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Yenn

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An earlier quiz question was about Aspect Ratio.

 

Question was:-

 

Aspect ratio refers to the ratio of.

 

a Wing span to chord line. The greater the ratio, the less the parasite drag and manouverability.

 

b Half the wing span to the chord line and the greater the ratio the greater the induced drag.

 

cWing span to chord line and the greater the ratio the less the induced drag.

 

d Wing span to chord line and the greater the ratio the greater the induced drag.

 

I don't know what CASA considers the definition of Aspect Ratio, but whoever set these questions doesn't seem to have any idea of what it is.

 

Would you agree?

 

What is your definition of Aspect ratio?

 

 

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I suspect they want you to answer c), but it is very poorly worded. In my view, 'chord line' is a line joining the leading edge radius to the trailing edge. Chord line does not have a length. Chord does, but is not mentioned in the questions.

 

 

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From the way I've always read it, it is the ratio of MAC (Mean Average Chord), divided into span, and expressed at a ratio (X:1), as opposed to a percentage (as section depth is).

 

My thought is the required answer is C?

 

I thought they may have been setting up a 'trick' question, where you had to look for the term MAC as part of the answer...

 

Looks like all GA beginners had better stick to flying early Cherokees.

 

 

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I think it's © but the question shows some lack of knowledge by them, in the wording.

 

The question is which one describes aspect ratio not what it's effect is. So is there a correct answer? ...Nev

 

 

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Surely the smart thing would've been for whoever put these questions together to have just copied them from the sample Q's given in reputable training manuals. At least they would've been written by someone who knows the subject and have been subject to proper scrutiny and editing process.

 

 

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An earlier quiz question was about Aspect Ratio.Question was:-

Aspect ratio refers to the ratio of.

 

a Wing span to chord line. The greater the ratio, the less the parasite drag and manouverability.

 

b Half the wing span to the chord line and the greater the ratio the greater the induced drag.

 

cWing span to chord line and the greater the ratio the less the induced drag.

 

d Wing span to chord line and the greater the ratio the greater the induced drag.

 

I don't know what CASA considers the definition of Aspect Ratio, but whoever set these questions doesn't seem to have any idea of what it is.

 

Would you agree?

 

What is your definition of Aspect ratio?

The tricky thing is that aspect ratio doesn't actually affect induced drag - despite what is taught. Induced drag is dependent on airspeed and wingspan.

 

If you change aspect ratio while keeping wing area the same, the induced drag changes - because span must change to maintain the same area. This is the source of the misunderstanding that induced drag is dependent on aspect ratio - because comparisons are made between aircraft of similar wing area.

 

An aircraft with a 10m wingspan and 1m chord will have essentially the same induced drag as an aircraft with a 10m wingspan and 2m chord (at the same weight and airspeed) despite one being 10:1 aspect ratio and the other 5:1.

 

Of course if you need to pass an exam you need to learn the expected answers - even if they are not completely correct!

 

 

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Like " what causes engine icing" answer Moisture !,

 

what! no temperature or venturi vacuume ?.

 

RAA exam, Got me, missed a pass by one question.

 

Now back to unbuilding the hummelbird, only a few thousand rivets to drill out.

 

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lightningformer.jpg.bd4ab31c255449f17ebc5feb9d9ef723.jpg

 

 

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. . .er,. . . .what aspect of the exam did that refer to ? ( ! )

It was Pylons comment that beginners should stick to early Cherokees, which I think he said because they have constant chord wings, referred to by the Yanks as Hershey bar wings. My subtlety may have slipped into obtuseness this time.

 

 

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It was Pylons comment that beginners should stick to early Cherokees, which I think he said because they have constant chord wings, referred to by the Yanks as Hershey bar wings. My subtlety may have slipped into obtuseness this time.

Ahhhh . . .Sorry PM, . . . .it really wasn't an attack of the "Thickies" it's just that I've only encountered the Hershey Bar reference used to describe the wing section of the Piper P-38 Trauma hawk, another constant chord design, and thus the "Cherokee" reference, correct though it is. . . flew right under my head.

 

Your subtlety was therefore, par excellence and most unobtuse in this case Mon Ami. . . .006_laugh.gif.0f7b82c13a0ec29502c5fb56c616f069.gif

 

 

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