Plane on Conveyor Belt

[odot]

I'll take some gerbil with that but twn won't share.

 

[Rondo777]

Wow, i'm shocked to see this post again. I better get my 2 cents in before its shut down. I was very vocal in our first post about this. On and on about the fact that i'm a pilot and insisting that the plane would not take off. I origionally said that if the belt speed was monitored to increase as the thrust of the plane increased then the plane would not take off. Seeing as the myth busters have no understanding or concept of flight they have once again F'ed up and jumped around like morons thinking that they proved somthing. Lets see them do that again with the car doing 70mph instead of 20. You'll be watching a plane get dragged backwords and those ******* will have somthing to jump around about.

 

[wheatonFJR]

...geez...another post with 200 replies coming... :blink: I didn't know FJR owners had such strong OPINIONS on this subject. :blink:

 

[Rondo777]

I watched it, and I felt they left out some very important factors. The focused on what the take off distance and speed was, but not the ammount of thrust used. That is a major factor in my book. If they used an ammount of thrust that only allowed the plan to move a maximum of 25mph on the ground, and the "craptacular conveyor belt" was also moveing at 25mph, would there have been any forward movement to get air under the wings?
The pilot used whatever ammount of thrust he wanted to take off, which could easily overcome the ammount of reverse directional thrust being created by the conveyor.

Least thats how I see it.

Ding ding ding, WE HAVE A WINNER, to do this right they need first get a calm day, get in the plane and take off using the minimal power they can to get off the ground and then check the rpm of the engine in the plane and the air speed indicator (if its calm then the Airspeed will be = to the ground speed.

Now take the plane, put it on the belt, start adding in power till the rpms match liftoff rpms in the first test and at the same time accelerate the car to the speed indicted in the airplane in the first test. If the plane takes off I'll eat the belt, the plane, the car and my fjr.

 

[GunMD]

Wow, i'm shocked to see this post again. I better get my 2 cents in before its shut down. I was very vocal in our first post about this. On and on about the fact that i'm a pilot and insisting that the plane would not take off. I origionally said that if the belt speed was monitored to increase as the thrust of the plane increased then the plane would not take off. Seeing as the myth busters have no understanding or concept of flight they have once again F'ed up and jumped around like morons thinking that they proved somthing. Lets see them do that again with the car doing 70mph instead of 20. You'll be watching a plane get dragged backwords and those ******* will have somthing to jump around about.

Not true. The tarp's speed has no effect on the plane's ability to push (or pull) against the air and propel itself forward.

20mph, 70mph, no difference

I watched it, and I felt they left out some very important factors. The focused on what the take off distance and speed was, but not the ammount of thrust used. That is a major factor in my book. If they used an ammount of thrust that only allowed the plan to move a maximum of 25mph on the ground, and the "craptacular conveyor belt" was also moveing at 25mph, would there have been any forward movement to get air under the wings?
The pilot used whatever ammount of thrust he wanted to take off, which could easily overcome the ammount of reverse directional thrust being created by the conveyor.

Least thats how I see it.

Ding ding ding, WE HAVE A WINNER, to do this right they need first get a calm day, get in the plane and take off using the minimal power they can to get off the ground and then check the rpm of the engine in the plane and the air speed indicator (if its calm then the Airspeed will be = to the ground speed.

Now take the plane, put it on the belt, start adding in power till the rpms match liftoff rpms in the first test and at the same time accelerate the car to the speed indicted in the airplane in the first test. If the plane takes off I'll eat the belt, the plane, the car and my fjr.

BUZZZZZZ! We have TWO losers!!!

 

[twowheelnut]

:haha:

Jebus, it was proved false. Twice. Oh, yeah, I forgot... the sun goes 'round the Earth, too.

:bleh:

 

[Ford68xl]

If you are still are able to argue about the outcome of this test, then watch the show again. They did measure the speed and distance it took for the plane to take off and marked the take off point with cones. Not sure where you are getting 20 mph from, but they did state that once the plane made an initial movement forward that Jamie then gunned the engine on his truck. The pilot also stated that he felt no difference at all between the belt take off and the non-belt take off. And if you watch the video closely the plane takes off at the same point as it did when it wasn't on the canvas, hence the belt movement had no effect on the plane!

Face it fellas, those who think the belt would have an effect are wrong. Its ok to be wrong. All of us have been wrong at one time or another. Really, its ok.

 

[gr8eyes]

Well from the looks of it that plane could have taken off vertically if they wanted it to. Its very obvious to me it needs no wind speed over the wings to take off.

Anybody here going to NAFO?

 

[Toecutter]

Anybody here going to NAFO?

I am, unless there's a hundred mph headwind, which would keep my Feejer from moving forward....

 

[Calimus]

Wow, I put what makes sence in my mind on the board without insulting anyones intelligence and so far I've had mine insulted twice. You guy's are how old?

 

[Bandit12]

From the little bit of aerodynamics I learned while on active duty in the USAF as a jet engine mechanic I think they screwed up the experiment.

When they started pulling the "conveyor belt" in a direction opposite to the heading of the aircraft, the pilot of the plane advanced his throttle to add engine speed. IMHO, the effect of this wwas to increase his airspeed, in other words the speed of the airflow over the wing. The only effect I can see was the belt moving in an opposite direction of the plane was to increase the ground speed of the freely rotating aircraft wheels.

If you think about it from a naval aviators perspective, anytime planes are launched or recovered from an aircraft carrier, the ships heading is adjusted to be into the wind. This has the effect of artifically increasing airspeed for take off and landing. If you could get a carrier moving at a speed of say 30 knots into the wind and had in excess of of 90 knots of headwind, then you have a total os 120 knots of airspeed while sitting still. As an example, the FA-18 needs approximately 140 knots of airspeed to take off, in a scenario such as this, the aircraft could nearly float off the deck. A smaller plane with a lower take off speed could be flown off the deck of a carrier with the engine completely shut down.

The engine of an aircraft, either turbine or propeller driven, does not generate enough air speed over the wings alone in induce lift. If it did, you would have to tie and aircraft down to the ground to do a full power run of the engine during a maintenance check.

The exception to this that proves this is the helicopter. It's vertical lift ability comes from the fact that it can change the angle of attack of its rotating wing to generate lift.

IMHO, if mythbusters really wanted to bust this myth, they would have to tie the aircraft down with a breakaway cable, similar to that used to tow a glider to launch, accelerate the "conveyor belt" to the aircrafts take off speed, run the engine to take off rated power and see if the aircraft rises into the air. If it does, then release the breakaway cable and see if the aircraft can maintain forward flight. Otherwise its just a tug of war. Just watch the video again. As Jamie accelerate his truck, the pilot runs up his throttle and the aircraft begins forward motion. The forward motion of the plane creates airspeed, thus creating aerodynamic lift allowing the aircraft to take off.

Ray

 

[twowheelnut]

Wow, I put what makes sence in my mind on the board without insulting anyones intelligence and so far I've had mine insulted twice. You guy's are how old?

12. What's your point?

 

[SouthernCruizer]

QUOTE from the video title >> An airplane cannot take off from a runway which is moving backwards (like a treadmill) at a speed equal to its normal ground speed during takeoff.<<

This was NOT the original wording on the first thread....that thread assumed that the treadmill would run at a speed equal to the SPEED of the accelarating aircraft, NOT the NORMAL takeoff ground speed. Makes this re-argument moot.

Jay

'04 FJR 1300

 

[Calimus]

12. What's your point?

How do you argue with that???

At any rate, if anyone would like to discuss this topic with me, PM me. I'm not looking to argue or for a fight, I'm interested in view points and trying to really figure it out. Don't care if it can or cant, I just want to know why it can or can't.

 

[germany]

The "myth" should be changed to "Can a conveyor belt keep an airplane stationary?". That is the "real question". And the answer is no.

 

[SouthernCruizer]

12. What's your point?

How do you argue with that???

At any rate, if anyone would like to discuss this topic with me, PM me. I'm not looking to argue or for a fight, I'm interested in view points and trying to really figure it out. Don't care if it can or cant, I just want to know why it can or can't.

*********************

Try this link in pursuit of answers >>> https://www.airplaneonatreadmill.com/

Jay

'04 FJR 1300

 

[jestal]

Looks like you can run that "experiment" in a variety of ways to get any answer you want..... The implecation is that the plane will take off on the treadmill but that must be a pretty long tread mill as the plane still needs a long ways to accelerate to a certain airspeed. If the treadmill doesn't keep it stationary then the treadmill needs to be as long as the runway to say the airplane would "take off on the treadmill"...otherwise it would run off the end of it getting up to the sufficient air speed.

 

[twowheelnut]

Looks like you can run that "experiment" in a variety of ways to get any answer you want..... The implecation is that the plane will take off on the treadmill but that must be a pretty long tread mill as the plane still needs a long ways to accelerate to a certain airspeed. If the treadmill doesn't keep it stationary then the treadmill needs to be as long as the runway to say the airplane would "take off on the treadmill"...otherwise it would run off the end of it getting up to the sufficient air speed.

What the hell does that have to do with oil?

 

[jestal]

Uh...well....uh.....there's oil in the bearings of the treadmill, right...??? NO..??? ****.

That's why it took off. No oil in the treadmill bearings. The treadmill freezes up and releases the plane and off it goes. There !!

Doing the experiment with an ultralight that needs little to no runway to take off violates the idea of an real airplane taking off. A 747 needs 10,000 feet of runway. If the treadmill were 10,000 feet long the 747 could take off on it even if it were moving backward but a treadmill of that length is beyond comprehension so the whole idea is somewhat pointless. What would happen if the treadmill were that long and suddenly turned on at 150MPH. By the time the plane had accelerated to 150 due to thrust the treadmill would have carried it far backwards making the treadmill length even longer. The whole proposition is a matter of semantics. It is worded to imply that the treadmill length would be "reasonable" and would keep the plane stationary by moving backwards. Obviously if the plane makes enough thrust it would move forward and move off the tread mill which would violate the spirit of the proposition.

Or....maybe the mythbusters used synthetic oil....or amsoil......

 

[donaldb]

what's more mind blowing to me is why odot wants sloppy gerbil seconds :bad: