Heinkel P.1076 - Veneered foam wings

[chiloschista]

Hello, 

here we go with another build thread of that plane, but with veneered, foam core wings. 

I've lost an amount of time trying to figure out why the software I did use until now refused to work on a new Windows 11 PC.

The only help from the programmer was to swap to another, older PC.

I was even prone to upgrade to the new version, but guess what? It didn't work either. 

I finally decided to dig into FCNX developed by Renaud Iltis and I discovered a jewel among the few softwares available.

What a greater, modern and cheaper tool! 

So I'm up and running again.

First cut went well at first attempt. Ok, I already knew kerf and temperatures values for those materials. 

Cores and sheetings ready for vacuum bagging.

Cores are in XPS Jackodur.

Sheetings are 0.6mm obeche.

There will be a fiberglass layer too.

 

[chiloschista]

Oh, some look test first, of course...

 

[chiloschista]

Everything ready

Sheetings rolled with slow curing resin, fiberglass applied and rolled

In the vacuum bag and curing for 24 hours now

[chiloschista]

And while waiting, it's time for some homework.

[chiloschista]

For the leading edge I choose the carbon rovings solution. 

A couple of the thicker I have was added to each wing. 

Added the sheetings for the intrados, closed and now curing in the vacuum bag.

[chiloschista]

A pair of wings came out of the bag

This is how leading edges look like after sanding

[chiloschista]

Quotes for ailerons cut

265mm and 126mm are root and tip chords

60mm and 30mm are ailerons chords

Ailerons start at 130mm from root

[chiloschista]

Out of curiosity, these are the weight progression while assembling the wing components and airfoil accuracy.

I'm wondering if I would be able to reproduce those results

P.s.: airfoil accuracy not taking in account finish, as I still don't know how it will be done.

[chiloschista]

More rovings.

On ailerons side, closing the box, those will help for rigidity.

On wing side they will help avoiding sheetings lift off. Wings are stiff enough, but epoxy resin adhesion to XPS is weak. If left open, with time there is the risk sheetings to detach.

One, single, 48k, 3200tex each.

[chiloschista]

I love alternatives. So double choice on tip side. One more or less scale and another one more aerodynamic, to see if it can reduce yaw swing. 

CAD, slice, print...

Green are servo trays in ASA, red are tip ribs in PETg and white are wing tips in low viscosity PLA.

There is missing a small, 3mm carbon rod.

[chiloschista]

Here is how the two different tips looks like. 

Easily swappable 

[chiloschista]

Wings are joined now.

Two pieces from the previous build were bored together to support dowels.

Cuts in the wings are done. Dowels are 6mm hard wood.

Everything is aligned and glued with 5 minutes epoxy. 

[chiloschista]

Wings join is reinforced with a layer of 163g/m² fiberglass. On bottom it is wider, so to differentiate an eventual break point.

... and if course a first assembly check.

P.s.: this one will get 3D printed stabilisers.