Mate Wings to Fuse

complete 23/10/2006

You need to attach the wings to the fuselage at least twice. The first time is to line everything up and drill holes for various installations. The second time will hopefully be forever. This is the first attachment. It was not as difficult as I had expected.

(26th September 2006) Today I spent two hours preparing to attach the wings to the fuselage. This is only a temporary attachment, and provides me with an opportunity to set some important parameters, adjust aileron travel, finalise wing attachment points, drill wing fairings and skins, and lay lines for brake hydraulic and fuel delivery. I made four 7/16" drift pins out of ordinary Grade 5 7/16" bolts. I ground the threads into a wide bulletnose so they would not mar the inside of the spar holes.

I had a look at wing wiring options. I am going to use connectors just in case I ever have to remove the wings for repairs or whatever. First image shows the fat grey shielded three-core cable for the Whelan strobe in the top grommet, along with a single strand of 16ga tefzel (for the nav light active connector). It is too tight and would be a night mare to install in every rib. The grommet below this has a length of 1/4 Al tube for pitot line, just trialing to make sure it fits. The second and third images show similar arrangements in other ribs. After talking with a few SAAA colleagues i decided that in the end I will drill 3/4" holes in every rib at Van's suggested locations, and install their black conduit. General opinion seem to be that autopilot, strobe, landing light and heated pitot is too much wire for the grommet method, but should fit easily into the conduit.

The fourth image shows an external view of the rectangular fuse hole where the wing main spar is to be insterted. the black rod is a drift pin located in position (see above). I resurfaced these so that the fit was tight, but manageable.

I re-attached the ailerons with proper spacers, washers and nut tensions. I discovered that the appropriate sequence to attach the ailerons is to first attach the short aileron pushrods. This is because once the aileron is in position on the wing you just cannot get a spanner in there to hold the AN3 nylock nut and the AN3 bolt. These pushrods must then be slid into the wing as the aileron is positioned. You need to leave the flaps off at this stage as they conceal the rear spar attachment point which will need to be drilled once the wings are on, setting both incidence angle and wing sweep. I had nice practice replacing and removing the piano hing wire to find this out!

(27th September 2006) My technical counsellor (John) came over for two hours to help me with the actual wing attachment. He says he has probably mated about 2000 wings to fuselages in his career! The fuselage was supported by low (about 8") sawhorses. Another higher sawhorse supported the outboard end of the wing. John grasped this end and gently wiggled the wings as I supported the inboard wing and guided the wing spar into the fuse spar hole. It was a tightish fit, but with care went in easily. When the rear spar edge met the fuselage, the 7/16" wing attachment holes were perfectly aligned. I must have cut the spar length off correctly - thank goodness!. A light tap on two drift pins, and the wings were attached. The actual instertion of both wings took about 40 minutes and was relatively painless. Image 5 shows the result. Does it look like an airplane yet? Image 6 shows the gap between wing root and fuse which will eventualy be covered by the wing root fairing. I marked every third rivet in the wing root rib as probable locations for wing fairing attachment platenuts. The drawings are none-too-clear on exactly where these platenuts need to go (not shown).

wires and tubing

grommets

more wires

fuse spar with drift pins

fuse spar with drift pins

Wings are ON!

Mind the gap

Ailerons need adjusting

There are a few interesting details to note. The first is that the aileron pushrods need to be adjusted. At the moment with the stick centred, both ailerons are about 5 degrees "up (image 7 above). This means that the "down" limit is only about 10 degrees deflection - not enough. I assume that this will correct itself once the pushrods are adjusted for neutral all around. I will need to use the bellcrank centering tool to do this properly.

The first image below shows where the tank attach bracket will go - more later. The second image shows the wing rear spar neatly mating the fuse rear spar. I will have to move this spar up and down and left to right until the wing incidence and sweep are set perfectly, and then drill a 5/`16" hole in the right spot. Lots of care required here!!! You get one go at it.

The next image shows one of those AN3 temp control surface inserts attaching the aileron pushrod..but.. as the next image shows, the aileron is pointing "up". I will need to get these level on both sides with the bellcrank "level" template in place. Next images shows the fuel tank connector ready to be connected to fuel delivery tubing. Image 6 shows the belly of the aircraft where the wing skin overlaps the fuse skin. I will need to measure back 3" on the blue lines and mark the locations of holes for countersunk screws and platenuts to attach wing skin to fuse skin.

tank attach

rear spar attach

aileron pushrod attach

ailerons both "up"

fuel tank attach (to come)

underneath overlap

(8th and 17th October 2005) In two weeks I have spent only two days on the plane. At this rate I will never finish! Too much "real" work - next year I think I will take a long break off real work and just work on the plane till its finished. Anyway, on the 8th of October I studied the plans and read the instructions all about setting the wing incidence and wing rake. Both are set by a SINGLE bolt-hole in each wing, where the rear spars of the fuse and wings overlap. I used a plumb-bob and a tight string to check the wing rake. Both wings were exactly square with the rear spars pushed in as far as they would go.

Setting Wing Incidence

To set wing incidence, you need to make an accurate block of wood exactly 3" thick. This is laid on the rear spar attach rivet line on the upper surface, and a spirit level placed along it, resting on the rivet line of the main spar (Images 1 and 2 below). The rear wing is moved up and down until the spirit level registers that it is parallel to the upper longeron surface of the cabin (image 3).I borrowed my TC's excellent digital level meter and, once I had made the adjustments, it read 0.7 degrees in both places (on the level and on the longeron). Yes I know the picture shows this device upside-down, but when I actually did the measurements, all was kosher. I then measured 5/8" from every surface of the rear spar assembly. The bolt centre must be at least 5/8" from the edges of all the interleaving spar tabs. The blue dots in image 4 show that I had about 3/16" room to move. I marked the exact cetre of this area and, with a long 1/8" drill, carefully drilled a pilot hole, making sure the drill was normal to the surface. After double-checking that nothing had moved, I increased the drill to 1/4". The final hole was drilled with a 5/16" precision drill. I tapped the bolt in place, hand tightened and checked again - all was kosher! (images 5 and 6) This was repeated on the other side without any dramas. It was truly nerve-wracking, knowing that, if I stuffed-up, there was nowhere to go!

Once the wings were bolted, I crawled under the fuse and measured 3" from the marks I had made on the wing lower skin, 3" from where the platenuts go which button up the skin overlap. I was only about 8" from the skin and the light was low. Now for some good old-fashioned optometry - at age 57, my eyes have very little residual ability to focus at near. I am "presbyopic". I could not see the blue lines at all - it was all a blur. Thinking "I wish I had some +4 dioptre lenses" I realised that, as a bloody optometrist, I did indeed have some! So I went back to the house, got out my trial lens set and trial frame and shoved some +4D lenses in the frame. Image 7 shows me wearing them to look at the lower fuse. It was perfect! I could see every detail. Anyway I marked and pilot-drilled as required and then crawled out feeling very pleased.

setting incidence

3" block

this helps

ready to drill

drilled, bolt in place

from above

presbyopia sucks

drilling pilot holes

The next job was to set the aileron positions and travels. To do this you must have the flaps on the wing. Using Van's aluminium template, I positioned the bell crank in neutral and adjusted the aileron pushrod till the aileron was level with the flap in its "full-up" position. I repeated this on the left side. Next I will need to adjust the lengths of the large pushrods so that (a) the joystick is straight up with the ailerons neutral, and (b) both ailerons are neutral at the same time.

Final aileron adjust

(23 October 2006) Dan Checkoway recommends using the tooling holes in the outboard ribs of wings and ailerons to find the "neutral" control position. I thought this was a good idea so I used a piece of scrap Al angle, some clecos and som clamps to line up the right hand aileron (Image 1). Image 2 shows the left hand aileron also level, after the adjustment process was complete. To do this, I placed the bellcrank template in position in the right wing, and adjusted the RH thin pushrod so all was kosher. This was followed by adjustment to the RH wing thick pushrod so that both joysticks were vertical. Then the bellcrank template was moved to the LH wing and the thin pushrod adjusted (with the LH thick pushrod disconnected). Finally, the LH thick pushrod was connected and adjusted until both ailerones were "neutral" at the same time (with the RH ailerone still clamped in neutral position). This all took only about 1/2 hour, and provided up/down movements of 28 degrees amd 18 degrees. within spec!

RH aileron neutral via tooling holes

After adjustment, LH true as well

Using the bellcrank template

Adjusting the big pushrod, LHS

Joysticks both vertical

Wing Fairings - This is a very tricky job. So tricky that I made a separate page reporting how I think I avoided the very real pitfalls in match-drilling these.

Fuel tubing and fuel vent tubing - This is also tricky if you have not dome it before. See the separate page on fuel tubing for details.