if the wheel speed in one direction = treadmill speed in other direction, then it should be still. The better way to look at it is if the treadmill is accelerating uniformly at a constant rate, and the plane is accelerating uniformly at a constant rate in the opposite direction, then the instantanious wheel speed = treadmill speed, but plane is moving forward.
so wait… what if the wheel speed was 100mph… what would happen then?
Ok ok… in all reality this is one of those GREAT engineering Theory Vs Reality questions.
In theory the plane will NOT take off due to no forward motion; if the treadmill is able to keep up with the rotational speed of the tires instantly (AKA, no matter what happens the treadmill speed == wheel speed) then the plane has no forward motion.
In REALITY this can never happen and there will be a delta in wheel speed on the treadmill Vs wheels.
This is what is causing all the issues. 1/2 the people are thinking theoretical, whereas the other 1/2 are talking real application.
And to be honest, arguments like this are CONSTANT in engineering between the guys who are doing Vs those thinking shit up. And the only way to prove it is to test the issue where theory either wins or looses.
In this case, the theory side of things is flawed due to physical constraints of the world we live in; Bearing stress, rotational torque, friction loading, Energy available for both the treadmill and Jet, etc.
[quote=“ILCisDEAD,post:262,topic:37377"”]
so wait… what if the wheel speed was 100mph… what would happen then?
[/quote]
if the wheel speed was 100mph…the ground speed of the plane would be 50mph in the forward direction and the conveyor would be 50mph in the oposing direction.
[quote=“LAFENGAS,post:264,topic:37377"”]
if the wheel speed was 100mph…the ground speed of the plane would be 50mph in the forward direction and the conveyor would be 50mph in the oposing direction.
[/quote]
but what if the treadmill was only 6 ft long! then it would run off the end of it… and the treadmill was 35 feet high, and the plane crashed into the ground… would it still take off with a bent to hell propeller?
[quote=“LAFENGAS,post:264,topic:37377"”]
if the wheel speed was 100mph…the ground speed of the plane would be 50mph in the forward direction and the conveyor would be 50mph in the oposing direction.
[/quote]
LOL then wheelspeed != treadmill speed
Wow…this again.
People don’t seem to understand how planes work.
[quote=“97FormulaWS-6,post:266,topic:37377"”]
LOL then wheelspeed != treadmill speed
[/quote]
shhh… it adds confusion to the people who can’t analyize the situation. adding serious input thus far has not been rewarding…atleast now i can start having fun with it.
The plane will fly
LOL
plane throttles up; the wheels spin, the plane doesn’t move… then the compressor overheats, engine starts on fire, starts the fuel tank on fire then everything explodes and burns to the ground including the plane, it’s wheels, it’s engines and the fucking treadmill!!!
:picard:
[quote=“jrod0187,post:269,topic:37377"”]
I guess I’m looking at the problem way too in depth, as I do with most things. I do however understand a little about avionics. At that standpoint I was looking into the problem. I wasnt looking at the wheels at all; jumping to conclusion about the generated positive lift under the airfoil. Newman gave me a few examples. I guess the question now is can the wheel bearings with hold the amount of friction created by the conveyor belt. For the sake of argument I still say no:eekdance:
[/quote]
FYI, most lightweight planes can take off before they reach 100mph…if the wheels speed is double (due to the conveyor going 100mph in the opposite direction)…you’re looking at a wheel speed of 200mph.
Your car wheel bearings are capable of withstanding the friction at these speeds. (Though rotational speeds will be higher with the smaller wheels)…these kinds of wheel speeds are nothing astronomical for bearings. Especially for a relatively short period of time.
i’m still trying to plot the function of wheelspeed/treadmill speed vs time in my head… it’s going to tend towards infinity very quickly…
Just put the plane in first and sidestep the clutch at about 4 grand. It oughta take off.
[quote=“newman,post:272,topic:37377"”]
i’m still trying to plot the function of wheelspeed/treadmill speed vs time in my head… it’s going to tend towards infinity very quickly…
[/quote]
math and physics were never my strongest subject but, thats how i am seeing it as well
for those who don’t think it’ll take off…what do you think would happen if a plane tried to LAND on a giant conveyor going in the opposite direction and never applied the brakes. Instantly go backwards?
[quote=“LAFENGAS,post:275,topic:37377"”]
for those who don’t think it’ll take off…what do you think would happen if a plane tried to LAND on a giant conveyor going in the opposite direction and never applied the brakes. Instantly go backwards?
[/quote]
i never said it wouldnt take off… i simply asked, what would happen between the wheels and treadmill. The wheels would HAVE to always be going just slightly faster then the treadmill right?
ugh josh can you please get the hover craft now? Im so tired.
[quote=“boardjnky4,post:277,topic:37377"”]
i never said it wouldnt take off… i simply asked, what would happen between the wheels and treadmill. The wheels would HAVE to always be going just slightly faster then the treadmill right?
[/quote]
Fuck now im doubting myself… That is true but the whole arguement is that the treadmill has to match the wheel spin then you have infinity…
What if the treadmill is going backwards at a simulated speed of 250 mph, the tires on the plane are popped, and the wheels are broken in half?
/adding fuel to the fire
[quote=“LAFENGAS,post:275,topic:37377"”]
for those who don’t think it’ll take off…what do you think would happen if a plane tried to LAND on a giant conveyor going in the opposite direction and never applied the brakes. Instantly go backwards?
[/quote]
i’d end up in your pants…duh.