Mid-Fuselage Bottom

Posted 11/19/2014

If there's one good thing to say about winter, it's that with cold weather arriving it gets easier to make time for digging into the new Fuselage kit!  As I start assembling, there are a few things that are clear to me.

1) There are a LOT of different parts to this kit.  Unlike the wings and tail, there are many many pieces and they are not intuitive as to what they are as you look at them.  I find it takes a lot more time to just FIND the piece that you are working on.  That said, it isn't taking very long into Section 26 before the crate gets fairly empty looking.

2) There is a LOT of deburring to do...much to the dismay of my minion crew.

3) I'm definitely finding that you have to beware of what you follow on the plans, unless you're a mindless drone who will install the exact avionics package they design around.

4) There are some things ahead that the builder will definitely need to modify and tweak...so when it comes to ordering the finishing kit, you'll have to look at the parts list before ordering.

5) There are some minor things that builders may run into with the construction where you may want some extra hardware, such as rivet callouts that may work better with other options.

For point #3, I'll give you an example.  I, like most everyone, installed the UAT cable in the tailcone.  At this point, however, we aren't even told what UAT they would intend to use.  So, will my cable work for what I plan to do?  I'm not so sure.  Another example:  In the drilling and dimpling of the bottom center skin, they have you drill a 9/16" hole.  Now, they don't tell you WHAT this hole is for, and without a complete wiring or finishing set of plans, it's left up to your imagination.  I believe that this hole is for an antenna.  But what kind of antenna is it? So knowing when to ignore or delay items on the plans is important, if you may be doing different avionics than they plan. I just believe that some things are being over-prepared for you. If you look at my previous update, you'll see the issues I find with the panel. Personally, I think they should have made the avionics wiring package completely separate from the airframe wiring package and made both packages optional, and offered just connector kits as an option.

Regarding #4, here is one highly important item for me:  Throttle Quadrant.  Van's apparently is not CURRENTLY planning to offer a throttle quadrant option for the RV-14. Now this may change, if every builder who wants one will email support@vansaircraft.com and use a subject like "RV14 Throttle Quadrant Request" or something like that.  It most certainly would be nice if they would design it in as an option, and I can tell you one area where it will definitely affect their plans....the fuse panel.  Van's put a fuse panel above the tunnel in the center below the panel.  If you do a quadrant, you'll likely have to change things around there too.  No worries for me, I think I'd want to change that a bit anyway...but be prepared to modify things, and on the quadrant, if they don't pull through for us, we're going to have to dig in and every RV-14 will be a custom job I'm sure.  Another area of concern is the wire routing.  As I build, I can see where they plan to route the wires, but I'm not sure if the capacity of the routes is going to be what I need or not.  I guess time will tell.

The cold weather got me motivated this year.  I had some roll-type double foil faced fairly high R-Value insulation around that I was going to use on the old hangar door years ago.  After last year's harsh winter though, and the ~$4.50/gal price of kerosene causing high heating expenses, I decided to use it in this garage.  The ceiling is only 7' high and I sealed the entire ceiling, making the heated space probably 60% the size of the space I had been heating.  The low ceiling traps the rising heat, making the garage much faster to heat up now.  I also bought a new Pro-Tech 7035 battery powered low level CO monitor to dedicate to this garage since I took my old one to the hangar.  It will only alarm at the normal UL listed levels, but it allows you to hit the button and see the current level.  Not wanting to die of something as dumb as CO poisoning, it was a good $70 investment.  I do find that with the smaller heated space, the heater kicks on more often, but for shorter periods, which does actually increase the CO levels.  A torpedo heater running hot doesn't make much CO.  But when they are warming up, and when they shut off, they do produce some.  So I'm now trying to change the way I heat the space...heating it up very warm, then turning it down and working until it starts to get chilly, and warming it back up hot again. That helps keep the CO low and give the heater a longer run time, with less cycling.

Lets continue on inline with the photos...

With the tailcone safely stored away (first 2 photos), and the wings gone (previous update), I finally had some garage space to work on the fuselage kit.  With my RV-10 build, I was able to stay with just 1/2 of a 2-car (22x24') garage for some of the initial build, but with the RV-14 I had 2 full work benches and quickly ran out of space.  The priming booth didn't make it easier, although it's set up in a pretty good way so it doesn't interfere much. The various spars and bulkheads are first, with no real surprises other than it gives the directions to use "Temporary" bolts and nuts in some places.  I don't know that it ever told me so far to install the permanent ones. My grade 8 bolts I had around fit very snug as temporary bolts for alignment though, so that was good, and I had non-locking nuts in my milspec hardware at the hangar, so it worked out.  It doesn't take too long to have the spar assemblies done.
Luckily I had some good help to keep the hole deburring moving, so I could do the edge deburring and get things built fairly quickly. You'll notice that on many areas, I've used the yellow Zinc Chromate primer.  The fuselage is kind of a pain when it comes to priming.  When doing wings and tail, you can prepare all of the parts, prime, and then assemble, all in one big process.  But with the fuselage, there are far too many breaks where you only work a few parts before you rivet them.  Nothing compares to the durability of the Akzo primer I use, but with a 30 minute induction time after mixing, it isn't at all convenient for keeping the process moving along.  So, while I was debating just NOT priming any of the Alclad parts, I have kind of recentered my plans a bit.  I use the Z.C. primer to do any non-alclad parts, especially areas where they mate.  Then I keep working.  And, when the time comes, I'll over spray the parts with Akzo after riveting.  Your coverage may not be perfect, but...  First of all, the Alclad parts aren't too likely to be a corrosion problem anyway.  Next, the worst corrosion worry for me would be rib to floor skin gaps, but I'm priming those gaps anyway.  So in the end, the Akzo that does get used (other than the skins) will just be "extra" primer.  It adds weight, so not priming everything has a benefit, but I do want to keep the floor and bottom of the ribs primed either way.
As I got to the under-seat ribs, I just kept going with the priming of the bottom of the ribs, and after preparing the baggage ribs and center section floor skin, it was a convenient time to spray primer again.  I didn't mix enough to do the seat ribs at this time, but I got all of the critical overlaps.  Next time I break out the primer I'll try to get the seat ribs coated a little too.
Working on the landing gear braces, I did find both a plans error, and a minor "gotcha".  First the gotcha.  They spend a lot of time for some reason, getting the vertical braces that tie into the seat ribs, aligned to exactly 90 degrees.  I personally found that just by inserting rivets into the 3 holes, mine were already lined up at 90 degrees.  The kicker is, once you rivet in F-01416 and F-01415, you will end up with a rivet underneath to the skin that you cannot buck any longer.  See in the 2nd and 3rd photo above...there's no way to buck that rivet.  It's an AN426AD4 rivet, and being that they used a heavy rivet there, I don't think a CS4-4 is a good replacement.  So, I'm going to use two of the CR3212-4-3 or CR3212-4-2 CherryMax rivets for those 2 locations (1 per side).  Then came the plans error.  If you notice in the 1st photo below, there is a rivet on that landing gear brace that calls out using an MK-319-BS rivet on each side.  This is definitely needed.  But look at the "DO NOT RIVET" callout on the last picture above.  Notice there are 4 holes listed...but on the 1st photo below, the next page in the plans, the "DO NOT RIVET" shaded area is including 5 holes.  So which is correct?  I don't currently know.  I filled the rivet in mine, not seeing the next plans page until it was too late. We'll see if I have to drill it out or not.  One other thing the plans don't you is that there are going to be two places that you'll be stuck using MK-319-BS rivets.  One I think is at the inboard forward end of the gear brace, on that next rib over.  So as you rivet, watch for that and maybe order a handful of extra MK-319-BS rivets to have on hand.
Riveting the skins on went very quickly.  We bridged the 2 workbenches with a pair of 2x4's and put the center section upside down.  With the help of my Rosie the Riveter Minion bucker, we had it done in short order.  And, a short time later we had the baggage ribs in place. One thing you will find as you build is there are clips on the sides of the center tunnel ribs where rudder cables and wiring will go.  I'm not sure if there will be enough conduit space for the wiring I plan to run forward.  It's tough to say at this point. But at least having the battery box on the firewall will mean no fat wires running aft.  Also, I think I will be adding an access panel under each seat before the seat pans are riveted in, for future access if needed.  It will also give better access to the wiring runs.  I may consider under-seat aux batteries, for centering them on the CG.  That's all for now, but this section comes together very quickly.

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