My Taylorcraft restoration project,  G-BREY
by Robert Lees

Cowls

Bootcowl
Nosebowl & Lower Cowl
Top Cowls
Completion of Cowls
Contaminated Paint

Bootcowl

I make paper patterns of the boot cowl pieces...

...to form new pieces from 0.025" 2024T3 sheet.

I use my extended slip rolls to form the curves.  I will also be using these to form the joggles & beads at the firewall & windscreen respectively.

Here's the dies being used to form the firewall joggle on the bootcowl...

...and the finished joggle ready for riveting.

After clecoing up, a trial fit of the screen and fillet strip goes relatively well...but still a bit of fettling to do.

	Windscreen bead completed...
	...new bottom piece...

...and coaming. The red tape is to protect the tube paintwork from being scratched.

Fuel tank is temporarily installed to ensure correct location of filler aperture.

	The finished article prior to riveting.
	The mating faces between sheets that will be riveted together are pre-painted to minimise any chance of corrosion.  These are duffed up with red Scotch-Brite, etch primed and then epoxy primed.

I have dimpled the firewall rivet holes to permit the use of countersunk rivets.  The dimple squeezer unfortunately caused some areas of the firewall flange to go awry, so I made up my own fluting pliers to return the flange to the correct alignment. Standard fluting pliers have too great a pitch. 1/8" Cherry Max structural rivets used.

My flying partner John (RV6 builder, hence the wing ribs) rivets up the stringers using 3/16 countersunk rivets.  The stainless firewall we attach using 1/8 Cherrymax structural countersunk pull-rivets for convenience.

A detail of the firewall edge.   Countersunk rivets used...both on the firewall and along the cowl where the stiffeners run. Stainless Dzus springs from D&D Aircraft, New Hampshire.

A dry run of fitting the replacement firewall pad (Airtex Interiors).

Nosebowl & Lower Cowl: 

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.

To fit the new nosebowl concentric to the prop flange, I have made a collar to fit snugly between the two. OD is 6" to fit inside the nosebowl hole, ID is 5.18" to fit snugly over the prop flange.

I have had the lower bootcowl made deliberately oversize, so that I can incrementally trim it to fit in situ.

I use Cleco's to hold the parts together...these holes will become holes for the Dzus fasteners.

I have had new stainless Dzus fasteners modified by drilling through...

..so that a tool with a pin will prevent the scratching of the paint.

An aperture is cut for the exhaust...

...and for the air intake.

New skills are learnt; here I folded the cut edges over to make a little bit of reinforcing.

On the lower cowl, I make new stainless reinforcing patches for the four corners (the shrinking tool helps get the curve in the folded edge...

...I do similar for the two lowest Dzus fastener reinforcing patches.  All of these stainless patches are flush-riveted on.

Using the original cowl as a pattern, I joggle the lower cowl to take the thickness of the top cowl to provide a flush finish.  The stainless firewall has a recess to allow this.

Reinforcing the nosebowl where the top hinge meets, I use some stainless plate.  There are three screws which attach the front hinge where the 1/8 clecos are; I will open the holes out later.

Top Cowls:

After much fettling, I can start to look at the top cowls...I use my slip rolls to get the sheet to conform to the curve.

I use my shrinker to bend some aluminium angle to the shape of the top cowls.  (This is the stringer in the middle of the top cowl).

I roll new top cowls using my slip rolls.   Final trimming will be done in situ.

On the new top cowls, I add an additional stringer at right angles to the original.

This will hopefully reduce the twisting of the originals. Again, all are flush riveted.

I make new stainless patches for the new top cowls (why all of these were stainless is, I can only assume, to keep thickness to a minimum for a given strength).

After alodining all components of all the cowls (except the stainless ones), I wet-rivet them up, then prime with etch prime. Here is the two-pack epoxy straight on top of the etch prime.

Completion of Cowls:

As I progress, with constant trimming, things start to look good.  I use duct tape to hold things until I drill the Cleco holes.

The Cleco's mark where the Dzus fasteners will go.  I will drill these out as one of the last operations.  Note also I am leaving the bronze ring around the prop flange during the whole process, so that I can be as sure as possible of correct  alignment to the crank.

All in all, the progress is satisfying.

Contaminated Paint

After priming all the cowling elements, I encounter some contaminated paint, unfortunately after I had sprayed the cowls.

All of the flush rivets were treated with a quick dab of "knifing putty" to seal the little circle of gap between the rivet and the skins; the excess gets sanded off. If this is not done, then the paint will not stick to the very sharp edge of the rivet head. I used JB Weld, a well-known Aviation two-pack epoxy product.

The photos are self-explanatory, and are of samples I did after I discovered the problem.  Of fours tins of two different colours, purchased from two different suppliers at two different times, two tins of red and one of white were contaminated.

The paint appeared to curdle, and would not cure correctly.  Fingerprints would remain in the soft surface, even after seven days.  I have no choice but to laboriously wet-sand to remove the film on most of the components.

Poly-Fiber did replace the defective product, and also supplied materials necessary to get back to where I was.  They however refused my invitation to compensate me for the additional hours I needed to spend correcting the situation.  The UK agent, Tony Young, acted very admirably with his assistance, however, and I cannot fault his customer service.

But the experience has severely dented my confidence in their product, and in the factory quality control methods.

I eventually get the white gloss completed, and mask off to paint the red.

Red top coat.  After the last coat of paint, I spray a very thinned down coat, mostly thinners, to increase the gloss level, but one must be very wary of runs!

After removal of the masking, the effect is very pleasing.

The old and new lower cowls side-by-side.

Taylorcraft.org.uk Home

Fuselage structural work
Fuselage Fabric
Wing Structural work
Wing Fabric
Ailerons
Cowls
Tailfeathers & Gear Legs
Doors Control Column & Panel
Final Assembly

Other restoration photos
Tools used