airplane on convayor

[verge]

I think the real lesson to be learned here is how to work with other people in a polite manner. Are we trying to solve a problem, or is this a competition? A bitter, angry competition, no less?


Terms like "You guys are joking, right?" or "I just can't believe you guys think..." or, even worse, "I have found an answer to it, so please don't talk on it further" aren't going to help solve a problem.


At least some of us are willing to admit that we're not experts in this field, and that we'd have to see it simulated to believe the results.


I think it would fly. I don't know for sure. One thing I know, this world is going nowhere if this is how engineers are going to treat each other. Try to swallow your egos every once in a while, everyone.


And thanks for this fun diversion, Isair. Now that I've succumbed to the general vibe and railed on everyone myself, I'd better get off my soapbox and back to work. Thanks for listening to me vent. Later...

 

[herb]

Did anyone see Mythbusters last night (30Jan08)? The plane took off!!! They pulled a long tarp down the runway with their truck while the plane went the other way and took off with no problem!!!


Bob

Bob, I saw that episode, too. But, I have to question their results. I noticed that the plane was not stationary in relation to the orange cones they had placed on the ground. The plane was moving faster in its "forward" direction than the conveyor was moving in its "forward" direction. I also question their statement that the propeller pushes air across the wing which created lift. I think this is an incorrect statement. I am not an aero engineer, but I believe that the propeller only provides forward motion. Itis the forward motion that causes air movement across the wings which causes lift. Any aero engineers out there that can confirm this?

 

[verge]

I guess the propeller doesn't actually cause air movement across the wings, but actually causes the wings to move against the air. And it would be this relative movement that causes the lift.


I think a lightbulb is lighting up in my head. Your description is somehow what I've been needing, Herb. Many prop designs have the props attached to the front of the wing; I'm thinking that helps by serving the dual purpose of moving the plane forward and pushing air over the wings at the same time. This is what I've been picturing all along. But what about a propeller on the nose of the plane? And what about a turbo jet engine, which is usually under the wing?


I think it's the term "airspeed" that's been confusing me. I'm definitely now drawn to the "it won't fly" camp. I'm seeing the error of my ways. It's all in the visualization...


Thanks, Herb.

 

[AHA-D]

Propellers can be in front as well as in the back, there are examples of planes having them in the back. I suppose it's more of a practical matter to have them in front : stability (compare with cars front wheel drive), no air disturbance at this point, airflow (bulky part of the engine is the front of the plane).


The basic thing to be remembered in this item is that airplanes move forward because of a reaction force on gasses being forced in the other direction. Whether these gasses are air being blown by a propeller or exhaust from a turbine really doesn't matter that much.


Alex


PS


After being out for a couple of months I was surprised to find this topic at page 11 ! But I'm not going to read all pages (I think)

 

[phoxeoy]

By design it is better to have the engine in the front because of weight. Take a paper airplane and add a little bit of weight to the front. It flies better.

This topic has been going on for some time now.