What kind of Aerofoil is this

Started by ujjwaana, November 07, 2010, 08:49:05 PM

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ujjwaana

Capt Randhawa seems to be flying this Piper Cub.

The Wing seems to be a Semi-symmetrical Aero foil. But look - the usual tapering 'Trailing' edge is facing to the front!!!

What is this ??

http://www.facebook.com/photo.php?fbid=168481683175941&set=a.167176043306505.37820.166040710086705&ref=nf
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anwar

#1
Isn't that just a camera angle illusion ?

The World Models ones look more like this, in reality (based on a better camera angle) :

http://www.rcuniverse.com/magazine/reviews/758/QscaleCub_Flying2.jpg

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prateek13

it is the tip of the wing that's the last part
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rajathv8

It just that the image does not show the cross-sectional view. The edge is protuding out on the upper surface than the lower surface causing the visual effect seen in the image.

ujjwaana

Rajath/Prateek,
I would beg to differer to your observation. This is clearly not a case of what is called 'Prespective-Control' issue for which Architectural Photographers use Tilt-Shift lenses.

This is hardly an angle at which Camera could fooled. And twice ? See another picture
<Anwar, I am not putting the picture as it may violate copyright etc>

http://www.facebook.com/photo.php?fbid=168481676509275&set=a.167176043306505.37820.166040710086705&pid=469988&id=166040710086705

This definitely an Aerofoil which needs explanation from experienced Aeromolders here.

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shadman_alam

i think i have seen this in one of the hobby shops in forum..bangalore..

anwar

Linking to pictures is Ok, it is a problem if you download them and then upload a local copy to RC India.

I am pretty sure it just a visual illusion, regardless of whether it is a World Models or Hangar 9 model.

For example, see this picture :

http://www.rcgroups.com/forums/attachment.php?attachmentid=1348426

The same plane is here too :

http://www.rcgroups.com/forums/attachment.php?attachmentid=1482204

Both pictures are from this thread :

http://www.rcgroups.com/forums/showthread.php?t=698597
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Drone

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cjg_gowda

technically what happens if trailing edge faces to the front?

ujjwaana

Now I would beg to apologies. I totally discounted such an tapering 'Wing-Tip' itself. The 2nd link Drone share clearly proves it.

Still the question , even raised by Mr Gowda. Could such aero-foil wing fly ? No! ain't ?
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KALYANPRODHAN

This illution is dur to camera positioning aligning with the top edge corner that appears the short length portion of the edge. Just cut a piece of thermocol and you can get the answer.
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ujjwaana

Bingo! Kalayan! Nail on the head!  {:)} {:)}
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izmile

Quote from: cjg_gowda on November 07, 2010, 10:44:24 PM
technically what happens if trailing edge faces to the front?

The model will still fly with such an airfoil. The top surface of the airfoil has more surface than the bottom surface. So, technically the Bernoulli's principle will still do its job.

Honestly, the airfoil shape matters little in model aircrafts. Almost any air foil would fly given the right thrust. If you are speaking of efficiency, load carrying capacity then you may need to squeeze your brains on airfoils.

-Ismail
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KALYANPRODHAN

Simply, Drag will be a little more and lift will be slight less.

But still it will fly.

Even a flat wing can also be used. The only parameter is the Efficiency. All this is much more important in Aeronautics but in aero-modeling, as a hobby, would be better, but not essencial. Only variables will be flight time (Taking Controlling will be unaffected as it's a close loop control, feedback by Eye.

Thanks
We have to unite and to prove ourself to make indigenous products as well as marketing / Canvasing them. I'm sure we must achieve success if we try unitedly.

flyingboxcar

Quote from: ujjwaana on November 07, 2010, 08:49:05 PM
Capt Randhawa seems to be flying this Piper Cub.

The Wing seems to be a Semi-symmetrical Aero foil. But look - the usual tapering 'Trailing' edge is facing to the front!!!

What is this ??

http://www.facebook.com/photo.php?fbid=168481683175941&set=a.167176043306505.37820.166040710086705&ref=nf


It is just the camera angle. :-)
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cjg_gowda

i do agree with kalyan and ismail. it should fly.

findvikas

I checked on my cub which I did not had perfect flat bottom and does not giving the perfect angle to show that effect. I decided to ask the Captain :)

My parkzone cub here -

Here is his answer, to satisfy you all