Hoerner Wingtip Build

[marcusofcotton]

Excellent. And hearty thanks for the detailed reporting!

[fairchild]

Battson--- had you considered forming them out of non-heat-treatable aluminum ? English wheel ? That way ?
Tim

[Battson]

Good God no!

[fairchild]

Battson--- you mentioned making kayaks---- there is that stuff that Milliken chemical produces that is being used to make rock-proof Kayak hulls---- It is a pre-preg dual filament
polyethylene matt. You thermoform it just like making an RV canopy -- heat and vacuum (or pressure) . It is strong enough that they make military vehicle armor out of it.
The product name escapes me at the moment--- but I can find it on-line. They will send you free engineering samples.
Tim

[fairchild]

Here is a link to the Milliken thermoforming product - called Tegris. Its an extruded PE fiber made so there is a core part of the fiber which has a higher melting point
than the surrounding cladding. The fibers are woven into cloth or mats similar to glass cloth. Once heated- the cores stay in solid phase and the cladding melts and bonds all
the layers together (like it was a resin in fiberglass/acrylic) and creates a solid mass with the cores intact as strength members. It is so strong they have made armor plates
out of it. Kayaks that are rock-proof. Floor boards for Mercedes cars----
Looks like you have to compress it into the desired shape while you heat it. That - I suppose could be done with a vacuum bag...… and maybe heated with steam
from a pressure cooker. Here is the link---

http://tegris.milliken.com/en-us/technology/Pages/overview.aspx

Tim

[svyolo]

Interesting. Kind of a pre-preg cored laminate. My guess is it would be rather expensive.

[Gerhard Rieger]

My version of the hoerner made of 2024T3 aluminum

[Gerhard Rieger]

More wingtip progress

[schu]

That looks very strong. What does it weigh?

[Gerhard Rieger]

I weighed all the components and it came to 7lbs ea, that exclude the lens.

[Battson]

More wingtip progress

That looks very strong. What does it weigh?

schu I finally got around to weighing them.

Stock fibreglass tips are 2.1kg each.
The hoerner wingtips are 3.9kg each, which could easily be made a few hundred grams lighter.

So a total weight increase of 3.6 kg (7.9 lbs).

I am seeing touchdown speeds as good as 30 KTAS with light tanks and two people up, if I really push the limits. So I don't mind the weight increase.

[marcusofcotton]

...Now that I know the plane's new limits, I am seeing touchdown speeds at 30 KTAS with light tanks and two people up...

Good to hear!

[svyolo]

I have seen some planes with small fences at each end of the flaps, sometimes on the bottom, sometimes on the top, sometimes both. Has anybody heard any pireps on those mods? Seem pretty easy to do.

[Chris In Milwaukee]

There are fences like those in the Patrol plans. I asked about those in the past, and I recall the answer being that Bob didn't find they made any noticeable difference.

[svyolo]

Bobs planes have comparatively huge flaps, albeit just plain flaps. Cheap mod to install and check out the difference.

[rodsmith]

I have known all along I would put Hoerner style tips on my Bearhawk. Only question was do I buy the tips from TQFiberglass and install them to fly sooner or go ahead and make them now. Couldn't see paying for those tips, taking the time to install them, just to remove them later. Considered trying to build them out of metal, similar to those on Vans RV-12 but have decided to build them very similar to Jon's but with carbon fiber instead of fiberglass. Appreciate all the great ideas in this thread and others. Will post on progress.

[Battson]

14 hrs sanding to make my own tips... that was just the sanding, never mind the rest. That time, spent at paid work, pays for a lot of wingtip.