Aerodynamics?

[OTTOL]

Have you tried the "soup-spoon and faucet" experiment (like the one in Jef Raskin's article). If you haven't you should. It's entertaining (for me it was...anyway). Imagine "musket balls" instead of water coming out of the faucet. Would the reaction be the same?



You are still locked into preconceived notions.

[Brett_Henderson]

The point of the "tube" was to incorporate Coanda (making the ball follow the tube back down).

The ball was a convenient simplification for the moving mass to illustrate N3.

OK.. lets imagine the tube is on long, horizontal rails, held at rigid AoA, but allowed to move up/down freely. Then we need a magical hose that does not "squirt" out water, but will follow the front opening of the tube and supply a constant source of "static" water as we move the tube "forward". It will move down first, then stop moving vertically until you stop the water supply.. and move back up as the last of the water is redirected out the end.

All my model was intended to show, is that YES.. when you redirect mass you'll get action/reaction.. but for an airfoil moving trough the air you can't get a net redirection, without AoA.

[Brett_Henderson]

Yes.. I've tried the spoon trick. It only shows what happens when there's

[OTTOL]

[quote]Yes.. I've tried the spoon trick. It only shows what happens when there's

[Brett_Henderson]

[quote]Here's a variable for ya': Imagine that I replace your solid ball with a micro-thin, gelatinous sphere that is full of a nice, soft, fluid. Now, assuming that it does survive being propelled from the gun. What will happen to the ball and fluid when it impacts the first bend in the pipe?

[OTTOL]

[Brett_Henderson]

Sorry.. lol..

[OTTOL]

[quote]Sorry.. lol..

[Brett_Henderson]

C'mon......just take a friendly stab at it.          What do you think would be the difference?  

Ok.. but if this turns out to be a semantics trap, I'm ready with a response  ;)

I'm certain a wing can be shaped as to lessen the the drag encountered while maintaining the AoA required to yield a net redirection, hence N3 lift.. and that that would lessen the "aparent" lift derived from pressure diifferential..

But I'm also certain that the aerodynamics get so complex at that point, that there isn't a single expert in the world capable assigning proper, proportional "credit" to the lfit. You could probably show a mathematical model favoring anything... and at LEAST show that pressure differential is what's making the redirection more efficient.

The bottom line remains (where I will not cede).. N3 don't happen without AoA..  Pressure differential DO.  It's what makes a wing a wing, and an airplane fly.

[OTTOL]

[quote]
Ok.. but if this turns out to be a semantics trap, I'm ready with a response

[Brett_Henderson]

But...if you increase AOA, don't you also increase drag? If what your saying is true. If I put enough power on a Cherokee 140 it'll fly faster and more efficiently that a Malibu.  

I dunno.. this gets into aerodynamics even MORE beyond the scope I've dared (or should) comment on, to date. I'm sure there are wings that will actually show a L/D spike at some point, as the AoA increases.. After all.. we've already acknowledged that there's a positive AoA in level flight (which I hope would be somewhere near where L/D is at its highest).

The Cherokee/Malibu comparison is interesting. I don't think the Malibu is a constant-chord wing though.. But that aside.. (and assuming, magical, structural integrity) a 140 on the other side of mach just might be more efficent than a subsonic Malibu (you didn't place realistic limits on "enough power"    )

[Brett_Henderson]

[quote]Why would you want a "flat bottom" wing in the first place? There is a good answer to this question.  
.

[OTTOL]

[quote][quote]Why would you want a "flat bottom" wing in the first place? There is a good answer to this question.

[Brett_Henderson]

THanks for the clarification

[OTTOL]

mmm-kay.....You're still not answering my question.

Maybe it's because I began my aviation life as a grease monkey and not an officially trained engineer. With that said, I tend to approach events with a caveman-ish outlook. "...bolt don't move.....get bigger hammer to remove bolt!"
We know why the latter model is different but what is the tradeoff? Where do you loose out?

Your telling me that the angle of the fuselage will be different (relative to the wing chord).

So the only difference will be a higher wing angle?

The only difference can't be that the "S" model doesn't look as cool because they had to mount that dang low performance, low vacuum wing at some jacked-up angle to make up for it's lack of efficiency can it?

If pressure differential is so crucial, where does the model with the positive camber wing (and resultant greater pressure differential) really show it's stuff?