Friday, April 17, 2015

First Start!

Big Day!  Finally got the electronics on-line and the engine started!

After meeting with Brent (EAA Tech Counselor), my next expert resource is Shane, the A&P who owns/operates the shop at KDLZ.  He’s pretty comfortable with Rotax engines and is listed as a Rotax Mechanic by their website.  I’ve known Shane for about 8 years and called him up for a favor of looking everything over before I put my engine to the test. I had to work fast to get things ready for his arrival, since our mutual schedules didn’t work out that well and we only had one day in April that worked for both of us.  (That came to bite me later, as I found out that I wasn’t as ready as I thought I was.)  Anyway,  he was game and spent a Saturday afternoon with me.  Like Brent, he was pretty pleased with what he saw.  I learned a bunch of little tips that were really one of the reasons I invited him over.  After we were done inspecting everything, it was time to try to get to work. Unfortunately, it didn’t work out that particular day.  (Bummer for Shane.)


IMG 4184

First Power to Avionics

The picture above shows the Skyview computer powered up for the first time.  The center panel is OK and correctly identifies our location (GPS is working).  The right panel is X’ed out because the ADAHRS isn’t even attached (it’s in the tail cone.)  The unpleasant surprise is the left panel, which is supposed to be showing me the engine gauges.  The help message isn’t particularly helpful at this stage: ‘Please review the “Getting Started” section of the installation guide.”    Shane & I reluctantly decided to quit here since there was no way I was going to start the engine w/o some gauges.

 That night, I finally found the page I needed in the installation guide and was able to do the configuration needed to get the electronics to recognize each other.

IMG 4185

Skyview with Engine Monitor & ADAHRS

This is a much nicer thing to see.  The engine monitor is on the left and shows what you would expect for a non-running engine.  (I found the loose wire for the R EGT.)

The next step was to get the engine oiled properly.  I tried hand turning the prop as suggested by Shane and even did a no-plug quick spin of the engine with the starter, but no pressure.  Back to the books.  The Rotax manual is even less inviting and readable than the Skyview.  I eventually found the page that directed me to remove the engine-to-tank hose and pressurize the oil reservoir while hand turning the prop until oil pressure registered.  Stacey held fingers on the appropriate outlets, Nick watched the oil pressure gauge and I hand turned the prop, but no joy.  The next day I found an oil puddle under the radiator.  Initially, that was bad news.  Then I thought about it and realized that it meant I had been successful in getting oil through the system.  I tightened up the errant connection.

I brought the plane out into the driveway and facing into the cul-de-sac.  One quick spin w/o plugs and oil pressure promptly climbed to about 45 psi.  Now we’re cookin’!   Spark plugs got installed and I tried to start it 3 times before realizing that this isn’t a Cessna.  In every other plane I’ve flown, the key switch is designed so that you have both mags enabled before you can get to the Start position.  Not so here.  I ground the starter 3 times before I realized that I hadn’t turned on the Ignition A and Ignition B switches.  (Note to self:  use your checklists!).

With that little bit of understanding, I made one more attempt at starting and....  Viola!   As you can see on the link, the engine started immediately and ran great.  I ran it a total of 3 min or so.  EGT’s, then oil, then CHT’s started to register as I played with throttle & choke a bit.  As an experiment, I pulled the emergency fuel cutoff valve in the cockpit and I think it took about 45 sec for the fuel pressure to fall to critical and the engine to start running rough, at which point I cut it off with the ignition switches.   There was a little roughness at ~3000 RPM, and I expect that that will smooth out when I do the carb synchronization procedure.  For now, I couldn’t be happier.

IMG 4191

Ready to Run

Wednesday, April 8, 2015

EAA Tech Counselor Vist #4

Back on March 28th, I had a very nice morning with a Tech Counselor from EAA.  Brent came over at the recommendation of my previous inspector, Bob.  Bob was tied up with other projects and felt that it would be more efficient to bring in Brent.  In addition, “the more eyes, the better”.  Brent works at NetJets and has built his own RV and is active at the DLZ Van’s flying group.  

Overall, he seemed quite pleased with my project and gave me “thumbs up” with the following write up. 


"David’s RV-12 is coming along very nicely. He is approximately 85% complete. He has installed and tested avionics, installed -but not tested-his FWF. Wings, empennage, and canopy are complete, but uninstalled as the aircraft is still at home in his garage. The level of craftsmanship is very high, especially for a first-time builder. There were no items of concern. The only constructive criticism was a couple of cotter pins installed bent improperly  on castle nuts. I'm looking forward to seeing the airplane again prior to flight, but at this stage I have no concerns that this airplane will turn out very nice."


Quite frankly, I’m surprised that he feels my workmanship is of good quality.  I look at every scratch or ding and feel like I’m just a hack.  OK, that’s enough beating myself up.  I’ll take the compliment.

Saturday, April 4, 2015

problem with Cowl vs Spinner

As mentioned several posts ago, I’m really pushing toward 1st start.  To that end, the prop needs to be attached.  Last night I spent about an hour figuring out the installation process.  The Book states to refer to the Sensenich manual, but that manual isn’t really applicable to the RV-12.  I finally figured it out, but discovered a Problem.

The photos below show the spinner backing plate rubbing against the cowl.  According to posts on VAF, there should be about 1/8” clearance, but I may be as much as 1/16” overlapped instead.  You can also see that the spinner plate is ~1/4” too high relative to the upper cowl.  I’ve got an email out to Support@vans and have posted these pics on VAF.

That discovery left me in a bit of a funk last night, but sleeping always helps.  I decided to press forward with the engine start, probably sans cowl (or at least, without the backing plate) for now.   The A&P from my airport does a lot of work with Rotax engines, and he’s agreed to come over to the house and give my project a review from an engine point of view. We might try to start it tomorrow.  Stay tuned.


IMG 4181


IMG 4182



May 26th

Time for an update, and it’s mostly all good news.  Ever since I found this mismatch between the cowlings and the prop plate, I’ve been slowly creeping up on a solution.  It was pretty obvious from the start that the cowl (I’m going to use the generic singular to refer to both the upper and lower portions) was too long.  That wasn’t good, as it meant that I’d have to remove the hinges and sand away the excess to re-align things.  I was pleased to note that it wasn’t short, as that’s an entirely different solution—buy  >$1000 of new fiberglass parts and start over!

I have noticed that I really drag my feet when it comes to doing re-work as opposed to new assembly.  This is especially true when I can foresee a problem for which I don’t have a solution.   I could shorten the cowl to fit by sanding and re-installing the hinges, but I couldn’t figure out what to do about the radiator tunnel.  When I finally got the cowl to fit, I had shortened it back by about 1/8”, and that’s roughly the thickness of the lip to which the gasket seal is placed to provide an air tight fit between the cooling duct and radiator.  I am very leery of re-gluing the duct seal back on because then it’s going to be too close to the radiator and will have a much higher spring-back force than ever before (and I think it was just barely acceptable before I trimmed the cowl.)   If I sanded back the face by 1/8”, there would be no face left upon which to glue the gasket seal.  

I finally figured out a solution:  mix up thickened epoxy and add to the back of the lip so that there’s something remaining after I sand away 1/8”.  I added blue food coloring to the epoxy  mixture (it turns pink, but then back to blue when it cures) and glopped it on the back of the lip.  The picture below shows the inside of the cooling duct lip with blue (previous application) and pink (wet) flox/epoxy on the inside lip.  Photo #2 is a bit farther back so you can get oriented as to where the close up is located.

IMG 4322

Close up of cooling duct lip build-up of epoxy



IMG 4321

cooling duct lip w/ epoxy build-up


The next time I get to the shop I will sand down the lip until I get to the blue/pink epoxy (thus having removed 1/8”) and re-attach the duct seal.  When that cures, I should have a finished cowl that fits!  Stay tuned.




Next time I say that “I will sand down the lip until...”  just remind me that it’s not so easy.  It was about 2 hours of sanding with a dremel drum to get down to the blue (pictured below).  I verified that I could get the 1/4” cardboard spacer in between the radiator and the lip of the cooling duct.  Shortly after this picture was taken, I started reattaching the duct seal.


IMG 4328

“new” surface of cooling duct lip





Finally.  It’s done.  After sanding down to the blue flox, I reattached the original rubber seal, let it cure and finally reattached the cowling.  It’s not an easy fit, and there’s a bit of a gap on the L lateral seam.  It’s also pretty ugly with the visible marker on the inside of the cowl and obvious drips of the epoxy.  It was also nearly impossible to get the top cowling pins in place, and they definitely require more “oomph” than they should (IMHO.)  I have to use a pair of pliers to get a firm enough grip to install / remove them.

I’m too impatient to redo the cowling this year, but I may bite the bullet and buy a whole new fiberglass assembly for the front end next winter.  For now, it’s flight worthy.

IMG 4334

Front End, fully assembled.

49-19 cooling shroud duct

A bit of a tight fit, but nothing unusual for this page.  Trim the SCAT tube to 11”, attach to the appropriate spots with clamps.  

IMG 4179

Cooling Shroud Duct

49-15 Cowl Duct Seal

Around the time that I was done with the control cables, the RTV holding the duct seal had cured enough for me to unclamp it.  Actually, I had to install the seal in two steps as I didn’t have enough small clamps to do it all at once. 


IMG 4178

duct seal

50-06 Choke Cable to Carb

And this picture shows the left carb with its choke cable connected.  The interesting tidbit about the cable connections was the final trimming.  A pair of diagonal cutters was totally worthless.  I went back to my recently-nominated-as-favorite tool—the dremel, this time armed with the cutting disk.  The resulting shower of sparks told me that I had been attempting to cut steel wires.  The Book offers the option of heat shrinking or soldering the ends to prevent fraying.  My 30 W soldering pencil wasn’t up to the task of heating, so I have a 70 W gun in the garage and will try it again later.

IMG 4176

Choke Cable

50-05 throttle cable attach

here we see the right carb with its throttle cable attached.  I have also replaced the throttle springs with the replacements sent directly by Van’s, in lieu of the ones packaged with the cable, which in turn were supposed to be in lieu of the ones from the factory.


IMG 4173

Throttle cable connected to Carb

50-04 control cable routing

Another page that was deceptively straightforward, yet painful.  This time, I had experience to know that in advance...   I’ve really come to despise the doubled cushion clamp technique for routing things around the engine mounts.  This one was in a hard-to-reach spot and I couldn’t use my regular needle nose pliers to hold everything together in order to fit the bolt.  I had a vague memory of reading about using safety wire, so I gave that try and it worked very well.  I looped safety wire around the larger cushion clamp and used the twist-pull action to tighten the wire, thus the clamp, enough to get it to accept the bolt.  The smaller clamp was not too difficult to close by hand (finger) pressure.  Another trick to file away for use again.

IMG 4167

routing control cables

50-03 control cable supports

I knew this would be trouble when I read about it.  The control cables are supported by cushion clamps.  There’s a layer of thick rubber made from a scrap of cooling hose.  (I think it’s to keep the axis of the control roughly centered with the knob itself.)  It’s impossible for me to contort myself to be able to get under the panel and work, so these were installed (and photographed!) blindly.   

IMG 4165

upside down view of control cable supports

50-02 Throttle & Choke controls

A little more creative problem solving here.  The factory upgraded the throttle controls and now are shipping vernier versions instead of the simpler push-pulls.  When I was preparing for this step, I experimented with then throttle and promptly discovered that it comes apart when you pull it too far.  Six oblong steel bearings fell out.  I was ready to ship the thing back to MacFarlane Aviation for re-assembly, but they reassured me it was actually easy to take care of myself and pointed me to a nice YouTube that demonstrated the process.  Wonderful!

Upon reading closely, I discovered that the vernier throttle requires a 3/4” hole, but the panel only has a 1/2” hole.  There’s room to simply drill it larger with a step drill, but that doesn’t leave room for turning the nut behind the panel to secure the throttle.  The Book has you grind a flat spot on the lock washer and turn the throttle into the fixed nut, but that will scape up the paint.  The Book then helpfully suggests that you remove the panel.  Not Going To Happen.

Instead, I made a 3/4” hole in scrap aluminum, then suspended that over a dowel (cap from the Sharpie) and traced a 3/4” hole that was tangent at the top relative to the 1/2” in the panel.  Some ginger work with a dremel drum enlarged the hole in a downward (and lateral) fashion to approximately the right size, then finished it off with a step drill.  Viola!  A properly sized hole that is far enough away from the under panel to permit ordinary installation. 


IMG 4163

Throttle & Choke controls

49-14 bonding cooling duct

This was another new experience that I had been putting off for about a year—working with wet fiberglass.  I purchased a fiberglass “beginner’s kit” from Aircraft Spruce last year when I realized that I would need to do some epoxy work on the wing tip lights (still not done, BTW.)  I read & read & studied, and it went very well.  I didn’t get any pictures of the wet layup of the cooling duct inside the cowl because I forgot to snap them before installing the cowls on the plane while the epoxy cured.  The representative photo that you see below is looking at the duct bonded to the lower bowl’s “mouth” after I used a touch of floxed epoxy to fill in the transition.  It went really well and did not take much at all.  The Book said to use bondo if there was a small crack, but I didn’t want to go out and buy bondo when I had perfectly good floxed epoxy sitting in the freezer from the night before.


IMG 4159

Cowl to duct interface


IMG 4161

final touch!

49-16 heat shield

I’d like to make a public service announcement.  Nothing sticks to rough fiberglass, even if you rough it up first.  The thick Al foil heat shield had a pressure sensitive backing, but it just didn’t stick.  The Book has a final comment of “seal the edges” with epoxy, and mine looks like a 1st grader doing his first finger painting.  

IMG 4157

Heat Shield in place

37-09 Fuel Tank install

Continuing the thread of logic...  In order to start the engine, I need gas.  In order to get gas, I have to install the tank.  The tank can’t go in until the floor plates and back bulkhead are attached.  Unfortunately, I’ll have to take out the tank and the bulkhead when I attach the tail cone, but there’s no way to avoid that.  (Until after I get signed off, then I’ll do the bulkhead modification that will let me remove it in pieces—one piece stays in place unless the tank is removed, but the majority can be removed independently.

Since I purchased the tank pre-assembled, I didn’t have to go through the entire construction process (with all of the Pro-Seal to deal with.)  I didn’t really find a page that said “install tank”, but 37-09 seemed to have the closest instruction. 

Oh, yes.  In order to get the tank in, you have to remove the ELT, too.

Oh, and one more thing.  There’s a nut plate on the vertical rib behind the tank.  It was put on wrong side so it got drilled out and repositioned.  I’m getting better.  It didn’t take more than 10 min and I didn’t even say any bad words! ;0)

IMG 4155

installed Fuel Tank, et al.

33-02 Seats pans, belts

I had an EAA tech inspection last week, and it went very well.  (I haven’t got the report back yet, but will publish it as soon as I receive it.)  All of the sudden, I realized that I’m in the end game and it’s time to start buttoning up loose ends—literally.  I want to try to get the engine started this month, so I decided to get all of the “little things” done that are required.  For instance, I have to have a place to sit so I can hold the brakes.  In order to sit, I must have the seat pans installed.  That requires putting in the seat belts, etc., etc.  The next several pages are in a similar vein.


IMG 4153

Seat Pans & Seat Belts