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Electrified wingsuit from BMW reaches 186MPH on first flight

robbreport.com

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

#161

Post by aeharding »

duxup wrote: post #146

Are these way safer than say the base jumping type wing suits? Obviously they're powered so they're different, but I remember a lot of wing suit debates where even professionals felt that the envelope between 'safe' and disaster on wing suits was way too small for even professionals to use. A lot of that seem to have to do with the jumper's sense of how stable they are / compared to how stable they actually are and h…

Just to clarify, he's jumping a BASE rig with a wingsuit - albeit technically a skydive (jumping from a helicopter).

It's a BASE rig since it only has one parachute, and the sole canopy is designed to deploy quickly and consistently.

Another clarification - BASE rigs with wingsuits are not inherently dangerous. In fact, BASE/wingsuit gear failure as a cause of death is extremely low. It's correlation vs causation - BASE rigs are used almost always (except for certain stunts like this) used in a BASE environment flying close to land, where the margin of error (time to impact) is extremely low compared to a skydiving environment.

In a skydiving environment, you can do everything wrong, even do nothing and likely live (automatic activation device triggered deployment of your reserve canopy). But with BASE, oftentimes you are flying so close to terrain that you cannot deploy your canopy and live, and your only option is to continue flying your wingsuit to a safe place to deploy - which is a problem if you stall, take a slightly wrong line down the mountain, etc.

Source: I'm a parachute rigger and I wingsuit (in a skydiving environment).

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

#162

Post by JohnJamesRambo »

Robotbeat wrote: post #97
JohnJamesRambo wrote: post #93

Earlier quoted context omitted.

>after another few decades of battery chemistry improvement How do you know we aren't near the end of what is possible with batteries already? I assume that people in the steam and internal combustion era thought things would just keep improving forever as well.

Because of where we are in the lab for better chemistries.

https://www.reddit.com/r/dataisbeautiful/comments/2kmz7d/lii...

This only goes to 2005 and is plateauing at 200. I checked and a Tesla is 250-260 or so. Seems rapid growth is definitely over and we are at the asymptote.

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

#163

Post by stjohnswarts »

dmurray wrote: post #95
Someone wrote: post #84

Earlier quoted context omitted.

For insects, hummingbirds, and quadcopters of similar size, there’s no danger in dropping from the sky. J.S. Haldane in “on being the right size”: “You can drop a mouse down a thousand-yard mine shaft; and, on arriving at the bottom it gets a slight shock and walks away, provided that the ground is fairly soft. A rat is killed, a man is broken, a horse splashes. For the resistance presented to movement by the air is…

> A rat is killed, a man is broken, a horse splashes. I had thought that cats could fall from any height safely, but that's not quite true: observational studies suggest [0] they have a 50% or 90% survival rate from terminal-velocity height onto hard surfaces, but not without injury. Still, I'd expect a rat could also "walk away". It's quite a lot smaller than a cat, though it may lack other evolutionary adaptations…

a huge portion of that is that humans have a much worse weight to surface area ratio, cats hit at about 60mph and humans at 120 mph. very few humans survive falls in which they reached terminal velocity.

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

#164

Post by usrusr »

henrikschroder wrote: post #111
Robotbeat wrote: post #18

Earlier quoted context omitted.

The periodic table is limited. Of all metals, lithium is the lightest. It also has the highest mass-specific conductivity and the highest chemical specific energy of all the metals. Hydrogen is not a solid or a liquid at room temperature and is also too volumetrically in-dense.

I have never really understood the hydrogen hype train, because liquid hydrogen is terrible in so many ways. A bucket of gasoline contains more hydrogen atoms than a bucket of liquid hydrogen, it contains more chemical energy, and you can actually keep it in a bucket at room temperature without anything terrible happening. Sure, liquid hydrogen has a lot of energy by weight, but energy storage needs to be good by wei…

Hydrogen storage becomes quite easy when you forget about H2 for a while and focus on the energy content instead. Add some other atoms into the mix and you get something much more benign with little energy loss. Methane (CH4) is the obvious first candidate because it's so close to what we are used to burn, but ammonium (NH4) is also a good "storage hydrogen" (this one you'd want to split before burning, but it's easier to make because there's far more N than C in the air). Ammonium liquefies at easily achievable -33C or at room temperature under pressures no higher than what you find in certain bicycle tires. Some are even exploring the viability of iron dust as an energy storage medium: it oxidizes quite violently and would be recycled from the resulting iron oxide dust with hydrogen.

So hydrogen electrolysis would be the root of renewable chemistry just like fossil hydrocarbon is the root of almost all current chemistry (where even processes that use hydrogen are sourcing that from fossil hydrocarbons). You can have a "hydrogen based economy" even without any meaningful amount of H2 ever stored or leaving the power-to-x plant.

Usage site H2 applications are a dead-end, that's something I would have signed ever since the "hydrogen economy" proposed by George W. Bush (funny how benign hindsight looks at him post-Trump). Admittedly, back then I was also completely unaware that "hydrogen based economy" wouldn't necessarily mean "H2 to the home", I was just shooting down that idea with basically the same inevitability arguments as yours.

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

#165

Post by bredren »

hamburglar wrote: post #149
bredren wrote: post #102

Earlier quoted context omitted.

I’m not going to post the link but they are called Twharf D Cell Batteries 1.5V/5000mAh D Batteries Micro. I really could not believe it when I charged them for the first time. Here is a pic https://i.imgur.com/2LoyZlR.jpg

Those look incredibly useful. I'll be ordering some in the future if they are still around and don't seem to have any reliability/safety issues (I'm slightly wary of Lithium batteries being crammed into places that haven't been thoroughly tested for that application, given the tendency of these things to catch fire. A Mag-lite with lithium batteries would be great but resembles a pipe-bomb a little too much for comfo…

I don’t know about their reliability, but the sheer novelty of recharging them is something else.

I’ve only done it once in six months for the cat feeder and it hadn’t run out.

No fires yet. Presumably the danger would be in the wiring and power electronics. I’d guess the battery is off the shelf, though I haven’t torn one down—they aren’t exactly cheap.

My favorite part is the action on opening the end. It is slightly spring loaded, but also limited, it won’t come apart. Someone clever designed it.

They have other standard sizes as well, but I haven’t tried them.

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

#166

Post by stjohnswarts »

tomc1985 wrote: post #122
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…

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 years and you're done" from.

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

#168

Post by usrusr »

Hnrobert42 wrote: post #79
CrazyCatDog wrote: post #19

Earlier quoted context omitted.

NiCd is actually more capable than NiMh, but suffers from memory issues (capacity decreases significantly if not carefully discharged and recharged; ie you cannot “top them off” without sacrificing capacity. Again, speaking from my lived experience, NiCd pushed to the limit resulted in many gnarly fires in high performance RC use, NiMh was never a contender given low output (again low discharge rates). LiPo is king h…

What about lithium and memory? Do lithium batteries have big memory issues, or is all the stuff rattling around in my head about batteries having memories mostly because I grew up when NiCd and NiMh were all the rage?

If you grew up with both you must remember how NiMH was initially championed as "no memory effect". It was still there, but so weak compared to NiCd that the claim wasn't really disputed. Lithium are at least another step of that size better than that, if they have memory effect at all. If they do have a tiny little memory effect left it's probably smaller than the extra cell aging one deep cycle would cause compared to to two smaller cycles of the same total capacity, as least as long as the smaller cycles are taking place somewhat close to nominal voltage. That would at least make memory effect irrelevant for all practical purposes.

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

#169

Post by usrusr »

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…

Nondegrading motors and electronics are indeed fine if you never leave the range defined by you -charging- pardon operating cable.

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

#170

Post by usrusr »

CrazyCatDog wrote: post #14

An electric ducted fan (EDF) is highly inefficient, had they put similar wattage through a gearbox to say a folding prop, efficiency may have doubled (albeit an admittedly more onerous form factor). This is just the beginning of electric assist single passenger flight! Reference: plenty of experience pushing 8KW+ through 2KG RC gliders (F5B) and far slower EDF models.

"electric assist single passenger flight"

If electric is assist, what would be the main power source?

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