Another light aircraft missing

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scraggane
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Re: Another light aircraft missing

Post by scraggane » Tue Dec 29, 2009 3:00 pm

hibby wrote: I hadn't intended to continue this discussion because it seemed to be generating more heat than light, and I value good relations more highly than I value trying to convince people that they are wrong.

However you seem to be taking a genuinely curious attitude and so I'll do my best to answer the specific issue you raised.

An aircraft in straight and level flight does not experience a cross-wind. There is no airflow moving laterally across the aircraft. Instead the aircraft "drifts" relative to the ground.

The hard part here seems to be to stop thinking with reference to the ground.
I'm not thinking in relation to the ground though. An aircraft is flying along, moving forward through or with the wind, such that there is a relative airflow over the wings and lift is produced and the aircraft stays in the air. But what happens when the wind from the side is so strong that it's speed approaches the IAS of the aircraft moving at right angles to it? It is intuitive (to me at least) that there may be a breakdown in the induced airflow over the wings (and that each wing would see a different airflow also).

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Re: Another light aircraft missing

Post by mr crow » Tue Dec 29, 2009 3:02 pm

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Last edited by mr crow on Tue Dec 29, 2009 5:58 pm, edited 3 times in total.

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Re: Another light aircraft missing

Post by RV BLUE » Tue Dec 29, 2009 3:17 pm

my friend posted it here.........

http://www.flyingmag.com/forums/trainin ... wind-turns

one eply so far......

hibby
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Re: Another light aircraft missing

Post by hibby » Tue Dec 29, 2009 4:12 pm

scraggane wrote:
I'm not thinking in relation to the ground though. An aircraft is flying along, moving forward through or with the wind, such that there is a relative airflow over the wings and lift is produced and the aircraft stays in the air. But what happens when the wind from the side is so strong that it's speed approaches the IAS of the aircraft moving at right angles to it? It is intuitive (to me at least) that there may be a breakdown in the induced airflow over the wings (and that each wing would see a different airflow also).
Imagine the wind is from the north at 100 knots. The plane is flying straight and level on an easterly heading at 85 knots IAS.

You seem to imagine that the aeroplane will experience a "wind from the side": a flow of air across the airframe from left to right. It will not. The plane will drift from left to right at 100 knots, giving it a track that is approximately south-easterly. The only airflow the plane will experience is the 85 knots in the nose-to-tail direction. The two wings see the same airflow and the aerodynamics are no different from flying at 85 knots in still air.

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Re: Another light aircraft missing

Post by Pilot » Wed Dec 30, 2009 2:07 pm

I hadn't intended to continue this discussion because it seemed to be generating more heat than light, and I value good relations more highly than I value trying to convince people that they are wrong
Likewise I hadn't intended on posting again....too much danger of us all falling out of nothing really...

But just wanted to (hopefully) help scraggane with one comment.

When you think of the aeroplane having a crosswind, try swapping the aeroplane in your mind for a hot air balloon.....does it too have a cross wind? If you put an ASI 'into wind' on it what would it show?

Assuming that you can now see what there isn't a crosswind on the hot air balloon, because it's being carried along in the wind, then try adding a small motor to pull the balloon along at 90 degrees to the wind, lets say at 10kts....(please ignore the effect on the ballon itself! don't want to deflate it!) Has a cross wind reappeared in your mind? Assuming not, then lets accelerate the baloon to 100kts.....no reason for the cross wind to reappear, but now where back to the exact same situation as the aeroplane at 100kts.

I hope you find this example usefull.....this is my last post on the subject....don't want to fall out with anyone over such a small issue ;)

Happy new year to all :D

scraggane
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Re: Another light aircraft missing

Post by scraggane » Wed Dec 30, 2009 2:39 pm

Your points are well made, Hibby and Pilot, and I think I agree with you now. Doesn't the inertia argument still have merit though? Happy New Year!

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Re: Another light aircraft missing

Post by patrickc » Sat Jan 02, 2010 1:14 am

Doesn't the inertia argument still have merit though
No.

scraggane
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Re: Another light aircraft missing

Post by scraggane » Mon Jan 04, 2010 2:07 am

patrickc wrote:
Doesn't the inertia argument still have merit though
No.
what a useful response. I've since come across the inertia argument in published texts on principles of flight, so i suspect you are incorrect.

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Re: Another light aircraft missing

Post by OnTheNumbers » Mon Jan 04, 2010 10:13 am

Hmmm... maybe I shouldn't have asked :D

Happy New Year, safe flying to to you all.

David
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Re: Another light aircraft missing

Post by mark » Wed Jan 06, 2010 6:59 pm

bumitch wrote:In light of all this discussion, went looking for this report. No longer seems to be available on AAIU website...
The report is back online now and it appears the pilots name has now been removed from the flight plan (as someone pointed out above). Don't know if there are any other changes as I never got to read the original.

Link at: http://www.aaiu.ie/AAIUviewitem.asp?id= ... G&loc=1652
Regards,
Mark Dwyer
www.flyinginireland.com

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