So, an American chap is going to skydive without a parachute

[hairyben]

Amused that he jumped out of a plane with no parachute but made sure he had a safety hat

[Deisel Weisel]

wc98 said:

it looked like he was wearing a one piece tracking suit . advantage being extra manouevrablity allowing him to make directional adjustments far quicker than a basic jump suit. fantastic achievement ,but nowhere near the level of these guys.
https://www.youtube.com/watch?v=-C_jPcUkVrM
https://www.youtube.com/watch?v=GASFa7rkLtM

Location of the first video?

[slipstream 1985]

LivingTheDream said:

davepoth said:

LivingTheDream said:

janesmith1950 said:

18,000 jumps?

Really?

If he did one every single day, that would be 49 years worth.

If he jumped 5 times every day he jumped, that would be 5 times a day, every day, for 10 years.

This is what struck me about the whole thing (yeah yeah, jump into a big net, very good)

18000 jumps?!? Seriously?!?

It's says he's a 3rd generation sky diver so let's say he begun early when his parents were jumping so say 15?

That's 27 years or 9855 days - so close to 2 jumps a day (1.83 actually) every day (yes 7 days a week) for 27 years!! That's bonkers!!

If you were working at a skydiving school where the weather is good year round you could get way more than 5 jumps a day in.

http://skydiverdriver.blogspot.co.uk/p/what-in-wor...

This guy is averaging 2.5 flights to 11,000 feet per hour, so it's quite conceivable that if the school had enough parachutes on hand an instructor would manage the same - so somewhere around 20 jumps a day I guess, in the busy season.

Ah ok - thanks

Don't know much about it but the numbers are boggling!

Plain crazy

[Foliage]

popeyewhite said:

Foliage said:

Muscle memory,

Doesn't exist. However if you practice something over and over and over again people may do it without thinking - in other words a simple reaction - especially when placed in the the situation where that specific action is normally required - Who hasn't stamped on the brake pedal when a front seat passenger in a mate's car?

Yeah, that what you done just describe is muscle memory.

http://lifehacker.com/5799234/how-muscle-memory-wo...

[anonymous-user]

slipstream 1985 said:

Plain crazy

Plane crazy!

Must admit, I didn't realise the schools would run that many jumps. To have no catastrophic failures in 18,000 jumps is pretty amazing as a stat.

[joshleb]

Just watched the video, he turned over higher up than I was expecting, so he wouldn't know if he was safe or not until impact it seems, and he wasn't far away from being splattered!

I read somewhere last week that it was nearly cancelled because the insurance company wanted him wearing a chute, but he wouldn't be able to do it with one on due to the added weight and forces it would put on his body when landing.

[audidoody]

Deisel Weisel said:

Location of the first video?

"Uh ... guys ... the SD card wasn't formatted correctly. Can you go round again please"


THAT IS BATst FREAKING MENTAL!!!!

[Zoobeef]

slipstream 1985 said:

LivingTheDream said:

davepoth said:

LivingTheDream said:

janesmith1950 said:

18,000 jumps?

Really?

If he did one every single day, that would be 49 years worth.

If he jumped 5 times every day he jumped, that would be 5 times a day, every day, for 10 years.

This is what struck me about the whole thing (yeah yeah, jump into a big net, very good)

18000 jumps?!? Seriously?!?

It's says he's a 3rd generation sky diver so let's say he begun early when his parents were jumping so say 15?

That's 27 years or 9855 days - so close to 2 jumps a day (1.83 actually) every day (yes 7 days a week) for 27 years!! That's bonkers!!

If you were working at a skydiving school where the weather is good year round you could get way more than 5 jumps a day in.

http://skydiverdriver.blogspot.co.uk/p/what-in-wor...

This guy is averaging 2.5 flights to 11,000 feet per hour, so it's quite conceivable that if the school had enough parachutes on hand an instructor would manage the same - so somewhere around 20 jumps a day I guess, in the busy season.

Ah ok - thanks

Don't know much about it but the numbers are boggling!

Plain crazy

You dont need to have lots of chutes on hand, you use the same chute. When i was learning i was doing about 3 a day as there was quite a few of us for the instructors to go up with. they were doing 20+
We'd get them drinks and food to eat so they had time to repack before the next jump.

When your doing it with friends it all depends how quickly you pack (less than 10 mins) and if theres space on the next flight.

[Jimbeaux]

hairyben said:

Amused that he jumped out of a plane with no parachute but made sure he had a safety hat

That is to set a good example, being a role model and all. We don't want every Tom, Dick, & Harry free falling from the Stratosphere without some head protection. Before we know it, they'll be leaping with improperly cusioned socks. Chaos...dogs and cats sleeping together.....

Edited by Jimbeaux on Tuesday 2nd August 14:24

[popeyewhite]

Foliage said:

popeyewhite said:

Foliage said:

Muscle memory,

Doesn't exist. However if you practice something over and over and over again people may do it without thinking - in other words a simple reaction - especially when placed in the the situation where that specific action is normally required - Who hasn't stamped on the brake pedal when a front seat passenger in a mate's car?

Yeah, that what you done just describe is muscle memory.

http://lifehacker.com/5799234/how-muscle-memory-wo...

Sure. It's not 'muscle memory' though - very misleading - it's neurons firing in the brain sending movement messages down the spinal column to the muscle. There is no 'muscle memory'. The memory of the movement is stored in the brain, not the muscle, and with practice becomes more deeply embedded, eventually moving to long term memory. Even there though memory of movement can be lost. Tried riding a pushbike after a 30 year lay-off?

I notice it's a Wiki article btw

[so called]

KTF said:

ATG said:

KTF said:

garyhun said:

Is he going to hit that net at terminal velocity or does he have any aides to help slow the descent?

This is the key part as they are making a big thing about him not having a parachute but he must have something else to slow his speed.

He's got the net to slow him down. He doesn't need anything else. He'll only be going at about 120mph. Look how far the net is above the ground. It has many meters to slow him from 120mph to rest without turning him to mush. The forces won't need to be at all extreme. In fact let's estimate them.

Let's say that the net has only 15 metres of give in it once he's put it in some tension, and we'll assume (unrealistically) that the retarding force on him is constant. He'll hit the net at about 120mph assuming he stays in an arched position all the way down.

v^2 = 2.a.s, so the acceleration, a, is v^2 /2.s

120mph is about 53m/s, we've said s is 15m, so the acceleration is 95ms^-2 ... that's about 10g which is at the very upper end of what a fast jet pilot would pull in a turn, but a fair bit less than he'd pull in an ejector seat. (At 10g, he'll stop from 120mph in about half a second, far less time than a pilot would have to endure a high g turn)

And the force is inversely proportional to the distance the net gives, so if it can slow him down over 30m, then he'll pull an average of about 5g, etc, etc

So the forces and impulses are going to be fine if he can hit the net ... if ...

Thanks for the calculations. I guess there is more give in the net otherwise he would black out when he hits it and experiences 10g which won't look good on TV?

I just calculated it using the length of time from hitting the net to stopping which I 'stop watched' at 1,2 seconds.
That gave me 4,6g.
So if you I got the time wrong then its working out at approx., .77g for every 0,1 second change.

Edited by so called on Tuesday 2nd August 21:09

[amancalledrob]

popeyewhite said:

Foliage said:

popeyewhite said:

Foliage said:

Muscle memory,

Doesn't exist. However if you practice something over and over and over again people may do it without thinking - in other words a simple reaction - especially when placed in the the situation where that specific action is normally required - Who hasn't stamped on the brake pedal when a front seat passenger in a mate's car?

Yeah, that what you done just describe is muscle memory.

http://lifehacker.com/5799234/how-muscle-memory-wo...

Sure. It's not 'muscle memory' though - very misleading - it's neurons firing in the brain sending movement messages down the spinal column to the muscle. There is no 'muscle memory'. The memory of the movement is stored in the brain, not the muscle, and with practice becomes more deeply embedded, eventually moving to long term memory. Even there though memory of movement can be lost. Tried riding a pushbike after a 30 year lay-off?

I notice it's a Wiki article btw

Muscle memory is a colloquial term that describes exactly what you've outlined above, you insufferable pedant

[anonymous-user]

Agree with /\ - everybody (well almost) knows it as muscle memory.

[popeyewhite]

amancalledrob said:

Muscle memory is a colloquial term that describes exactly what you've outlined above, you insufferable pedant

No, it absolutely isn't and doesn't.

Whilst this isn't the 'Health Matters' forum so ignorance of basic human physiology is accepted, I'll take the 'pedant' tag in the knowledge I've joined a number of others of the same on NP&E

[Murph7355]

popeyewhite said:

No, it absolutely isn't and doesn't.

Whilst this isn't the 'Health Matters' forum so ignorance of basic human physiology is accepted, I'll take the 'pedant' tag in the knowledge I've joined a number of others of the same on NP&E

You need to look at the company you're keeping in that club before being happy about it

[popeyewhite]

Murph7355 said:

You need to look at the company you're keeping in that club before being happy about it

I'll pass on that.

[amancalledrob]

popeyewhite said:

amancalledrob said:

Muscle memory is a colloquial term that describes exactly what you've outlined above, you insufferable pedant

No, it absolutely isn't and doesn't.

Whilst this isn't the 'Health Matters' forum so ignorance of basic human physiology is accepted, I'll take the 'pedant' tag in the knowledge I've joined a number of others of the same on NP&E

Muscle memory, motor learning, motor memory, most people would recognise that these terms are in most cases and for most laypeople synonymous. Muscle memory has been used interchangeably with motor learning as per Consolidation of Motor Learning, Krakauer and Shadmehr

http://www.cell.com/trends/neurosciences/abstract/...

[popeyewhite]

amancalledrob said:

Muscle memory, motor learning, motor memory, most people would recognise that these terms are in most cases and for most laypeople synonymous. Muscle memory has been used interchangeably with motor learning as per Consolidation of Motor Learning, Krakauer and Shadmehr

http://www.cell.com/trends/neurosciences/abstract/...

I don't think you've completely got the grasp of that abstract Rob, or even understand the differences between motor learning (practising movement) motor memory (imprinted movement) and muscle memory (doesn't exist and isn't synonymous with anything other than lack of knowledge, and because WIKI says it does doesn't make it so ).

[NEEP]

Jimbeaux said:

hairyben said:

Amused that he jumped out of a plane with no parachute but made sure he had a safety hat

That is to set a good example, being a role model and all. We don't want every Tom, Dick, & Harry free falling from the Stratosphere without some head protection. Before we know it, they'll be leaping with improperly cusioned socks. Chaos...dogs and cats sleeping together.....

Edited by Jimbeaux on Tuesday 2nd August 14:24

or maybe he just didn't fancy ripping off or friction burning his ears, nose, face when he made contact with the net at a 120mph

[amancalledrob]

popeyewhite said:

I don't think you've completely got the grasp of that abstract Rob, or even understand the differences between motor learning (practising movement) motor memory (imprinted movement) and muscle memory (doesn't exist and isn't synonymous with anything other than lack of knowledge, and because WIKI says it does doesn't make it so ).

I'm always prepared to learn, but I see nothing wrong with describing memory of muscle movement as 'muscle memory'. It does exactly what it says on the tin

If muscle memory doesn't exist, how do we remember how to perform motor tasks?