Bernoulli's equation is BS!

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My "heat in the air" post came from a humor book about "better living thorugh plywood," and was a real attempt at humor. If you didn't take it that way ... I can only ask that you get a sense of humor since it was a post that was frivolous but not intended to offend anyone, even the French.

If any Frenchmen were offended, maybe we could do some cooking and be firends again. Sauces would be involved, I'm sure. Since My last name is Pascal, My heritage IS French (Yes, I have my family Coat of Arms ...), so I can poke fun at my own ancestors and hopefully not offend anyone.
 

Mon Dieu! Mon Frere! Or as JFK would say: "Ich bin ein Parisienne!" any relation to Blaise? (the physicist and mathematician not the British secret agent who are depicted below in reverse order...
 

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If you look up Mr. Bernoulli he was in the sewer business An airplane operates in 3 dimentions...a wing will stall when its critical angle of attack is exceeded...doesn't matter if it is straight up, straight down, or inverted. The seperation of airflow from the curved top of the wing will result in a loss of lift, period. If Bernoulli's principle wasn't relevant we could fly airplanes with wings made of flat sheets of plywood. An airfoil that has exceeded its critical angle of attack has stalled, but it still has air pushing on the bottom that cannot sustain the weight of the aircraft. Herein lies speed, once the angle of attack is lowered and the aircraft accelerates the area of low pressure on the top of the wing once again balances with the area of pressure on the bottom. This is wing loading. If you look at the airfoils on almost any aerobatic aircraft, or fighter they are fully symetrical or semi-symetrical. The wing doesn't care if it is right side up, inverted, straight up, or straight down. Bernoulli didn't want to make an airplane fly, he wanted crap to flow faster through a sewer.

jim
 
Sorry, the computer I'm in front of now won't let me check. It's the first lecture, I'll check the minute and get back to you as soon as i can look at it again. In the meantime, googling 'Bernouli v Newton' brings up lots of discusion, the general concensus seming to be that while Bernoulli's equation is relevent and assists in flight, the effect is insufficient of itself, and the classic model of the airflow separating over the curved wing is, at best, an oversimplified and incomplete explanation of the physics of flight. Casting no aspersions on Meneer Bernoulli of course, who could never have anticipated that his equation would be used in this manner.
 
My nomination for the 'designer who should have been paying more attention when the lecturers were talking about lift' award - John Lloyd. He thought that flaps pertained to birds, not aircraft, and he designed the Armstrong Whitworth without them. Unfortunately Bernoulis equation proved insufficient to get the beast off the ground so he fell back on Newton and angled the wings with the leading edges high for a greater angle of attack. That got the Whitworth into the air, but when the plane levelled off it assumed a nose-down, bum-up attitude. The thing looked like a bottom feeding guppy and produced more drag then a Les Girls convention. Luftwaffe pilots proably missed the Whitworth consistency by firing below it in the beleif it was diving, when all it was really doing was trying to stay airbourne.
 
There is a simple experiment that allows you to experience both Bernoullis equation and angle of attack in a dramatic fashion.
Do as follows:
1: come to my store and plunk down $1000 bucks for a nice mattress.
2: place it in the back of your pickup. (box spring on bottom, mattress sitting level on top of boxspring, no airspace between boxpring and mattress.)
3: head down the highway at a good rate of speed
4: Observe a stunning display of aerobatics
5: come back to my store and plunk down $1020 bucks, for a nice (undamaged) mattress and some tie straps.
 
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