JSF-TC Posted July 29, 2020 Share Posted July 29, 2020 I'm building a large (1/7 scale) all composite RC Buccaneer from scratch and I'm looking for information on the tailplane airfoil section. A photo of current build progress below. Usually, a symmetric airfoil would be expected, but photographs I have seem to imply that the upper surface may be almost flat. With the tailplane flaps that deflect trailing edge up when the wing flaps deploy, I'm wondering if the tailplane is more of an inverted 'flat-top/ curved bottom' section rather than symmetrical. The graphic in the AP seems to imply both a flat upper and flat lower surface, with just a rounded leading edge, but I'm not sure if the graphic of the tailplane internal structure can be relied on to that accuracy. Any info gratefully received. Thanks Paul 6 1 Link to comment Share on other sites More sharing options...
Julien Posted July 29, 2020 Share Posted July 29, 2020 This would seem to suggest an aerofoil section? We have 7 different threads in the walkaround section here on the site for the Bucc 2 Link to comment Share on other sites More sharing options...
JSF-TC Posted July 29, 2020 Author Share Posted July 29, 2020 Julien, Thanks, and as I look at those photos, I am convinced it is an inverted flat bottom airfoil, with the flat side on the top. Now, if only there was a great detail photo of that weird flattened section on the tailplane tip fairing. Paul Link to comment Share on other sites More sharing options...
Julien Posted July 29, 2020 Share Posted July 29, 2020 37 minutes ago, JSF-TC said: Now, if only there was a great detail photo of that weird flattened section on the tailplane tip fairing. Paul This one? Link to comment Share on other sites More sharing options...
71chally Posted July 29, 2020 Share Posted July 29, 2020 (edited) 1:7th scale, you could get in that and fly it! Lovely looking model. I've had a look in the AP I have, but nothing on the aerofoil sections, would agree with you about the inverted aerofoil. Edited July 29, 2020 by 71chally Link to comment Share on other sites More sharing options...
John B (Sc) Posted July 29, 2020 Share Posted July 29, 2020 Since the air blow on the tailplane was on the underside, so I suspect it was indeed an inverted section aerofoil. Link to comment Share on other sites More sharing options...
JSF-TC Posted July 29, 2020 Author Share Posted July 29, 2020 9 hours ago, Julien said: This one? No, this one. https://www.dropbox.com/s/upgpcqqjjnz3olh/InkedTailplane Tip_LI.jpg?dl=0 Sorry, I don't have a web-host for images, so resorting to a Dropbox link. Linked images don't work with Dropbox........ Thanks Paul Link to comment Share on other sites More sharing options...
Julien Posted July 29, 2020 Share Posted July 29, 2020 9 minutes ago, JSF-TC said: No, this one. https://www.dropbox.com/s/upgpcqqjjnz3olh/InkedTailplane Tip_LI.jpg?dl=0 Sorry, I don't have a web-host for images, so resorting to a Dropbox link. Linked images don't work with Dropbox........ Thanks Paul That looks like a dent to me, or something added. Dont forget thats a restored ground runner. Link to comment Share on other sites More sharing options...
JSF-TC Posted July 29, 2020 Author Share Posted July 29, 2020 It does look like a dent, but it is visible on all the various a/c that I can find photos of. Paul Link to comment Share on other sites More sharing options...
Graham Boak Posted July 29, 2020 Share Posted July 29, 2020 It is quite normal to have an inverted aerofoil on the tailplane, as for reasons of stability the lift force is required to act downwards. Link to comment Share on other sites More sharing options...
John B (Sc) Posted July 29, 2020 Share Posted July 29, 2020 Found it ! In a Cranfield report on blowing trials, the tailplane section is described as an RAE 102, 5% , with negative camber. The main wing section varies, but is variously RAE 100 9.25%, RAE 101 8% and RAE 102 8% cambered, from inner to outer wing. So the tailplane section fairly similar to outer main wing section. Hope that helps 3 Link to comment Share on other sites More sharing options...
canberra kid Posted July 29, 2020 Share Posted July 29, 2020 I've had a trawl through all my AP's and these are the only two drawings that give a clue to the shape, John 4 Link to comment Share on other sites More sharing options...
JSF-TC Posted July 29, 2020 Author Share Posted July 29, 2020 That is all great info. Many thanks to all. Paul Link to comment Share on other sites More sharing options...
bobsyouruncle Posted July 30, 2020 Share Posted July 30, 2020 The curious looking flattened off area on the tip of the tail plane is something I’d never have noticed until reading this thread (another great reason to be here), but as said previously I can’t unsee it now and it’s there on all the Buccs I’ve managed to take close up shots of. Exquisite looking machine you’re creating there and I hope you’ll keep us updated here please. 1 Link to comment Share on other sites More sharing options...
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