Monday, November 24, 2014

Seats!

No page number associated with this page, just a happy smile.  I received the seats & carpet kits several weeks ago, but today was the first day that I had a real urge to unwrap them and take a good look.  They’re certainly not needed at this point, but it was a nice way to spend 30 minutes.  I’m planning on installing a bit more hardware for the rudder cables and elevator cables, then routing the cables to the baggage bay.  After that, I’ll lay in the covers for the floors and tunnel to keep out any loose objects (Foreign Objects, in both medical and military parlance).  Those will just be held in with one or two screws, and left in blue until their final installation.  

 

IMG 3792

Seats


32-10 final drilling Torque Tubes

One of the simpler jobs complicated only by the fact that you have to disassemble things to get to it.  In this case, I needed to remove the torque transfer arms (visible as the brighter white in the photos) in order to finish drilling them for the bolts. Got them out, drilled everything, put them back in, installed the new Torque Tubes.  Not bad at all.  It gave me a pleasant morning in a chill, but workable garage to just be one with the building process.

 

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Torque Arm bolted to Torque Tube

 

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Torque Tube outside of skin

 

Friday, November 21, 2014

32-09 Torque Tube prep (attaching wings)

Wheee!  This was a fun day, as I got to install the wings and look at my beautiful bird coming together!  I had the assistance of Nick and Nick (son & son-in-law).  The whole point of the day was to get the fuselage out of the garage, attach the wings, line up the two components of the torque tubes and match drill 2 holes on each side.  Like many things, the day was full of challenges that made it fun.  As you can see in the pictures, it was a cold day—about 20 °F.  (BTW, yesterday, it only took my frozen fingers about 2 hours to remove the gas tank fitting so I could have access to the R torque tubes.)   I worked 3rd shift last night and woke at 3:00 this afternoon to get this done before it got dark and (too) cold around 5:00 or so.  Advice:  if you are in a hurry, stop and reschedule so you aren’t in a hurry.  

Big Nick was granted a few hours of ‘guy time’ by his fiancĂ© and helped me out.  First thing we did was scrounge in the garage to find some 1/8” shims to put a measured amount of droop in the flappers.  (Discussion on VAF about how the wing was designed for the flapperons to be neutral in flight, but wind loads force them up just a tad into a reflexed position, so The Book has you install them with 1/8” droop to allow the wind loads to put them in neutral in flight.)  Then we chiseled and shoveled layers of sheet ice off of the driveway so we weren’t guaranteed to slip and fall.  I maneuvered the plane out and into the driveway, then Big Nick & I maneuvered the wings into the plane while Nick guided the flaperon activation tab into the appropriate slots of the torque tubes.

I then noticed The Book calls for a 0.063” shim to be placed between the inner and outer torque tubes.  Argh!  I really should stop working and sleeping so I can do a better job of reading ahead.  A few moment of rummaging around in the garage revealed that the hinge material was very nicely dimensioned to be the long strip of 0.063” shim.  A quick pass with the bandsaw to remove the eyelets and we were ready to go.

I didn’t even take any pictures of the actual drilling of the torque tubes.  This photos on this page are really all about the fact that I got to see the wings and the gear on the fuselage.  (All it needs is a tail section, the canopy, an engine with prop & cowling.  Sigh....)

 

IMG 3477

Aft view of 012 with wings and wheels, in the driveway


IMG 7603

3/4 frontal view 

My beautiful bride snapped this from the front door.  You can see the main gear still has some camber, and the nose wheel looks way to far forward without the engine.  The turtleneck is still sheathed in blue, as it’s only held with cleco’s and no rivets.  From here, the wings good perfectly smooth and ready to lift!  (The roses didn’t do so well in the snow fall, however.)

35-06 #4 / SB 12-09-26

 

It’s a bit fuzzy but, you can see two holes on the edge of the riveted skin; the one on the left is open, the right has a 3/8” metal plug installed.  These are the holes that weren’t there.  I did a bit of research and memory dredging and recalled that there was a Service Bulletin about re-checking the torques on the landing gear bolts due to some cracks.  The inboard bolts can be access through the access holes in the belly, but the outboard bolts aren’t accessible.  The SB says to drill some 3/8” holes.  The holes are too small to get a socket through, but you can pass a socket wrench extension through them, attach the socket via the access holes and thence proceed to check or re-torque the outboard bolts.  Pretty simple, eh?

Whenever you see that something is “pretty simple” you know that there’s going to be a catch.  in this case, it was finding the darn metal plugs.  my usual technique of ordering directly from Van’s didn’t work, as the part doesn’t appear to exist on their master order form.  I’ve had this happen a couple of times in the past, as their system is a static parts list of what they sell—it’s not a live database of everything they actually have.  OK, on to Home Depot.  A quick computer search verified that these were items that they had listed and actually had in stock.  They lied.  Turns out that the local Home Depot store was in the process of doing inventory in that isle, so they’ll probably figure out that that little drawer was empty.  OK, on the next not-quite-local Home Depot.  Better; they had 3 (but not 4) of these 3/8” plugs.  While I was there, I grabbed a 3/4” plug for the hole that is under the mixer’s main bolt & cotter pin.  Last stop: Lowe’s for the 4th small plug.  After that, it was pretty simple.

 

IMG 3780

 

Access Holes for SB 12-09-26 

 

35-06 (except #4) finishing caliper brake lines

Here’s the final page of the brake line installation.  I was also able to install the final baggage corner skins as well as the brake cover plates.  I’m planning on drilling the flaperon torque tubes later this week, so the corner skins have to go on now.  The Book calls for them to be installed after the tail cone goes on, but I’ve been shown that it’s possible to get the overlaps correct even if I go out of sequence.  (I think standing on a stable surface and looking right at the torque tubes will be much better than trying to crawl into a completed airframe and drilling at a weird angle.)

The brake caliper lines were placed on the trailing edges of the main gear legs last page: this page just tweaked their placement and secured the anti-abrasion sleeves that I had previously installed. 

The only step that wasn’t completed was #4, which calls for installing some sheet metal plugs in the access holes on the bottom of the fuselage.  Just two problems—I didn’t receive any sheet metal plugs and there aren’t any access holes!  Stay tuned...

IMG 3778

Brake Caliper Lines tie wrapped in place

Saturday, November 15, 2014

35-05 caliper brake lines

Only a little bit of trepidation with this page.  For some reason, I’m just not comfortable working with tubing.  I managed to ruin one segment when I put too much of a bend on it without realizing that the collar had migrated proximal to the bend. No matter what I tried to straighten out the segment, I couldn’t get the collar back into position.  I was quite pleasantly surprised to find that I had sufficient AT0-032x0.25 to make another caliper brake line.  It’s almost like the folks in Oregon kind of expected that not all of us would get it right on the first time!

I also took the liberty of sliding the protective clear tubing over the brake lines on this page, rather than slitting them and placing them over the finished brake lines after they were installed (as called out on the next page.)

 

IMG 3774

Brake Lines at Inboard Gear Attach Bracket

I didn’t realize it when I took this picture, but it’s a pretty good match for the detail view drawn out on page 35-05.  We are looking straight up (through an access plate) into the bottom of the main channel.  The wedge shaped structure on the bottom is the tapered main gear leg.  You can see the AN4 and AN6 nuts holding things together. On the upper side of the Inboard Main Gear Attach Bracket you can see the main brake line terminating in a brass fitting; on the lower side is the just-installed caliper brake line terminated with the blue anodized AN hardware.

 

 

IMG 3775

Caliper Brake Line looping around Main Gear Leg

I really like this picture.  I managed to substantially dim the flash with my fat finger, but the effect was excellent for highlighting the key point in image.  I’m also really surprised that I was able to make this structure at all, much less make it look nice & professional.

Wednesday, November 12, 2014

52-02 & 52-04 Tow Bar

My timing worked out perfectly in this case.  Once I committed to putting the plane on its gear, I would no longer have the convenience of the mobile platform I built with the castoring wheels, thus mobility in the garage would be a bit of a challenge.  I ordered the tow bar / parking brake kit last week, and it arrived the day I finished the nose gear.

As part of the ‘build-ahead’ motivation described earlier, I elected to do some fairing pre-work on the nose gear fork prior to installing it.   (The instructions in section 36 require removing not only the tire/wheel, but also the nose fork, so I did some work prior to its installation.)   It turns out that I would have had to remove the fork in order to insert the bolts & washers that the tow handle uses, so that was already done.)

Page 52-03 describes how to measure & modify the handle so that it can be used as an ersatz parking brake. It’s quite ingenious, really.  The handle is used to put pressure on the brake pedals and is then wedged into the structure beneath the seat.  In order to make the proper measurements and drill, I have to have the brake system completed and filled with fluid, so that page will be deferred.  For now, I have a proper way of maneuvering the plane in/out & around the garage.

IMG 3767

Tow Bar

35-07 (x #7) Nose Gear

Major Milestone!  The airplane is now standing on it’s own 3 wheels!   This was a pretty easy page, with nuts & bolts and tapping and wrenching, but nothing magic.  I was a touch concerned at first that upon dry fitting, the upper portion of the nose gear weldment didn’t match up to the engine mounting brackets.  Needless to say, when you tighten up 13 bolts and have the plane resting on the gear instead of the gear hanging down, things matched up nicely.

 

IMG 3762

Nose Gear Assembly

IMG 3764

Standing on her own!


IMG 3765

positive camber on main gear

Like the concern that things weren’t aligning properly with the nose gear weldment, my eye doesn’t like the amount of camber that I see here on the main gear.  On the other hand, the plane isn’t finished and is severely underweight.  I expect that there will be a much lower camber value when it’s completely assembled and loaded with pilots & fuel.

35-04 Main Gear & Brakes

Figuring out how to install the brakes was a moderate challenge. On two occasions I started taking apart things that Shouldn’t Be Taken Apart, but I didn’t do any damage.  It was pretty straight forward after I got through the mental imagery of what attached to where.

 

IMG 3745

front view of L Main Gear

IMG 3746

aft view of R Main Gear w/ Brake

In this aft view, you can see the fitting for the brake line and the shoes on the rear aspect of the disk.  You can also see the re-attached fairing support and clearly see why it had to be removed in order to put on the brakes.  Live & learn.  (If I ever build another RV-12, it’ll be a lot easier to spot the redundant assemble-disassemble-reassemble sequences.)

36-05 Gear Fairing Hardware

As mentioned in the previous post, I do try to read forward in The Book to identify places where I can avoid re-work.  Here’s an example of getting some of it.  I had read that it’s a good idea to install a bracket for the gear fairings when installing the main gear, as you have to remove the tire.  It turns out that you have to remove the entire axle as well.  Here’s the axle with an adaptor bracket on the inside edge of the gear.  That, in turn, supports a mounting bracket that will be used to support the fairings.  I installed it because it allowed me to check off this page as complete.  I was very proud of the fact that I got the adaptor bracket in place before I mounted the tire.  On the other hand, I promptly had to remove the fairing bracket to install the brakes...  Like I said, I got to avoid some of the rework...

 

IMG 3742

35-03 Main Legs

I actually got a lot done in 2 working days.  Probably one of the more physically demanding tasks was accomplished with the help of my son, Nick.  I thought I’d need the assistance of my future son-in-law, Nick, but Nick stepped up to the plate and did a great job of manipulating nuts, bolts and washers on the top of the main structure while I worked underneath and supported the gear legs and played with my own collection of nuts & bolts (not to mention the greased retaining plates!)

After we got both gear legs attached and snugged, I decided to do a bit extra.  The gear retaining hardware and wear plates were greased as per The Book.  I noted that most of the bolts had grease on them by the time they were laboriously fit through all of the hardware and I just have a bad feeling about putting lubricants on devices that are designed to hold together by friction.  Much to Nick’s dismay, we removed each & every nut & bolt (except for the AN6’s that were recalcitrant) and cleaned off all of the grease with some isopropyl alcohol.  (The AN6’s were cleaned in situ.) 

I then had the opportunity to use my brand new “big” torque wrench.  The one that was recommended for the kit was not capable of reaching the specified torques for the AN6 hardware.  I made an estimate of the prevailing torque for the nuts, for the rotation of the bolt and ended up using a final torque of 20 ft-lbs.

 

IMG 3739

Main Gear Leg

 

IMG 3740

Attachments of Main Gear Legs

A sharp eye may have noticed that the axles are already installed on the main gear legs, which isn’t actually called out for until the next page.  I tried to read pages coming up and stay ahead of the book, so to speak.  I was moderately successful in this case.  I elected to install the main axles and do the toe-in/toe-out check prior to torquing the main gear attachments.  My intention was that if there was a slight mis-alignment, there may be some room to “settle” things before tightening up. Much to my surprise, the axles are well aligned and do not require any “settling” or any shims to be added!  (I even looked at pre-purchasing a 1° and 0.5° shim just to have in my shop because I hate getting close to finishing a page, only to have to defer.  I discovered that the shims are about $20-30 each!  Not going to buy ‘em unless I need ‘em!)

The picture of the attachments shows the lacquer I use to visually assure myself that I used a torque wrench to set things.  The other nut is not visible due to the wiring conduit.  That had to be removed and replaced in order to finish this page.

Tuesday, November 4, 2014

EAA Tech Counselor Visit #3

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EAA Tech Inspection Form #3
Bob returned for his 3rd visit of my project.  He brought along a friend, Ken, who is a semi-retired helicopter pilot and is contemplating jumping into the RV building trade.  It turned an inspection into an opportunity to share my enthusiasm and tips with a "new recruit.”  It made the inspection process really fun, as I explored being “senior” to someone in this domain.  All in all, Bob had no significant adverse comments.  He made reference to getting very familiar with an FAA reference document on workmanship techniques.  I can’t recall it right off the bat, but will spend some time looking for it and adding it to my technical library.
“View fuselage assembly.  Project coming along very well. Discussed proper method of installing cotter pins.  Discussed future installation of avionics and engine. Already performed some fuel flow testing."
PS:  Bob just sent me the link for AC43-13-1B.

-----------------------------------------
Addendum 11/15/14
Hey Bob,
Just wanted to drop you a line.  You brought to my attention the orientation of a couple of bolts.  I was under the impression that The Book had called out for them to be inserted inverted, but I was mis-remembering a different location.  The blue oval encloses the correctly replaced bolts. The blue rectangle shows the ones that confused me.
Thanks again,
-dbh
IMG 3771
Repositioned bolts (annotated)