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Title: What kind of Aerofoil is this Post by: 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 Title: Re: What kind of Aerofoil is this Post by: anwar on November 07, 2010, 09:06:46 PM 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 (http://www.rcuniverse.com/magazine/reviews/758/QscaleCub_Flying2.jpg) Title: Re: What kind of Aerofoil is this Post by: prateek13 on November 07, 2010, 09:13:48 PM it is the tip of the wing that's the last part
Title: Re: What kind of Aerofoil is this Post by: rajathv8 on November 07, 2010, 09:18:57 PM 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.
Title: Re: What kind of Aerofoil is this Post by: ujjwaana on November 07, 2010, 09:59:56 PM 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. May day May day!!Calling Capt. Manish! Title: Re: What kind of Aerofoil is this Post by: shadman_alam on November 07, 2010, 10:09:02 PM i think i have seen this in one of the hobby shops in forum..bangalore..
Title: Re: What kind of Aerofoil is this Post by: anwar on November 07, 2010, 10:26:33 PM 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 Title: Re: What kind of Aerofoil is this Post by: Drone on November 07, 2010, 10:32:40 PM I guess this will explain it all (the illusion!!)
The second pic does look like the TE is facing front. http://www.rcuniverse.com/magazine/reviews/758/QscaleCub_RTF3.jpg http://www.rcuniverse.com/magazine/reviews/758/QscaleCub_Flying1.jpg http://www.rcuniverse.com/magazine/reviews/758/QscaleCub_Flying12.jpg Title: Re: What kind of Aerofoil is this Post by: cjg_gowda on November 07, 2010, 10:44:24 PM technically what happens if trailing edge faces to the front?
Title: Re: What kind of Aerofoil is this Post by: ujjwaana on November 08, 2010, 12:24:35 AM 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 ? Title: Re: What kind of Aerofoil is this Post by: KALYANPRODHAN on November 08, 2010, 01:27:19 AM 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.
Title: Re: What kind of Aerofoil is this Post by: ujjwaana on November 08, 2010, 01:47:19 AM Bingo! Kalayan! Nail on the head! {:)} {:)}
Title: Re: What kind of Aerofoil is this Post by: medicineman1987 on November 08, 2010, 02:05:32 AM Hey guys, about aerofoils flying backwards, check this out.. http://www.rcuniverse.com/forum/m_5278991/mpage_1/key_/tm.htm
Title: Re: What kind of Aerofoil is this Post by: izmile on November 08, 2010, 03:54:56 AM 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 Title: Re: What kind of Aerofoil is this Post by: KALYANPRODHAN on November 08, 2010, 11:45:40 AM 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 Title: Re: What kind of Aerofoil is this Post by: flyingboxcar on November 08, 2010, 12:59:16 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. :-) Title: Re: What kind of Aerofoil is this Post by: cjg_gowda on November 08, 2010, 06:40:59 PM i do agree with kalyan and ismail. it should fly.
Title: Re: What kind of Aerofoil is this Post by: findvikas on November 09, 2010, 02:26:35 AM 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 - (http://www.horizonhobby.co.uk/aeroonline/e3parkzone/e3_pkz3900_j3_cub/e3_micro_j3_cub_art/e3_micro_j3_cub.jpg) Here is his answer, to satisfy you all |