Physics Puzzle

[doitall]

not land speed
speed through air ie the speed of air over the wing creating lift,
you said it yourself

land has no reference directly

yes the static pressure decreases with the speed of airflow, to get that you need a landspeed. or a very large wind tunnel, problem with an wind tunnel is you won't be able to go anywhere, unless you come out the end at a 100 mile an hour, you will hit the deck hard.

 

[doitall]

and all require a land speed,

You don,t require any land speed, you could theoretically, fly a plane in a very large wind tunnel, land speed zero.

True but the point of air travel is to go places, not up and down in a tube

 

[mrgtv01]

Dont think this ones been posted here before.

//www.diynot.com/forums/viewtopic.php?t=54168

SEARCH

 

[Trazor]

Dont think this ones been posted here before.

//www.diynot.com/forums/viewtopic.php?t=54168

SEARCH

You obviously don,t do irony.

Perhaps you should have searched this thread, before posting.

 

[tim west]

You obviously don,t do irony.

Perhaps you should have searched this thread, before posting.

No trazor, I think it had something to do with a plane on a runway, not with ironing.

 

[Trazor]

I think it had something to do with a plane on a runway.

Really, I had no idea, perhaps you ought to create a new thread about it.

 

[tim west]

Really, I had no idea, perhaps you ought to create a new thread about it.

Do you think I ought to?

 

[megawatt]

I'm sure land speed is very important to vehicles which are driven on the land but it has no bearing whatsoever on an aircraft's ability to get airborne.

 

[doitall]

I'm sure land speed is very important to vehicles which are driven on the land but it has no bearing whatsoever on an aircraft's ability to get airborne.

Hazzard a guess why they need a long runway then Megawatt.

If I poodle down Bristol Lulsgate at 30 mph, (that is landspeed by the way) do you really think I'll get take off.

Remember we are talking planes not rockets or vertical take off jets.

 

[sooey]

doitall, if the planes engines are thrusting it forwards, and the wheels are freewheeling backwards because of the runway. why can't it reach take off speed?

 

[doitall]

doitall, if the planes engines are thrusting it forwards, and the wheels are freewheeling backwards because of the runway. why can't it reach take off speed?

Because the conveyor is stopping forward motion.

Think of an exercise threadmill, you can run as fast as you like, but you can never go fast enough to outpace the machine.

An escalator is another example, if it sped up to match your speed you would never get to the top

 

[tim west]

doitall, if the planes engines are thrusting it forwards, and the wheels are freewheeling backwards because of the runway. why can't it reach take off speed?

Because the conveyor is stopping forward motion.

Think of an exercise threadmill, you can run as fast as you like, but you can never go fast enough to outpace the machine.

An escalator is another example, if it sped up to match your speed you would never get to the top

The difference is that the wheels theoretically have no friction in their bearings and therefore there is no relationship between the traction of the tyres and the runway and the rotating speed of the tyres to the plane speed.
therefore the backwards motion of the runway plays no part apart from just spinning the wheels, with eliminating that from the equation the only affecting factor is thrust, enough thrust will push the plane forwards until it reaches take off speed,
.............................

Or does it?

 

[doitall]

No it doesn't

Take a magical run way Bristol Lulsgate runway 27

I'm sat in me plane doing 100mph, and the runway is doing 100mph the opposite direction, would I break the starting tape or would the plane be stalled.

 

[tim west]

No it doesn't

Take a magical run way Bristol Lulsgate runway 27

I'm sat in me plane doing 100mph, and the runway is doing 100mph the opposite direction, would I break the starting tape or would the plane be stalled.

I dont know the take off speed of your plane so couldnt say if it would take off or not but if it was 100mph then youd be airborne

 

[sooey]

doitall, if the planes engines are thrusting it forwards, and the wheels are freewheeling backwards because of the runway. why can't it reach take off speed?

Because the conveyor is stopping forward motion.

Think of an exercise threadmill, you can run as fast as you like, but you can never go fast enough to outpace the machine.

An escalator is another example, if it sped up to match your speed you would never get to the top

How is the conveyor stopping forward motion when the wheels are just freewheeling and not providing forward thrust?