Airplane on a Conveyor conundrum

[da SLUG man]

Listen stand on a tread mill on a sakteboard grab the front rail you stay in one place pull yorself forward and no matter what speed the tread mill is doing you and the sakteboard will move forwards off the front of the tread mill

WHY the thrust drive ect is not dependant on the wheels excerting a force on the tread mill the thrust comes from your arms pulling

The plane is driven forward by thrust not acting on the tread mill same as pulling with your arms

Your skateboard will fly off the front of the tread mill with you on it
Your plane will do like wise FLY

no!...

while the treadmill is running, you will have to hold on... speed up the treadmill and you will have to hold on harder...
if you pull forward, you must overcome the force of the treadmill pulling you in the other direction.

[KERRSURF]

if the conveyer goes up to say 300mph the wheels will have to go 300mph but the engines can still push the plane forward depending on how much thrust they produce.

[KERRSURF]

no!...

while the treadmill is running, you will have to hold on... speed up the treadmill and you will have to hold on harder...
if you pull forward, you must overcome the force of the treadmill pulling you in the other direction.

Only friction in the wheel bearings would make you need to hold on harder.

[Chillitt]

no!...

while the treadmill is running, you will have to hold on... speed up the treadmill and you will have to hold on harder...
if you pull forward, you must overcome the force of the treadmill pulling you in the other direction.

notice the bit where the chap on the bike is freewheeling... thats a clue..
http://www.kewego.co.uk/video/iLyROoaftJWh.html

[yoshie]

no!...

while the treadmill is running, you will have to hold on... speed up the treadmill and you will have to hold on harder...
if you pull forward, you must overcome the force of the treadmill pulling you in the other direction.

whats this hold on nonsense Im on a skateboard it will run free and static with treadmill speed till i decide to add thrust ie my grab of the rail and pull and off the front I and the skateboard go

Plane will run free and static till I decide to add my thrust ie engines to max
then off the front I and the plane go

This aint hard to grasp ffs

[KERRSURF]

lol, love Jackass

[KERRSURF]

whats this hold on nonsense Im on a skateboard it will run free and static with treadmill speed till i decide to add thrust ie my grab of the rail and pull and off he front I go

Plane will run free and static till I decide to add my thrust ie engines to max
then off the front go

This aint hard to grasp ffs

[yoshie]

The 20 it wont fly votes all togethere now DHOOOOO!!!!!!!!!!!!!!

[Slugsie]

no!...

while the treadmill is running, you will have to hold on... speed up the treadmill and you will have to hold on harder...
if you pull forward, you must overcome the force of the treadmill pulling you in the other direction.

The force you are overcoming is simply the friction within the bearings. Nothing more. If you were to fit completely friction-less bearings (no such things exist, but for the purposes of a thought experiment you can use them to simplify the initial system, and just factor them back in later if necessary) you wouldn't even need to hold on.

Taking this back to an aircraft, it would be similar to an aircraft attempting to take off whilst the pilot applies a small amount of brakes - or the aircraft is fitted with slightly stiffer bearings. Anyone think such an aircraft won't take off?

[da SLUG man]

The force you are overcoming is simply the friction within the bearings. Nothing more. If you were to fit completely friction-less bearings (no such things exist, but for the purposes of a thought experiment you can use them to simplify the initial system, and just factor them back in later if necessary) you wouldn't even need to hold on.

Taking this back to an aircraft, it would be similar to an aircraft attempting to take off whilst the pilot applies a small amount of brakes - or the aircraft is fitted with slightly stiffer bearings. Anyone think such an aircraft won't take off?

so, if you stood on a skateboard on a treadmill without holding on, and turned it on... it would stay still??... or would it move with the treadmill??

[gwh200]

Listen stand on a tread mill on a sakteboard grab the front rail you stay in one place pull yorself forward and no matter what speed the tread mill is doing you and the sakteboard will move forwards off the front of the tread mill

WHY the thrust drive ect is not dependant on the wheels excerting a force on the tread mill the thrust comes from your arms pulling

The plane is driven forward by thrust not acting on the tread mill same as pulling with your arms

Your skateboard will fly off the front of the tread mill with you on it
Your plane will do like wise FLY

now swap your arms for a jet powered back pack.as you approach ,say,100 mph you increase the jet engine power to overcome the belt speed,but unlike your summation and very much like the original premise,the belt speed increases,matching your velocity.now grab hold of the hand rails again and pull your self forward a bit,some extra thrust has been introduced and a bit of ground made up,but the original premise calls for the belt speed to match your velocity,so your initial velocity plus any subsequent increase needs to be matched by a belt speed in crease.

by the tread mill analogy,matching a belt speed ,then using a fixed point of fererence to overcome belt velocity(the handrail) would result in thebelt slowing,usng an unfixed form of propulsion would result in an in crease in belt speed

but much more importantly mrs gwh has given me the nod for a scottish tour early next year !!

[Slugsie]

so, if you stood on a skateboard on a treadmill without holding on, and turned it on... it would stay still??... or would it move with the treadmill??

If the bearings on the skateboard were frictionless, then yes, you would stay still. Using normal low friction bearings you would move, just very slowly, and you'd only need small thrust (i.e. pull from your arms) to overcome this.

[yoshie]

now swap your arms for a jet powered back pack.as you approach ,say,100 mph you increase the jet engine power to overcome the belt speed,but unlike your summation and very much like the original premise,the belt speed increases,matching your velocity.now grab hold of the hand rails again and pull your self forward a bit,some extra thrust has been introduced and a bit of ground made up,but the original premise calls for the belt speed to match your velocity,so your initial velocity plus any subsequent increase needs to be matched by a belt speed in crease.

by the tread mill analogy,matching a belt speed ,then using a fixed point of fererence to overcome belt velocity(the handrail) would result in thebelt slowing,usng an unfixed form of propulsion would result in an in crease in belt speed

but much more importantly mrs gwh has given me the nod for a scottish tour early next year !!

Excellent mate will be great to meet some of you guys plenty beer BQs and mud
Now maybe the question was possed wrong but as I see it the belt speed matches wheel speed the thrust was is introduced in a way that is irrelevant to the wheels interaction with the belt

But hey we can get smashed one night you are up and the conversation will be much more entertaining

[Slugsie]

now swap your arms for a jet powered back pack.as you approach ,say,100 mph you increase the jet engine power to overcome the belt speed,but unlike your summation and very much like the original premise,the belt speed increases,matching your velocity.now grab hold of the hand rails again and pull your self forward a bit,some extra thrust has been introduced and a bit of ground made up,but the original premise calls for the belt speed to match your velocity,so your initial velocity plus any subsequent increase needs to be matched by a belt speed in crease.

by the tread mill analogy,matching a belt speed ,then using a fixed point of fererence to overcome belt velocity(the handrail) would result in thebelt slowing,usng an unfixed form of propulsion would result in an in crease in belt speed

The fact is though, if you are doing 100mph, then you're doing 100mph. The treadmill is doing 100mph backwards, so the wheels are rotating at 200mph. If you had wings, and your take off velocity was 100mph, you'd be away.

[gwh200]

sorry dude,lost interest,yoshie mentioned barbies and stuff