Priming VS, rudder, HS spar components [6.0 hours]

Not much progress lately due to various farm and domestic distractions. I did set aside today to do some priming. There were a lot of components for the VS, rudder and HS spar assemblies, and I decided to do them all as one batch, and do the two HS spars and three skins another day (soon). There were a lot of minor setup things to take care of since this is the first time I’ll have done a significant quantity of material. A dip tank for the acid etch that I’d half made, for instance. So the actual work didn’t start until 3 pm, after which it took me 6 hours to degrease, acid etch, spray on EAP-12 and then spray on the PPG primer.

Results were good. I kept it thin for the most part. There was a lot of over spray with so many small parts, and they all jangled around a bit as I moved from piece to piece. A bit of spitting on a few parts, still learning how to best spray on the primer. Some blue bleed through in parts from the EAP-12 which I put on too thick in a few places. I mixed up 200 ml of primer for this job, and due to the small size of most of the parts, much of it wound up on the (plastic) floor of the booth.

Set up for priming VS, rudder, HS spar components

Set up for priming VS, rudder, HS spar components

VS, rudder, HS spar components primed

VS, rudder, HS spar components primed

 

Horizontal Stab front spar [13.5 hours]

There’s a lot more work in the front spar preparation, compared with the rear spar assembly.

Cut and deburred the HS-1013 spar caps. Deburred the HS-1002 front spar. Match drilled #30 from the spar web to the spar caps, and deburred. Match drilled #40 from the spar flange to the spar caps, and deburred. Deburred the HS-1007 doubler.

Made the HS-1008 right and left brackets. Van’s only gives you enough material to do this once, so I spent a fair bit of time to make sure I didn’t mess them up, being so far freight-wise from Oregon. A milling machine would have been handy, but I don’t have one so I decided to use the compound saw to do the cuts. I used a bit of cheesy hardware store aluminium angle to verify the saw calibration and setting of the angles, before finally doing a couple of trial cuts on the real material, and then the real cut for the HS-1008R piece. After that I changed the saw around and cut the HS-1008L piece, and they matched up well. Clean up was easy because the Aluminium blade cut is quite clean to start with. Fiddled around with the drill to get the holes accurately positioned. Don’t be fooled by the cross slide vice in the picture(s), it is a piece of cheap Chinese rubbish and barely worth the trouble. The HS-1008 parts cleaned up well.

I used the same 2 inch Aluminium angle that I have prepared for the rudder trailing edge assembly to clamp the HS-1008 brackets to while match drilling from the spar assembly. Not done yet but the front spar assembly is close to being ready, all that remains is match drilling the rest of the #30 holes between the spar and doubler, and a few countersinks in the doubler.

  • hs5
    hs5

    hs5

    Cleaning up HS-1013 spar cap ends after band saw cuts
  • hs6
    hs6

    hs6

    Preparing HS-1013 spar caps
  • hs7
    hs7

    hs7

    Match drilling spar caps with #30 drill
  • hs8
    hs8

    hs8

    Ready to match drill spar caps to flange
  • hs9
    hs9

    hs9

    Cutting HS-1008-R, after a few trial cuts to make sure the saw drop was straight/correct.
  • hs10
    hs10

    hs10

    Cutting HS-1008-L
  • hs11
    hs11

    hs11

    Cutting HS-1008-L
  • hs12
    hs12

    hs12

    Trimming height, both parts clamped together, just to save some filing
  • hs13
    hs13

    hs13

    Drilling pilot holes, for the 1/8" holes
  • hs14
    hs14

    hs14

    Finished HS-1008 parts
  • hs15
    hs15

    hs15

    Set up to drill the 9 holes through each spar/doubler into the HS-1008 brackets.
  • hs16
    hs16

    hs16

    Ready for match drilling the remaining spar/doubler holes

Horizontal Stab rear spar [6.0 hours]

The horizontal stabilizer (HS) build steps describe relatively simple assemblies of the front and rear spars, to the point where they need to be primed if a builder chooses to do so. It would be a pain to prime just these spar assemblies on their own – such a small job – so I decided to go ahead and prepare them, and prime the entire vertical stabilizer, rudder, and HS spar assemblies in one preparation and painting session.

I pulled the necessary parts, and completed the rear spar assembly today through to the point where it is ready to be primed. That leaves the front HS spar assembly, which is a bit more work but doesn’t look too bad.

  • hs1
    hs1

    hs1

    Deburring HS rear spar
  • hs2
    hs2

    hs2

    Match drilling HS rear spar and doubler
  • hs3
    hs3

    hs3

    Match drilling HS brackets to rear spar
  • hs4
    hs4

    hs4

    Match drilling flange bearing to HS-911 brackets

Almost done with rudder components [4.5 hours]

Spent most of the past week recovering from a run-in with a surgeon. Glad I slept through it all.

Finished dimpling the rudder components. Now, the standard Van’s plans don’t call for electrical bonding between control surfaces and the air-frame, and don’t include any facility for static wicks. For a VFR platform, this may be OK. For an IFR platform, this may or may not be OK, it’s easy enough to find anecdotal evidence for either case on the various forums, so this topic is a bit like priming. It’s not hard to add the facility to bolt on static wicks while building the rudder. It’s messy to add static wicks after assembly if they have not been allowed for at this stage. There’s a placement document floating around – here – that describes recommended static wick positions for the RV-10.

I didn’t like the approach described by some builders, of drilling extra rivet holes in the rudder skin and countersinking those holes, using the combined thickness of the skin and stiffener to achieve adequate countersinking depth. The only extra “holes” I wanted to put in the skin are those for the wick mounting bolts, so I used existing skin rivet positions for one of the elastic anchor mounting holes, and made up a doubler so that the “other” anchor mounting hole could be an internal rivet between the rudder stiffener and the doubler. The doubler is countersunk as required. The elastic anchor nuts are cadmium plated and can’t be countersunk – that would expose raw steel across the surface of the underlying dimpled alclad. Each mount uses one MS21080-3 single lug elastic anchor and one MS21078-3 two lug elastic anchor. There’s not much room for the aft most anchor, and the bolt that is used to retain the wick will have to be carefully sized and perhaps trimmed so as to not protrude beyond the anchor (to the extent that it contacts the opposing surface).

The wick mounts are on the left side of the rudder. Although the doubler adds a fair bit of stiffness, that’s going to happen anyway since the static wick mount is completely solid/stiff. After match drilling, countersinking etc. the components were assembled onto the rudder skin and a 3.5mm drill was used to drill down through the skin, using a pair of “fitting” anchors as the drill guide. Then the holes were carefully enlarged from the outside of the skin using a tapered hand reamer. Once a sample MS35206-261 machine screw would just fit through the holes, I disassembled everything and used the hand reamer to slightly enlarge the holes in the skin to a good clearance fit, and enlarge the internal holes in the stiffener/doubler combination to be slightly larger than those in the skin. After deburring everything, the entire assembly fitted together well and the skin holes were perfect.

During assembly, I’ll use a small amount of pro seal between each internal surface around the wick mounting holes, to prevent any water ingress. If there is no wick mounted, each hole will still require a screw, so that the screw end into the elastic part of the anchor provides a weather seal.

The final step in preparation of the rudder components was to countersink the trailing edge wedge. With a little set up time it was easy to bore consistent countersinks using the drill press. It’s tedious because there are a lot of holes. I completed all of one side and just started on the other side but elected to leave the rest for another day because I looked up at the clock and it was almost beer o’clock.

rudder_te_wedge

 

While cleaning up, I had a container to label. I’ve been slowly putting common rivets from the various kits into containers, and I noticed the following interesting bag of rivets. Missed this one when I did the empennage inventory … Van’s did get something wrong after all.

Van's sure got this one wrong

Van’s sure got this one wrong

Match drilling, deburring rudder [6.5 hours]

Match drilled the assembled rudder. I also match drilled a 50×50 mm piece of Aluminium angle to the trailing edge, to use later on during rudder assembly. I’m planning to use the technique described here to set the trailing edge. After match drilling, I disassembled the rudder and deburred both skins. That leaves skeleton debur, R-1006 countersink, and dimpling.

Deburring rudder skin after it has been match drilled

Deburring rudder skin after it has been match drilled

More rudder work [7.5 hours]

Finished deburring rudder components. Assembled and match drilled the rudder skeleton. Deburred the skins. I cleco’d the skins together along the trailing edge, and used a vixen file to debur both skins at once so that the trailing edge of the skins stayed identical. I then cleco’d the skins onto the skeleton, ready for match drilling.

  • rudder3
    rudder3

    rudder3

    Rudder skeleton match drilled
  • rudder2
    rudder2

    rudder2

    Most deburring of trailing edge done with skins cleco'd together
  • rudder4
    rudder4

    rudder4

    Rudder assembly cleco'd together
  • rudder5
    rudder5

    rudder5

    Rudder assembly cleco'd together
  • rudder6
    rudder6

    rudder6

    Rudder assembly cleco'd together

Started on rudder [10.0 hours]

I’ve started preparing the rudder parts. I may get the rudder to a point where the parts are ready to prime, and do the rudder and vertical stabilizer in the same preparation and paint session. The following set of parts is the result of ten hours of cutting, filing and de-burring over the past two days. Still a few parts (covered in blue  plastic) to go.

Rudder parts

Rudder parts