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Fuzzy logic as applied to aviation


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Hi All,

A post on another topic has got me thinking about some of the stranger theories of flight I have heard people come up with over the years, so I thought it might be amusing to see who has heard what proffered as a serious proposition.

Now the rules are that whatever stories you post on here have to have been held up by someone at some point as a serious theory of flight.

I'll start the ball rolling with these two which have both been put to me in all seriousness as genuinely held beliefs....

1. The reason that the model (a slope soarer) appears to turn the "wrong" way when it's flying towards you is that we always face into the wind and so when the model is flying towards us it is flying with a tail wind and the effect of the rudder is reversed. Elevator is unaffected by this phenomenon because up is always up and down is always down.

2. The model will stall more readily in a turn because a proportion of the airflow is diagonally across the wing rather than over it.

Any takers?

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Hello Jim.

I fear the subject would soon lead to discussion as to a models behaviour when flying in an infinite block of air which is moving over the ground at a speed determined by the wind ,and the airing of such things as down wind stalls surprise.

I did ask a chap who had been flying quite a while ,how does a wing create lift ? he answered " when the wing is at an angle to the wind it bounces downwards which pushes the wing up "......... Yea right.!

Tom.

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I suspect he was referring to the "Newtonian" theory which some people seem to think has displaced Sr. Bernoulli's theories as the reason that many tons of airliner can get up to the stratosphere. Personally, I believe it's a combination of the two...the Newtonian explanation being of lift being created from the equal and opposite reaction from air being deflected downward by the wing.

Like you, I didn't want to risk re-opening the old chestnut - can we make a plea to raise some new "odd theories" in this thread?

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I remember a thread like this two years ago that resulted in loads of arguments in and out of the thread. Resulting in member/s leaving this forum altogether. It's not just an old chesnut. It can prove to be a terminal one too.

My pennies worth. God holds 'em up. The devil knocks 'em down !

Debate at your peril - devil

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Posted by Jim Newberry on 12/03/2012 22:18:29:

1. The reason that the model (a slope soarer) appears to turn the "wrong" way when it's flying towards you is that we always face into the wind and so when the model is flying towards us it is flying with a tail wind and the effect of the rudder is reversed. Elevator is unaffected by this phenomenon because up is always up and down is always down.

Is it 1st April............

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A pearl of wisdom given to a friend at a full size gliding club in darkest Yorkshire many years ago about wave soaring at high altitude was along the lines of, "You need to be careful, lad - those isobars are made of solid ice".

I was assured that the dispenser of this sage advice was quite serious and had presumably got confused with cirrus cloud which is made up of ice crystals and the typical "bar" shaped lenticular cloud which often forms in wave conditions.

 

Edited By Martin Harris on 13/03/2012 09:11:13

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One theory I subscribed to until quite recently was one that said air must flow faster over the top surface of a wing because the airstream parted by the leading edge rejoined at the same point (in the airstream) at the trailing edge ergo the air going over the top must be travelling faster.....

'Tis not true.........embarrassed

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