. There is no configuration yet to ensure both hover and cruise performance. A multi-rotor cannot compete in hovering performance with the classic single rotor helicopter due to disk loading and reduced Reynolds number flow of smaller rotors. A cruise wing-borne VTOL aircraft has too many sources of drag to compete even to a very poor performing fixed wing. I think a good VTOL configuration is yet to be developed, and that is the job of aerodynamicists and not software designers or electrical engineers.
The vertiport hubs proposed today by so many interested parties is supposed to reduce travel time, but best time travel reduction is only realised by point to point direct flight, especially for short flights. Short duration flights increases the proportion of hover flight segment and since the hover performance is driven by disk loading that is linearly dependent on weight, it makes more sense to develop small personal VTOL aircraft, maybe for 1-2 peoples, but able to take off and land anywhere, from small verti-pads easily installed in personal driveways, backyards and local grocery stores. Sure, a lot of things need to change before that, from public acceptance, safety, personal weather awareness, to regulation point of view, and I guess large vertiport hubs are a step toward that.