"A" model Hoerner wingtip design (updated)

[MidGenerationAL]

Within the limitations of me not being an aerodynamicist (or anything close to one) I think this design is closer to the conclusions of Hoerner's 1949 study.
The planform from above is square.
The cutback is obviously concave, but the cut profile is convex.
I moved the wingtip light up to where it is bisected by the outboard edge. There were some noisy-looking pockets the way I had it before.
Some of the transitions between cut sections will need a little bit of smoothing work with sanding or filler when this is out in real life.
Interested in comments/feedback/suggestions.

My idea is to make a reverse mold of this shape via 3d printing. Due to printer size constraints I will need to break it up into 6 pieces and glue them together. There is always some sanding and filling on a 3d printed mold but nothing like the work of making a plug from scratch.
The light bay will have to be a separate piece - the mold will have an uninterrupted leading edge.
My father has a vacuum pump and experience making composite race car parts but this is larger and a bit more complicated than what he's previously done. Will explore whether to try and make the parts myself vs having a professional lay it up.

There are some online CFD tools. Tempting to try this, but I am not sure I'd know what to do with the results and I think it's a bit pricey for an idle curiosity experiment.

[Battson]

That's the shape I have, I reckon it works great. We based our decisions on the available NACA research and later practical testing by Wittman and others who Bob recommended.

Unscientifically speaking, when rounding off the leading edge, to blend it into the outboard edge, you want to avoid the air having to deviate downward before it reaches the outboard side. In other words, if you view the wingtip from the front, there should be no part of the underside or outboard side which is hidden behind the leading edge "overhang", where you blend the shapes together.

Achieving that aim means either you need a complex curve on the underside of the wing tip, or you can achieve the same thing with a linear surface on the outboard by blending it appropriately at the leading edge.

[MidGenerationAL]

That's the shape I have, I reckon it works great. We based our decisions on the available NACA research and later practical testing by Wittman and others who Bob recommended.

Unscientifically speaking, when rounding off the leading edge, to blend it into the outboard edge, you want to avoid the air having to deviate downward before it reaches the outboard side. In other words, if you view the wingtip from the front, there should be no part of the underside or outboard side which is hidden behind the leading edge "overhang", where you blend the shapes together.

Achieving that aim means either you need a complex curve on the underside of the wing tip, or you can achieve the same thing with a linear surface on the outboard by blending it appropriately at the leading edge.

Can you please post a picture of your or other examples?
I think I follow you but a visual aid would help a lot

[Battson]

Sure - please refer to photos in this thread:

https://bearhawkforums.com/forum/bearhawk-4-place-plans-build/24611-hoerner-wingtip-build/page2

[MidGenerationAL]

That's the shape I have, I reckon it works great. We based our decisions on the available NACA research and later practical testing by Wittman and others who Bob recommended.

Unscientifically speaking, when rounding off the leading edge, to blend it into the outboard edge, you want to avoid the air having to deviate downward before it reaches the outboard side. In other words, if you view the wingtip from the front, there should be no part of the underside or outboard side which is hidden behind the leading edge "overhang", where you blend the shapes together.

Achieving that aim means either you need a complex curve on the underside of the wing tip, or you can achieve the same thing with a linear surface on the outboard by blending it appropriately at the leading edge.

What I had in my head from your description, and your linked pictures, and my latest updated CAD model, are all very similar..
There are a couple of the intersections on the underside of this model that aren't quite right, but extremely difficult to define in CAD.
However, the parts I don't like are "outies" on the model, thus will be "innies" on the mold - and therefore very easy to correct with a small application of body filler. After that I think what I came up with is very close to yours with the exception of the landing light window and the wingtip light mount (where this joins the upper airfoil I also have some corrections to make with filler)

[Bcone1381]

I curious if you made any progress on this?

Here is what I’m up to. I fabricated a model from foam and had it scanned. The “Scanner” printed a miniature model to inspect for errors. Next step is to print a full size what I’d call a “rib cap model” to verify the fit of the model to the wing.
IMG_4891.jpg
IMG_4955.jpg

[Bcone1381]

I am learning that a significant barrier to a printed wing tip is the material strength combined with the method of attachment. I think I will end up with a study mold to fabricate wingtips uisng a composite layup of Fiberglas or Carbon Fiber. The fragility of my foam mold is significant at the trailing edge and I'm going for a mold that is sturdy and re-useable.