G-BREY Restoration (5 of 8)

My Taylorcraft restoration project, G-BREY
Page 5, May 2004 - Feb 2005
Go to page 1 2 3 4 5 6 7 8

by Robert Lees

Click on the thumbnails to enlarge, use the browser's Back button to go back.

May and June 2004 Wing work commences:

The fuselage gets taken away for storage, and the wings come out of storage and are delivered to my house.

It's a tight squeeze...

...but better after I relocate the other wing to the living room.

		I had previously removed the butt fittings (front and rear spars) to inspect and measure them. Note in the left photo the severe corrosion (painted over) on the rear fitting, so much so that someone decided to add a doubler to take the loads. A real wasp's nest!
		The magnesium aileron brackets are removed and disassembled for inspection. These can be prone to dissimilar metal corrosion between the magnesium and the steel end fittings. The right-hand photo shows removal of the oilite bushings, using the same drift as used on the tailfeather bushings.

Wing aileron bracket after bead blasting....

...and after Magna-Dyning. Next step is etch-prime and then epoxy prime.

The four other aileron brackets

	Using a cycle spoke key to undo the wing bracing wires (No.10 slot seems to work great).
	Removal of those pesky, corroded slotted screws is simplified with the use of a small right-angled screwdriver, upon which pressure can be borne to keep the blade from "camming out". I cleaned out the slot of each screw beforehand with a mini hacksaw blade.

The little fibre components inside the wing get a clean-up...removal of decades of grime, paint and varnish; they turn out like new.

Some of the threaded end fittings of the wing bracing wires are of different sizes....any explanations forthcoming?

..and the compression strut shims also show minor differences.
Port wing is S/No. 7352, stbd is 7284 (implying that the starboard wing is 78 units earlier than the port wing. Airframe S/No is 7299.

My rather Heath-Robinson but effective wing rotating jig on the butt end of the wing.

One of the two laminations that make up the front spar has a splice installed at the factory.

Some of the holes where the fabric wire goes through the ribs are slightly deformed, so I use a suitably-sized drill bit to bring them back to the contour of the rib cap.
The cap has a depression along its length, to permit the wire to lie level with the upper surface of the rib.

	The ribs get the acid-etch and clean-up treatment...
	...and some of the two-sided ribs I have to fettle and reinforce where previous knocks have dented them.

Late June

View of drill jig for opening out the existing holes in the front spar. Using this jig, a hand-held drill can be used.
Behind the spar is a block of wood to drill into. The original bushings need removing (pressing out with a drift) after alignment but before drilling.
Note that the root rib and first nose rib both need to be removed.

The frame has five jig-bored 11/16" holes at the correct spacing.
The frame holds two 11/16" diameter locating pins which fit inside the existing 1/4" holes. As each hole is drilled, the locating pin can be pushed in to the drilled hole.
An 11/16" diameter bush holds the Forstner bit.
The pins and bush are interchangeable in each hole of the frame to permit each of the five spar holes to be opened out.

Here's the result...five aligned and parallel bores in which to glue new bushings.

This is the comparison in diameter between the old bushings (on the left) and new ones (on the right) - same size bolts though...

..and this photo shows the new bushings installed dry in the bores.

I glue the bushings in, but to ensure final alignment while the glue dries, I bolt up the new butt fittings. These fittings were manufactured on the same DRO Bridgeport as the drilling jig, so I am confident of the fit. The straps were ground on their faces over full length to ensure that they will fit between the ears on the fuselage.

July to August 2004

The new fittings for the rear spar; the originals were severely corroded.

The end bracket is manufactured using a male and female press die, with a drilling hole for the undersize hole (this to be reamed out after welding).

	I use a wooden piece as a dummy spar to check the assembly, which has an angled end. Note the pin used to ensure alignment of the end hole...
	..and after welding & painting, here's the result.

Spacers are used for the correct spacing of the strut attachment brackets...

..and after welding of reinforcing plates.

	The butt ribs are severely corroded where they butt up against the spars...requiring amputation of the cancerous bits... [rectangular hole is aperture for spar butt fitting]		..and so needing some serious patches where both front and rear spars meet the rib. The reliance upon the Alclad to protect the material against moisture and wood acid erosion was misplaced, perhaps in the light of what we know now. Parts will be painted to protect them, before riveting together
	More patches!

Various wing internal components are bead blasted and painted...

...and after painting, the internal bores are treated with oil to prevent corrosion.

More painting!

September 2004

I completely de-riveted the aileron cove parts (to get rid of more of those horrible steel rivets), and after cleaning up, re-fabricked the inside of the cove. Flush solid rivets then installed in new holes to reattach the stiffening edges. Pigeon Poo used during rivet installation (wet-riveting).

Previous problems with the last trailing edge rib before the aileron bowing (because of fabric tension) will hopefully be resolved by stiffening the rib with some 0.015" braces riveted on...

..and here is the result after screwing on the other side of the rib, (braces fitted both top and bottom...space required between the two braces for aileron cables).

Although I varnished all the holes through the spars, you need to ream them out to fit the new bolts. Therefore there is always the risk of the holes permitting bare wood and bare steel to come into contact (bad for corrosion).
So I use "Duralac" (Pigeon Poo) as a wet sealant immediately before inserting the new bolts.

But wing reassembly is progressing!
(Drag wires go under anti-drag wires...but I am assembling inverted, so in my case, they go the other way around).
Bare steel bolt heads will be wax-oiled for corrosion protection).
One of the compression struts is shorter than the rest; this goes at the strut bracket fittings.

October 2004

String lines assure the straightness of the spars during trammelling. The right-hand photo shows the wing with a block inserted under the front spar to simulate the wash-out to verify that nothing alters.

The original Dahlstrom "C" section used as bracing each end of the wing trailing edge were suffering a bit...so I am going to replace them with stiffer and lighter aluminium tubing. Ali tubing annealed at the ends using a light flame prior to bending/flattening.

I used the more complete Dahlstrom pieces from the wing to make new ones for the ailerons.

The leading and trailing edges undergo necessary corrosion removal, repairs and fettling, prior to filling out the final few dents with Poly-Fiber "Superfil". The blue slab is the wing, protected against the up-and-coming overspray.

Several iterations of paint/sand/fill, paint/sand/fill were necessary.

So the port wing is structurally complete...

...well, almost. After turning over to attach the underside of the leading edge, some more filling needed.

In the meantime, I have conducted cheque-book aviation, and had a new nosebowl and lower cowl made by the local panel-beating shop. 16 gauge aluminium (thicker and stronger than original). Grilles from Aircraft Spruce.
See Nosebowl Grille fitting problems for why a new nosebowl is required.
The lower cowl is 2" oversize all round, so that I can do the final fit & fettling in situ and get all the holes etc in the right place.

November 2004: Ailerons

		The ailerons themselves are in fair shape...a bit of crushing on the attachment points, so new spars to be made.
		I designed a drilling jig to get all the aileron spar holes in the right place. Sample piece of wood shows correct alignment.

	Planing the new aileron spars. I modified a cheap electric hand planer with longer blades to do the cut in one width.
	I made a mess of measuring up the old spars, so my new replacements need a lamination to get to the correct depth. Doh! One can never have too many G-cramps.
	Using aluminium foil as a wrap-around of the timber load-bearing blocks when clamping up glued surfaces, prevents the glue sticking to the blocks.
	I am using aluminium reinforcing plates (0.080") on the new aileron spars instead of plywood. Floating anchor nuts will be used to permit any tightening of the bolts from the front of the spars, eliminating the need for cutting a hole in the aileron fabric to get a spanner on the nut. Using floating anchor nuts will ensure correct alignment of the bolts. The plates will be glued on, in order to eliminate the wood splitting with age around the bolt holes.
	Here is the result for the inboard bracket on the rear wing spar(1). Note also: (2) I have not yet completed the final trammelling and lock-nut tightening on the drag wires (3) The aileron brackets still need attaching to the aileron cove with little angles.

I can now drill the 3/16" holes in the aileron spar using my jig. The depth of the jig allows me to free-hand the drilling; the jig itself ensures alignment.
Some of the L2 drawings (on CD) were very useful in getting the correct dimensions of the spar.

After varnishing, I temporarily mount the spar to the wing brackets (to make sure it'll fit!)

The centre reinforcing plates are attached. I am using a structural two-part adhesive. The purpose of the adhesive is not to ensure attachment (the clamping of the through-bolts does this), but rather to bond the wood to prevent longitudinal splitting of the spar where the holes pass through. I also drilled 1 mm (0.040") diameter holes through the plates and nail through these holes as per the drawing.
Note the use of tin foil to prevent the adhesive sticking to the wood backing piece.

My friend David manufactured new aileron brackets for me...and a jig to press them and drill them accurately.
A spot-welded piece on one side will prevent rotation of the pin in service.
Thanks, David, your skills and patience are very much appreciated.

I found it important to identify which rib came from which location, to ensure that the screw holes match up between the metal parts.

After gluing on and nailing the outer two attachment plates (after the ribs are slid on), another "dry run" ensures the trailing edge lines up. I have increased the spar length by 1/4" each end to reduce the enormous gap between the wing and the aileron ends.

The inboard end of the aileron gets a rib reinforcing piece to prevent bowing under the fabric tension loads. This is a one-piece "Vee-section" aluminium brace, countersunk riveted on to the aileron butt rib AFTER the butt rib was nailed onto the spar.
Remember the round aluminium tubing used on the wing braces? Well, I cut the corroded ends off the wing Dahlstrom pieces and re-used them in the ailerons.

I use my slip rolls to create a new tip leading edge. The old one is Cleco'd to the new to get the right contour.

December 04/Jan 05: Wings (continued)

Much of the last month or two has been rebuilding the structure of the starboard wing, so no real news to report, other than the following:

As per the port, the starboard wing spars were varnished, and then masked off for spraying of the ribs (here in etch-prime). Those components removed for rework were also etch-primed.
Two-pack epoxy prime to follow.

During rebuild of the aileron spars, I first ensure alignment of the old aileron spars to the new aileron brackets. Then I can be sure that the new aileron spars, when drilled according to the drawing, will fit.

Note that the lower edge of the aileron cove (this photo taken while the wing is upside down) has drain holes for the lower section. These must be allowed to ventilate to atmosphere.
The aileron cove was rid of the pesky steel rivets, and new flush rivets installed.

Damage to the trailing edges of the wings and ailerons is hammered out using a hardwood block, sanded to the correct contour.
Removal of rivets/staples holding the trailing edge is required, but with care, can be reinstalled.
The final contour will be dressed with micro to get the proper shape.

The trailing edge of the starboard wing contained the remnants of wasps nests...probably from Texas in the late Eighties.

February 2005

A trial re-fitting the leading edge. The Cleco's fit rivet holes as found...there had evidently been previous damage to the wing tip, necessitating replacement of the outboard leading edge. Note the truss rib previously used as a replacement. This damage probably occurred in 1987, of which I have heard anecdotal evidence, but no log book entry.

Some repair work required on the trailing edge of the wing, due to corrosion of the original section. Note the round aluminium tube used as bracing instead of the original Dahlstrom section.

After trammelling the wing, the starboard aileron is jigged to the wing. I found it very valuable to do this while both the wing and aileron were uncovered, since some shimming of the magnesium brackets (on the wing rear spar) and of the aileron trailing edge were required to get the best alignment.
Note that I only dismantled the starboard aileron after rebuilding the port, so that for both, I would have a pattern to work from.

After final aileron jiggering and pokering, I can secure the magnesium brackets to the cove.

Go to page 1 2 3 4 5 6 7 8

Other restoration photos
Taylorcraft.org.uk Home