YouTube Classics, Part Deux

[nsaspook]

The aerodynamics of flying portable toilets.

 

[DennisN]

A very handy little kit...

 

[fresh_42]

A very handy little kit...

... and we call this "pocket knife" over here!

 

[Psinter]

I was looking for that song for a long time and I didn't know the name. Time (0:23)

Now I know it is Bethoven Symphony No 9. The music that plays when you are doing a difficult math exam, yet you know you are acing it and you are confident in your work.

 

[DennisN]

Neil deGrasse Tyson on Star Wars and Star Trek, very funny!

 

[nsaspook]

 

[DennisN]

Kids react to old computer, very funny!

 

[fresh_42]

Kids react to old computer, very funny!

And if you hand them your old car key the time they get their driver license, they will push it like mad and wonder why the car doesn't open.

 

[nsaspook]

Tesla flying car option.

 

[jim hardy]

Tesla flying car option.

Needs pitch control, doesn't it ?

I assume a crash landing is what prompted the pretty girl with pony tail to run that direction ?

 

[nsaspook]

Needs pitch control, doesn't it ?

I assume a crash landing is what prompted the pretty girl with pony tail to run that direction ?

It just needs to be faster so the time between when the front tires start to drop (alter path) from gravity thus imparting angular momentum while the rear tires are still on the ground is minimized.


Just some good old boys, never meaning no harm...

https://www.barrietoday.com/local-n...cks-crashes-into-parking-lot-8-photos-1029716

 

[fresh_42]

It just needs to be faster so the time between when the front tires start to drop (alter path) from gravity thus imparting angular momentum while the rear tires are still on the ground is minimized.


Just some good old boys, never meaning no harm...

I don't think that is the clue. It looks as if the center of gravity is mostly given by the weight of the motor, in which case a faster car and thus wider jump will result in an even steeper angle.

 

[Borg]

Just before it showed up on the right, there was a bright flash. Maybe it was Doc Brown coming back from the future.
Marty warned him that the reentry was a little rough.

 

[nsaspook]

I don't think that is the clue. It looks as if the center of gravity is mostly given by the weight of the motor, in which case a faster car and thus wider jump will result in an even steeper angle.

Maybe but from what I've been told the center of gravity on a Tesla is centralized pretty low from the bulky battery being centered low under the car. It's really hard to roll over.

 

[DennisN]

Just before it showed up on the right, there was a bright flash. Maybe it was Doc Brown coming back from the future.
Marty warned him that the reentry was a little rough.

Exactly what I was thinking too!
"Where we are going we don't need any roads."

 

[jim hardy]

Hmmm.

Looks like they could use a more robust rear wheel attachment.

It just needs to be faster so the time between when the front tires start to drop (alter path) from gravity thus imparting angular momentum while the rear tires are still on the ground is minimized.

Imagining a free body diagram

If the front wheels are clear of the ground
and the rear springs are still compressed transmitting downward force to the ground
then the moment between rear wheels and CG apply torque to pitch the vehicle nose down.

so i think @nsaspook has a point.

Moral:
If you're going to do jumps, get some rear shock absorbers that are really slow in the extend direction.
Maybe from a vehicle with spring rate 3X heavier than yours.

 

[nsaspook]

Hmmm.

Looks like they could use a more robust rear wheel attachment.
View attachment 230093

Moral:
If you're going to do jumps, get some rear shock absorbers that are really slow in the extend direction.
Maybe from a vehicle with spring rate 3X heavier than yours.

Or wait for the SpaceX option: https://www.digitaltrends.com/cars/tesla-roadster-rockets/
https://www.wired.com/story/heres-how-fast-that-jumping-tesla-was-traveling/

https://goo.gl/maps/wZjh8mp38SL2

 

[jim hardy]

Okay i see. That's what the Tesla driver saw a he approached the railroad tracks.

Here's where i think the security camera was ?

If he was stopped at that traffic light that's remarkable acceleration. I guess Teslas are known for that...
but 0 to 99mph in 260 feet ?

old jim

 

[Tom.G]

The numbers at least look close. (I found 'em, you can calc them)

"...a revamped version of its original Roadster, with crazy fast acceleration of 0 to 60 mph in just 1.9 seconds, 0 to 100 mph times of only 4.2 seconds..."
From:
https://techcrunch.com/2017/11/17/watch-teslas-new-roadster-show-off-its-record-breaking-speed/

 

[jim hardy]

you calc 'em

v = at (eq1)
and
s = at²/2 (eq 2)

if s =260 ft from traffic light to railroad track (i got that from google map)
and the Tesla is capable of acceleraton a = 100mph / 4.2sec = (146.67 ft/sec) / (4.2 sec ) = 34.92 ft/sec²
then to go 260 feet would take how long?
Rearranging (eq 2),
t = √(2s/a) = √(520 / 34.92) = √14.89 = 3.859 seconds
at which time eq (1) says its speed v=at would be 34.92 X 3.859 = 134.75 ft/sec = ~91.9 mph

Not quite ten percent short of Wired magazine's 99.8mph estimate from the video.

So it's plausible he started at that traffic light.
I sure hope he wasn't running through them at 90+ mph. You wouldn't hear an electric coming - "It purrs like a kitten with no lake pipe roar"...

old jim

 

[nsaspook]

If you want to test your flying car do it some place safe, like the track.

https://jalopnik.com/watch-a-3000-hp-lexus-is-f-attempt-flight-crash-1692369488

 

[CWatters]

Do you think that Tesla owner would sell me his motor and battery pack?

 

[nsaspook]

https://mashable.com/article/weatherman-dramatically-braces-for-storm/#T4tjFx9DTPqa

 

[DennisN]

https://mashable.com/article/weatherman-dramatically-braces-for-storm/#T4tjFx9DTPqa

When I watched your clip, I looked like this:

 

[nsaspook]

https://motherboard.vice.com/en_us/...oor-magnetic-field-ever?utm_source=reddit.com

 

[jim hardy]

Is this right ? 1200T / 4πX10^-7 = 955 mega-amp turns per meter ?
No wonder it blew up.

 

[DennisN]

https://motherboard.vice.com/en_us/...oor-magnetic-field-ever?utm_source=reddit.com

That's what happens when you install the absolutely latest Windows version on your computer.
And that's why I always use operating systems that are a couple of years old.

 

[david2]

dunno if it is posted here before

 

[OmCheeto]

dunno if it is posted here before

Watched too much Sesame Street, IMHO.

 

[nsaspook]

Hitting a bullet with a bullet.

 

[nsaspook]

 

[fresh_42]

I find these have to be on our site! Somewhere.

 

[nsaspook]

 

[nsaspook]

 

[Borg]

That is beyond awesome.