That plane/conveyor problem - filmed solution

[KB_S1]

Tris.E said:

KB_S1 said:

Would Tris.E please answer the question regarding the skateboard.

From what you said the skate board will stay still unless im missing something.
But how does that prove that a plane would take off as a plane uses air flow to fly and as it is staying still it can't fly and as the engines wouldnt be able to go at full thrust due to the lack of air flow they would not create enough trust to force it into the air.
And thats the last im saying on this subject as its just getting stupid now with people just slaying each other why dont we just start a roasting page so they can get it all out of there system??????????????????????????

That sums it up for me. You are arguing that a free wheeling device will not go downhill due to a moving surface under its wheels.
I think you must be missing something.
Why would the plane lack airflow? it is not staying still, it is still moving forward as always. how does any plane take off? they don't get a push start.

I am not slagging you off here, just pointing out a fundamental flaw in your thinking.
can you seriously see a skateboard being held stationary on an a downhill slope purely due to the slope moving?

[sputnik]

orgasmicliving!! said:

mackie1 said:

sputnik didn't insult you in the post you replied to though. Let's keep it on topic shall we?

he did. there's some background there that you are not aware of. you'd need to have access to the sin bin and to my email exchange with him and references to a couple of other threads...suffice it to say you don't have the whole picture.

I have never been sin-binned.

I have never had any email exchanges with you either. Even more

Perhaps a mod could clear this up?

This is my last post on this thread. I refuse to argue with someone who resorts to personal insults and changes the wording of the original question as they realise they are wrong.

Nik

[orgasmicliving!!]

i never said you were sin binned. i was...and that's where the discussion about your post (which is what led to my being sin binned) took place.

and the email exchanges were with pistonted.

glad to know i am wrong...because you say so.

Edited by orgasmicliving!! on Thursday 14th December 17:01

[orgasmicliving!!]

KB_S1 said:

Tris.E said:

From what you said the skate board will stay still unless im missing something.
But how does that prove that a plane would take off as a plane uses air flow to fly and as it is staying still it can't fly and as the engines wouldnt be able to go at full thrust due to the lack of air flow they would not create enough trust to force it into the air.
And thats the last im saying on this subject as its just getting stupid now with people just slaying each other why dont we just start a roasting page so they can get it all out of there system??????????????????????????

That sums it up for me. You are arguing that a free wheeling device will not go downhill due to a moving surface under its wheels.

If the wheels' tangential velocities are the same as the surface's velocity, then no, it won't be going anywhere. if it is, then the velocities HAVE to be different. which is a case we needn't concern ourselves with. the question states that the speeds are the same. that's all we need to worry about.

said:

I think you must be missing something.
Why would the plane lack airflow? it is not staying still, it is still moving forward as always. how does any plane take off? they don't get a push start.

actually, they do. the engines do the pushing. unless they are prop driven or gliders. then they are pulled. or carrier launched. then they are shoved.

said:

I am not slagging you off here, just pointing out a fundamental flaw in your thinking.
can you seriously see a skateboard being held stationary on an a downhill slope purely due to the slope moving?

no, but that's because they are gravity assisted. on a level ground, i can certainly envision a skateboard sitting there, wheels happily turning. can't you?

Edited by orgasmicliving!! on Thursday 14th December 17:07

[Yertis]

orgasmicliving!! said:

munky said:

exactly. a plane will take off on a conveyor belt for the same reason.

completely different. if you wanted to make it a similar situation, you'd make the helicopter sit in the middle of a spinning wind vortex, revolving and accelerating at the same rate as the helicopter blades and in the same direction. without affecting the rest of the helicopter.

now...would the helicopter take off?

Edited by orgasmicliving!! on Thursday 14th December 16:13

No, in the same way that the aeroplane won't leave the conveyor belt if if the airmass surrounding the aeroplane accelerated at the same rate and direction as the aeroplane. But neither of the questions I've seen make any assumptions about wind-over-deck, AWA, AWS or any other wind-related criteria.

[orgasmicliving!!]

ok, fair enough. the analogy was flawed.

[ehyouwhat]

orgasmicliving!! said:

sputnik said:

lots of nonsense

I can guarantee that my command of both english and my physics are better than yours. but this thread isn't a pissing contest, is it?

Command of your physics? That's why you're getting it wrong over and over again, you only have a good command of your physics - most other people have a good command of actual physics.

Perhaps you didn't mean to include the word 'my' in that statement? On second thoughts you must have meant to use the word - your command of english is great, after all.

Only teasing OL.

Edited by ehyouwhat on Thursday 14th December 17:15

[Davi]

trackdemon said:

munky said:

ok.. so.. will a helicopter take off if it's on a hydraulic lift that decends at the same speed at which a helicopter can climb?

Of course

ermmm... actually this is one where the answer would be not necessarily. Without going into it in too great a depth there is a point at which a helicopter cannot recover from descent without EXTREME difficulty, in some cases it just can't period.

I currently have one heli awaiting repairs after getting into this exact situation

[8]

Davi said:

trackdemon said:

munky said:

ok.. so.. will a helicopter take off if it's on a hydraulic lift that decends at the same speed at which a helicopter can climb?

Of course

ermmm... actually this is one where the answer would be not necessarily. Without going into it in too great a depth there is a point at which a helicopter cannot recover from descent without EXTREME difficulty, in some cases it just can't period.

I currently have one heli awaiting repairs after getting into this exact situation

Vortex ring, or vortex doughnut as my flatmate once called it in an aerodynamics exam.

[orgasmicliving!!]

ehyouwhat said:

Perhaps you didn't mean to include the word 'my' in that statement? On second thoughts you must have meant to use the word - your command of english is great, after all.

Only teasing OL.

Edited by ehyouwhat on Thursday 14th December 17:15

eh? you what??!!

[ehyouwhat]

orgasmicliving!! said:

ehyouwhat said:

Perhaps you didn't mean to include the word 'my' in that statement? On second thoughts you must have meant to use the word - your command of english is great, after all.

Only teasing OL.

Edited by ehyouwhat on Thursday 14th December 17:15

eh? you what??!!

[orgasmicliving!!]

i have something really cool (helicopter related) for all of you ...hold on!

[JonRB]

orgasmicliving!! said:

I can guarantee that my command of both english and my physics are better than yours. but this thread isn't a pissing contest, is it?

Are you sure? It certainly seems to be when someone starts bragging that their command of a subject is better than another's.

For the record, I graduated with a BSc in Applied Physics from Liverpool John Moores University in 1992. When and where did you get yours?

[orgasmicliving!!]

JonRB said:

For the record, I graduated with a BSc in Applied Physics from Liverpool John Moores University in 1992. When and where did you get yours?

I got mine last night.

[

Edited by orgasmicliving!! on Thursday 14th December 17:34

[orgasmicliving!!]

You guys seen this?? I love it!

Edited by orgasmicliving!! on Thursday 14th December 17:34

[trackdemon]

8 said:

Davi said:

trackdemon said:

munky said:

ok.. so.. will a helicopter take off if it's on a hydraulic lift that decends at the same speed at which a helicopter can climb?

Of course

ermmm... actually this is one where the answer would be not necessarily. Without going into it in too great a depth there is a point at which a helicopter cannot recover from descent without EXTREME difficulty, in some cases it just can't period.

I currently have one heli awaiting repairs after getting into this exact situation

Vortex ring, or vortex doughnut as my flatmate once called it in an aerodynamics exam.

A better - and more accurate - answer from me would have been "I couldn't care less". Given that, this is my last post on the thread

[combemarshal]

My god, were some people asleep when they did physics at school, it will take off for gods sake!
Why can't some people see that???

As for tyres, wasn't it stated before that they are rated to at least 3 times the max ground speed on the plane?

[s2art]

combemarshal said:

My god, were some people asleep when they did physics at school, it will take off for gods sake!
Why can't some people see that???

As for tyres, wasn't it stated before that they are rated to at least 3 times the max ground speed on the plane?

Just depends on your interpretation of the question. (although I think OL's interpretation is a litle perverse)
Re tyres, the last debate on this subject an engineer claimed that normal airliner tyres are only rated safe up to approx 240MPH, so that needs verifying.

[JonRB]

s2art said:

although I think OL's interpretation is a litle perverse

Well there's a surprise.

[orgasmicliving!!]

combemarshal said:

My god, were some people asleep when they did physics at school, it will take off for gods sake!
Why can't some people see that???

No.

combemarshal said:

As for tyres, wasn't it stated before that they are rated to at least 3 times the max ground speed on the plane?

No.