Guess what's on Mythbusters?

[Bama]

Lets put it this way. Having an aircraft with its parking brake on and on a conveyer should essentially do the same thing. The aircraft will be stationary in point of place. Now, if you add full takeoff power, with the parking brake on, the airplane might, if the brakes are poor, being moving forward quite slowly, due to the airflow over the propeller. Overall, it will remain stationary. If an aircraft is stationary, even WITH full power, is there enough airflow over the wings for it to takeoff?

No. But that's not the point.

The propeller is designed to pull it's way through the air. And that's what it does. Conveyor or no.

End of story

 

[surreal1221]

:banghead:

Not this again.

 

[LarryinTN]

Correct me if I'm mistaken, but its a fundamentally different problem than the converyer BS.

It's not a problem, it's a joke!

 

[SpiceWeasel]

No. But that's not the point.

The propeller is designed to pull it's way through the air. And that's what it does. Conveyor or no.

End of story

Well, duh. We all know the propeller pulls its way through the air. But if the aircraft is forced to remain stationary it can't. A perfect opposing force to the only thing allowing the aircraft to have a minimum coefficient of friction (the tires), would in effect create enough friction for the aircraft not to overcome it. The aircraft HAS to roll in order for it to gain lift. All you all acting like you're the s* haven't thought deeply enough about it. It was a poorly designed experiment because while you all think it's "duh" in the other direction, if the variables were all taken care of, you could field a completely different result.

 

[Thunder-Robo]

Forgive my youthful innocence, but why are we still going on about this? the myth is false, every single time.

It is the Prop is is adding velocity to the aircraft (pulling the aircraft froward) [DeltaV /t] *relative air*

Taking off on a treadmill will only add drag at X(coefficient of Friction) *Relative carpet* from The tires, as they are rollers, they are just along for the ride. (not powered by aircraft) and in the end will only slow the aircraft down a bit *relative air*

Not that hard to understand??
Grade 11 physics actually...

On to the next topic...

 

[Thunder-Robo]

The aircraft HAS to roll in order for it to gain lift.

What if i had a 60kt head wind? and the takeoff speed for my aircraft is 60kt... :bandit:

All you all acting like you're the s* haven't thought deeply enough about it.

mm... when you point your finger at someone... theres always three pointing back

'Pwned' by someone who's still in high school

 

[madmax]

Nobody is arguing that an airplane is actually propelled by it's wheels.

Wheelspeed is relevant, though, because the wheels are what make contact with the ground (treadmill) and there is a limitation on how fast they can spin (max tire speed) before they fail.

So the wheels fail and you take off, how does that change anything?

Isn't this the same idea as taking off upriver in a float plane?

 

[TXaviator]

Well, duh. We all know the propeller pulls its way through the air. But if the aircraft is forced to remain stationary it can't. A perfect opposing force to the only thing allowing the aircraft to have a minimum coefficient of friction (the tires), would in effect create enough friction for the aircraft not to overcome it. The aircraft HAS to roll in order for it to gain lift. All you all acting like you're the s* haven't thought deeply enough about it. It was a poorly designed experiment because while you all think it's "duh" in the other direction, if the variables were all taken care of, you could field a completely different result.

what in the world are you blabbering about??

 

[TXaviator]

Isn't this the same idea as taking off upriver in a float plane?

yes. in fact, its exactly the same.

there will be some MINIMAL rolling/fluid friction from the "conveyor" or river.... but it will be easily overcome by the prop.

END OF STORY.

 

[Thunder-Robo]

yes. in fact, its exactly the same.

there will be some MINIMAL rolling/fluid friction from the "conveyor" or river.... but it will be easily overcome by the prop.

END OF STORY.

mmhmm... :yeahthat:

Like i was saying :nana2:

 

[splash]

Thats kinda like the speed of light problem. If you are in an aircraft traveling the speed of light what would happen if you turned on your landing light? would it not work or would it go twice the speed of light?

 

[TXaviator]

Thats kinda like the speed of light problem. If you are in an aircraft traveling the speed of light what would happen if you turned on your landing light? would it not work or would it go twice the speed of light?

no. in fact its NOTHING like a speed of light "problem".

if you were travelling very near the speed of light and turned on your lamp, in YOUR frame of reference, the light would shine normally.

 

[TXaviator]

in fact, if you want to learn something, go read this link. it talks about relativity (with pictures!) and will help you understand the flashlight in a traincar idea.

http://library.thinkquest.org/C008537/relativity/why.html

what it boils down to, is the person shining the flashlight is observing time at a different speed than the stationary person.

 

[derg]

This thread reminds me of one of my uncles that tried to convince me that supersonic planes can't fire a 20MM cannon because they'd end up running into their own bullets.

 

[splash]

OK, so it has nothing to do with it. Just thought I could throw it in here anyway to put a different spin on this dead thread. cool link, but the trust me part and the 98% speed of light doesn't seem too convincing. I'd like to see them do this on Myth Busters. Well, they can't do the speed of light problem but the supersonic plane firing the 20mm cannon would be nice to see on the show.

 

[TXaviator]

This thread reminds me of one of my uncles that tried to convince me that supersonic planes can't fire a 20MM cannon because they'd end up running into their own bullets.

they can. easy. i could see where they might hit their own bullets though if the air friction of the bullet rapidly decelerated the bullets after leaving the cannon however..... i dont know much about bullets and their air resistance and/or the speeds they travel.

its still dissimilar to the flashlight problem because we're talking about bullets, and they have mass ;-) light does not.




sidenote, the M61 vulcan cannon muzzle velocity is 3,450f/sec or about 2,300mph.... or mach 3ish....

 

[TXaviator]

OK, so it has nothing to do with it. Just thought I could throw it in here anyway to put a different spin on this dead thread. cool link, but the trust me part and the 98% speed of light doesn't seem too convincing. I'd like to see them do this on Myth Busters. Well, they can't do the speed of light problem but the supersonic plane firing the 20mm cannon would be nice to see on the show.

"doesnt sound too convincing"????

i suggest you go take it up with Einstein, then. i cannot possibly help you.


:banghead::banghead::banghead::banghead::banghead:

 

[Thunder-Robo]

sidenote, the M61 vulcan cannon muzzle velocity is 3,450f/sec or about 2,300mph.... or mach 3ish....

holly carp!

when i think cannons i think P51s lol...

Speed of Mach is a variable of air density right? or is it air temp? oh damn... i'm going to fail gr12:banghead:

 

[TXaviator]

holly carp!

when i think cannons i think P51s lol...

Speed of Mach is a variable of air density right? or is it air temp? oh damn... i'm going to fail gr12:banghead:

mostly temp.

 

[SlumTodd_Millionaire]

Well, duh. We all know the propeller pulls its way through the air. But if the aircraft is forced to remain stationary it can't. A perfect opposing force to the only thing allowing the aircraft to have a minimum coefficient of friction (the tires), would in effect create enough friction for the aircraft not to overcome it. The aircraft HAS to roll in order for it to gain lift. All you all acting like you're the s* haven't thought deeply enough about it. It was a poorly designed experiment because while you all think it's "duh" in the other direction, if the variables were all taken care of, you could field a completely different result.

:banghead::banghead::banghead::banghead::banghead::banghead::banghead:

That high school student just pwned you.