A puzzle for all.

[Outatime]

Mike and Rich,

Try to think of the story with my example, it will make you understand why the plane could still take off (assuming all the stuff Nick said). :wink:

[NickT]

RichH Wrote:Absolutely not.

Where's the lift coming from?

The forward motion of the aeroplane !

[Chris Williams]

bozzzydmc Wrote:Rich beat me too it ....

If plane it not in motion there is no lift......

I'm with the cannot take off without lift. ie; Air mass below/above the wing, hense why speed (V1, V2) is reached = is the correct amount of lift across the wing, all varies dependant on weight, size of areoplane Etc....
Chris
(Aircraft technician)

[Outatime]

Hehe, afterall, I guess the only thing to clear the "dispute" is to make up a scaled runway + scaled planes and do the test :lol:

Any club members here who has RC planes handy?

[Outatime]

These are videos that people produced to try and prove that the plane could in theory take off....

With a model plane:
http://www.youtube.com/watch?v=cDliz-YinyY&NR
http://www.youtube.com/watch?v=kHUnAU0MyHM

With computer simulation
http://www.youtube.com/watch?v=eSxUHHcfsro
http://www.youtube.com/watch?v=mAA_WbgyD8I

[stunned_monkey]

Are you serious?

Edit: Sorry, badly placed reply. Was referring to Rich's post

[MikeH]

im in agreement with most, the plane needs to be moving to get the lift under the wings which in turn pushes it up, thats why planes have flaps

[stunned_monkey]

This happened on the Skyline forum too. The NO camp start moaning on about "where's the lift coming from" and start quoting the principles of flight.

The YES camp (me, Nick, John) aren't thinking of a plane, we worked out the thing will move as normal and therefore plane, bicycle, or a bloke on roller skates, it doesn't matter as long as propulsion is provided WITHOUT driving the wheels.

[Guinney1971]

stunned_monkey Wrote:The YES camp (me, Nick, John) aren't thinking of a plane, we worked out the thing will move as normal and therefore plane, bicycle, or a bloke on roller skates, it doesn't matter as long as propulsion is provided WITHOUT driving the wheels.

ah, so the hypothetical bloke on rollerskates doesnt necessarily need to be moving his legs, he could for instance harness an alternative form of movement like a jet pack?

[stunned_monkey]

Or a big long rope, on which he's pulling, as John suggested.

[Guinney1971]

stunned_monkey Wrote:Or a big long rope, on which he's pulling, as John suggested.

cool - so do I win a prize now? :lol:

[Chris Williams]

But you are not getting the air movement to cause lift across the wing, probably if you attain an high enough ground speed you will attain air movement acroos the wing by sheer volume of air being drawn through the engine, however even then engines are placed deliberetly so far in front of the wing to get 'clean' air (undisturbed) so that the wing gets full lift to do its job. The idea of 'Flaps' and 'Slats' (the bit the comes down at the front of the wing) is to give the wing more surface area and give an increse in lift.
This is all far to deep for a Saturday evening, Ti's making me think :?
Chris

[Guinney1971]

Chris & Suzie William Wrote:This is all far to deep for a Saturday evening, Ti's making me think :?
Chris

I know mate, its frying my brain (mind you, thats not hard).

Saturday night = stagger 100yds up road t'pub (soft drinks for me tho ) - I think I owe Phill a beer or several after all the work he's done on Guinney these last few days

[arranj]

I think Martin/Nick/John may be right, but now I'm not sure. In order to go forward (which I'm not disputing does happen) wouldn't the wheels inevitably be dragged faster than the conveyor belt is going backwards, causing a failure in the principle of the argument - i.e. conveyer is always going at the same speed as the wheels - hence making the question impossible because it can't be done?

!

[stunned_monkey]

My simple answer is this: The plane will move forward as usual and therefore gain airspeed and have the ability to take off.

Assuming a north/south runway. Plane starts at south end. Control tower sitting at the side firmly rooted by its foundations.

Plane starts travelling North.

Conveyor belt starts moving South.

Conveyor belt exerts no force on the plane. It can't. The plane is on free-spinning wheels. THIS IS THE CRUCIAL BIT.

Plane hits 20mph going North, waves to control tower on way past. Conveyor hits 20mph going South. Wheels spinning at 40mph.

Plane keeps accellerating till it hits takeoff speed going North

Conveyor going same speed South.

Wheels spinning twice takeoff speed.

Plane takes off.

I for one can't think of any simpler way of stating it, yet the NO camp will still be stuck on "the plane can't move"......