Roee Kalinsky's RV-7A Project

2006.03.18: (2.0) Started preparing (edge-finishing, etc.) parts for the the aileron attach brackets.

2006.03.19: (1.5) Done edge finishing the aileron attach brackets.

2006.03.21: (1.0) Applied corrosion protection (AKZO) to the aileron attach bracket parts.

2006.03.22: (1.0) Riveted the aileron attach brackets.

2006.04.xx: (2.0) Edge-finished the aileron gap fairings.

2006.04.10: (1.0) Match-drilled the aileron attach brackets to the wings.  Had to do some more trimming so that they would nest in the radius of the rear spar flange and sit flat on the spar web.  So... I have to wait until I can touch up the primer in the trimmed area before installing them.

2006.04.13: (1.5) Started trimming and edge finishing the flap braces.

2006.04.19: (1.0) Done trimming and edge finishing the flap braces.

2006.04.22: (3.0) Sprayed AKZO on on the flap braces, aileron gap fairings, inspection hole cover plates, and the areas I had to trim on the aileron attach brackets.

2006.04.23: (1.0) Started installing the aileron attach brackets to the wing.  Got as far as I could reach with the squeezer.

2006.04.29: (0.5) Finished riveting the aileron attach brackets to the wing.  Used the squeezer with a 4" yoke and a 5/8" tall flat set, effectively creating a longeron yoke with a 4" reach.  I bought the 5/8" tall flat set from Avery.

2006.04.30: (1.5) Match-drilled the A-406-1 and A-407 brackets to the ailerons.

2006.05.03: (0.5) Tapped the tie-down blocks to 3/8-16 coarse thread for the Van's tie-down rings.

2009.05.28: (0.0) Finally got back to the wings a couple of weeks ago.  Here's a summary:

Trimmed the inboard ends of the aft spars per DWG 38.  Rough cuts with a die grinder, just a little bit at a time to keep heat buildup in check, then finish with a file.  Some builders report an interference between the inboard end of the aft spar and a domed rivet just above the attach point on the fuselage, necessitating either additional trimming of the spar or replacement of the rivet with a flush head Cherry Max.  I'm holding off on this for now.



Installed the aileron gap fairings.  An issue came up, where the top skins needed to be bent downwards slightly into position.  Not a problem where the aileron gap fairing will hold them in place with minimal tension.  But there's a section of the outboard top skin that extends inboard of the ailerons and is therefore not supported by the aileron gap fairing, so it needed to be pre-bent by hand so that it will match the contour of the supported area.  Did this carefully with good results.  Also, the aileron gap fairings needed to be trimmed slightly to clear some interference with the aileron hinge brackets.


Fitted the ailerons to the wing.  Installed the A-406 and 407 brackets to the ailerons, and mated them to the wings.  DWG 13A shows the spacers (washers and aluminum tubing) around the bearings that set the spanwise position of the ailerons, noting that these spacers may have to be adjusted for "proper fit".  Indeed, the spacers as called out didn't quite add up on my wings/ailerons.  I called up Van's to make sure I knew what constrains this "proper fit", if there are any critical dimensions.  They assured me that this wasn't critical aerodynamically, and that I just had to make sure that there is adequate clearance, nominally 1/4", minimum 3/16", between the aileron and the flap and between the aileron and the wing tip.  They suggested that I initially set my spacers for the middle of the range of adjustment that I have, so that I can later tweak it slightly in either direction to even out the clearances to the flap and wingtip.  Sounds good to me.  So, using the outboard bearing as reference, my range of adjustment is as follows.  Most inboard aileron position: three standard washers outboard of the bearing, one standard washer inboard of the bearing.  Most outboard aileron position: two standard washers outboard of the bearing, two standard washers inboard of the bearing.  Center and initial aileron position: two standard washers and one thin washer outboard of the bearing, one standard washer and one thin washer inboard of the bearing.  Until I have the flaps and wing tips fitted, I'll hold off on making the aluminum spacers for the inboard aileron bearings.  CORRECTION 2009.09.14: The stackups of washers listed above are too wide.  The aileron bracket sits more squarely with one thin washer less.  The two possible stackups are therefore two standard washers outboard and one standard plus one thin washer inboard, or two standard and one thin outboard and one standard only inboard.

Rigged the ailerons to the bellcranks.  Firstly, I noticed that DWG 15A specified a dimension of 2-7/16" from the aft face of the spar web to the center of the bolt on the bellcrank, while the actual W-730 bellcrank jig used to set this dimention actually measured 2-3/8".  Slight discrepancy, but I called Van's to clear this up.  They instructed me to use the W-730 jig and not worry about the plans.  Ok...  Moving on, I made a simple jig to set the neutral position of the ailerons themselves.  The neutral position is specified as the trailing edge of the aileron being in-line with the two tooling holes in the aft wing rib.  I used a piece of Al angle and a couple of 3/16" AN bolts that slide through it and into the tooling holes, and marked a line extending through the centers of both bolts.  Simple and effective.  One aileron at a time, I held the bellcrank in its neutral position using the W-730 bellcrank jig, and adjusted the pushrod end bearings until the aileron was also in its neutral position.  Note that these are the skinny pushrods from the bellcrank to the aileron.  The fat pushrods that go the fuselage haven't entered the equation yet.  Note also that I have not yet made the spacers for the pushrod attachment to the aileron.  I'll hold off on these until the flaps and wing tips are fitted, and I've determined the final span-wise position of the ailerons.





Now I'm starting fit the various sensors and actuators that will go in the wing, so that I can finally close out the outboard bottom skins.  These will include the pitot probe, AoA ports, OAT probes, autopilot aileron servo, and landing lights.  Wiring runs will also have to be provided for the strobes, nav lights, and antennas that will be installed in the wing tips.

2009.09.09: (0.0) Update on various tasks in the wings:

I created some drawings (in OpenOffice Draw) to plan the layout of the various sensors, actuators, wiring, and plumbing runs in the wings.  Also created a spreadsheet (in OpenOffice Calc) to select appropriate wire gauges for the wiring runs.  I'll put these up on the web page soon.

Installation/fitting of the various sensors and actuators is coming along nicely.  These are documented in their respective pages.

Holes for wiring

Started making accomodations for the physical wiring runs.  I considered several options, including those suggested by Van's in this note.  I ultimately decided to add a hole in the ribs as shown in option 2, but use snap bushings rather than conduit [I don't see that conduit would add much utility in this case, and it presents potential problems with chafing as the wires enter/exit the conduit].  My plan is to select snap bushings that are just slightly bigger in diameter than the wiring harness at every point in the wing.  I don't have all the needed varieties of wire and cable yet to get these measurements, but I can make some rough guesses.  On the inboard section of the wing (wing root to aileron bellcrank) 1/2" diameter or less should suffice, and on the outboard section of the wing (aileron bellcrank to wing tip) 3/8" diameter or less should suffice.  I therefore drilled the holes in the inboard section to 5/8", which can accomodate snap bushings with inner diameters up to 0.500", and drilled the holes in the outboard section to 1/2", which can accomodate snap bushings with inner diameters up to 0.391".  Snap bushings with smaller inner diameters are also available for these outer diameters.  See chart of available Heyco snap bushings.

Drilling these holes is another instance of a task that could have been performed very easily before the wing was assembled, but was a lot more tricky on a pre-assembled QB wing, especially on the inboard section where there are several closely spaced ribs and the bottom skin is already on.  I first used a properly scaled printout of the drawing in Van's note to locate and pilot-drill all the holes.  It ultimately took many steps, some yoga-like body contortions, an angle drill adapter, drill extensions, standard drill bits, extra-long drill bits, and unibits to enlarge the holes to their final size.  What finally made the job possible (and would have made it just a bit simpler if I had it a couple of days sooner) was a 12" drill extension for 3/8" shaft diameter bits (Irwin #3 unibit) that could fit through a 5/8" hole.  To my surprise I couldn't find such a thing.  But I did find one that had a 3/4" max outer diameter, and my buddy Buzz was kind enough to have one his buddies machine it down for me on a lathe to 9/16" outer diameter.  The original tool was a Ridgid 12" Hole Saw Extension, p/n 7035.  It was about $10 at the aerospace isle at Home Depot.  Note that Home Depot also had extensions for 1/4" shaft diameter with about 9/16" max outer diameter, and perhaps this could have been bored out to 3/8" inner diameter.  Just another option.




OUTBOARD BOTTOM SKINS:

Working toward getting the outboard bottom skins ready to close.  Firstly, I had a lot of work to do on the rib flanges.  This is yet another instance where doing the job right prior to wing assembly would have been a lot easier.  Unfortunately, the QB factory did flute the rib flanges, but seemingly without any particular objective in mind.  The rib flanges were far from square to the rib webs, and the rib webs (and more importantly the flange rivet lines) were far from straight.  I took several hours to get these into shape.

Secondly, a few of the small rib flanges that meet the main and aft spars are somewhat mis-shapen and create a gap between themselves and the spar.  In most cases the gap is sufficiently small that it should pull together when riveted.  But on the outboard rib of the left wing, the gap to the rear spar is substantial.  I made a shim from 0.032" aluminum to fill the gap.

Now to the skins themselves.  I decided to dress the edges and prime the inside surfaces before match-drilling the holes.  When I removed the blue protective plastic from the left wing skin I had an unpleasant surprise: the beginning of filliform corrosion was evident in several areas along the edges.  I had heard that in some cases leaving the blue plastic on there during long term storage can actually promote corrosion, not sure exactly how/why.  And I haven't seen this happen with any other parts.  Anyway...  After dressing the edges, I used scotch brite pads to abrade away the corroded areas down to clean metal, then gave them a swipe with the alodine pen.  I then cleaned and abraded the entire inside surfaces of the skins and shot AKZO primer on them.

2009.09.14: (0.0) Clecoed the outboard bottom skin to the left wing and match-reamed the rivet holes to final size (#40), except for holes that are already dimpled or countersunk on the wing (1. the main spar, and 2. the skin overlap) which I will ream to final size in isolation.

Also took the opportunity to fit the flap.  First I fit the flap brace.  I had already dressed the edges and primed it a long time ago, but clecoing it on it became apparent that some massaging will be necessary to get a good fit.  The angles of the flanges are pretty much dead on for the main portion of the flap brace, but the short sections at the ends didn't sit quite right because of the different angle that they attach to the rear spar over the doublers.  Clecoing everything into position would put tension on the structure and distort the skin.  So I clamped the flap brace to the work bench and carefully adjusted the flange angles.  It only took two iterations of eyeball and trial and error to get it just about perfect.  Now everything can be buttoned up with no stress and no deformation.

Now to the flap.  The flaps themselves were actually completely assembled at the QB factory, so fitting them to the wings simply means setting the exact location in attaching the (half) hinge to the wing side.  The span-wise position of the flap is set in reference to the aileron, so I installed the aileron at what I now consider its nominal position, with two standard washers and one thin washer on the outboard side of the outboard aileron hinge.  The flap is then positioned such that there is nominally 1/4 inch (minimum 3/16 inch) clearance between the outboard edge of the flap and the inboard edge of the aileron.  I set mine to 1/4".  The chord-wise position of the flap is set so that nominally its trailing edge matches the trailing edge of the aileron while in the neutral position.  Some builders have reported problems with this, stating that a wider hinge had to be used to set it sufficiently aft without violating the edge clearance requirements.  I didn't find any such problems.  The holes ended up smack dab on their nominal location on the hinge, with edge clearance to spare, and the trailing edges are dead on.  Maybe it was a problem early on and Van's later fixed it, or maybe I just got lucky.  Anyway, all went well.

2009.11.01: (0.0) Flap hinge pins: There are basicall two options for insertion and removal of the flap hinge pins.  1) Drill a hole through the inboard aileron hinge bracket so that the flap hinge pin can slide through it, or 2) Remove three hinge eyelets (one from the wing and two from the flap) in the middle, and slide in a half-length hinge pin in each direction through the gap.  I chose the latter, and built in a neat arrangement for securing the hinge pins.  A picture is worth 1000 words:



And... I finally riveted the flap braces to the aft wing spar.  By doing this before riveting on the bottom skin, I was able to at least use solid rivets at the outboard end where the wing bay is still open.  (I also used a solid rivet at the most inboard end).  Now riveting flap brace to the skin and hinge will have to wait until the outboard bottom skin is riveted on, which will hopefully be very soon.

2010.01.22: (0.0) Closed the right wing, i.e. riveted on the outboard bottom skin.  Did this over several sessions totalling about 8 hours.  A big thanks to my riveting partners: my good friend and flying partner Jimmy for the three inboard bays, and fellow RV builder John Francis for the three outboard bays.

In closing out this skin I took a slightly different approach from Van's normal method.  Van's method as described in the manual is to start with the inboard aft corner, peeling the rest of the skin away to provide bucking access, and working out toward the outboard forward corner half a bay at a time.  This is fine access-wise, but what I didn't like about it was the potential for warping and wrinkling due to uneven distribution of tension in the skin, a fairly common problem seen on many RVs.  My preferred approach was to do as much riveting as possible with as much of the skin as possible clecoed (or already riveted) in its proper position on the wing with any stresses evenly distributed.  I still worked generally from the inboard end toward the outboard end, but with the skin fully clecoed on the wing most of the time.  Following is a summary of the sequence is used:

1. Cleco the entire skin to wing, taking care to line it up as well as possible and distribute its tension as evenly as possible.

2. Rivet the three inboard bays while the skin is fully clecoed.  Every rivet in the three inboard bays can be bucked through the access hatches.  [Note that I started by putting in a few rivets along the main and aft spars in these three bays to "tack down" the exact position of the skin so it can't creep or shift around in one direction or another.  Only then I filled in the remaining rivets inbetween, again in such a distributed order such as to not induce creeping.  I use this technique throughout.]

3. Un-cleco the skin from the outboard-most two bays of the wing, as well as the main spar of the next bay.

4. Rivet the next bay, which has to be done basically by Van's method, with the skin peeled back from the bays further outboard.  There's just no other access to bucking those rivets.  [It would sure be nice if there was one more access hatch!  Then the whole wing could be done without peeling back the skin!]  Here too, I started by putting in a rivet near the outboard end of that bay along the aft spar to tack down the geometry.  Then filled in the remaining rivets along the aft spar and along about the aft half of the rib.  I then clecoed along the main spar and riveted the main spar and the remaining forward half of the rib.

5. Re-clecoed the skin to the entire remaining section of the wing.

6. Rivet the remaining two bays (the outboard-most two bays) while the skin is fully clecoed.  These can be bucked through the oubtoard end of the wing.

The results look great.  The skins look smooth and the tension feels right and is well matched across all wing bays.  I should have a straight wing.

WORD OF CAUTION: Some serious "yoga" is needed to buck a few of the rivets using this approach.  And I have long skinny arms.  Some folks will surely not be able to do this.  Before committing to it, I did a dry run just to be sure I could reach all the rivets this way.  I strongly suggest that anyone considering this approach should first do such a dry run themselves.

2010.01.22: (0.0) Finished closing the left wing, again over several riveting sessions with help from John F. and Jimmy.