So you have a plane and a conveyor belt....Does it take off?

Cupersool · Post by **Cupersool** » 14 Nov 2006, 10:59

I see Q as the 17th letter of the alphabet.

You can also divide it by Wednesday, and get 2 for the price of 1......

(I think I missed the question......can you repeat that please?)

Cupersool · Post by **Cupersool** » 14 Nov 2006, 11:03

I missed the Q part…..sorry!

The way I see it is the same way they explain it at http://travel.howstuffworks.com/airplane2.htm
With drag.

The only way that plane will take-off is if all other factors involved (like wind etc.) is tied to that conveyer belt

capanno · Post by **capanno** » 14 Nov 2006, 11:04

How do you interpret the scenario? Does the belt compensate for the rotational velocity, or the translational velocity.

Why do I get the feeling you have not read the thread...

Cupersool · Post by **Cupersool** » 14 Nov 2006, 11:06

....and move in the same direction as the belt (with the belt)

capanno · Post by **capanno** » 14 Nov 2006, 11:12

Your not making sense. So you see the question like its the belt moving in the opposite direction at the same speed as the plane?

Cupersool · Post by **Cupersool** » 14 Nov 2006, 11:28

Yes, I see it as the belt is moving e.g. ----> (right) @200km/h and the plane is "moving" <--- (left) @200km/h. That gives you zero airspeed.

If you sit in the plane while it's "moving" on the belt and you look outside, everything would stand still, meaning they will stay in the same position. If you stick your hand out the window, you will feel no wind (taking this as in perfect conditions). Where is the drag that is suppose to cause lift on the wings?

If all else fails, phone these guys @ http://www.fts.co.za/. I know they will give us an answer.

capanno · Post by **capanno** » 14 Nov 2006, 11:31

LOL. Not another one!

Please, please read the thread.

Cupersool · Post by **Cupersool** » 14 Nov 2006, 11:55

First of all, I can't find the "Q" you asked me about and on your second question on rotational velocity or the translational velocity, I only had science on std.grade in matric (didn't pay much attention..... in those days I didn't know that there would be internet and a PC Format site asking difficult questions.)

If I understand rotational velocity and translational velocity correctly, I don't see the relevance of that in the original question. As far as I'm concerned, that plane has got zero airspeed, doesn't matter how fast the jets, or props go...the belt will keep on canceling out the speed the engines would generate.

capanno · Post by **capanno** » 14 Nov 2006, 11:59

The Q, is on page 1. And.... READ THE THREAD.

Cupersool · Post by **Cupersool** » 14 Nov 2006, 12:27

Sorry, I thought the "Q" was part of some formula or something. I didn't know you ment the question!!

My appologies

Slasher · Post by **Slasher** » 14 Nov 2006, 12:35

Graham1 wrote:Slasher, I think you, Moses and myself should go out for a beer, or better still, a case of beer - each, to celebrate our mutual understanding. Actually no, make that brandy and coke.

Dude, the idea sounds fine, except I dont drink brandy & coke, much less beer... Hate the taste of teh stuff...

Now I need a job, seeing as my hoped-to-be employer decided to scrap the post they advertised AFTER telling me they want me for final interviews

O well, at least I only have one exam paper left...

Cupersool · Post by **Cupersool** » 14 Nov 2006, 12:37

I interpret the question exactly like it is asked: would the plane take off? With the answer in the question:

“…but the source of thrust is at the back of the plane so it never provides airflow over the wing. “

This is what I based my answer on:

“…never provides airflow over the wing.”

If a drag racer, (refer to example used earlier in the thread), was built flat on the ground (grammar? punct?), no air can get under the car, it will stay on the ground at any speed, doesn’t matter how slow or fast. But now they build it “more aero-dynamic” less wind resistant by lifting it a bit off the ground. As soon as that car starts traveling at high speeds, the slightest wind under the car will get it airborne. That is why the F1 cars have got “wings”, to keep the cars “stick” to the ground. The pressure of the wind (airflow) pushes the car down. That is why they don’t (normally) get airborne.

So, if there is no airflow, then no lift and no take-off.

This is just how I see it, it is my opinion and yes…..I can be wrong!!

capanno · Post by **capanno** » 14 Nov 2006, 12:41

The source is at the back. It merely shows that its not like a prop in front that can provide some airflow.

Here's a detailed analysis.

http://www.pcformat.co.za/modules.php?n ... 053#405053

Slasher · Post by **Slasher** » 14 Nov 2006, 12:56

Cupersool...

Do you interpret it as that the conveyor belt matches the speed of the wheels rotation, or the actual physical forward speed of the aircraft as a whole?

That is the big divider in this argument...

Cupersool · Post by **Cupersool** » 14 Nov 2006, 13:18

Conveyor belt matches the speed of the wheels rotation

Cupersool · Post by **Cupersool** » 14 Nov 2006, 13:34

The way I see it is that the question is about the aircraft taking-off, so the ground speed doesn't matter because it is matched by the belt, so it equals zero. It doesn't matter about the tires or thrust because for now, that has got to do with whatever goes on on the ground.

If a fixed-wing aircraft is stationary (engine off) and it is tied to the ground with a piece of rope, say about 10m long and a strong enough head-wind picks up, it can actually make the aircraft fly (glide) like a kite….lots of airspeed vs. zero groundspeed.

rustypup · Post by **rustypup** » 19 Aug 2009, 10:42

doo_much · Post by **doo_much** » 19 Aug 2009, 10:46

I'm unsure whether this counts as a necro of note or an interesting spin (pun intended) on the original thread.

GreyWolf · Post by **GreyWolf** » 19 Aug 2009, 11:45

mythbusters did this experiment. Plane took off, end of story.

Helicopter on turntable? Helicopter stays on ground.

UrBaN · Post by **UrBaN** » 19 Aug 2009, 11:52

Depends on the direction of the turntable relative to the rotation of the blades. Even if they are the same direction though, the blades rotate much faster, hence there will be lift and take off.

rustypup, Obvious troll is...obvious?

Post by **Stuart** » 19 Aug 2009, 12:00

Oooo ... oooo ... PLEEEEEEEZE can we see teh puppi banned for two weeks?

(No, not really.)

UrBaN · Post by **UrBaN** » 19 Aug 2009, 12:01

I second the notion. That's 2 against one, democracy rules, BAN HIM!

GreyWolf · Post by **GreyWolf** » 19 Aug 2009, 12:05

rabid squirrel is rabid

if the turntable is rotating in the opposite direction of the blades and maintains the same rpm as the blades, then the blades will stay stationary in relation to the air around them and the helicopter will not take off, it will be an interesting ride for the pilot though.

Post by **Stuart** » 19 Aug 2009, 12:08

GreyWolf wrote:rabid squirrel is rabid

if the turntable is rotating in the opposite direction of the blades and maintains the same rpm as the blades, then the blades will stay stationary in relation to the air around them and the helicopter will not take off, it will be an interesting ride for the pilot though.

It would need to be a pretty big turntable.

UrBaN · Post by **UrBaN** » 19 Aug 2009, 12:14

GreyWolf, That's a valid point.

However, consider the following:

A helicopter typically has a peak RPM of about 2000RPM.
A turntable typically rotates at 45 or 78 RPM.

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So you have a plane and a conveyor belt....Does it take off?

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Re: So you have a plane and a conveyor belt....Does it take off?

Re: So you have a plane and a conveyor belt....Does it take off?

Re: So you have a plane and a conveyor belt....Does it take off?

Re: So you have a plane and a conveyor belt....Does it take off?

Re: So you have a plane and a conveyor belt....Does it take off?

Re: So you have a plane and a conveyor belt....Does it take off?

Re: So you have a plane and a conveyor belt....Does it take off?