Sooo, after extensive search online and my first E-619-1-020 Elevator Trim Tab attempt was ruined thanks to Van's bad sense of humor with the procedure of bending the side flaps, I decided to go for the highly debated riblet method. Here is my procedure to all of you who look for an easy (yet not so quick) way to do it with beautiful end results.
I'm building an RV-8, but I believe the same principle applies to most models.
, DO NOT, under ANY circumstance cut the flaps until you are DEAD SURE you know what you are doing and have measured everything and also have the riblets fabricated and ready to fit. If you have already trimmed the little buggers, there may still be a solution.
I-Miguel Vidal (mvidalr), Van's Airforce Forum, website, webmaster, and owners will NOT be held responsible for which ever way you may choose to use this information, its effects and its end results.
Like all boring disclaimers: This is for informational purposes only.
You build your airplane at YOUR OWN RISK.
If you agree, then read on..
I mentioned it is an easy way, yet not so quick because you have to order 3 E-703 Elevator End Ribs
(or which ever similar end rib uses your Elevator). One for the Inboard and one for the outboard sections of E-619-1-020 Trim Tab, and the third one for the inboard of the Trim Tab on the Elevator side.
Here's a visual representation of what I did:
Measure and cut each rib's tip to its final size. It is always better to cut more than the minimum, in case of any screwup.
The same goes for the Trim Tab and Elevator Skin Flaps
Deburr edges and corners.
Measure the distance where the rivet holes will be drilled. Minimum edge (margin) distance is important here, so measure according to a reliable reference, such as MIL-R-49196A.
Draw the rivet line and rivet-to-rivet distance separation (pitch) (remember to measure from rivet center)
Drill the rivet holes on the skin first. These will later be used as pilot holes to drill the riblet's rivet holes.
If you decide to attach the riblet to any Spar and it's holes (highly advisable), you will have to bend both riblet flanges and drill a relief hole for each of the bends.
Finished machining of one of the riblets. This one attaches one flange to a spar, as you can see there is only one bend. An extra 1/8" hole was also drilled at the center of the riblet web. It's used to attach a 1/8" cleco which will serve as a grip to handle and move the riblet in place.
Next thing is to position the riblet in place and hold it secure with cleco clamps. Drill/match-drill the rivet holes.
(picture taken BEFORE the relief bend and hole) It certainly looks good!
You then need to deburr and dimple the edges and holes, and prime as required and as usual.
And begin final fitting and installation.
Where regular solid rivets are hard to squeeze, Life saving MK-319-BS or CS4-4 blind rivets can be used.
Sorry for the HUUUGE pics..
I really hope you find this information useful.
Always remember: Safety First!