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Sport Aviation - Glattli RV - wing/fuselage intersection

blaplante

Well Known Member
Page 58 of the Sept 2018 Sport Aviation caught my eye... the article on Bill Glattli's RV 3 noted that he built a different wing/fuselage fairing, based on his experience with doing the same on his RV-6 and gaining 7 mph.

This video https://www.youtube.com/watch?v=rxvoDbZpoY8 also got me looking at the 6 and noticing that the fuselage starts to taper before the trailing edge of the flap. Seems like there is something to gain here and Glattli says "... I think is worth the relatively small amount of work involved".

Great!

But... I just can't visualize how to taper this back into the fuselage correctly. The video mentions needing to create an 'after body' to do this. None of the photos of Glatti's 3B show the area in detail.

What would be great... does anyone have a photo of the trailing edge wing/fuselage area on RV-6A N51WG? Or you've seen it and can describe?

Thank you
 
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Look backwards!

Have a look at the root fairings on the DC-3 and Spitfire (to name only a couple examples). The DC3 had to climb to a specified altitude on one engine, and the Spitfire had to retain energy in an aerial battle. Both goals used the same thoughts: smooth out the airflow at the wing root, along with other facets. Both goals were met - as we now know.

Now, the fairings on those planes might be exaggerated a bit, tho I would think both were highly optimized for the task at hand. Those fillets had to be rather large.

The AR5 has smallish fillets, but Mike knew where the canopy had to be relative to the wing, so it seems his fillets ended up smaller than the dramatic parts on the transport and fighter.

I produced wing root fillets for the F1, but as far as I know, none were tested without those parts attached. I did sell some of those to other racers, but again I did not get any feedback regarding speed. One fella did say the plane felt more solid at lower speeds - but what does that mean regarding performance?

I also recall one fellow producing fillets that bulged as opposed to the std sort of fillet - seems I heard they worked, or did not - at about the same frequency.

So it seems you have to specify to yourself what the use of the part is to determine it's size, but it does seem to provide at minimum a better climb rate, or lower drag at high alpha angles.

If you proceed, please let us know what your opinion is after installing the parts.
 
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