Joshua's RV-9A Project

Drilled the holes to size on all the firewall parts, then disassembled for deburring and countersinking.  Fabricated a new fuel pump doubler plate when I accidentally countersunk the wrong side of the platenut attach holes — the flush heads go on the aft side of the firewall, opposite the rest of the rivets on this piece.  (This is so the fuel pump can sit flat against the aft face of the plate.)  Deburred/countersunk all edges and holes of the smaller pieces, leaving just the firewall and recess to deal with.  Deburring the stainless looks like a chore.

Spent a few hours before work today in the shop, and completed fabrication of the various angles and doublers that are needed in the firewall assembly.  There’s some pretty hefty angle to chop up in this step.  I may try to get components done up through the bulkheads, and then have one big priming session…though the progress of riveting something, like the firewall, would be a good motivator.

Working with the firewall has me contemplating the recent thread on VAF about firewall insulation; one of the guys is a proponent of engine-side insulation to protect the aluminum components, but I wonder if it’s really necessary–how many RV’s have had in-flight engine fires, and of those who have, how many were hot & long enough to melt the aluminum rivets and cause the firewall assembly to fail?  Before this most recent thread twist, I was thinking of using the ceramic sheets/blankets with some sort of tabs or sheets to hold them in place, on the cabin side, since a flame-thrower test showed that solution to be effective for occupant protection.  Some anecdotes also suggest not insulating the FW at all, since the heat from normal ops helps heat the cabin in cooler climates.  What do production aircraft do?  Much to ponder.

Started to putz with the fuselage by laying out the firewall and clecoing the various angles, stiffeners, and such in place.  Some searching was necessary to find all the little bits, and I’ll have some doublers, angles, and reinforcing plates to fabricate.  I’m thinking that I will install the fuel pump doubler plate, even though I plan an injected engine–one can never tell what the future might hold, so best to be prepared.

Some odds and ends on the ailerons…put torque-seal on the bracket bolts, short pushrod ends, and put the ailerons back on the wings for safe-keeping.  Spent some time tidying the shop as well.  Still haven’t primed the long pushrod parts, as it’s been an insanely busy week.

Prepped the long aileron pushrods for primer, along with touching up spots on the wing needed to be spot-primed after assembly.  Greased and installed the aileron bellcranks; torqued the bracket-spar bolts, and the pivot bolts.  Also replaced the 4 bolts on each aileron that may have been overtorqued with fresh bolts & nuts.  The removed ones showed no signs of distress, but better to be sure than wondering when it comes to control surfaces.

Pulled in the wing conduits; a painless–if rather loud–process.

No real work on the project today (a large portion of which was dedicated to a choir “retreat”), but I did research and order some parts.  Various hardware parts (bolts, nuts, washers, etc) from Van’s, and a couple tubes of grease (Aeroshell 33, billed as a “universal airframe grease” good to -100*F; and Aeroshell 22, which is listed for use in stuff like wheel bearings; full catalog of Aeroshell greases) from Skygeek.

Spent some time monkeying with the internal workings of the wing.  Reamed the bellcrank bushings and turned them down to the proper length, then assembled both bellcranks.  Some of the bolts that came with the autopilot servo install kit are too short, so it looks like I will need to order a few longer bolts…add to the list.  I also need to look up what an appropriate grease is for the bellcrank bushings–the manual says “your favorite multipurpose grease.”  The stuff I have says it is rated to -20F.  Presumably, the possibility exists that the thing could be colder than that at altitude, so is it appropriate?  (Of course, my truck is lubed with the same stuff, and has worked fine in temps colder than -20F…)  I’m sure there’s a common aviation grease of some sort for this purpose, too.

Cut and drilled the pushrods, making them a bit longer than plans, as I’ve heard of some people wishing they had, when they had a hard time obtaining the required amount of thread engagement on the rod ends.  After dosing the insides with primer, I assembled the short steel pushrods (riveted per plans), but the longer aluminum ones still need to be primed & riveted.  Also had a bugger of a time locating the jam nuts for the rod ends (hint: look in the bag marked “spar bolts & misc”).

Temporarily put the bellcranks in the wings (I didn’t realize before that the bellcrank brackets had to come out, as the center bolt is too long to insert with the bellcrank in position.) and set the pushrod length using the straightedge aligned with the tooling holes and the bellcrank alignment tool.  I’ll have to get the protractor out and see if there is enough aileron travel the way it is, or if the spar pushrod holes need to be relieved to allow more clearance; the pushrod swings up/down and in/out as it moves through its travel.

Finished up the riveting of the left flap by attaching the bottom skin and squeezing the trailing edge.  After checking for twist (all looks good), hung the flap on the wing.  Flaps are done!

Fit the top skin and leading edge skins to the left flap, and riveted them in place.  Made a couple light smilies when I lost track of the gun during the vertical riveting.  Sigh…but no big deal.

Tonight’s session also saw the passing of the 500-hour mark on the build.  It doesn’t seem like that much time, but I have been working on the project for over two years (I started in earnest in May, 2007).  This means I’m somewhere between 1/4 and 1/3 of the way done, based on hours.  So, 4-6 more years?