Mythbusters, Plane on a treadmill..

[go!ng for broke]

They say the treadmill speed will match the a/c speed in reverse. all that means is the wheels will be spinning for 80mph and the plane will be going 40mph and it flys

 

[Herman Bloom]

Isn't the whole point of having a real fast tread mill, to keep the aircraft from moving forward? So considering no matter how fast a treadmill moves, it won't restrict an airplane from accelerating and it should fly, right?

Right.

 

[blott]

I hate to say it, but the only thing working against the whole deal , in the above case - bearing friction. no, seriously. ugh...

B

 

[AceyFO]

Well if you are running on a treadmill you dont get any wind resistance, so wouldnt that be the same for the plane?

 

[go!ng for broke]

feet for thrust on treadmill
prop for thrust on air

now if you had a prop engine or big fan blow in to just the prop dia. at the same speed as prop air out ......

 

[jergar999]

WTF The wheels and bearings can go fast man like real fast. No drag at all. If I drive my ford ranger 300,000 miles for 22 years at 55 mph and then go 100mph one night down a long hill looking for my wife who just drove away on my harley do the wheels fly off? Do the bearings go nuts? The plane will fly only if the trap does not suck up into the prop. Do pretty girls f@rt was better. I learned to fly in a plane similar to that. JO spins his wheels all the time and his airplanes still fly.

You don't have to go anywhere near a hundred miles an hour to catch a Harley.

 

[blott]

if the wife was driving the harley, it must have been a sportster-best to just let it go.

B

 

[V-1]

Maybe the wife was big enough to handle something bigger than a Sportster?

On second thought, I agree...just let her go.

That raises another question...
If your wife were riding a Harley on a treadmill and you were driving a _______ could you catch her?

 

[belchfire]

Maybe the wife was big enough to handle something bigger than a Sportster?

On second thought, I agree...just let her go.

That raises another question...
If your wife were riding a Harley on a treadmill and you were driving a _______ could you catch her?

If your wife is stupid enough to put a Hog on a treadmill and try to get away-

1) You have made at least one very poor choice in you life...

2) You might as well compound your error-bring in a louge chair and a cooler of beer and watch and drink beer and throw the empties at her!

 

[jergar999]

What...you think the wife might have been a good choice???

 

[Amish RakeFight]

Well if you are running on a treadmill you dont get any wind resistance, so wouldnt that be the same for the plane?

Does your airplane have feet or wheels that drive it?

It is not the same as running on a treadmill where forward motion (provided by the runner's legs) is countered by the conveyor. The planes wheels do not advance the airframe. That is the job of a jet or prop. A jet will push the plane forward, regardless of the wheel movement. A tractor prop will pull the airplane forward just the same, irregardless of reverse movement under the wheels.

The plane will indeed fly. This shouldn't be so conceptually challenging as it appears to some individuals.

Think of a seaplane taking off into a strong current moving in the opposite direction. It will still lift off.

 

[COOPERVANE]

I used to be in the
"It will never fly and if you think so you are a moron"
crowd. Until I thought of a good analogy.

YOU are on a treadmill on roller skates. You have a rope tied around your waist. The other end is held by 5 strong men.

When they pull on the rope you move forward right? How fast must this treadmill move in order to keep you stationary?

It CANT because the "thrust" is being provided by the rope, not the wheels. You WILL move forward and wind WILL blow in your face.

The propeller is the rope that pulls the plane.

 

[siucavflight]

Bump.

 

[Amish RakeFight]

Bump.

you're so evil!

 

[go!ng for broke]

how many people think the tarp will suck up into the prop? When does this air??

 

[Captzaahlie]

Does your airplane have feet or wheels that drive it?

It is not the same as running on a treadmill where forward motion (provided by the runner's legs) is countered by the conveyor. The planes wheels do not advance the airframe. That is the job of a jet or prop. A jet will push the plane forward, regardless of the wheel movement. A tractor prop will pull the airplane forward just the same, irregardless of reverse movement under the wheels.

The plane will indeed fly. This shouldn't be so conceptually challenging as it appears to some individuals.

Think of a seaplane taking off into a strong current moving in the opposite direction. It will still lift off.

The seaplane analogy was the best explanation that I can think of....well done!

 

[Alltheway]

So if I sit at the end of the runway and apply full full power with the brakes on (not moving) I will make the cessna fly ?

 

[Say Again Over]

Alltheway, the point is you can't compensate the forward movement of the airplane by increasing the speed of the treadmill, just won't happen. Consider a rope tied to a grocery cart, the cart is on a treadmill, not you, you grab the end of the rope, now the tread mill starts running, do you have the strength to hold the rope at 30MPH, 60MPH, 250MPH, the answer is yes.

 

[Thedude]

Jeez....no airflow = no fly

 

[Singlecoil]

So if I sit at the end of the runway and apply full full power with the brakes on (not moving) I will make the cessna fly ?

The plane will fly if it is parked on a frozen lake and you are holding the brakes, which is another analogy for this treadmill business. Picture smooth glare ice with a layer of water on it. Perfectly slick, zero friction. In this case the tires aren't moving at all and the plane takes off. In the treadmill case, the tires are moving faster than normal, but the plane still takes off at the same airspeed as normal.
The point is, airplanes move by pushing air. How they interact with the ground (floats, skis, wheels) is secondary to the fact that thrust is produced by pushing air.