February 2017 update. Wing structures ready for cover

 

 

July 2016 Update.

It's actually February 2017 as I am writing this blog, but I had to break it into meaningful chapters and this is one important one completed. Basic wing structures are completed, fitted, brace wiring done, bamboo extensions installed, fittings made. 90% done, 90% to go. Just cover and fly ?

 

Building the wings

I initially expected the wings to be a simple process, after all, I had drawings and materials were straight forward. Sitka spruce, 4130 chrome moly, the wires and turnbuckles, covering materials. Nothing new here. Right?

WRONG.

Turns out that the drawings were woefully inadequate, primarily they did not adequately show the twist of the wings. Seems that 5 degrees washout appears correct, plus another 2 degrees at the tips. That was made evident after studying many photos and sketches. Plans were not revealing. Plus mine would be made in 2 inner and two outer panels, hinged where they joined to provide folding in order to bring their overall size down to a manageable dimension, but creating yet another challenge. My hangar is 45 foot wide ( outside dimension ) and the wingspan is 47 foot.

Building the wing structures actually turned out to be a two year project. I was able to work in my heated workshop- up to the point of installing the bamboo extensions - or I would not be able to get them out of the shop. Boat in the basement syndrome. The setup was complicated, getting the twist and everything correct, with two separate panels. Here goes:


So this is what I had to work with

 

Translated into black on white, much better 



Root Rib profile, thanks Heinz.

 

Translating onto fixture board

All the main components needed to be fabricated first  

 

Getting the radius for the tip bows figured out

 

Bending and gluing the tip bow strips in a fixture, after steaming






Making # 13 ribs, where the folding hinges will be installed

Rib 13 in place

my indoor-outdoor saw mill



Wing tip bows completed

 

10 to 1 taper jig and cut

Joining to leading edge

 

Planning never to come apart

 

Gluing several spars at the same time

 

My poor man's glue curing oven during cold weather

 

Each spar is made of two laminates, total of 12 spars.



Notching the leading edge for the rib caps 

Homemade router jig

getting the angles set up, note the twist

 

Starting to lay out the spars

Fitting the spars

 

Corner blocks and gussets

  

Note the washout

 

Rib 13, where inner and outer panels meet

 

One of the 6 hinges, one per spar

 

Hinges in place

 

folding trial

 

One of the bracing fittings

Fitting the fitting

Cross bracing each panel

 

Using a laser to get it nice and true. ( Overkill )

 

Miles of Sitka spruce rib cap strips

Cap strips installed

 

Lots of stiffener blocks installed, each one different

 

Seemingly hundreds of stiffener gussets, each one needs to be individually fitted

 

.. and glued into place

 

That's where a lot of time goes

  

My poor man's steamer, works like a charm

 

Just add wood.. and steam away

Then place in fixture, let dry, next day glue together in same fixture.

Temporarily fit bow at inboard end of wing for later assembly

 

Install scalloped leading edge plywood and wing walk stiffeners

 

Remove and varnish 2 coats

 

Lay out and admire

 

Making all the pieces for the bridge out of laminated ash 

 

All the fittings needed for the bridge and folding mechanism

For one wing, after sandblasting, and powder coating

 

Some of the fittings for the 49 wires , two of each

  

Fitting the left inner panel onto the fuselage

 

Then the right

 

Then both

 

Starting the bridge and folding system, left side

 

Same shot, from the front. Still snow on the runway

Bridge and bracing wires and washout trimming 

Note the aluminum angles clamped to the underside of the wing, to allow digital level to be used to get the washout correct 

 

Getting cramped already

Leading edge hinge and bracing wires and fittings, to get the wires right

 

Bridge junction at station 13 for folding mechanism

Fun building this junction, where the outrigger wheel will mount

 

Designing all the 49 wires for each wing and their fittings

 

Yes, 49 different wires, each side

Not done yet, now come the bamboo extensions, each one gets fitted with at least a half dozen wood wedges, glued  and then taped.  I am using cloth tape, excellent stuff.

Very solid

The outer panels almost double in size

 

Tip wire gets installed and secured with copper wire and soldered

  

Time to inspect

and admire some more

 

So this is where I am in July 2016. 90% done, 90% to go.