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Last Modified August 6th 1998
July 1st Sanded back the filler on the throttle lever housing.
July 2nd - 6th No building due to a combination of the flu and 40th birthday celebrations. Luckily the former didn't impact the latter too much. I did manage to get out and help John with the third of his four wing lay-ups on Sunday - we are getting quite good at making wings now though John did groan a bit when I suggested that the next planes we build should be biplanes!
July 7th Fitted the bushings to the retract arms. The bushings have to be cut out of a single piece of material and I found it easier to cut these roughly to length, bond the bushings into place and then use a fine file to bring the faces flat. The next task was to fit the undercarriage frame into place. I found that the recommended AN3-13A bolts were too short for the lower fittings due to the fact that there was a gap between the frame and the cockpit module. As the manual clearly states that the nuts must be only loosely tightened before packing the space between the tube and the module with redux and flox I elected to select bolt lengths based on aircraft engineering practice rather than those supplied with the kit. This resulted in AN3-15A bolts being used for the lower fittings and one of the AN3-15A bolts on the upper fitting being substituted for an AN3-14A. These bolt lengths ensure that a minimum of 1.5 threads are visible upon tightening the nut and that thread locking doesn't occur. I have found that it is well worth having half a dozen of each of the AN3 bolt sizes from -5 to -15 on hand in order to prevent delays associated with sourcing replacement bolts if the planned design sizes don't quite fit properly - or if the cat hides the last one! Did a dummy assembly of the rudder pedals to ensure that all was straight and that the tufnol bearings would rotate freely.
July 8th Floxed between the tubes and the cockpit module. This isn't too bad a job on the two lower tubes that feed inside the cockpit module but it is rather messy to accomplish on the two upper tubes. While I had flox to hand I bonded the reinforcing tubes into the rudder pedals.
July 9th Bolted up the firewall
July 10th No building
July 11th
Assembled the trim damper assembly and mounted it and the trim
motor to the rear bulkhead. I then did the setup of the trim tabs
according to the manual. At this point I discovered a little
problem! The port trim tab, for some reason, is lower than the
starboard. I had done the setup of the trim drive tabs earlier
but for the life of me I can't work out why they should be
misaligned when on the aircraft. After some thought I decided
that the only solution was to adjust the position of the trim
drive pin on the port tab. I ground the glass off the top of the
pin plate, prised the plate off and cleaned up the area under the
plate. I then floxed the underside of the plate, pushed it into
place and then remounted the stabilator. With the trim set to
neutral and both tabs in line I ensured that the plate was
positioned correctly and left everything to set. I have fitted an
AMP Mate-n-lok connector onto the trim motor in order to provide
some means of removing the trim motor if necessary. Like many
other builders I have reversed the bolts on the trim motor. The
manual specified placing the nuts on the aft of the bulkhead
however this will prevent removal of the trim motor if it ever
needs to be replaced. With the bolts reversed it will be
practical to remove the trim motor. In order to secure the bolts
I will flox them into the back of the bulkhead.
July 12th The two trim tabs now move in line with each other. I can't do the cloth lay-up over the plate yet as the humidity is too high for glassing but I did cut out the slots for the trim drive arms. These slots ended up longer than the marked places on the body before they stopped fouling the body. The next challenge is that the tabs have insufficient movement. The ideal offset from the stabilator when set at its maximum up movement of 12 degrees should be 15.7 degrees. At a minimum the offset should be 14.4 degrees - mine only go to 12.1 degrees. To fix this I have to extend the tab drive rod which will change the neutral position of the trim motor and to fix this I have to relocate the trim motor which is already bolted in place. A small change to the manual here... insert "Clamp the trim motor in place until full movement of the trim tabs has been confirmed. Once the tab movement is correct then the trim motor's final position can be established." In order to prevent the stabilator from pulling the trim drive arm horizontally when the stabilator are removed I am adding a disk to each of the arms. This disk is made out of a disk of glass and will be bonded into place just prior to the rear of the aircraft being closed up. Having seen the width of the slots required for the trim tab drive arms I am very tempted to make up a longer plate to block the holes off. This will prevent weather and wildlife from entering the rear of the aircraft.
July 13th - 15th Relocating
the trim damper mechanism didn't fix the problem so that means
there must be a problem with the trim tab drive pin location.
Having first spoken with Andy at Europa who has no idea why the
offset should be wrong, I removed the stabilator from the plane,
took it into the lounge and played with pin positions until I was
convinced that relocating the pin would fix the problem. I sanded
back the glass over the pin bracket and removed the pin. I then
floxed the pin back in place slightly closer to the top surface
of the tab and waited until the next day before testing it again.
The result was favourable but could still be improved. If you
look at the manual one diagram shows the pin offset being 2
inches from the centre of the hinge and the pin setting template
being positioned at the front of the hinge. When you make the
template from the paper figure supplied the pin ends up being set
2 inches from the top glass surface and in line with the front
edge of the glass. I still haven't decided which is correct!!
While I was playing around with the pins I
discovered that I had goofed with the positioning of the damper
in relation to the torque tube. I had made up the positioning
template from instructions provided in the manual but had made
the mistake of not checking the template against the paper
diagram after construction. My hole saw had made a hole some 2mm
larger than required and had resulted in the damper mechanism
being 2mm lower than optimum. Wrist slapped for shoddy
workmanship. I have already proven that this 2mm really doesn't
make a large degree of difference to the trim tab ratio as this
is the long end of the lever arm but I will relocate it anyway as
it may give me the extra movement I require. To do this I'll fill
the original holes with flox and then drill new ones in the
correct location. Rather then repositioning the trim motor by 2mm
I will shorten the drive rod by that amount. To take my mind off
the tabs I started on the rudder drive mechanism that Graham
Singleton had suggested following last months log entry. Rather
than use the original tail wheel mechanism as a drive arm he has
designed a lighter assembly which sits on the aft side of the
bulkhead. In order to support this assembly two ply plates are
set into the bulkhead with a glass lay-up covering them. A 6"
x 1" hole is then cut into the bulkhead for the swing arm to
operate through. I positioned the hole immediately above the
metal plate embedded in the bulkhead so as to match the original
rudder drive arm positioning as closely as possible.
July 16th Sat down with the stabilator in the lounge and thought long and hard about how these things actually work!
July 17th Took the day off and spent all day trying different pin and trim damper positions. Came to the conclusion that the pin positions I have are correct when the pin centre is in line with the centre of the hinge and the pin centre is 2 inches from the top surface of the glass.
July 18th Fixed
it! I had to raise the trim damper by a mere 3mm from the jigged
position to get the required travel. I now have 16.8 degrees
upwards offset and 5.2 degrees down which are both within
specification. I remounted the trim damper then checked that I
had 6 degrees of trim motion each way before remounting the trim
motor. With that job out of the way I turned to the front of the
aircraft. With the rudder pedals set in place according to the
manual I drilled the holes for the tufnol bearings and then
riveted nut plates into place on the underside of the pedal
floor. I found that I had to extend both of the holes in the
firewall in order to position the pedal arms correctly but this
is not an issue as the gap will be covered with a plate later on.
Back at the tail of the plane I mounted the pitch counterbalance
arm. The photo on the left shows the arm before the two
tensioning cables are added. These cables are wrapped twice
around the plastic tubes on the torque tube and nicopressed into
place. This is definitely a two person job with one person
tensioning the cable while the other removes the skin off the
back of their hands while squeezing the nicopresses! The other
end of the cable goes to a metal tab located just behind the
weights. In order to provide some means of tensioning the cable I
added a turnbuckle into each of the cables as the standard design
has no provision for tensioning these cables. Just out of camera
in this photo are the three cans of baked beans strategically
positioned on the stabilator in order to raise the arm while I
was working on it. The assembly is overbalanced forward at the
present time and this will be corrected to give a 100% balance
once the stabilator are filled and painted. Also visible in this
picture is the pitch push rod and the hole created in the
bulkhead for the rudder arm assembly. The cable tie is a
temporary fixture to prevent the weights falling off and making a
large hole in the fuselage..
July 19th Helped John Caukwell lay-up his final wing surface.
July 20th - 21st No building.
July 22nd Prepared the cloth for the rudder floor lay-up.
July 23rd Worked on the support plates for the rudder pivot modification. These plates are made out of 50 gauge 2024 T3 aluminium, have some position sensitive holes drilled in them and have a flange. Having never before made anything like this myself I have done a bit of research on the proper way to do this. The first thing I did was cut the outer shape of the plate out of my sheet. When making a flange in 50 gauge aluminium the normal bend radius is 1/4" with a minimum radius of 1/8" and the bend must be across the grain of the aluminium. As I don't have a bending brake I filed a curve on the outside edge of a piece of aluminium angle to act as a curve guide. I bent back one of the edges of the angle so that I could slightly over bend the flange and allow it to reflex back to 90 degrees. I clamped the piece between that angle and another placed in my vice then, protecting the aluminium with a block of wood, hammered the flange over. Once I had created the flanges in both pieces and amazed myself that they were identical I placed them back to back on the kitchen bench (flattest surface I have) and clamped the pieces together with cleco locks. I marked out the positions of the holes and hole punched the locations. Preparing both pieces together as one like this ensures that the holes are in matching positions. I drilled 3/16" pilot holes in all locations with my bench press before following these up with 1/4" holes. With the two separated I used a 25mm hole punch to open up the three lightening holes in each piece. The pieces gained a few marks along the way but I am able to take these out with 600 grit wet and dry followed up with 1200 grit. I must say that I am really pleased with the way the pieces look. The next stage will be to cut back the angles on the plate and tidy the pieces up before alodyning them.
July 24th Finished off the metalwork.
July 25th Primed the metalwork then cut out the plywood for the pitch stop retaining bracket.
July 26th Bonded in the rudder pedal floors. In order to keep these in place while the micro was setting I raided the pantry of cans and used these as weights. I had thought that I would have to do the glass lay-ups at the same time but found that I could bond the wood into place first, then remove all of the metalwork and do the glassing as a separate exercise. The wood had warped slightly due to the fact that it had a lay-up done on only one side so it took a bit of persuading to stay in place correctly. The rudder pedals have stiffened up quite a bit now that they are clamped in place and I will have to open up the bearings a bit to counter this.
I felt like doing something big so I decided to do the work required for the baggage bay modification. I cut off the original bulkhead at the top of the tunnel and clecoed the new bulkhead assembly's front flange to the back of the old bulkhead. I had originally thought that the new floor would be level but it does in fact slope upwards slightly towards the aft of the aircraft in order to ensure sufficient clearance above the pitch tube. The final position will be established once I cleco the top of the place on in a couple of weeks. The effect on the cockpit area is rather dramatic and does certainly open up the inside of the aircraft. With the new bulkhead in place it was obvious that the fuel drains were rather awkwardly placed so I heated them up with a hairdryer to soften the redux and simply pulled them off. I will lay-up a single layer of bid over the hole later and apply flox from the outside. The fuel drains will be reinstalled later once I have established the position of the battery which, with the new firewall forward kit, is now installed aft of the cockpit.
July 27th Received an email from Graham Singleton advising me that he has had to redesign the pivot bracket! Ah well, I suppose that making the first bracket was good practice and really didn't take me that long to make. I'll make the new set once I get back from Oshkosh.
July 28th - 29th No building.
July 29th - 31st At Oshkosh.
