Answer My Answer for My Question

You fail to grasp what propels a rocket. Think about this.

Rockets work just fine in a vacuum, sailplanes and helicopters don't.

So, some force is at work to give.the wing lift when operation in air. Either negative pressure above the wing or down ward flow off the back of the wing.

You also fail to grasp how a sail plane stays aloft.

Dear very respected Lyn- I think that a rocket differs from helicopter and sailplan by the fact that all the mass of the rocket's thrust is carried already in the rocket, in contrary to helicopter, and quite different from a sailplane.

I like to know what is you attitude for my experiment?

I assume that your wing is attached rigidly at the "front" of the air foil.

By attaching "a piece of paper" you increased the total area of the wing, which would add some lift.

Without seeing drawings or pictures, I can't say much else.

A rocket gets it thrust from gasses expanding against the exhaust cone and forcing the cone, and the rocket forward. That's why it will move in a vacuum.

As far as the rocket's thrust being already in the rocket, I guess I can't argue with that logic.

Dear Lyn- for some reason I'm not able to copy my scanned drawing to my reply.

In past, I succeded doing it several times, but now not.

I think that if you give me some email, I'll send it there.

sorry!

I'll PM my e-mail address to you.

I have copied AZ Native's wing here for the forum.

I'd prefer to bring the discussion back here instead of continuing it via PM.

I hope that's OK.

A sailplane is just like a powered airplane. The wing still deflects air downward to generate a reaction force (lift). It all boils down to conservation of momentum, whether it's air being deflected downward or rocket exhaust directed downward.

A sailplane has wings with a very high aspect ratio (length/width). Very high aspect ratio airfoils have low induced drag, i.e. drag caused by the air flowing out from under the wingtips generating wingtip vortices. High lift to drag ratio mean a good glide slope angle.

What do you think about my experiment?

What do you think about my experiment?

It's tough to say without looking at it. You have to consider that if the air is deflected due to the wall (floor in this case?), a reaction force will be imparted to the wall that is not being taken account of.

I still think in any case to develop a lift force that the air has to be directed downward due to conservation of momentum. If a plane flies a parabola (vomit comet) where the occupants are weightless, then there would not be any lift generated nor downdraft generated.

If a plane flies a parabola (vomit comet) where the occupants are weightless, then there would not be any lift generated nor downdraft generated.

You still have the airfoils on the wings passing through air. Don't they continue to generate lift and downdraft? Low-G is experienced because the airplane's movement vector matches the acceleration of gravity.

If the plane were generating any lift force, the occupants would not be weightless. It has to be trimmed to a no-lift configuration so that it will follow a free fall parabolic trajectory.

Actually, you are correct. The total amount of lift would be zero for an airplane flying a parabola, but for an airplane with the horizontal stabilizer in the back (not a canard) and the center of mass in front of the center of lift, the tail produces negative lift (i.e. downward force) while the wings produce an upward force. This pair of forces or "couple" provides pitch stability. (When the airplane pitches down and speeds up, these forces increase to pitch the airplane up and reduce speed. Likewise, pitching up lessens the forces which pitch the airplane down to increase speed.)

In my thinking, I was disconnecting gravity from the motion through fluid. That gets problematic because "lift" is defined relative to a gravity vector. How can you have "lift" without gravity to lift against?

The airfoil, due to its motion through a fluid, is still generating lift, I thought. And if it's doing its thing, then the fluid should be deflected "downward." I thought the way the vomit comet works is that its parabolic flight path effectively cancels out the lift's effect on the airframe and those inside it by flying downward through the Earth's gravity field.

I don't know more than that about the parabolic flights. When you mentioned trimming you got deeper than my understanding.

At zero-G, the vomit comet is still flying, meaning that its wings are still generating lift. Right?

I would consider lift as an aerodynamic force perpendicular to the direction of motion and drag as the component parallel to the direction of motion.

http://en.wikipedia.org/wiki/Lift_(force)

My #19 applies to an aircraft in level flight. The weight of the airplane is trying to pitch it forward because the center of mass is forward of the center of lift. The tail pushing down and the wing lift pushing up oppose this force, providing pitch stability. I was in error in thinking that #19 applies to a parabolic flight. The aircraft itself is weightless, so there would be no "pitch down" torque due to the weight of the airplane.

To fly a true parabola, there should be only two forces, i.e. drag and thrust, which are directly opposing. Any sideways force (i.e. lift) would cause the trajectory to deviate from a parabola, and the occupants of the aircraft would not be truly weightless. The elevator control must be set at a neutral position so that the aerodynamic forces on the aircraft are in direct opposition to the thrust provided by the engine.

So is this a duplicate thread or an ill-considered extension to the original one?

You have to go back further, it's a reoccurring theme....

Then it's reportable to Admin.

Pneumatic (vacuum) tubes would indicate that lift can be generated without downward airflow. What's really needed is a pressure differential. Airfoils create this by their shape and motion through a static (for local analysis purposes) fluid. Vacuum tubes create the differential by, well, creating the differential between sides of the payload.

Had you inserted smoke streams in your wind tunnel, you would have seen downward air flow, assuming your observation of lift is accurate.

As AH reminded us some time ago, and as I observed as my next door neighbor built a Pitts Special in his garage, symmetrical wings will fly just fine, thank you.

It's all in the angle of attack.

I'm still unclear what AZ Native is saying.

Unclear is not the word I would use. Need to take some fluid dynamic classes and go to an Aeronautical school for aircraft design. My guess Lyn.

But as long as their happy its ok my me. I will fly my little acrobatic aircaft with my symmetrical wings and have fun producing a large sh!$ eaten grin, while dong so.

The angle of attack and the air foils (including flaps) provide lift or airplanes would not be able to fly upside down.

don't you know about bernoulli's lift?

Hey Lyn- since I'm not an observant Jew, I didn't go the the sinagogue to participate the prayer for the Jewish new year, instead I spent many hours to repeat and make a reliable experiment to prove my caim for lift.

In my small bathroom I can't use smoke for the experiment, instead I used a piece of cotton tuft which I adhered to the leading edge- Then I installed this in my "wind tunnel" [ I cut already a window in its side and placed a transparent plastic there, and as the fan worked , the airfoil lifted, and the up curved winglet didn't prevent the lift, and the cotton tuft remained straight.

If you have access to a real [non toilletus...] wind tunnel you may repeat the experiment, or do you think that it would be worthy to convince my friend in the Haifa Technion to give me a chance for this experiment?

Perhaps you can explain to him in person what you have done and ask his opinion if it worthy of further experiment.