Myth Busters


#1

Myth Busters is doing a show on airplanes and seeing if anyone can land 747 safetly. airliners.net/discussions/ge … n/3734840/


#2

They also are going to test whether a plane can take off from a conveyor belt. THAT discussion should only take a few months to sort out on this board - any takers? (and you can’t invoke angels or other divine beings as part of your explanation)


#3

Can with clear glass / plexiglass climb assistance - ya said nothing angelic or devine :smiley:

https://www.youtube.com/watch?v=cDliz-YinyY)

Can’t (without assistance)

https://www.youtube.com/watch?v=cDliz-YinyY)

And the answer is???


#4

how would you do those in a simulator how are they going to test them


#5

Assuming you are referring to the treadmill myth.

Who needs a sim? One HUGE treadmill and a dinky C152 will do the trick.


#6

http://www.websmileys.com/sm/comp/comp11.gif


#7

what bout for the 747 one


#8

I am sure those folks have a deep enough pocket to rent a 747 for their needs, whether it be the real deal plane or sim. That show, they do some crazy stuff.


#9

All this demonstates is what happens during take off given a strong tail wind. Lots of ground speed but no lift.


#10

id like to see them flying a 747 :smiley:


#11

No way an insurance company or FAA (or foreign equivalent) will let them do that in a real 747. The sims are plenty realistic, however. One of the flying mags already did this (in a sim) to see if a GA pilot could survivably land a large jet and the answer was yes, sort of.


#12

Huh? The apparent wind over the wings would be zero for an aircraft on a conveyor belt, so the answer is heck no!


#13

There goes that sarcasm thing again… :wink:


#14

I think a plane could take off from a tread mill.

We need to turn it around though, instead of positioning the a/c “into” the belt, how about with it? Start it slow and allow the wheels to roll, get the belt up to speed and hit the breaks. The tires stop rolling and the a/c moves. Wind over the wings and the a/c flies. Of course as soon as it gets air born with out thrust (engine or friction/tread mill) it will be landing again.

In the sim we can do an ice covered runway and put in a head wind equal to rotation speed and make the a/c hover. Add any power and we can move over the ground. Sure it’s a sim, but the theory is sound; it’s the actual testing that would be really hard.


#15

Hoo-boy…

That makes NO sense!

If you’re considering that the treadmill could be used like a catapult to “launch” the aircraft by locking the plane’s brakes, just stop to take into account the forces involved in getting the aircraft up to flying speed in what, two feet?

Never mind getting the plane’s tires to stick to the treadmill to transmit the thrust!


#16

I use FSX and it is pretty realistic. I can land the 747 I’m not sure how it compares but if it is anywhere near that it should be possible.

Holton :smiley:


#17

If this imaginary treadmill can exactly match the speed of the aircraft during acceleration the airplane will have no relative movement. Like running backwards on a moving walkway (or, duh, a treadmill) that can exactly match how fast you’re running. You can be running flat out on a treadmill with absolutely zero wind in your face.

“yeah but the airplane affects the air

Put a shopping cart on a treadmill. Stick a rotax engine and propeller to the back. Start it up, but just idle so it doesn’t move.
Crack the throttle a bit to start rolling. Start the treadmill to match the speed.

Open the throttle some more. Increase the speed of the treadmill.

The more thrust you produce, the treadmill matches. You will eventually get the little rotax up to full throttle and the imaginary treadmill flat out, and the shopping cart will still be sitting there, spinning its wheels.

The engine produces thrust, and the friction produced by the wheels matches that thrust.


#18

I should have added the tongue in cheek smiley :-J

Boy with all the fighting in the other threads you guys are on edge.

I was thinking a bigger treadmill. :astonished:


#19

This whole forum could use a little http://www.websmileys.com/sm/love/458.gif


#20

Change the treadmill to a conveyor belt and it would take off just fine depending on the aircraft’s characteristics and the ultimate speed of the conveyor belt.

Given the fact that there are conveyor belts in varying places around the world that are miles long (the record is 100 km IIRC) you’d just need to find one fast enough to launch whichever plane you select.