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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

#41

Post by Robotbeat »

adrian_b wrote: post #38
Robotbeat wrote: post #36

Earlier quoted context omitted.

We will never run out. Lithium is infinitely recyclable, is common in underground brines and some rocks all over the world, and has sufficient concentration in seawater that it can usefully be extracted (for non-insane cost) if for whatever reason all other sources are exhausted.

Correct. Certain kinds of lithium batteries can be limited by the availability of other elements used in them, which are less abundant than Li, e.g. cobalt. There are efforts to reduce or eliminate the use of such elements.

Yup, and worth pointing out such chemistries are already common, although slightly heavier. Lithium iron phosphate, for instance, which also tends to be safer and have longer cycle life, has improved to the point that Tesla is planning on using it for low cost versions of Model 3 (and/or whatever their $25k model will be called), as is already common for electric cars there. Iron and phosphorous are very common and cheap.

So there are lots of alternative batter chemistries that all have lithium as the common element.

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

#42

Post by gorgoiler »

xwdv wrote: post #35
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…

Does this mean when we run out of lithium we will fall into some kind of dark age?

The lith in lithium is the same word that describes the Earth’s crust.

To a reasonable approximation, the day we run out of lithium is the day we’ve mined the entire planetary surface.

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

#46

Post by swiley »

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…

It's funny but I happen to be reading this on a desktop with an AGM (sealed lead acid in fiberglass) battery backup.

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

#48

Post by Retric »

freeflight wrote: post #40
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 .

I don't fly wingsuits, but from a bit of quick research it seems that 180 MPH is fast even for a wingsuit. The article itself mentions typical horizontal speeds of around 62 mph. The Wikipedia article on wingsuit flying says: > A typical skydiver's terminal velocity in belly to earth orientation ranges from 180 to 225 km/h (110 to 140 mph). A wingsuit can reduce these speeds dramatically. A vertical instantaneous vel…

Minimum level flight speed is called an aircraft’s stall speeds, which is different than their ideal glide speeds. Wingsuits have a glide ratio of ~2.5:1 (horizontal:vertical) which is not that much better than just falling as a normal skydiver can hit 1:1.

To maintain level flight they need to generate a lot more lift, while carrying the extra weight of an engine. By comparison a 747 has a glide ratio of 15:1 and depending on specific model and how much weight it has onboard it will stall in level flight around 180MPH. While many aircraft can fly at much lower speeds, a wingsuit is a terrible aircraft.

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

#49

Post by CrazyCatDog »

Robotbeat wrote: post #28
CrazyCatDog wrote: post #16

Earlier quoted context omitted.

Lithium ion cannot output enough (low C) to make this feasible (yet). Much more likely using Li-Po cells, which are far more adept at emptying themselves at high load—but thermal runaway (eg insanely hot fires) is all too real with Li-Po, though less so today than say 6 years ago!

You’d be surprised. There are some high-C lithium ion cells, but they’re not as easily available as LiPo. If you need to dump your power over 4-10 minutes or longer at peak power, there are lithium ion cells available. Less than 4 minutes, LiPo is still better for now.

Totally agree. My use case: 3 seconds max (launch), 3 seconds in-flight would be out of sight— total power on time between charges is well below one minute. I’m tempted to guess that this would be the most efficient way of converting electricity in wing suit applications as well.
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