Roee Kalinsky's RV-7A Project

2004.08.16: (0.5) Separated the rudder stiffener stock into individual stiffeners using a Dremel cutting disk mounted in the air drill.

2004.08.18: (1.5) Rough-cut the tapered (aft) ends of the stiffener flanges on the band saw.  Started filing down the long cuts.

2004.08.21: (2.0) Finished shaping the tapered ends of the stiffeners using a vixen file followed by the bench grinder.

2004.08.23: (2.5) Cutting/shaping the forward (non-tapered) ends of the stiffeners.

2004.09.11: (3.0) Finished fabricating and deburring the stiffeners.

2004.09.18: (3.0) Match-drilled the stiffeners to the skins, deburred all the holes.  Used 1/4" particle board under the skins and drilled right into it as suggested in the manual.  Worked great.

2004.09.20: (1.0) Fabricated the control horn shim.  Shaped the top edge of the control horn to fit the bottom rib.

2004.09.22: (1.0) Finished fitting and match drilling the control horn assembly with the bottom rib, front spar, etc.

2004.09.??: (2.0) Prepared the spar and ribs (edge finishing, fluting, etc.).

2004.10.17: (2.0) Edge-finished the right side skin.  Dimpled the right side skin and stiffeners.

2004.10.29: (1.5) Edge-finished the left side skin.  My new favorite way of finishing long edges on skins is as follows:
1. File down the edge to remove large burrs and other marks from the cutting press.  A 6" bastard cut mill file works well.
2. One or two passes with the file at 45 deg on both sides to break the edges.
3. One or two passes with a 1" fine scotchbrite wheel in a right angle die grinder to remove filing marks.  After this step the edge is rounded and smooth to the touch.
4. A quick pass with maroon scotchbrite pad for good measure.

2004.10.30: (1.0) Dimpled the left side skin and stiffeners.

2004.11.04: (1.0) Fitted and match-drilled the counterbalance skin and ribs to the spar.

2004.11.05: (0.5) Beveled the counterbalance skin where the main skins overlap the edge to the spar.

2004.11.06: (2.0) Alodined all the stiffeners.  Capped one end of a 1" PVC pipe and filled with alodine.  Dipped the stiffeners using monofilament.  This worked fairly efficiently.

2004.11.13: (3.0) Prepped and alodined the hinge point spar doublers.  Sprayed epoxy primer on the spar doublers and skin stiffeners.

Also alodined and epoxy coated a scrap of 0.016" 2024-T3 alclad (same as the rudder skins) to experiment with drilling and dimpling material that has already been treated.  There has been some debate among builders about whether the epoxy primer can withstand the dimpling process without cracking.  My experiment showed that the epoxy held up just fine.

2004.11.21: (2.0) Alodined the interior surfaces of the skins (including the outer surface of the left skin where the right skin will overlap it at the rolled leading edge).  Used my newly acquired Henkel Surface Technologies "Touch-N-Prep" alodine 1132 pen with very good results.  I applied two very light coats at 90 deg to each other as described in the data sheet.  If color is any indication, this method appears to be more effective than brushing on alodine 1201.  And there's no cleanup!  Surface preparation is the same - clean, abrade, etch.

2004.11.24: (1.5) Sprayed epoxy on the interior surfaces of the skins.  Created an easel-like arrangement -- suspended the skin with a few nails to a particle board backing with a 1"x1" support beam behind the top edge, all leaning against a ladder.

Notice the lap joint region at the leading edge of the left skin.  It's details like this that really make the hours add up...

2004.11.26: (2.5) Time to rivet the stiffeners to the skins.  Used some 3/8" particle board to create a level surface around a steel bucking plate for back-riveting.  Tried back-riveting for the first time on some scrap.  Couldn't be easier!  Riveted the stiffeners to the right side skin.

2004.11.27: (2.0) Riveted the stiffeners to the left side skin in 52 minutes flat.  That's what I call high RPM (rivets per minute).  Clecoed together the rudder for final drilling.

2004.11.28: (2.0) Final drilled the skins to the rudder skeleton and trailing edge wedge.  Fitted and drilled the rudder horn brace.

2004.11.29: (1.0) Made the attachment strips for the fiberglass rudder bottom.  Match drilled them to the rudder.

2004.11.30: (3.0) The builder's manual states that the aft three holes in the skins that attach to the fiberglass rudder top should be drilled and dimpled at this time because this will be difficult in the completed rudder.  So I decided to do some preliminary fitting on the fiberglass tip and match drill the whole thing.  The initial fit was actually pretty bad, and will need much more work later.  But for now I just trimmed it enough so its relative position can be nailed down.  Also, I don't like the idea of blind-riveting the fiberglass tip to the rudder, so I'll use #6 machine screws and nut plates instead.  This will give me access to at least the top of the counterbalance arm where I can make adjustments to the counterbalance mass (a second weight, the main one is boxed in and completely inaccessible).  Otherwise, the only way to remove mass (lead) is to drill it out through the counterbalance rib, and there is practically no way to add mass.  So... match drilled the holes to #27 drill (for #6 screw).  Disassembled the rudder.

2004.12.02: (1.0) Deburring holes and dimpling while watching a Discovery Channel special on Burt Rutan's SpaceShipOne.

2004.12.04: (2.0) More deburring and dimpling...

Just got some more dimpling dies and countersink bits from Cleveland.  One set for #10 screws (for the counterweight attachment) and one set for 1/8" 120 degree countersunk blind rivets, like CS4-4.

2004.12.05: (1.0) And some more...  Modified my Avery vice grip dimpler on the bench grinder to help it get into even tighter places, like the last few holes in the ribs near the trailing edge.

2004.12.06: (1.0) First not-so-successful attempts at countersinking the trailing edge wedge.  This task is slightly complicated for a couple of reasons:

1. The wedge is very thin, so the holes are enlarged once countersunk from both sides.  This means half way through countersinking the second side, you no longer have a good guide hole and the bit tends to chatter.

2. Since the wedge is a wedge (redundantly redundant) the holes aren't quite perpendicular to the surfaces, also affecting the guide pin of the countersink bit.

First attempt using a hand drill holding the wedge flat against the countersink cage had limited success.  For a second attempt I used some thin plywood and clecos to support the wedge with its upper surface perpendicular the countersink cage in drill press.  That was better, but there was still a tendency to chatter on the second side.  Will try adding rigid back support or clamping to the table to minimize motion.

2004.12.07: (1.0) Took a trip to a local metal supplier and bought some alum angle.  Cut a piece to act as backing and match-drilled it for three rivet holes on the wedge.  Note that because this is a backing piece the holes should end up at an angle to it, so that they're perpendicular to the opposite surface of the wedge.  Used larger pieces of the angle to act as rails to support the wedge on the drill press table.  A picture is worth a thousand words, so here it is.  This worked very well.

2004.12.15: (1.5) Prepped and alodined the rudder skeleton parts.

2004.12.16: (1.5) Shot AKZO on the rudder skeleton parts.

2004.12.18: (1.0) Started riveting the skeleton.  After driving a few rivets on the counterbalance arm, I decided that a squeezer yoke with a 4" throat will be a better alternative.  Ordered one from Cleaveland.

2004.12.24: (1.5) With my new 4" yoke that just arrive, I easily squeezing the remaining rivets on the counterbalance skin.  Now riveting the skins to the skeleton.

2004.12.27: (2.5) A long awaited order from Van's just arrived -- an assortment of NAS1097AD3 rivets, which are like AN426AD3 but with smaller heads.  Used these to attach two 10-32 nutplates to the top rib, which will be used to secure additional counterbalance mass if needed.  Finished riveting the skins to the skeleton.

Started riveting the dreaded trailing edge.  There's been much discussion on the message boards lately about different techniques for doing this.  I decided to go with a method of my own.  I laid the rudder down flat on its left side, with the fully clecoed trailing edge hanging off the edge of the workbench (control horn hanging off the edge as well).  Then one by one I replaced a cleco with a rivet, inserted from the top (i.e. manufactured head on right side), squeezed far enough to get a good grip but nowhere near flush with the skin.  Note that all the squeezing at this point is perpendicular to the plane of the manufactured head, so it's crucial that the die does not come in contact with the bottom (i.e. left) skin.  The rivet sequence I used was basically starting from the extreme edges, then half way between, then split the halves into quarters, etc. for the "even" rivets.  Then the same sequence again for the "odd" rivets.  Every few rivets I checked the trailing edge for straightness and made slight adjustments as needed.  The idea is that the trailing edge starts out straight and fairly rigid by virtue of all the clecos.  Then it gradually becomes more rigid, and should be vigilantly kept straight, as clecos are replaced with rivets.  At this point, all rivets are in an partially set.  Next, they'll need to be fully driven by back-riveting.

2004.12.28: (1.5) Finished the trailing edge by back-riveting.  The result is not perfect, but pretty good.  The trailing edge has no bow in one direction or the other, and is straight to well within the 0.1" tolerance recommended in the construction manual.  The flush shop heads, which are all on the left side of the rudder, actually look ok.

2004.12.29: (3.0) Did the rolled leading edge to finish the rudder.  I thought this step would be easy, but it actually took a lot work to persuade the leading edge into proper form.  Because the leading edge profile tapers along the rudder's span, the curvature is more parallel to the spar than it is to the leading edge lap joint.  So the broomstick/pipe method (dowels of various diameters in my case) described in the manual actually has to be modified somewhat, to tape the dowel at an angle to the edge of the skin that will form the lap joint.  Then some freehand coaxing to finish the job.  A job like this is never perfect, but I think it came out pretty good.