Last Modified January 31st 2000

January 2000, Out of the Jig

January 1st Got up early this morning and, unless otherwise challenged, claim the first glass fibre layup of the century!

First layup was the glass reinforcing strip behind the baggage bay bulkhead. I found that the easiest way of doing this layup was to lie on my back with my head through the hole in the bulkhead. I also found it important to keep the bid strips to a reasonable length otherwise they fell off before being able to tamp them into place.

With that job out of the way I microed the foam forward lift pin reinforcing rib, floxed the edges and then laid up three layers of bid over each of the ribs. These ribs add considerable stiffness to the forward lift pin area and should now remove the occasional problem we have when derigging in that the side of the aircraft bulges and traps the forward lift pin thus making derigging a two person job.

Most of the rest of the day was spent working on the tunnel bulkhead. I had originally made this to fit the tunnel shape prior to my port side LA mod so had to modify the shape to accommodate the modification. Other factors introduced since I made the original bulkhead were the introduction of lots of pipework and the relocation of the rudder cables. The rudder cable relocation was easily accomplished by patching over the original holes and cutting new slots. Accommodating the new tubes was a bit more complex as it had to be practical to insert the bulkhead as well as providing clearance for normal operation. I found that the most practical was of achieving this was to split the bulkhead horizontally and make a tie bar to lock the two parts together. Angle brackets top and bottom secure the pieces to the fuselage and these were attached to the fuselage with epoxy and flox..

I had four wires that needed to be plumbed to the fuel sensors and wanted a tidy way of doing this within the tunnel.

A technique we use use in data cabling is the concept of blown fibre where empty tubes are laid in place and subsequently filled with fibre cables as required. I reproduced this concept by laying in a 1/4" polyflo tube, attaching it with tie clips, and then pushing through the four wires to their destination. I terminated the wires at the terminal block near the fuel flow sensors then went and painted the tunnel bulkhead.

My last task for the day was to remove the peel ply from the layups I had done over the last few days.

January 2nd I laid up the reinforcing strips on the wing root fairings. After applying a flox in the gap between the fairing and the wing I strapped the fairing to the the wing with 2 ply bid strips. While I had some bid strips left I fitted my comms aerial. This is one of Bob Archer's artefacts and is positioned on the port fuselage wall about 60cm aft of the baggage bay bulkhead. To hold the aerial in place I used a number of bid strips strategically located around the folded dipole aerial. I had attached the cable to the aerial prior to installing it to save a lot of messing around inside of the fuselage. I am going to apply a few blobs of silicone sealant around the perimeter of the aerial to eliminate any resonant vibration problems.

I am using ThinNet Ethernet cable for all of my comms coax cabling. ThinNet is a high quality 50 ohm coax cable with an integral drain foil as well as the braided screen. The drain foil provides a much better shield than conventional RG58 which, theoretically, should result in better transmission capabilities.

I have decided to speckle coat the entire centre console rather than just the top so I masked off the areas not requiring painting then primed and applied the speckle. While I was in the painting mood I primed then painted the control columns - plain white this time.

It was then back under the aircraft to do a bit of tidying up with the wiring around the fuel flow sensors before fitting the tunnel bulkhead into place.

My final task for the day was quite symbolic - akin to driving a golden spike and marking the end of a major building stage, the tunnel is complete. I lifted the undercarriage into place and drove home the bar that holds the undercarriage arm in place against the damper mechanism.

I was quite surprised to discover that everything lined up nicely and it took a few light taps with a hammer to drive the bar into place before fitting the two split pins to lock the bar into place.

Next free fine day I will rig the wings, set up the bungee counterbalance cord, and then move the wings into storage. At this point the fuselage can come out of its jig.

January 3rd Fed the bungee cord around the frame and wired up the gear up and gear down microswitches.

January 4th Glued tie bases into place for the fuel vent pipes and drilled holes through the baggage bay bulkhead to accommodate the filler vent and sight vent hoses.

An advantage of moving the fuel sight gauge into the baggage bay is that the area immediately to the left of the flap handle becomes available for other purposes. I made up an aluminium bracket and then used this to support the choke knob. The bracket is attached to the tunnel side with a pair of AN3-7A bolts with large washers under the heads inside the tunnel.

The slot immediately above the choke knob will be filled up and will house several switches.

January 5th Sanded back the filler on the fuselage port bonding line. Next on the list was fitting NACA scoops on the fuselage sides. I am using a pair of adjustable NACA scoops from Aircraft Spruce for this job with the front of the scoops located 90mm aft of the firewall joint line and the centre line 110mm below the joint line. I cut out the holes according to the template provided with the scoops though next time I think I would cut in from the inner skin and then cut the outer skin later. This would save having to fill the outer surface around the NACA scoop. Once the scoop was scuff sanded I bonded it to the inside skin with flox and then used the remaining flox mixed with filler to build up the edge around the scoop.

January 6th Having achieved the impossible and got a 15 year old son out of bed early on a holiday morning we rigged the aircraft for the bungee setup. I tensioned the bungee while Stefan sat in the cockpit and operated the undercarriage. Once Stefan was able to easily operate the undercarriage both ways with just one finger we decided that we had the tension right.

The manual has you tie off the bungee on the top bar at both ends however, following advice from Neville at Europa, I tied one end off on the lower cross bar as this gives access in the (almost inevitable) event that the bungee tension requires altering later on.

I wasn't happy with the routing of my brake cable as there was a lot of movement in the cable when the gear was retracted. I rerouted the cable over the large cross arm then up to the top of the tunnel and then across above the flap arm which resolved the problem.

Several times while retracting the gear I had the gear latch in the up position. The only way of releasing the gear was to grab the wheel and pull it down. This was causing me concern so I dove under the aircraft to find out what was binding. A tell tale mark on the starboard tunnel wall showed that one of the bolts on the now rotated brake cylinder was striking the wall. A rapid retraction of the undercarriage was causing the arm to swing higher than normal and jam against the wall. At the same time the safety wire on the bolt had been torn off and had to be replaced. To eliminate the interference I ground back the skin and foam leaving the skin on the other side intact. I will add a bid patch on the other side of the tunnel to recover the skin strength at this point. I also noted that if the arm went over centre that the bolt touched the rudder cable. To eliminate this problem I relocated the tufnol block supporting the fairlead. With Stefan back in the cockpit we went through thirty or so retract cycles confirming that there was no more interference and that the motion was effective. I then spent a couple of hours sanding back the filler around the wing fairings and NACA scoops before diving into the back of the aircraft to tie off the fuel vent tubes.

I have now completed all of the setup requiring the wings so tomorrow they are off to the storage shed to free up some space in the garage.

January 7th Brought the trailer up from the storage shed and loaded the wings on to it. I removed the flaps and marked out the position for another aileron hinge in the centre of the aileron. I decided to add another hinge following discussions with Alister at my last inspection when we both concluded that if I had some spare hinge available then it certainly wouldn't do any harm to add a central hinge and may well reduce hinge wear overall.

The wings went back to the storage shed and then it was the turn of the fuselage to come out of its jig. Remembering to put the gear down first, we cut away pieces of the jig allowing the fuselage to eventually settle onto its own wheels for the first time. To keep the aircraft upright I have temporarily added blocks to the sides.

January 8th - 9th Not a lot of time spent on the aircraft this weekend due to other commitments. I did a bit of work on making up a pair of outriggers on Saturday which will allow me to roll the fuselage around. The outriggers are bolted to a pair of dummy spars - the port side being a spare Europa spar while the starboard consists of two pieces of 12mm ply and a piece of 6mm fibre board laminated together with a urea formaldehyde wood glue. Stefan improved his upper body strength by cutting up the jig.

January 10th Finished off the work on the outriggers. I found that I had to add a couple of side braces to prevent the outriggers from moving fore and aft. These side braces slip over the dummy spars and have pins that fit into the lift pin sockets.

Once I was happy that everything was stable I rolled the fuselage out on its own wheels for the first time. While putting the aircraft back into the garage it became very apparent that a tailwheel puller is going to be required in short order as you can't push this plane backwards.

Now that the wings have gone I can't get over how much free space there is in the garage. It is certainly going to make the job of finishing off the fuselage a lot easier.

January 11th I received an email from Martin Tuck advising me that he believed my bungee cord was too slack - he could tell from the picture (!!!). I strapped back the nitrile sheet in the flap slot to remove as much friction as possible then undid the bungee and played with the tension until the arm centres when taken out of either slot. When Stefan returns from camp in a couple of weeks I will bring the wings back from the store and repeat this process with the wings rigged.

Spent an hour sanding the port side filler and then over the rest of the surface with fine grit paper. It is amazing how many small defects you discover once you start this process. Many of these are in areas where the fuselage has a sharp bend in it like the lead in to the fin and represent bubbles that were present when the pre preg glass was pushed into the mould during the fuselage construction at the factory. I have no doubt that someday I won't be able to find any more of these but until then it's a case of out with more filler and more sanding. To sand around the complex curve areas I am finding that a piece of sandpaper wrapped around a piece of blie foam 1cm or so thick does the job very nicely. The foam allows the sandpaper to conform to the general curve of the fuselage and results in a nice smooth finish.

January 12th An hour and a half of sanding had the port side, including the fin to an almost finished stage. There are a couple of areas at the leading edge which will need a bit more building up but overall it is looking very good. I must say that I am rather enjoying the artistic challenge of creating a really smooth surface.

I had some feedback from Andy regarding the brake caliper tunnel conflict. He suggested that it would probably be wise to crease some form of upper stop to prevent the gear swinging over centre thus avoiding any possibility of the brake caliper bolt getting jammed against the tunnel wall - design time! He also said that from my description I had the bungee tension just about perfect. Oh well, it will only take me a few minutes to get it back to the point where I can raise and lower the gear with my (or Stefan's) finger tips.

January 13th Drilled out holes in the upper tunnel firewall for the cables and brought the cables through. To secure the cables and fuel pipes to the frame I used cable ties using a spiral lock technique. This method of strapping locks the cables both vertically and horizontally.

January 14th Mounted the intermediate engine frame. I found that the 5/16" bolts wouldn't go through the holes in the undercarriage frame so I drilled these out with a 5/16" drill which fixed the problem.

I spent some time working out how to fit the GFlight phenolic tunnel firewall.

January 15th No building

January 16th Filled some of the low spots on the port side of the aircraft and then spent the rest of the afternoon designing and then implementing an upper undercarriage stop. I opted for a simple bracket attached to the port side of the tunnel which would contact the undercarriage arm before the arm conflicted with anything else in the tunnel.

The stop is made from a 50mm long piece of 50mm x 50mm x 3mm angle aluminium. The vertical flange is trimmed back to 30mm at the start of the process. The bracket is attached to the port tunnel wall on the thigh rest support plywood.

To get the position of the stop correct it was necessary to establish its position in relation to the undercarriage arm. As the spacing is pretty tight between the undercarriage arm and the tunnel side it's necessary to use a few smarts to establish the stop position.

I clamped the stop onto the top of the undercarriage arm with the end coincident to the start of the curve at the end. The lateral position is established by trial and error.

The position of the stop has to allow the undercarriage arm to go higher than its normal resting place so that the normal lowering technique of pushing the lever arm slightly forward before moving it out of its gate can be accomplished.

I established the stop position by taking the gear to its normal up position then jacked it up further until it conflicted with the tunnel before dropping it down slightly. The other potential points of conflict, depending upon the aircraft, are between the wheel and the throttle housing or between the wheel and the brake cylinder on the XS. Marking the position of the stop on the tunnel wall is quite a challenge given the available space and a bit of light thievery helped here. I took the tip off a felt tip pen 'acquired' from a son's bedroom and clamped this in a haemostat to act as a small marker.

With the position confirmed I marked out the tunnel wall then lowered the wheel and marked the horizontal portion of the stop at the point where it coincided with inside of the undercarriage arm. Under no circumstances must the stop go inboard of this edge or tyre damage may occur.

The stop was unclamped from the undercarriage arm and the horizontal portion trimmed to size. Two 4.8mm holes were drilled on the vertical face. These are mid way up the face and spaced 15mm in from each end.

Diving back under the aircraft I used an angle drill to make one hole and then inserted an AN3-5 nut, temporarily tightening it with a 3/16" nut and confirmed that the position was correct. To prevent marking the undercarriage arm it is is important to ensure that the stop is parallel with the arm and I verified this. I also checked that no conflicts still existed and that I could still drop the undercarriage. I ended up with about 2mm of forward movement of the lever arm at its upper gate before contacting the stop. This equated to around 10mm of movement at the stop point.

With everything verified I drilled though the second bolt hole and then tightened the bolts up with MS21042-3 nuts with backing washers.

I carefully confirmed operation of the gear again. Raising the gear gently results in the lever arm sliding gently into the upper gate. Raising the gear with more force ends with a most noticeable clunk as the inertia of the wheel drives the arm over centre and contacts the stop. The arm, once again, can be easily inserted into the upper gate.

Dropping the gear is a simple matter of either sliding the arm sideways out of the gate or moving it forward until the stop is contacted and then moving the arm sideways.

I am satisfied that this modification removes the opportunity for the arm, tyre or brake caliper to conflict with anything in the tunnel and also completely eliminates any opportunity for the gear to get locked up as a result of anything getting jammed against the tunnel sides.

Before bed I pushed back the foam in the small area I had set back in the tunnel and floxed the edges. I also floxed the holes that had been created to hold the front of the aircraft.

January 17th Sanding

January 18th No building, working in Wellington. Got the thumbs up from Andy Draper for my undercarriage upper stop implementation.

January 19th Did some 'flight' testing of my retractable landing light. I made up a mount which allowed me to clip the mechanism to the drivers door on my car and took it for a drive. It extended and retracted well, held its position at lower speeds and all went well until the third high speed run. At higher speeds I noted that there was quite a bit of shaking when the light was extended so repeated the run to see what was happening. On the third run the lamp and its retracting support plate departed the bracket - followed very shortly thereafter by part of the servo drive arm. In a field outside of Manurewa one day someone is going to come across a rather battered quartz halogen lamp and wonder where it came from! As I don't have a limitless budget for this sort of thing I have relegated the retractable landing light to the rubbish bin and will now look at ways of fitting one to the lower cowling. I have a spare lower XS cowling (albeit slightly damaged) so I can hack that around until I get something I am satisfied with.

Sanded the fin (again).

January 20th Punched out the first of the holes in the main panel. Unfortunately the hole worked out to be too low so that panel is going into the rubbish bin. Marked out another panel, centre punched and drilled all of the guide holes. I found it extremely difficult to find the spacing required for the six main instruments so for future reference here is a set that works...Using the lower right corner of the panel as the datum. The base of the lower row of holes is 12mm from the lower edge. The right hand edge of the holes is 9mm from the right hand edge of the panel. The spacing between the holes is 5mm.

January 21st Punched out the primary six instrument holes. I had drilled out a 1/4" hole for each instrument the day before. First task was to ream these open to the size of the bolt that goes through the punch. I then punched out each of the holes using the hole punch that I had been persuaded to buy at Sun 'n Fun by my father. He made a good decision as the holes come out looking great. I used a hole guide to drill out the screw holes - also acquired at Sun 'n Fun, then turned my attention to the two holes with side slots. The really tricky one is the altimeter and I have to admit that I fouled it up first time. Luckily the panel is going to be painted so I was able to fill the slot with Selley's Metal Knead It filler and then repeat the filing process. This is marvellous stuff and is great for fixing up miscut areas on aluminium panels - be it for model railways or for aircraft!

January 22nd Wiggle and Grin Day!

For those who aren't of a technical bent, wiggle and grin day is when you get to put the whole aircraft together on its own wheels for the first time, sit in it and wiggle everything that moves. The grin comes naturally :-)

I checked the operation of the control systems and all worked well apart from a bit of slack in the port aileron. This is being caused by a small gap between the two aileron bellcranks. I will fix this later by adding another shim as I have done on the starboard side. With the tests complete I jacked the aircraft up and readjusted the bungee tension. Using Nathan as my tester I adjusted the tension until he could raise and lower the undercarriage with ease.

January 23rd Just a little bit of build time available today so I finished off the cutting of the holes in the main panel. Most of these were rectangular so I used the technique of drilling a sequence of holes around the perimeter and then filing the remaining material away to create the hole. With the panel complete I marked and drilled out mounting holes and then fitted nutplates onto the support areas that I had left on the panel assembly. A bit of filing of the main assembly to create a bit more clearance had the main panel engineering work complete.

January 24th I knew things were going too well. I torqued the bolts holding the swing arm to the aircraft. The first two went well and at 144 inch pounds they closed up nicely. The third was a different matter. On the third swing of the torque wrench it became very easy to rotate, extremely easy, frighteningly easy. I took the torque wrench off and pulled the shaft of the bolt out - leaving the threaded portion deeply buried inside the swing arm. I called around a friend who is an engineer and we tried to extract the bolt without success. Discussions later in the day with Andy Draper lead us to concur that the bolt was faulty and another swing arm is on its way out. I'll have another go at removing the bolt tomorrow but I am not too hopeful.

On a brighter note... I painted the main panel and then later in the evening populated it with the bits I have. Of note for AV10 owners - the case is wider that a standard instrument by around 2mm all round. It is sitting in there without a case at the present time and will probably end up being recased as I am not remaking that panel after doing such a good job with it.

Top row, left to right. Gear up warning light, starter engaged light, holes for primary and secondary alternator warning lights, RPM gauge, turbo fail light and directly underneath turbo timer warning light.

Middle row, left to right, ASI, AV10 engine instruments, Altimeter, MAP gauge, turbo servo disable switch.

Bottom row, left to right, trim indicator, turn and slip, electric AH, RMI microencoder.

I placed the AH on the bottom row as the pull to cage button conflicted with the altimeter adjustment knob when it was on the top row. If I have to resort to instrument flying my panel scan is reduced to the bottom row as the microencoder is an altimeter, ASI and VSI.

January 25th Got up very early and took the undercarriage arm off. With the help of some people who have a lot more aircraft engineering experience and advanced tools than I, the errant bolt thread was eventually removed from the swing arm and the threads in the hole examined to ensure that no damage has been done. All is well and the panic is over - all I need now is a replacement bolt. On examination under a microscope the bolt shows a clear area in the centre of the fracture where the metal looks like it has a flaw. I suppose the good thing about this is that the fault showed up now rather than later in the life of the aircraft. Spent the evening refitting the swing arm. The three bolts that I have, including one in the problem hole torqued nicely to 144 inch pounds.

January 26th Fitted the remaining indicators into the panel.

January 27th No building, SAANZ meeting.

January 28th Marked out a few revisions to the other panels. I am moving the most frequently used in flight switches to the centre panel so that they can be accessed very easily with my right hand and moving the two current meters to the lower panel.

January 29th No building, Stefan's competitive rowing season starts so on many Saturdays for the couple of months it is up early to drive to a rowing regatta. A day sitting by a lake is great for designing!

January 30th Did a couple of hour's work sanding back the fuselage and then reshaped some areas that I wasn't happy with. I then fitted the lower part of the firewall.

January 31st Sanded back yesterday's filled areas and the starboard side of the fuselage. With that complete, the boys and I laid the fuselage down on their bean chairs (stolen from their bedrooms) and then place the fuselage on its port side. Having made the base of the fuselage accessible I filled the areas that needed attention. To finish the day off I fitted the non return valve - a job also made easier by the fact that the fuselage was on its side.