Is there not a theory about how we don't actually know how planes and helicopters fly????

The United States has a serious problem with a lack of students interested in science and mathematics. Or at least a lack of students interested in trying it. We're way behind compared to other countries, which is a shame because being such an innovative country is what got us here in the first place. Though that's a topic for another thread, or another several threads. (Not aimed at you btw, just the thread in general.)
 
It seems logical, but I'm rather sure that it's the same exact principle as a rocket nozzle: the gas is forced through a smaller opening, thus it speeds up so the same volume of gas goes through. Same thing as when you put your finger over the water fountain to spray someone- smaller hole, same amount of water.

The wing essentially presses the air moving over it against the air above it- and while you'd think that air can just push up into the atmosphere and do whatever the willy-nilly it likes, the wing actually acts exactly like a rocket nozzle- only three of the sides are made of air, and the wing is just one.

That's my understanding of it, correct me if I'm wrong.
 
You have most of the basics but your word use and description is terrible.

Technically the Bernoulli principal only works with laminar flow for an airplane wing. Its not that there is less pressure pushing down on the wing, pressures act normal to a surface, it is that there is a lower pressure above the wing sucking it into the air. Of course the Bernoulli principal is based on conservation of mass and applies to many different fluid flows and is not limited to airplanes. At very low and very high speed angle of attack is much more important to lift. This is why fighter jets can fly inverted, their wings are basically symmetrical. There is something called "slow flight" that all pilots must learn which is where you put a plane in a very steep upward angle and slow speeds, what creates lift is the air being forced under the wing.

Helicopter rotor blades are in most cases basically symmetrical, what causes lift is the angle of attack of the collective which changes the angle at which each blade is. The tail rotor on a helicopter creates no "lift". Lift is up, gravity is down, thrust is forward, drag is backward. It creates a force on a lever arm to stabilize the rotational force of the rotor.

The swash plate controls the angle of the entire rotor, it does not change the angle of specific blades, it changes the angle of the entire rotor in relationship to the airframe.

You are basically right but I felt I needed to correct some of your lingo.
 
Yeah that definitely makes sense to me, I'm all about following the laws of physics hahaha. I'm still trying to remember exactly what the argument against the traditional theory of lift is but I'm not getting much further than that. Thanks for the explanation.
 
I may have forgotten to add "This is my understanding, correct me if I'm wrong".

As for the language- this is NS we're speaking to, and though I know the terms you put forth well enough (I'm no aerospace engineer, but I've got the high school physics + a childhood obsession with the most technical details of how certain things work) but really decided to restrain myself to the layman's terms.

I know the tail rotor doesn't create lift, but I had already explained the concept that the main rotor pulls up- and for simplicity's sake, chose to use the same terminology for the tail rotor as well.

I didn't know that the blades of a choppa were symmetrical, I had always been under the impression they were shaped like wings- flat bottom, curved top. Like this:
IMG00039.GIF


As for your saying that the rotor as a whole tilts in directions- I know for a fact you have to be wrong. The rotor acts as a giant gyroscope, and instead of it tilting, the whole heli would tilt in the opposite direction.

This is what a rotor head looks like:

tete-rotor.jpg


The dark blue bit sits on the grey thing on a set of ball bearings. It spins with the rotor assembly, while the grey thing just sits as is. The grey thing can be tilted in any direction, and with it does the blue bit.

As the blue bit tilts, it pushes and pulls the pink arms, which do not tilt the whole rotor assembly, but rotates each rotor along the length of it, so each rotor is pushed slightly up or down.

I'm sorry I don't have the correct terminology for these assorted colored parts, but that is how it works.
 
you are right, I reread what I wrote and this description is right. The swash plate changes the plane in which the rotors rotate is what I should have said.

And to the OP the mechanics behind flight have very little to do with the Bernoulli principal which is what you are referring to. If Bernoulli principal was the only force acting on a wing a Cessna would have to travel 400 mph.
 
Here is a wonderful set of animations to help explain what the swash plate does, for those who don't have a clue what we're talking about.

 
i totally agree...

capitalism only works when everyone works their butts off. nowadays everyone's attitude towards life is "gimme! gimme!" without having the drive to work for their success. People want the good life handed to them on a silver platter.
 
yes for a time being they found that the wait and wing span did not mach up and could not be enugh to make them fly. but after looking close up they found out the wings spin like a helacopter
 
You got a good grasp on it but there's some stuff that's not necessarily wrong but not necessarily right.

The curve that you refer to is camber which increases the lift coefficient by increasing the effective AOA. Not all airfoils have a camber, they will have symmetric curves on the top and bottom. These curves as well as most curves on an airfoil are not meant to directly increases lift by speeding up the flow but rather keep the flow attached to prevent stall. The thing that produces lift is primarily the angle of attack. If not for flow seperation and structural complications, you would see planes flying around with flat plates as wings as it would have less drag and would produce the same lift.

Bernoulli's principle when applied to subsonic airflow is not really the whole story. It really has more to do with the change in momentum of the flow cause by the airfoil. Look up " momentum theory of lift" if your interested.

With an airfoil in a supersonic airflow, expansion and compression shocks will form which will result in a higher pressure on the lower surface and a lower pressure on the upper surface similar to what you were describing.

 
I totally see what you're saying. one of these: \ would make more lift than one of these: ^ because of the fact that there's more space for that volume of air to fill, thus being less dense, but it would make for very instable flight with lots of failures possible. I didn't put too much thought into my posts earlier, and did little to no research to back myself up. Thanks for the correction.
 
Thats false actually. Lift is the force acting perpendicular to a lifting surface. The horizontal tail of most aircraft produces a negative lift to keep it trimmed. The vertical tail produces lift in the horizontal direction when the rudder is deflected or when there is sideslip.
 
Semantics, lift is defined as the force perpendicular to fluid flow. The tail rotor produces a stabilizing force and does not contribute to lift. You are talking about an airplane and I am talking about a helicopter.
 
Actually I guess you are right, it would be considered lift if it is acting perpendicular to fluid flow so a tail rotor on a helicopter creates lift in the horizontal axis. touche.
 
bahahahaaa

seriously, make a thread about something at least a LITTLE relevant to the game that's never going to be available.
 
I am a mechanical engineer at an aerospace company... and I know very little about the fluid dynamics of helicopters rotor blades :)

With that said I am payed to design or redesign parts and draft drawings so that the manufactured part may achieve a desired function as described in the scope of work by our customers. Therefor, if I am required to calculated a simple load or force acting on a part I am usually able to just find it in one of my old textbooks. This has not lead me to an advanced understanding of rotor dynamics. I can say, with 100% certainty, that all of the concepts have been well documented and then analytically described in theory as well as experimentally so that there will be no confusion on how a helicopter will work to people like me.

The analyst at my company is amazing though. You can ask him a question and he will almost instantly recall the answer or know exactly where to find the answer to any aerospace related question. It is pretty cool, although he is a bit of a wierd guy.

Now quantum physics... that is something we don't fully understand.
 
Considering that Super Meat Boy sold millions of copies, along with plenty of other games, there no reason to doubt. They only had 1 designer, and 1 programmer.

Plus, PC is king, and will be forever.
 
this thread proves 2 things...

jib life hasn't changed in the slightest.

And ns seems like it was a lot smarter back in 2009.
 
You must log in or register to reply here.
Back
Top