Fournier Resurrection Part 5
Fournier Resurrection Part 5: putting it back together again
Now it's time to put it all back together
Wagon’s fuselage is re-covered, its wing is recovered, so now all I have to do is bolt it together, right? Sadly, as I discovered, no. I guessed there was still quite a lot of work to get my Fournier back into the air. What I hadn’t realised was just how much there was. Somebody had ripped off the firewall
and pulled apart its three sandwiched elements. I don’t know why, but it had ruined my firewall and uncovered the raw asbestos previously safely sandwiched between the two outer metal sheets. So now I have to fabricate a new one. That shouldn’t be too hard. It’s not made of stainless steel, only softer and more malleable aluminium, and I have the RF4D drawings with material specifications.
I ask my local metal supplier for the specified AG3, 530mm by 450mm and 0.8mm thick. “That’s a French specification, but 5754 is the same, only we don’t have any.” Okay. I make a quick call to LAA Engineering, “Don’t worry, 2024-T3 Alclad is an acceptable alternative.” Back to Rudgwick Metals. Yes,
they can supply 2024-T3 but I’d have to buy a full eight-foot by four-foot sheet. This was not the first instance of what I came to call the ‘Fournier Foxtrot’, a dance with which I have become very familiar over the years. It goes: one step forward, two steps back! Luckily they had an offcut more than big enough but in slightly thicker 3/64-inch thickness which they sold me for a very reasonable price. Good.
Now, how can I prevent heat transfer to the wooden airframe, since asbestos is banned nowadays and mine is ruined? I search through the Aircraft Spruce and Specialty catalogue. Aha, this modern Fiberfrax washed ceramic fibre stuff looks good. Both better at temperature resistance and lighter than the original, it comes in 24-inch widths and two thicknesses. I order three feet of the thicker, 1/8-inch variety from their British stockist, LAS Aero.
While waiting for that to arrive I made a start on the two aluminium sheets, by first cutting a template from MDF identical to the fuselage Station One (the very front, wooden firewall bulkhead) with my grandpa’s old jigsaw. Getting the 21.5° taper around the edges was tricky, but when I offered it up against the fuselage it matched very well. Now I could mark and cut the first, inner sheet to shape around that, again using the jigsaw, but this time with a metal-cutting blade.
Next I clamped the outer aluminium sheet in place with my template, allowing enough extra material around the edges for the flange that would overlap the forward fuselage sides. I used the old, damaged outer firewall to mark out the many required holes in both sheets. In the centre was a big one for the magneto housing, while there were also five more quite large ones for various wire and tube conduits, plus sixteen for the engine mounting bolts, eight for the cowling fastener brackets and a handful of others. I had to be careful, because some of those holes were now redundant and a couple were over-large, and of course nobody wants any more or bigger holes in their firewall than they can possibly help. By drilling them all through my MDF former I ensured there were no burrs.
With everything clamped together on the forward fuselage I started hammering over the front sheet’s flanged circumference−as learned in metalwork evening classes many years ago. Of course metals suffer from hysteresis, so when the flange was finished it still wasn’t flush with the fuselage sides. But it was easy enough to un-clamp my MDF template and the outer aluminium layer, turn them around so the taper was reversed and keep hammering until the flange was the required shape. In fact I had to cut away more of the MDF’S chamfer to get it perfect.
When that was done I could clean off the white plastic protective coating. Meths should do that OK. No? Well then, how about acetone? Nope, that didn’t work either. What is this stuff? Right, I’ll bring out the big guns. Horrible, stinky MEK will dissolve anything so I’ll use that. Well I’ll be blowed, the MEK made it nice and clean, but doesn’t show the slightest sign of dissolving it, no matter how long it soaks.
Fournier Forum advice suggested paint-stripper, so I toddled off to our local hardware store and discover two things about modern Nitromors: nowadays it is green, presumably as a sop to the environmentalists, and it is nothing like as strong as formerly. More Fournier foxtrotting: a whole afternoon and two cans of that feeble stuff later, by scraping away with an old credit card I eventually had two clean and thoroughly washed sheets of aluminium. Now I could prime and spray these firewall sheets with Smooth Hammerite, which I have been using for decades. It doesn’t need a primer on steel (although you have to use a water-based primer on
aluminium), it makes a thick coat with a high-gloss finish, is resistant to scuffs and chips and, most importantly, it stays flexible for years. I have used it on all my aeroplanes. Yes, there is a limited range of colours, but they are all bright and cheery−although I mostly use black, silver and white, as on this firewall.
When the Fiberfrax arrived I was fascinated to see how clean, soft and light it was. Cutting around its outline with scissors was simplicity itself. Next I marked out the position of its required holes with my MDF template to make them with an ordinary punch, but then I had a realisation. Clearly this material’s heat insulating properties came from the minuscule air pockets trapped within its ceramic matrix. Unfortunately it is easily squashed, so if I simply glued it into place between the two aluminium sheets and then tightened all the bolts it would become compressed. That would spoil its heat-resistance, and my engine mountings and everything else would soon become less than firm. So I ordered a pack of stainless steel washers from LAS to use as spacers. But how to punch out those bigger holes? Brainwave! Taper a foot of tough aircraftquality 4130 steel tubing of the required diameter to make my own punch. That worked a treat. Now I could glue in place the inner aluminium sheet, stick the Fiberfrax onto that, and clamp them both with my MDF former until the adhesive set.
I was fascinated to see how clean, soft and light the Fiberfrax was, and easy to cut
Although the fibreglass magneto box had never previously been insulated against an engine compartment fire I decided this was imperative, so I lined it first with Fiberfrax and then with a layer of adhesive aluminium tape to reflect heat. Meanwhile I similarly lined the new cowlings I had earlier bought from Italian Fournier specialist Eugenio Lanza di Casalanza. Then I fitted the engine compartment’s underbelly exit scoop and made new aluminium heat-shield panels for the fuselage sides where the exhaust pipes leave the cowlings. It soon became clear that filling, painting and fitting these new cowlings would take several days, and possibly weeks at my normal work rate. So while I did weigh ‘Wagon’ with these new, larger cowlings, I simply re-fitted the old ones for the test flying, leaving the new set until after I had got back into the air−my driving imperative since I had been forcibly grounded for 22 months.
While I waited for things to be delivered, there were plenty of other jobs. Rather than undertaking tasks in a logical, successive order, I was often doing half-a-dozen things concurrently, such as cleaning, painting and re-assembling my dismantled tailwheel unit on another bench before fitting it into its new block on the upturned rear fuselage. I also stripped and re-painted the steel tailplane fittings and several other components−all with white Hammerite of course.
When the fuselage was upright on its trestles I tried fitting its tailplane and fin to make sure nothing had shifted during those woodwork repairs. I also added reinforcing fabric patches around the rudder cable exit holes, static vents, rear fuselage
lifting handle, where the wing root fairings and cowlings fitted, and around the instrument panel surround and the rear of the cockpit, where the Leatherman tool on my belt had scuffed off paint in the past. I then doubled that cockpit protection with automotive stone-chip tape bought from Merlin Motor Sports. Meanwhile the divers components of my retractable mainwheel glowered at me from the dining room floor where I’d laid them out for reassembly. The wheel lever lock latch arm was missing, so I’d have to make a new one. I wasn’t sure whether that had to be done in situ, which would be awkward, so I kept putting it off. Eventually I cut one out of 4130 steel and it worked perfectly.
While being busy either in my garage or at Dunsfold, I also had to update Wagon’s documentation. I mostly did that in the evenings. Resenting having to pay the LAA fees for modifications somebody else had previously incorporated, I just had to bite the bullet to make my aeroplane legal. On top of that I wanted new mods of my own, including camera mounts, improved controls, drag reduction measures, and unlimited aerobatic approval. After completing lots of paperwork and a few practical demonstrations, they were all approved.
I also made a new wiring loom in the evenings. The RF4D’S original electrical system was simple: just a gel-cell battery supplying the red stall light, plus another yellow light and a horn to warn the wheel wasn’t down when the throttle was closed or the spoilers extended. This battery should live in a holder on the back of the hinged inspection panel at the rear of the baggage shelf, but Wagon’s had been in the left footwell, an unapproved modification that must have altered the centre of gravity, so I relocated it where it should be.
Nowadays a radio has virtually become a necessity, especially for display flying, plus of course I had wires out to my wingtip smoke pods. I wanted a warning horn in parallel with my stall-warning light, and another, louder one just behind my head for an unlocked mainwheel. I also needed provision for a possible transponder and an ipad charging socket. All of this needed wiring, so I searched around for the correct Duminivyn, finding the last known spool in captivity at nearby K Lacey, Rustington. Then I made a purpose-designed loom, sheathing it in many layers of heat-shrink tubing for protection against abrasion in Wagon’s snug cockpit. Fitting this loom was another matter. It took time and trouble, and I didn’t yet have an instrument panel, so connecting that would have to wait until later.
The fuel tank had been refitted before the fuselage was re-covered, which is wrong. The fabric ought to have gone on first, and then the tank would be sealed into place over it. Having seen the damage previously suffered here I had used three layers of Oratex, two on the upper forward fuselage plus a reinforcing circle around the filler. So now three layers of nice new fabric came right up to the edge of the filler’s cut-out, but I couldn’t tuck it down inside to glue it for security as I should. I just knew the moment a drop of fuel got spilled or overflowed it would seep between those fabric layers and either separate them or soak the plywood. This would not be good, so I hunted for a sealant that would adhere to both the aluminium filler neck and the fabric, and be impervious to avgas and mogas, even if it should contain alcohol. And I found just what I wanted: Dow Corning 730 RTV solvent-resistant sealant. It was available in white, so (at great expense) I ordered a tube. It was easy to apply and smooth off, so for once something worked out. As a finishing touch I applied avgas stickers of matching red.
For the fuselage trim and wing sunburst I decided it would be quicker and easier to use red Oratex because it would probably be lighter and certainly smoother than brushed paint, would ensure the colours matched, and should result in cleaner lines with no need for laborious masking and painting. The subtle shape of Wagon’s forward fuselage curve hadn’t been right since a big repair in the early seventies so I traced this shape from another Fournier which still had its
I made a purposedesigned wiring loom in the evenings
original paintwork, re-traced that on to the back of a length of red Oratex and cut it to shape before transferring that shape onto the fuselage and painting adhesive onto both areas. Ironing the fabric into place was simplicity itself−one of my few time-saving ideas that actually worked out!
The registration would have to be painted because cutting such an intricate shape into fabric was going to be beyond my skill-set. I now made the most wonderful discovery. Red Smooth Hammerite is precisely the same shade as Oratex’s ‘Fokker Red’. With a can of that and a pre-cut masking sheet from local stickermakers I was in business.
At this point my wife Karen joined me from family and business commitments in Australia. With that, and the arrival of spring, things looked up. Karen is a professional artist, so with a sweet smile I pointed to the registration mask and handed her paint and brush. Of course we wanted it to spread nice and evenly without runs, so first we had to turn the fuselage on to its side. Then, when one side was dry, we had to turn it on to the other side. In our cramped garage, and struggling under its weight and awkward curved shape, I was thankful we didn’t cause any damage.
Meanwhile I screwed on the ‘cheek cowls’−fibreglass fairings either side of the sprung wheelwell doors−and re-assembled the main undercarriage. I had already cleaned everything, inspected the three big aluminium alloy castings for
The registration would have to be painted on
corrosion and checked them for cracks with Ardrox dye penetrant, and re-greased the wheel bearings. Unsurprisingly, the neglected brake drum had a light patina of rust, so I cleaned that off. The tyre had also gone soft, so I checked it and its inner tube for leaks before reinflating and fitting them, and re-attaching the whole wheel and brake assembly into their castings. With the fuselage on its side I bolted the lot back in place before carrying out a couple of sideways retraction and extension tests.
With great difficulty I reached into the rear fuselage to re-fit the twin static lines and ports before screwing into place that inner inspection panel with its integral battery holder. Next I fitted to the cockpit floor the big, black fibreglass wheel well fairing known as ‘the snail’ because of its shape. Finally, I re-fitted the re-painted canopy hinge pins and made a trial fit of the canopy. This had been misshapen ever since the Perspex bubble had been replaced by a so-called expert, but there was little I could do about that. Then, like a dolt, I realised I hadn’t fitted the exCitröen handbrake or cable, so I had to remove the canopy and snail again to crawl inside and connect this all up to its repainted handle (Hammerite silver, of course). More foxtrotting, but after minor readjustment it all seemed to work.
Meanwhile the engine had been languishing on the floor in a corner, awaiting the return of its magneto which I had removed for overhaul by my old friends at Deltair. Karen and I struggled out of the garage with the fuselage to turn it around so I could fit the engine by the
light of day. Then we put my Workmate in front of it. We tried hoisting up the 56kg engine on to that in one go but were defeated, so we did it in two stages, first on to an old milk crate, and then−after a breather−up from there on to the Workmate.
By chocking it up with various bits of wood (rather precariously, now I look back on it) I was able to line up the engine mounts, so it was simply a matter of pushing it backwards and inserting the bolts. Then I re-connected all the engine wiring, fuel lines and controls. Karen followed me, touching up any inevitable chips and scratches in my nice
The original throttle cable had multiple kinks
new firewall while I re-fitted the carburettor.
This is when I remembered the original throttle cable had multiple kinks at its engine end, causing excess friction and making it difficult to make the tiny modulations needed for formation aerobatics. So I replaced that with a new one, also from LAS Aero. Needless to say I was dancing the Fournier Foxtrot again: this ten-minute job turned out to take a couple of days, because while the original knob and bracket fitted nicely at the cockpit end, the engine end had to be lengthened by adding an extension piece ordered from America. Even then I had to make up a new bracket and actuating arm to ensure full and free movement of the carburettor’s butterfly.
Finally I bolted on the lovely Hercules propeller and spinner, checked the tracking and wirelocked the bolts. At last we had something that looked like a real fuselage. Time for a celebratory cuppa. Looking back on it all now, it’s hard to remember just how many little jobs had to be done. The thing is, it’s a thousand times easier to pull an aeroplane apart than to put it all back together again. If you use Oratex, replacing the whole fabric covering shouldn’t take more than a month or cost much more than £5,000; doing all the rest takes longer and costs more.
THIS PAGE TOP TO BOTTOM: the old firewall split apart, revealing the asbestos core; using the original to mark out a template in MDF and forming the edge of the outer sheet
THIS PAGE TOP TO BOTTOM: the bare Alclad-fiberfrax firewall in place; Bob’s improvised hole punch; and the finished job, with engine mount brackets etc all fitted
There was a wide ariety of potential tailwheels to choose from - which would be best?
Wheel retraction/extension was tested horizontally
Tailwheel chosen, assembled and back in place
BELOW: fuel filler sealed with solventresistant sealant and labelled, ready for fuel. Note classic brass float fuel gauge!
RIGHT: the engine balanced and chocked - somewhat precariously - on Bob's Workmate, ready to connect
Karen touching up any damage to the firewall after the engine went back in
BELOW: the Perspex canopy bubble, misshapen by the same previous 'expert', fitted back in place
BELOW: firewall done, engine attached, propeller on, nearly there... time for a celebratory cuppa. Cheers!