rmh

It's all related -

cyclops2

Thanks for taking 55 years off of my age.

Taurus Flyer

Hello Dick,


What is your profession, piano mover? Ground effect!
We can change the subject of the thread especially for Dick: “Relation of impact effect and piano width!�
LOL

Cees

cyclops2

This thread is like a 1 line comody shoo.

rmh

My comment may sound rather unprofessional but if you study it, it is not incorrect.

PS. nice old Taurus -

phlpsfrnk

Refer post #18:
Can any one direct me to or furnish info on the relationship between plane size (chord) and when that chord starts interacting with the ground surface." The relationship is more wing span than cord as described by Red B.'s post and its one wingspan.
"Is their a factor that can be used to calculate when GE comes into play?" Not sure this answers the question but speed to maintain flight in ground effect is less than the normal wing stall speed. There's probably a formula for calculating that speed but I don't know it.
"If there is a relationship is it the same for landing and takeoff?" Yes!
"It seems that with a greater distance between the two it would lessen the landing 'float' of some models if the landing gear were 'taller'." Your statement is true.

My above responses (red) were to the original thread. All references as to whether ground effect is applicable or not to RC aircraft or if RC pilots can perceive it is off topic. If my responses above are incorrect or misleading please explain my error/s.

phlpsfrnk

Why is the term "buoyancy" which is a term relating to objects in fluids being used for aircraft which fly in air (a gas)?

phlpsfrnk

You got that right.

da Rock

Because it is an acceptable term that is used all the time by some disciplines. Drawing parallels to nautical analogies is also done all the time.

phlpsfrnk

buoy·an·cy The upward force that a fluid exerts on an object less dense than itself.
I respectfully disagree.
In the context used the term is not appropriate. If I use that reasoning then we would not need to create lift to fly we would just need to increase buoyancy. The discussion is not about lighter that air craft.

da Rock

From Websters New World Dictionary:
buoy-an-cy (-)
1. the ability or tendency to float or rise in liquid or air.
2. the power to keep something afloat.
3. lightness of spirit; cheerfulness.

There are obviously many more sources that can be quoted for the definition. But buoyancy happens to be only one word in this ever looping discussion.

Keep in mind that many different people have many different interpretations of words. And each of us might have a different dictionary.

Cut some slack and LIGHTEN UP on each other.

Let's see if we all can go more with definition 3, ok?

da Rock

OK, we got 3 or 4 posters taking shots at each other. Some of it appeared at first as if it might be friendly kidding. In retrospect, even so, it doesn't belong.

Let's take a timeout on this.

DT56

My Feedback: (18)

Nice article on flat foil aerodynamics and wings operating in ground effect.


http://www.twitt.org/Bixel_WIG.html


Going to build a model of a Bixel type WIG one of these days.

Shoe

Dick,
I have to respectfully disagree, because I think some aerodynamic mumbo jumbo helps to understand what is going on in ground effect. I was watching a video of a discus launched glider flying inside a large gymnasium, and it's launch "topped out" just below the ceiling. Would you expect a plane flying within a half span of a ceiling to experience "ceiling effect"? If you think about ground effect as a pressure buildup phenomenon, then you would probably say "no" because the pressure above the airplane is actually lower than ambient air pressure. Would a plane flying within a half span of the ceiling "float"? (would it take less or more power to stay level). In order to answer this question, you need to really understand what's going on. I submit without proof (although I suspect those who have studied the mumbo jumbo behind ground effect would agree) that an airplane will float in ceiling effect just as it would in ground effect.

For an explanation of a phenomenon to be really useful, it has to be valid when you use it to predict what would happen under different conditions. In this case, I think that intuition might lead you down the wrong path.