Repairing a Goldberg Ultimate Biplane fuse for Cadez.

[Frank v B]

Greg challenged me to repair the fuselage of a severely damaged 60 size Ultimate biplane.  Like the sucker I am, I took him up on it.  The entire nose and firewall were missing.  Greg's summary was best "it looks like it nosed in and someone took the motor and ripped it out... firewall and all".  He found a new fibreglass nose section making my job easier.

When I started the repair a week ago, it became very obvious the damage was severe.  Most of the formers ahead of the cockpit were destroyed, cross braces were missing, sheeting was shattered and the front hard points for the upper wing cabanes were shattered.

There is nothing to which I can attach the firewall.

This is an interesting challenge.

Frank

[Frank v B]

The photos show the method I always use:

1) start securing the broken joints that help stabilize the fuse.  Glue the loose joints at the formers, secure the hard points for the cabane struts.
2) start strengthening the structure- made and glued cross braces, made a balsa former to secure the stringers on the fuse top (pinned in place in the photograph), secured the break in the bottom wing saddle (3" missing), etc.
3) start securing/replacing the 1/16" fuse skins (front top and sides and around the area where the cabane struts enter the fuse).
4) add a new firewall and glue it to the new balsa structure
5) re-inforce the heck out of the structure so it can withstand a Power 60.  I will probably use fibreglass at the edge of the firewall and wrap it around the fuse.

and then:
6)....hand everything back to Greg, run like hell and don't look back.

Frank

[Frank v B]

I cut open the damaged fuse top and cut away the damaged/crushed wood.

The  former beside the cabane strut was broken on the opened side so a new cross brace was cut and installed (at the clamp and the red pin).

F.

[Frank v B]

Applying a balsa patch on a curved surface:

step 1- make 2 edges fit (left side, bottom) and leave it large on the other 2 dimensions. 
step 2- Once it fits along two sides- glue it down on one edge only (bottom edge in the photo).  Photo 21
step 3- trim the patch to fit the curve and all 4 edges.
step 4- wet the balsa (I use a wet paper towel) and glue it down and pin it down. Photo 23
step 5- your best friend, light weight filler.  From Home Depot in the paint section- pick up each container- the one that feels empty is the correct one.  Photo 24

Frank

[Frank v B]

Patching around the cabanes.

Left side
- make a piece that fits two sides (bottom and left.  Cut the cabane slot in the correct place and cut an opening on the short side. Photo 25
- slide it in place and glue the bottom side only.  Photo 26 and 27 and let dry.
- Once the glue is dry, cut it to size, wet the balsa to curve it and glue it in place.

Right side: small patch (visible in an earlier photo- copied below (Photo 08)
- I glued cleats to two sides under the balsa deck and let it cure.  This is so the patch can be glued.
- made a patch that would fit
- glued in place.  Photo 29

F.

[Frank v B]

final touches:  How about a new firewall.

Made a new firewall out of two layers of 1/8" lite-ply, five minute epoxied in place.
The photos show fibreglass cloth being glued in place.  Secured it to the fuse side first, then when cured, I will fold it onto the face of the firewall.
The waxed paper is there to squeeze the air out of the cloth and to smooth out the surface. 

F.

[Frank v B]

Final coat of epoxy on the new firewall to smooth it out.
The fibreglass cowl fits over the repaired area.

Now over to the finishing guru.... Cadez himself.
He will cover it, add the weed whacker electric motor, about a pound of electronics and two pounds of batteries and....voila.

Frank