Trent's RV14 Build: 14-02/3: Wing Rib Preperation

Flap Rib Nomenclature

Section 14 contains instructions for the prep of the wing ribs and similar to other parts of the plans, only shows instructions for the left side (i.e. Left Wing).

When i inventoried the wings, there were a lot of parts with a -L or and -R part number, so my assumption was this meant the -L parts were for the left wing (and vice versa). Nope!

Fortunately, pages the plans detail the various systems holes which show BOTH wings, and from this i worked out that the -L and -R part numbers meant the direction that the flange is pointing on the rib. I.e. a W1011-L rib, could be installed in EITHER wing, but in all cases would have it's flange pointing to the LEFT hand wingtip.

R5 is in the right wing, but is a W-1011-L part (flanges of rib point to the left)

Deciding i needed a better system, i made up some little tokens and punched then with L1-L14, and R1-R14. As i select the correct part number rib for the locations called out in the images above from the parts pile, I mark the part number on the part along with "L3" etc with L1 and R1 being the root ribs, and L14 and R14 being the tip ribs. From here on i will reference the ribs by this nomenclature and not the part number. The tokens are there to preserve the rib location during etching and priming.

Flap Hinge Ribs

Starting this section in earnest involves some cutting apart of some parts to make L and R versions (again, this didn't mean they were on the Left or Right wing and careful checking of the plans needed to be made). The large, thick flap hinge pieces were straightened using the "WHANG" technique, then deburred and all parts were match drilled.

The flap hinges will have a bronze bushing pushed into them as the bearing surface that the flaps will hinge on - when these parts are primed, i will therefore mask inside the hole where the bushing will be forced into.

Parts laid out carefully - once in position all parts were labelled with their rib number - i.e. "R3"

This belongs on rib L8

The rear end of these parts needed to be eased so that it didn't interfere with the rear spar when the ribs are eventually riveted to the rear spar.

Root Rib / Aileron Actuator Bearing Brackets

The root ribs each carry a bracket with a flange bearing, to mount the aileron actuator arm assemblies (?) - aka, the parts with translate the stick movement to the aileron pushrod! Once match drilled etc, these assemblies need to stay together, so they were labelled with their rib number.

This shows the amount of relief that was needed for the parts to nest inside the flanges of the root ribs.

Tip Rib Modification

As per the plans, the flange was cut off both tip ribs - this will be held to the rear spar with the outboard aileron hinge assembly at a later date. I just used a dremel, then cleaned it up with the Vixen file.

A Note on Priming

Since there seems to be a number of parts which need to stay together with their parent rib, i have decided to complete the priming in batches. There are 28 ribs total (14 per wing). The inboard 7 ribs have the aileron actuation assemblies (as above) as well as one flap hinge (on the #3 rib). The outboard 7 ribs have only the outboard flap hinge (on the #8 rib). Given this, i will prime in 4 batches - the inboard 7 ribs on one wing, then the inboard 7 on the other wing, then the outboard 7 etc. This will mean i will only ever have one set of "additional" parts, and they won't (shouldn't?) get mixed up, all done in 4 priming batches.

Wing Spar Hardware

Each of the wing ribs is attached to the spar with AN470 universal head rivets. However, at the top and bottom of the spars is the thick stepped bar - the factory has set some massive AD5 rivets in these to hold them together, but it is obviously impractical to try and attach a thin rib, at home!, using very long AD5 rivets. Hence, the factory pre-drilled the spars and shipped them with bolts and nuts installed. Almost every single hole was a slightly different length bolt and a lot of them are in different orientations. These are all laid out in the plans, but the hardware needs to be removed from the spar in order to cleco on the ribs and match drill them (for the rivets and also the bolts).

As such, i copied an idea i have seen at work (on windscreen removals where it is a safety critical task to put the bolts back in the same places). When the bolt is removed it is stored in a piece of cardboard in the correct location. I took the opportunity to mark the cardboard for each spar with the correct bolt callout from the plans and also it's orientation. This allowed me to check each bolt length as it was removed against these callouts to make sure the factory didn't make any mistakes (they didn't). The bolts now have a nice storage location until they are needed later. A note: I will replace all the nuts, but reuse the bolts.