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Electrified wingsuit from BMW reaches 186MPH on first flight

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Re: Electrified wingsuit from BMW reaches 186MPH on first flight

#191

Post by mPReDiToR »

dr_dshiv wrote: post #54
Hnrobert42 wrote: post #17

Earlier quoted context omitted.

If you are so inclined to answer, I’d live to know why lithium batteries and not some other form of battery? That is, do other elements not have the right properties? Are they too rare? Are they dangerous? You sort of answer a bit in your last paragraph. Why did it take until now to get to lithium batteries? Why way NiCad the thing before? Will lithium continue to dominate, or are there other competitive solutions ju…

Asimov promised me miniaturized nuclear batteries. Sad face.

They were supposed to fit in a belt buckle!

Re: Electrified wingsuit from BMW reaches 186MPH on first flight

#192

Post by afarviral »

JKCalhoun wrote: post #53
Robotbeat wrote: post #12

Lithium-based batteries (and associated tech) are to the 21st century what the internal combustion engine was to the 20th century and what the steam engine was to the 19th century. There’s a ~90% chance you’re using a device powered by a lithium chemistry battery to read this right now (laptop or tablet or phone). The smartphone alone (enabled by lithium based batteries) has transformed the world. Lithium-based batte…

Allow me my cynicism (this is HN after all): the rise of electric R/C planes and "foamies" has been a fascinating change in the model-airplane hobby but at the same time it has shown that you can practically put an electric motor + lithium cell on anything and it will "fly". So much so that I feel like the art/science of aerodynamics in modeling has fallen by the wayside. Your run of the mill quadcopter is an ideal e…

I fly FPV drones and can confirm the propellers and motor technology has come quite far. Not to mention the leaps and bounds of flight controllers in the last few years. There seems to increasingly few things that can go wrong with my drone. Bent prop/motor shaft; no problem. Missing parts of propellers; you can still fly home. Its aerodynamics, materials and software... and most of those things are off the shelf, just an afterthought for the drone builder and pilot. Its cool to be able to shift focus to flying but agree heavily its a different craft now.

Re: Electrified wingsuit from BMW reaches 186MPH on first flight

#193

Post by salawat »

girvo wrote: post #182
3princip wrote: post #113

Earlier quoted context omitted.

One could argue that the increase in hardware performance of computers has led to the art of software design falling by the wayside. Horribly inefficient software runs because the hardware performance hides the truth under the hood.

That in theory gives a programmer who does care about performance an edge: they can leverage the amazing performance of modern day chips in a way that the average product doesn’t, and it should mean a business advantage... In practice it seems more complex than that — but I have experienced a softer version of that idea in practice with my own work. Performance does matter, but it isn’t the only factor.

Unfortunately, you lose that advantage because in days of yore, people knew the implementation details of their hardware, and would optimize around that. With microcode. and the sheer size of certain instruction sets, it is very difficult to do the same thing, particularly mow that the philosophy of programming/computing has shifted to accomodate the industry as an omnipresent actor in your execution environment, and furthermore one with even more rights to observable machine state than you, the owner of the damn thing.

Your point on inefficient code stands, but there is far more at play than mere "programmers aren't skilled enough" and "imagine the possibilities!"

I'll wager a true Mel would not be an easy thing to reoccur nowadays.

http://www.catb.org/jargon/html/story-of-mel.html

Re: Electrified wingsuit from BMW reaches 186MPH on first flight

#194

Post by kerneis »

dmurray wrote: post #177
qppo wrote: post #103

Earlier quoted context omitted.

You can buy a helicopter. They're expensive, loud, and dangerous. The noise is really bad and one of the reasons I'll vote against any local ordinance that would make heli-transit more available.

Or you can buy a canoe - GP was willing to sail instead of fly. Cheap, quiet, safe-ish - paddling across the shipping lanes of the Hudson is probably mostly fine, but if you do it every day you'll have some close calls. The Hudson River is less than a mile across at Manhattan. This could be faster than car/train/ferry/bike for some very specific commutes.

It's very much doable: https://edition.cnn.com/2016/11/01/americas/zach-schwitzky-c...

"Living in Hoboken, New Jersey, the other side of the Hudson river to Manhattan, Schwitzky kayaks across the water in around 20 minutes."

Re: Electrified wingsuit from BMW reaches 186MPH on first flight

#195

Post by Amezarak »

stjohnswarts wrote: post #166
tomc1985 wrote: post #122

Earlier quoted context omitted.

Internal combustion engines don't degrade to uselessness after three years

Are you joking? Electrical motors can go for decades before they need replacing if they're built well. Same with electronics. Contrary to HN bits don't rot, electronics fail though over time depending on robustness. Just because you don't update to the latest and greatest every couple of weeks doesn't mean anything if the device you're using is serving it's purpose well enough. I'm not sure where you're getting "3 ye…

> Are you joking? Electrical motors can go for decades before they need replacing if they're built well. Same with electronics. Contrary to HN bits don't rot, electronics fail though over time depending on robustness.

This is a mighty big "if."

Re: electronics, the electronics are by far the highest-failure item in ICE cars and in the mechanical appliances I own. Indeed, every failure I've had in cars I own and those of my family owns has in the past ~15 years been an electronic problem. That's only usually been the case with appliances and tools.

Re: Electrified wingsuit from BMW reaches 186MPH on first flight

#196

Post by demarq »

hwillis wrote: post #159
demarq wrote: post #24

Something seems suspect here. There is just no way that small unit could generate near enough thrust to make a real difference. I think we need to look deeper into this claim

https://www.youtube.com/watch?v=mxJJ17HV1yU Fans that small put out enough force to literally push you straight up. Jetcat has an engine 23 cm wide which can pull 110 kg. For the same size an electric fan passes much more air. https://www.jetcat.de/en/productdetails/produkte/jetcat/prod...

those are jets, not EDF

Re: Electrified wingsuit from BMW reaches 186MPH on first flight

#197

Post by usrusr »

lillecarl wrote: post #190
usrusr wrote: post #160

Earlier quoted context omitted.

But brushless electric motors are so much more reliable than combustion engines (internal or turbine), the comparison is not even funny. They are basically solid state devices. "Losing power" is simply not much of an error state outside of complete battery failure. And if you still want to be safe from motor failures (or from propeller failures), octocopters exist. I share the "multicopters are boring" attitude, but…

Absolutely, as long as they're operating within parameters there's no failing them. I've been running brushless systems in RC cars for the last 7 odd years. The only motor failures has been when It's been subject to extreme abuse, as in the rotor reaching 100+° (internally), going from ~55-60K RPM to 0 in fraction of a second or the rotor being forced through the bearings. For unmanned flight i do agree on multicopte…

Well, simple propeller pitch control is a lot easier than a swash plate because it's idle when the pitch is kept the same and it's no problem if making it slower simplifies it. A swash plate is active on each rotation and needs to be fast enough to work the blade through a certain range of pitch values within have a rotation interval.

Re: Electrified wingsuit from BMW reaches 186MPH on first flight

#198

Post by sudosysgen »

Robotbeat wrote: post #186
sudosysgen wrote: post #141

Earlier quoted context omitted.

Isn't the efficiency of jet turbines, even microjets, wildly dependent on velocity? I don't know how you can calculate an efficiency without qualification.

I used figures from a hobby turboprop which gives mechanical power output in kilowatts (or horsepower, if you prefer) and it’s basically independent of velocity.

Well yes, that's a turboprop. But fossil fuel wingsuits don't use turboprops, they use turbojets, whose efficiency very much depends on speed, which in practice means that they are most efficient right before their peak mach, up to around mach 2.

Re: Electrified wingsuit from BMW reaches 186MPH on first flight

#199

Post by lopmotr »

tomc1985 wrote: post #133
lopmotr wrote: post #129

Earlier quoted context omitted.

Of course, otherwise those fancy cameras would have no market and disappear. Just like film is pretty much completely gone now, as are glass plate cameras. The truly inferior tech disappears and what's left fits some extreme niche where it surpasses the cheap consumer stuff in some way. There are things you can do with a PC that you can't with a smartphone too.

That's incredibly optimistic of you to call the PC dead. I really, really, hope (and am pretty sure) that you are wrong

Not death of the PC! Just the presence of more numerous and cheaper smartphones. They're superior to PCs for most people but not for everyone.

Re: Electrified wingsuit from BMW reaches 186MPH on first flight

#200

Post by anonytrary »

peterwwillis wrote: post #180
anonytrary wrote: post #124

Earlier quoted context omitted.

This sounds like a "Karen" comment. Do you really think a few guys flying in turbulent air will spread covid? Have you seen all of the people who gather in parks in San Fransisco? This flying experiment is not even comparable to other vectors of the virus that immunocompromised people are exposed to on a daily basis.

It's not so much a 'Karen comment' as actually respecting human life. But sure, let's all spread the disease whenever we feel like it just because other people spread it worse. It's amazing how little morals people have nowadays when I have to defend not wanting people to die.

Coughing at 10,000 feet is completely harmless. That sort of turbulence/condition is an unviable transmission vector for a virus as it reduces the PPM beyond effectiveness.
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