A new set of aileron hinges

One of the common maintenance issues with Taylorcrafts is th onset of wear in the aileron hinges caused by the hinge rotating against the clevis pin. This is often noticable on the outer hinges and can be checked by pushing the aileron up at the tip; you will feel the movement on the hinge, it's fairly obvious. A small amount of wear is acceptable but as mine are worn to a point where they are only just acceptable I've been on the lookout for a new set of hinges.

Initially I approached the Factory but due to complications regarding the export of stock oversees, and the fact I discovered that I had Rob's jig for the job, I decided that it would be just as easy to make a new set. The jig, in two parts forms the basic shape of the hinge and allows the mounting and pivit holes to be drilled and reemed.





The basic set of six hinges took a weekend to make using the jig and some 0.050" 4130 steel sheet.


1) Six oversize blanks were cut from the sheet steel. The size is sufficient that each piece fits snuggly in the jig ready for pressing.







2) The basic shape is pressed using a vice.









3) While still in the jig, the mounting and pivit holes are drilled and reamed.
















4) The blanks are roughly shaped (original hinge shown for comparrison).







5) Final finishing with file and wet/dry paper and comparrison with an original hinge.







6) The final modification is to spot weld a tab onto the hinge to provide a flat. Each clevis pin will have a flat filed to fit thus preventing the pin from turning against the hinge.

Lastly, my thanks must go to Rob Lees and David Nowill, who between them, designed and manufactored the jig, and then let me use it.

Finishing the Ailerons

I have finally gotten two refurbished ailerons, but before I put them to one side, I wanted to check that everything fits in relation to the wings. I'm basically using the wings as a jig to check the alignment of the ailerons with the new hinges.



The port aileron fits without a hitch but the alignment on the butt rib of the starboard aileron is out for some reason and of course I've no photograph to check the alignment prior to the rebuild.

The extent to which the but rib is out of alignment can be gauged by looking at this photo, about 1 cm at the trailing edge.

To rectify this, I've used a piece of trailing edge, cut down so that it forms a box section that will fit inside the existing trailing edge when it is cut.

After riviting, I will fill the gap with micro balloon filler so that the repair will be less obvious. The rivit heads will be visible because they couldn't be countersunk but tey are no worse than screw heads used all along the trailing edge.

I've checked the fit after the repair which gives a much better fit now with the wing. The ailerons will now be put aside, uncovered, until I come to rig the aircraft way in the future.

Now back to the fuselage and a lot of welding work....

Ailerons and Skylights

Aileron

Just a quick update on the progress of the 2nd aileron. Firstly all the ribs, leading edge, trailing edge and hardware have been cleaned, etch primed and epoxied and are ready for reattaching to the spar. The spar has had some repairework carried out to fix the crushing similar to the first spar. There was also a minor crack running lengthways along the spar from the but, about 6" long and about half the depth of the spar. This will be patched as the majority of the crack lies under a plywood reinforcement plate. The spar had a second coat of varnish at the weekend so I shall be able to start reassembling the aileron next weekend (although I may have to do some gardening as well!).

Skylight

In the mean time, I progress with the skylight woodwork.

Lets refresh our memories of the old skylight. It extended from the windshield back for nearly two bays, held in place by wooden formers and steel angle (see below).

The second bay does not increase the viewable area and just adds to the weight of the aircraft for no advantage; so on the rebuild I will stick to a single piece skylight covering the first bay only.













The frame will be made from the same Ash plank used to make the door frames, using the existing frames as a template. These are rough cut with a band saw then shaped with a spoke shave and finished by sanding. Various notches where cut with a fine chisel.


Some time later after many trial fits, the basic frame sits on the fuselage. Note that instead of using a piece of steel angle on the sides, I'm using 1" thick wood (still much lighter).







My plan is to fix the skylight (3mm clear acrylic sheet) to the frame by embedding a threaded insert (below) into the underside of the frame that I can screw into. In addition I will have four internally threaded steel tubes welded to the cross frame of the fuselage which will suport the skylight and give it some rigidity

I hope to pick up the acrylic sheet next week which will be cut to shape, drilled and used to determine the location of the threaded inserts.





Next week I'll try and update you with the aileron reassembley and possibly a bit more on skylight progress. Untill then happy flying.

First Aileron Complete and a New Hat Shelf

A few photo's of the completed starboard aileron showing the strenghtened but rib.

The tip end rib also had to be replaced as the wood was cracked and had lost much (if not all) of it's residual strength.

Two general pictures showing the end result.

Although I will be starting on the second aileron next week I have also started looking at the design of a map shelf to fit behind the baggage sling. The design (I admit) was taken from that used by Rob in the restoration of G-BREY. Steel tabs will be welded to the fuselage so that the aluminium shelf can be screwed in place with machine screws. The map shelf is large enough that it require stiffening to prevent it from sagging even though it is not intended to support any real weight. It is far enough to the rear of the aircraft that any weight in this area will impact on the c of g of the aircraft.

Next week I'll post more details on the design of the map shelf and the stiffeners to be used.

Completing the first Aileron

By early December the spars have had all the plywood doublers glued in place, drilled for the aileron brackets and varnished with Randolf spar varnish. The ribs are in place but not yet nailed and most other components are primed ready for reassembly.

The first job is to nail the ribs in place. To achieve this I jigged the spar by mounting it onto the workbench with brackets attached with AN3 bolts through the holes drilled for the aileron brackets. I used the old nail holes to locate the position of each rib, and for completeness, screwed the trailing edge to the ribs. I was also able to offer up the leading edge skins to ensure the screw holes still lined up. Once confident that everything is in place, I nailed the ribs to the spar.


Following advice from Rob Lees (G-BREY), I decided to reinforce the butt rib as this has a tendency to bow in with the tension of the fabric when it is applied. A wedge was made from 0.020" 2024T3 aluminium which would fit inside the rib preventing it from warping. The wedge was riveted in place with blind rivets as I couldn't get a bucking bar in the space available if I was to use solid aluminium rivets. The three pictures below show the assembly of the wedge.










The aileron is made up mainly from aluminium parts except for the tip bow which is a 1/2" 4130 steel tube bent to shape and all screws which are stainless steel. Because there is the possibility of dissimilar metal corrosion where steel and aluminium come into contact (even though all parts are primed) I used Duralac, either painted on using a brush or as a dip with the screws which will act as an additional barrier preventing corrosion. The Duralac was wiped off after assembly to keep the structure clean.










The inside of the 4130 steel tip bow was treated with Lanolin (oil) to protect it from moisture which will also cause corrosion. Lanolin is the traditional British treatment whereas America tends to use Linseed oil instead. The downside to Linseed is that it is flamable which can be a problem if a weld repair is required at a later date.









Finally, the leading edges were screwed into place using the old screw holes. Oversize nails were used to secure theleading edge to the spar and the aileron brackets were bolted on.










The aileron will then be checked against the wing to ensure that the brackes align correctly before the aileron is put into storage. I will cover the aileron along with the rest of the aircraft after the final rigging is complete. This is probably better done without fabric on.

New Door Hinges

Three pictures showing the manufacture of new door hinges. The original hinges were fixed with four small bolts to the wooden door frames. These had worked loose over time as the holes elongated so I've decided to replace the old hinges with a set that will be welded to the fuselage frame. This idea came originally from Rob Lees when he restored G-BREY.

The template was made from needlework template sheet which is a fairly stiff plastic sheet marked out with a grid pattern. I was able to bend it round the original hinges which gave an acurate measurement including the 90 degree bend which would need duplicating in the new hinges.

The hinges are made from 0.063" 4130 steel.

The hinges after adding the 90 degree bend.

Offering up the hinge to check alignment with the hinge on the door. The hinge was deliberately left 'long' because it will have to be fitted to the curve in the fuselage tubing. The door and frame will be used to get an exact fit when welding although I'll use the old door frames and not the new ones when tack welding the hinges in place.

New Door Frames

Mid September and I receive an 11 foot length of 2"x8" Ash wood which will be used to replace the old door and skylight frames. I've decided to go for the door frames first as they are in some respects easier to manufacture.

The first task was to cut a set of 1/2" deep blanks from which each new frame would be cut. After some head scratching we (myself and a good friend David who has an aladins cave of a workshop with all manner of equipment) managed to get 9 blanks from a single 4 foot length of Ash.




The original frames were used as templates for the new frames, in hindsight I should have spent more time studying the old frames as there were some defects which although not serious or problematic (after all the old doors fitted OK) have to some extent been copied onto the new frames.




The new frames were cut using a small band saw and jointed by hand. To provide the required strength and regidity, the frames were screwed and glued and left to cure in situ. Two pairs of hands make this job a lot easier, in this case my farther John spent two days helping.

The frames still need finishing off which will include a slot for the door catch, sanding down, varnishing and final fixing although this will be left until after the fuselage is beed blasted and primed.

The doors are slotted into the frames to check that all is well. I'm happy that the fit is snug and when finished the doors will not be draughty as long as some door seal is used.

Not much of a gap here.

I'm still working on the aileron and have started the metalwork for all the bits that will need welding onto the fuselage. This is because I would like to finish both ailerons (minus the covering), get various bits welded onto the fuselage and crack on with the interior before the end of the year. Next up, the door hinges.