Category Archives: Section 07, Rudder

Rudder – Static Wicks

I performed my first modification to the plans today by drilling attachment holes for the static wicks. Based on the manufacturer suggestions , they should be placed on the outer edges and most rear portions of the plane to properly dissipate an electrical charge. Using a pair about 12 inches apart is also recommended. The rudder on the RV10 has two rib stiffeners at the top almost exactly configured for this application.

The modification requires measuring, drilling and countersinking holes for nut plates to secure the static wicks.  There are special jigs available for different sized screws, so I bought one (~$35) for 10# screws to fit the Dayton Gardner 16165 wicks.  Because the skin and stiffener on the rudder are only a combined .050″ thick, I started the main hole with a #40 drill, then progressively got bigger (#30, #21, #17, #12, #10) until the final hole diameter was reached.  This was a bit tedious, but kept the thin skins from bending or tearing. The jig then is used to exactly align the attachment rivet holes.  Since holding the wick in place is not considered structural, an ‘oops’ rivet with a smaller than normal manufactured head will be used to keep the countersink small and shallow (more on ‘oops’ rivets in later posts).

The hardware list for the static wicks and bond straps:
MS21078-3 two lug elastic insert anchor nut
MS21080-3 one lug elastic insert anchor nut
MS35207 machine screws (various lengths will be used)

IMGP3705Here using the #10 nut plate jig to position the rivet holes relative to the main screw holes. The jig essentially provides a perfect fit every time. I cannot imagine spacing the three holes properly without that tool.

 

 

 

IMGP3706Final drilled holes for the nut plates with plastic inserts.  Notice the three hole design on the left compared to the single lobe method on the right.

 

 

 

IMGP3716This picture shows the decreasing headroom moving r-l towards the trailing edge. Notice why the use to the one lug anchor plate is needed here.

 

 

 

IMGP3727The attached holes have been hand countersunk with an ‘oops’ rivet head used to check depth. This picture shows approximately how it will look when the final riveting is completed.

 

 

 

IMGP3714Dry fit of the Dayton Gardner static wick on the uppermost rudder rib. The result looks good.

Rudder Drilling – Part 2

Used a chart and homemade guide to get the necessary 5 degree angle to drill perpendicular to the chord line as per instructions.

IMGP3685A rough drawing of the trailing edge configuration.

 

 

 

 

IMGP3687Home drill guide in operation.

 

 

 

 

IMGP3688Drilling in progress.

 

 

 

 

IMGP3689This close-up shows the trimmed trailing edge.  A bit more rounding is needed to smooth the AEX piece.  I intend using ProSeal (or equivalent) on the trailing edge, so hopefully some of the empty space will get filled with this material.

Rudder Drilling – Part 1a

The last few days I have been researching how to drill and countersink the rudder trailing edge.  By hand measuring the AEX aluminum strip I determined the acute angle to be about 10-to-12 degrees.  If the common drilled hole through both sides is perpendicular to the chord, this means the countersinking bit will be about 6 degrees off the drilled line when removing material to accept the skin dimples. This angular difference does not seem like much, but we shall see how it goes.

I have also spent quite some time finalizing the bonding strap and static wick configurations.  Using #10 screws, nut plates, and a 3/8″ braided copper mesh should do the trick for effective electrical connectivity.  My intention is utilize the open area near the middle hinge for the bonding strap.  Parts were ordered and have arrived from Aircraft Spruce.

MISC LOGISTICS – continue to acquire painting supplies and work on the configuration of the shed for alodine/prime processes.  I have my eye on a 7.2CFM, 2HP air compressor, but need our finances to stabilize a bit before pulling the trigger.

Rudder Drilling – Part 1

Eric helped match drill all the rudder skin holes common to the spar and stiffeners.  I do not understand the instructions drilling the trailing edge. In one step the plans call for drilling perpendicular to the chord of the rudder, later it talks about countersinking holes perpendicular to the trailing edge surface.  Right now these seem like contradictory instructions.  I will need to get some clarification before proceeding.

Rudder Skins

The rudder skins were prepped and rigged ready for match drilling (Sections 7.6.3 – 7.6.5)

IMGP3662Today I used the soldering iron trick to cleanly peel away vinyl from the edges and rivet lines on the exterior side of the skins.  There is a big debate in the community about the utility of leaving the vinyl on (scratch resistance vs. corrosion potential), but I think it looks cool.  Besides the plane parts are currently stored in our climate controlled bonus room, plus I do not intend to spend decades waiting to process and corrosion treat these materials.

 

 

IMGP3665Removing the vinyl strips…

 

 

 

 

IMGP3667Final product.

 

 

 

 

IMGP3669Here the rudder trailing edge is being attached for final trimming to appropriate length.

 

 

 

 

IMGP3671and the whole nine yards clecoed together ready for match drilling.

Rudder Framework

All the steps for 7.4 and 7.5 were completed today, along with 7.6.1 and 7.6.2. This means all the rudder framework parts (spar, horn, ribs, stiffeners) have been drilled, countersunk, and deburred ready for corrosion prep.  It took about 5 hours to get this done.

IMGP3642 The first steps involved countersinking nut plate fastener holes on the Rudder Horn.  This is a crucial part of the airplane steerage mechanism as the rudder control cables will attach here.  Countersinking this side with a micro-stop countersink cage was easy, the backside not so.

 

 

IMGP3643the back part of the horn piece is rounded, meaning the countersink cage cannot be aligned perpendicular to the surface and parallel to the hole.  As a result, hand countersinking was required.

 

 

 

IMGP3646Voila.  Using a hand crank attached to the #30 countersink bit, I was able to get the proper alignment.  It took a while longer to hand-bore out the metal, but actually I liked the control.  The appropriate flush rivet was continually used to check the depth, which in my opinion turned out quite nice.

 

 

 

IMGP3649Next was drill out the lower spar rib and corresponding flange part to match the attachment points to the horn.

 

 

 

 

IMGP3655aThe striker plates were also countersunk by hand.  These will eventually be flush riveted to the lower rudder spar.  They serve as the contact points for the rudder stops prepared in Section 6 for the vertical stabilizer.

 

 

 

IMGP3653Horn, striker plates, lower rib and spar clecoed together after match drilling and deburring.

 

 

 

 

IMGP3658Stiffeners attached to the rudder spar.

 

 

 

 

IMGP3659One rudder skin clecoed in place for stability.  Next steps will be debur the other skin and peel vinyl strips off the exterior surface along the rivet lines.

 

 

Rudder Ribs

Finished separating the ribs parts with associated deburring from steps 7.2.1 and 7.2.2.  Also ordered inital round of attachment hardware for the bonding straps and static wicks to be used on the vertical stabilizer and rudder.

IMGP3636IMGP3638

 

 

 

 

 

MISC – Peter helped move the first dunk tank section out to the shed, plus added bracing to work surface legs. The premium buckets which will hold the alodine and brightener chemicals also came in yesterday.  These were relocated out to the shed this afternoon.

Rudder Start

Started on the rudder section of the build plans today.  The initial effort involved separating stiffener and rib pieces with tin snips after marking carefully.  The usual deburring process then ensued.

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