Fuselage: Fwd Mid Fuselage Side Structure. Vents.

I had the pleasure of installing the side vents twice.  The first attempt, on 8-Mar-16, failed because the method I chose to clamp them was ill-conceived and gravity, the ultimate downer, caused them to slide down.

Preparing the vents for match drilling.  Not shown is the later scuffing and painting of the vents.  As can be seen, I returned the stock plastic eyeball vents and upgraded to the expensive aluminum ones on advice of a friend with an RV-9A who has experience with both.  Apparently the former leak whilst the latter do not.

Here is the foolish methodology for clamping the vents when adhering them.  Don't do this.

As is visible, the vents slid down overnight, adhering themselves in the wrong locations.

So I had to pull the vents off and scrape the sealant off both the airframe and vents.  That took exactly 4 hours of scraping.

More than a year later, on 7-Apr-17, I engaged in a second attempt at adhering the vents.  This time I used high strength, rare earth magnets to keep them in place whilst the sealant cured.

They came out pretty good. You can also see that I chose to paint them black to keep with the red/black accents in my interior.

Right side.

Left side.

If you look closely at the interior shots, you can see where I painted with a brush some of the silver paint to cover up the scuffed areas and the extraneous sealant.  Though those areas are obvious in the images due to the camera's flash, they aren't easily noticeable with one's eyes.

As a side note, the plans call for using silicone to adhere the vents.  I chose to use sealant.  And based on how exceedingly difficult it was to remove the vents when I originally placed them, I am entirely confident that they are staying put with sealant.

Fuselage: Forward mid fuselage side structure. Completed.

I believe Section 29 encompassed some 80+ hours of work.  40 of which were with help.  There are a lot of rivets, which in itself isn't an issue, however many of the rivets are in hard-to-access places and in many cases bolts and other things need to be removed and later reattached.  A few rivet lengths in the plans were too short.  Always keep the rivet gauge handy.

The side skins get cleco'd on with the longerons.  At this stage, my aft empennage is just in the way.  I later turned it around to reduce its footprint.

Riveting progresses.  This marked the first time that the fuselage was "sat" in.  Below is the momentous occasion which happened to be captured by my time lapse camera setup.  That's my friend hopping in.  I have yet to sit in it. 

Something interesting happened that didn't become apparent until after-the-fact:  From this point on, we began referring to the build as "the plane".  For example, my friend now got "in and out of the plane" and we had to "move the plane around" to rivet, etc.  It was an interesting, purely psychological, maturation of the build.

This is prior to the center section channel, arm rests, roll bar base and associated gussets being installed.

I decided to paint the seat back brace red as I had paint left over from painting my rudder pedals.  It looks better when viewed from above.

Section 29 is done!  Well, except for one rivet holding a nutplate on the upper root faring attach angle.

Sometimes a little creativity helps you buck rivets.  Below is riveting the outboard-most AN470AD3-3.5 rivet joining F-01460-L intercostal to F-01422-L side rib.  Here we used a heavy bucking bar with hole drilled in to it to accept a standard rivet set.  With the gun holding a back-rivet set, hitting the rivet from below, the rivet was bucked.

Another point worthy of sharing is that I had neglected to chamfer the F-01461A-L/R roll bar angles (page 29-11, shown below left).  So when the seat back brace was placed (shown on above left picture), I couldn't get the 1/4" holes to line up (bottom right).  After wasting much time diagnosing this self-induced problem, a phone call to another builder exposed my oversight.  A quick application of a file fixed the issue.  I seem to never miss an opportunity to be humbled.

Fuselage: Cowl hinges. Length uncertainties.

An updated revision of the plans, Rev. 1, which was released on 5-May-15 by Van's, changed both the length of the hinge and the location of eyelets on FF-00006-L/R.  Below shows Rev. 0 on the left and Rev. 1 on the right.

The hinge fits in the location illustrated below.

I originally cut the hinge according to Rev. 0.  However, I was concerned that the location of the eyelets specified in Rev. 1 was critical.  So I bought new hinge (when I happened to be in Oregon last month and stopped by Van's for an over-the-counter purchase) and match drilled it to my original hinge (since I had already dimpled the firewall flange).

Upon sealing the firewall flange and riveting the shorter Rev. 1 hinge to the firewall and shim, I noticed that the hinge was too short to cover the entire length of the shim.  In fact, it was short by exactly one hole.  I decided to drill out my Rev. 1 hinge and replace it with the longer Rev. 0 hinge (which exactly matches the length of the F-14134B-L/R cowl hinge shim) plus, I removed an additional eyelet according to a recent post on VAF.

Here is a direct comparison of the Rev. 0 and 1 hinges relative to the shim.  Again, I removed an additional eyelet on the Rev. 0 hinge.  This is the one (white hinge below, now erroneously labeled "scrap") installed on my aircraft now.

The right side now looks like this.

In retrospect, looking at Section 35, Upper Forward Fuselage, I could have just lengthened the upper hinges by one hole as those hinges too have shims.  Oh well.

Fuselage: Forward mid fuselage side structures. Side skins ready.

Getting the side skins ready for install.

F-01470-L/R side skins get cleco'd for various match-drilling needs.

The F-01418A-L/R upper longerons get countersunk.  This is the left longeron.  The holes will need to be re-primed.  The lower longeron gets the same exercise (not shown).

The F-01485-L/R side plates get countersunk.

FF-00006B-L/R cowl hinges get countersunk.  See my later post for my thoughts on these hinges.

I back-riveted the side plates and F-01464-L/R to the side skins.  It's important to keep things clamped down lest the rivets find themselves prideful.  I used AN26AD4-7.5 instead of the -8s called for in the plans.  The -8s were too long and kept clenching over.  I also used AN426AD3-4 on the rivets holding the side plate to the skin rather than the called out -3.5 as I felt the latter were too short.

Fuselage: Forward mid fuselage side structure. Firewall wasn't straight. Now it is.

When the upper longerons are placed against the firewall (page 29-08), the upper engine mounts should lay flush against the firewall gussets F-1401L. The right side clearly did not. Only the lower inside corner of the engine mount made contact with the gusset. This meant that the engine mount wasn't straight relative to the firewall.

Looking from top, left on left and right on right.

Further inspection revealed that the two aluminum angles, F-01401D and F-01401J, that compose the upper C-channel of the firewall have a curve in them. They are not straight. A straight edge laid across the top of the firewall illustrates this curvature (convex with respect to the aft side).

A call to Van's yielded the suggestion that I use a bottle jack and 2x4s to take out the bow.  I lack the skills to make that happen (in fact, it's worth questioning whether I have any skills at all).  It turns out, another  builder of an RV-14A that I'm in touch with is a shop-master. He owns and operates a very well-equipped machine shop.  He very kindly came up with the following contraption to straighten the upper firewall C-channel.

It's a steel support bar with three points of contact on the firewall. Two are the upper engine bolt holes with Delron standoffs. The center point is just a thick threaded screw with its head cut off, placed in a Delron sleeve to prevent marring of the C-channel's surface. As that screw is advanced, it pushes the center of the C-channel, whilst the outside screws hold the C channel's edges back. Let's call this device the Clifflatron.  Here it is in place ready to do its dirty deed.

It took this much bow, about an inch at the center, to take out the firewall curvature!  And yes, this was not an easy to task to do only because I was waiting for the explosion of overstressed parts. 

And now the firewall is straight.  Left is pre-straightened. Right is post-straightened.

One would think that the issue with the engine mount is solved now that the firewall is straight.  It wasn't.  In fact, there was no change!  Left is pre-straightened. Right is post-straightened.  I can't explain it.

When the temporary 3/8” bolt is tightened, the gusset and angles deform a little bit and ultimately conform to the engine mount, closing the gap.  I've accepted this and moved on with the build.