see, I understand exactly everything you guys are saying, but I still don't think they proved anything with their test. I understand the bernoulli effect and why/how it works, (it creates a pressure differential on the two sides of the wings which creates lift) but it seems to me like they "myth" they're tring to "bust" is that driving down a runway doesn't cause (in combination with the turbines) the air flow necessary to lift the plane. OF COURSE DRIVING FAST DOWN A RUNWAY CAUSES LIFT ON THE WINGS, EVEN IF THE PROPELLER ISN'T GOING. Why do you think F1 cars have those big fins? Those fins are actually just upside-down plane wings which PUSH the car onto the ground so that it can make very sharp turns without flipping over (the cars themselves are very light), and I'm pretty sure F1 cars don't have propellors... only wheels. So here's my problem with the whole thing:

What exactly is the myth? If you have air flowing around the wings of a plane it will fly. That's pretty much common knowledge to anyone who took junior high science classes. I don't understand what they're trying to prove by putting it on a conveyer belt. It seems to me they're trying to prove that runways don't actually serve any purpose to helping a plane take off when in my mind they clearly do. It just seems really fucking retarded. Am I still missing something?

Jamie said it right at the end... the motor drives the propeller not the wheels. So the plane may take off at 25 mph air speed. Putting a conveyor belt under it at -25 mph means that the planes wheels are turning at a rpm equivalent to 50 mph, but the plane still moves at 25 mph air speed to take off. The conveyor belt does nothing but make the wheels turn faster under the plane. That is why runways are necessary, the distance it takes the plane to reach that 25 mph stays the same with or without the conveyor belt.

Sorry for the lack of Mec input on this discussion, I was bedridden with flu/strep throat for the last 3 days. Anyways to start:

A turbine forces thrust or a force to propel a plane forward not force air over a wing... well they're related in a way, the more thrust you have the faster your plane goes, the faster your plane goes the more air is forced over the plane of the wings. Enough force and you get lift and suprise, suprise you fly.

So a runway is used so a plane's turbine can build up enough thrust so you can get the force required to propel a plane at enough sped to get lift. VTOL aircraft can actually land VTOL but taking off is another matter. Due to their ducting engines and a lack of turbine build up, (if you are taking off straight up) this severly drains the fuel as they are forced to provide all the lift, none are provided by the wings. So this is why we don't have all VTOL planes, not very fuel efficent and very mechanically dificult to maintain.

Now as for the long build up before flight well think of it this way, Lets say you're in my car and say I turn to you and say I'm going to make this thing go to 220 km/h. If I just floor it and we get to 220 in 45 seconds you'll feel a ton of gees. But if I wuss out and get there in 5 minutes you won't feel jack, you'll see a build up of speed but you won't notice the acceleration. Same speed but different level of gees for the passenger. That's why commercial planes take so long to build up speed to take-off, I mean they could throw on these monster engines which can build up the required thrust and speed in say a 100 meters, but I don't think anyone would enjoy the ride.

As for the point of the myth I think they are trying to say the plane won't build up the necessary speed to get lift. The conveyor built idea is like you on a thread mill, you maybe running at 15 km/h but the threadmill is going in the opposite direction at 15 km/h therfore you aren't moving anywhere. I guess this proves the idea wrong. I'm wondering if the thrust or in this case pulling force of the propeller was strong enough to build the lift even though the observed speed should of been zero. Sounds like too much math and engineering, probally need to do a free body diagram too, I'll assume they are correct

What makes you think the conveyor belt will have any effect on the plane at all?

okay, so I had to watch it to see if I understood correctly:



If the conveyer belt and the plane are moving at the same speed, why does the plane drive forward for quite some distance before it takes off? That's not impressive at all. It honestly doesn't look like they proved shit in that video. I'm not even sure what they're proving exactly. It seems like a stupid episode to me.

hmm... I always assumed that the reason we have runways is precisely in order to force air over and under the wings of an aircraft in combination with the turbines which aid the process. Otherwise, why do we even fucking bother with runways??? Why don't we just make evey volanter VTOL-capable then? We don't need runways? That sounds fucking retarded to me. Of COURSE we need runways or we wouldn't keep spending millions of dollars making and maintaining them. That's the most retarded shit I ever heard.

Kottke liveblogs Mythbusters testing the airplane on a conveyor belt question. (Spoilers.)

The result that Adam and Jamie come up with isn't that surprising. The response in the comment thread ("they didn't do it right", etc.) is a bit so.

Trees Reviewed:

Trees. It seems like you see them everywhere these days. But are trees viable in the long-term, or just another flash-in-the-pan fad for the under-30 crowd?

Sweet, Tony, I just sent off my application for an elective in Halifax. Everything is going according to plan...

And, good to hear, Dana, that there weren't any serious injuries and that that emergency plan was up to snuff.

Yeah, my mom called me about that explosion last night. Apparently it was a steam injection unit or a vac truck (not sure which one). My brother-in-law was in town when it happened. Noone was seriously hurt, luckily, but I think it tested the towns emergency response system!