Thread: The Case of the plane and the conveyor belt

I don't know why your stuck on this. Or maybe we don't get your conveyor belt. I see a conveyor belt moving backwards and a jet trying to move foward. They are BOTH PUTTING OUT the same energy to their respective distance. The plane is going 85 MPH one way, the conveyor is going -85 the other way. That means that this airplane isn't moving. It doesn't matter that it travels beyond the plane of the conveyor belt, but as long as the plane is still on the conveyor belt, it aint gonna grab lift. If airflow don't make it up and over the airfoil of the wing, it aint gonna go up. Do the math. +85 THRUST - 85 CONVEYOR (or negative progress)= 0 AIRSPEED. 0 AIRSPEED = NO LIFT.
Or you can say WORK=FORCE+ENERGY. WORK is the "LIFT" and FORCE is the SPEED and ENERGY is the NEGATIVE SPEED. End result is WORK=ZERO meaning all this work placing a plane on a conveyor with fancy gadgets got you alot of oohs and ahhhs but in the end, NO RESULTS!



QUOTE]Originally posted by ColoAvs19:
What I'm saying is, friction aside, no matter how fast you got the conveyor going, the aircraft would do a normal takeoff roll.

It would still require the same amount of runway. It would still move through the air.

I'm not saying that the engines would create lift. I'm saying the aircraft would roll forward as normal, creating lift by attaining airspeed.

This is sort of on the same page with the high school CO2 cars. They have large back wheels, which makes no sense, because the thrust comes from the CO2 canister, just like a jet or rocket. So you want the smallest surface area possible touching the ground.[/QUOTE]

You're right. The jet engines push the airplane through the air to create airflow, but it has to get off the ground first to capture the airflow. Once its in the air, the engines do the work, but if its on the ground in a tread mill, and this tread mill is going equal to the thrust the opposite direction, there is no airflow so its impossible to fly. If this were the case, the MARINES would not be spending huge bucks on HARRIERS jet fighters and you could be taking B-777's off aircraft carriers equipped with a huge tread mill that could carry alot more personell. Right? That is why they use HELICOPTERS or HARRIERS off AIRCRAFT CARRIERS. The jets that take off ships face off into the wind and utilize the slingshot effect to push them through the carrier flight decks to gain the needed lift. What you're saying, is that any airplane would take off any carrier equipped with a huge tread mill because the engines would eventually lift the plane up right? The design is just not there my friend.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by ColoAvs19:
Thanks Chris.

Thanks Palms for coming around a little.

I still say that the engines push it through the air, creating airflow. The ground could go incredibly fast, it wouldn't matter. Plus, a rocket vs. a jet wouldn't make an ounce of difference in this situation. </div></BLOCKQUOTE>

I have got to admit. This question and your responses had me thinking about this for some time, and the more I think of it, the more I see what you guys that think this plane would still flight despite the conveyor. Being that the engines push against the air instead of the wheel spinning on the belt itself, I can just visualize this and the more I think about it, you guys may be right. But this leads to another possible problem. Tires aren't designed to withstand speeds that fast and my question then would be this. Would the wheel bearings take the heat? Would the tires become too hot also causing a possible explosion? SO, this being the case in theory that this plane overcomes the conveyor for flight, the question is, how fast and for how long would these wheels spin before the plane would gain enough speed for lift? Obviously about double its speed more than it would be normally made for. Not being to nit picky, the tires aren't designed for spinning that fast, with that much weight. If a tire explodes on take off, that's crucial. If a tire explodes from heat after the landing gear is put into the wheel wells, without enough time to cool, that could cause rupture inside the wheel well to alot of hydraulic lines or the resevoir and electrical components itself. Would have to leave the landing gear down for a long time up in the air to give them a chance to cool down. Then upon landing, hope your bearings don't piss off too much the poor mechanic that has to change wheel bearings.


<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Migflanker:
Hmmmmm, forward thrust versus free rolling wheels....will have to do more scientific testing.
Just got back in town give me some time to set up my equipment.

Keep'em flying </div></BLOCKQUOTE>