Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Electrified wingsuit from BMW reaches 186MPH on first flight

robbreport.com

Post reply on HN
Print view View original

171–180 of 203 posts

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

#171

Post by h2odragon »

wombatmobile wrote: post #154
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.

> had they put similar wattage through a gearbox to say a folding prop, efficiency may have doubled (albeit an admittedly more onerous form factor) They chose not to do this because the more onerous form factor results in amputation of the pilot's viscera and legs.

> results in amputation of the pilot's viscera and legs.

Granted, that could be an issue, but once the government contracts for production of a few thousand units such minor flaws can be addressed with a field upgrade package, barely tripling the unit cost.

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

#172

Post by robotresearcher »

im3w1l wrote: post #147
robotresearcher wrote: post #116

Earlier quoted context omitted.

Multirotor designs are not limited to 4 motors. You can add more for redundancy. Four is common because it’s the smallest number that has good control characteristics.

Mind explaining that one? To me it seems they have an unnecessary degree of freedom: the "diagonal" one. ox xo What issues do you get with three motors in an equilateral triangle? EDIT: I managed to find it, with even number of motors you can prevent unwanted yawing, by letting half spin clockwise and other half spin counterclockwise.

Yep. More generally, you can induce the yaw rate you want (up to a limit) in either direction, including zero.

I’m not an expert but IIRC with three rotors you need to be able to control a bit of roll of just one of them to have stable flight control.

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

#173

Post by strbean »

tachyonbeam wrote: post #78
simias wrote: post #61

Earlier quoted context omitted.

Quadcopters also usually have terribly autonomy. Gliding is a lot more efficient at conserving energy so there's still a lot good engineering to be had in aerodynamics whenever you need to be in the air for more than a handful of minutes at a time. That's why if you look at professional drones you generally only see quadcopters when being able to hover and/or execute very precise motions is required, for the rest win…

It seems to me like there's a good future for electric VTOL. Whether for package delivery or for carrying people, you can take off vertically, and then transition to a horizontal flight regime using wings that's more energy efficient, so you can get more range.

That's what they're hoping for at Joby Aviation: https://www.jobyaviation.com/

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

#174

Post by usrusr »

Toutouxc wrote: post #145

Why does this, of all things, have to be electric? It's a wing suit. They're basically strap-on death. Their glide ratio is somewhere between a really bad plane and a brick, they're unusable in any shape or form for real transportation. They could've had gone with a jet or even a rocket engine and it wouldn't have made the thing more dangerous or less green or anything. Don't get me wrong, I love it, but I don't real…

Rockets or jets would limit your candidates for a sponsoring contract to Red Bull and Red Bull. If you are making a bit of a career out of BASE and/or wingsuit you are probably tired of them by now, or they are tired of you or both. It's a very small market and surely weird given that the buyer has a monopoly, whatever that means.

With electric, apparently BMW becomes another candidate (who seem to be desperately looking for ways to get their name visible in a context that somehow combines "electric" and "exciting").

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

#175

Post by Retric »

chrisweekly wrote: post #112
Retric wrote: post #27

Earlier quoted context omitted.

Sure, I just find it funny how in most cases 180MPH is fast, but that’s about the minimum speed for horizontal wingsuit flight. You really can strap a get engine to a brick and get it to fly, but you can’t stick a jet engine to a brick and get it to fly slowly. EX: F-15 landed safely with just one wing. A little cough propaganda, but still interesting: https://www.youtube.com/watch?v=M359poNjvVA .

IIRC terminal velocity for a skydiver in free-fall is approx 180mph. (It's at least in that vicinity.) So the direction of "flight" certainly matters a lot in making sense of numbers. Also, when I was in 5th or 6th grade (over 30 years ago) I was obsessed with the F-15. Talk about thrust:weight ratio. The idea that you could take off, point the nose to vertical, and accelerate past the speed of sound, then level off…

First a belly down skydiver falls at about 120 MPH. Face down with streamlining they can do up to about 300MPH.

So someone starting with a deep dive in a wingsuit can level out and get very fast horizontal movement. There are a few videos of people doing this and reaching almost level flight though their slowing down. It’s maintaining speed that requires thrust, but speed is enough for level flight.

Also, while you could effectively balance on a jet engine to hover, that amount of thrust would also allow you to do not just level horizontal flight but rapidly gain altitude, making it kind of a meaningless from a minimum speed to requirements for minimum thrust perspective.

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

#177

Post by dmurray »

qppo wrote: post #103
skizm wrote: post #82

I'm genuinely wondering when I can buy a personal, commercially available, vehicle that will let me fly (or maybe sail) over the Hudson river on my commute into NYC. What are the stoppers for something like this? Landing? Economics? Regulation? I'd pay more money than a car for something like this.

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.

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

#178

Post by usrusr »

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…

I really like your observation of a "lithium battery age".

But people tend to greatly overestimate how much lithium batteries improve: we remember a class of battery powered devices that ran on NiMH, then at some point LiIon became cheap enough for that use case so that the next generation that we got was so much better. We then extrapolated a fantasy battery improvement speed from that one-time jump and this mistake is rarely corrected. Instead it was supported by the next device class that got absorbed by the ever shrinking lithium price threshold. This process is now about finished, very few NiMH applications left to get "lithiumized". But the fantasy also supported, one a lower intensity but enough to impede corrections, by how the actual actual progress within lithium batteries (not quite as big as we wish, outside of price at least) gets complemented by devices becoming more efficient (think LED flashlights) and devices dedicating an increasing fraction of their mass/volume to the battery (smartphones, laptops, also cars if you compare to pre-Tesla electrics)

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

#179

Post by peterwwillis »

FabHK wrote: post #140
peterwwillis wrote: post #44

Nice to see they aren't bothering with social distancing. I mean, sure, they might be spreading a deadly virus, but how else are they gonna talk about how bad-ass that wingsuit flight was? Totally worth killing immunocompromised people.

They're outside and (in the last congratulatory shot) almost all wearing masks. I think that is defensible.

It's not defensible, because you still have to social distance even when outside.

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

#180

Post by peterwwillis »

anonytrary wrote: post #124
peterwwillis wrote: post #44

Nice to see they aren't bothering with social distancing. I mean, sure, they might be spreading a deadly virus, but how else are they gonna talk about how bad-ass that wingsuit flight was? Totally worth killing immunocompromised people.

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.

Post reply on HN