Step 14.4, First flight

When building an airplane one is cognizant of the fact that from the start, right up until it flies, it's just a pile of aluminum that is worth far less than what you've got into it.  The day that it actually takes flight is when the economic magic unfolds.  Your bottomless money pit with wings suddenly becomes just a very deep hole.  If one ignores the time value of money and figures his own labor at a generous, albeit negative rate (you pay to work), then one might suppose a modest increase in value on the investment.

However, no one with even a passing acquaintance with rational thinking would ever think of a project like this as an investment.  It is a monumental time sink and it is stupidly expensive.  It is also life changing by way of it being an impossibly long project that requires uncommon tenacity to complete.

But it is also a journey that very few will ever experience.  I am grateful that I have been given this opportunity.  Only another builder will ever really appreciate the finer points of the construction process -- the long hours of research, the gauntlet of problem-solving, and the logistical gymnastics required to keep the materials flowing in so that there is never, ever, a single day that progress stops for lack of inventory.   And then there's the solitude. Hundreds and hundreds of hours spent alone in the shop.  If you're the kind of person that favors social interaction, don't build an airplane.  Or, try to find ultra-reliable friends who quite mysteriously, have the same schedule of free time as yourself and who also want to build an airplane.

That is not to say that I built this plane by myself, far from it.  I had plenty of help from my wife Carolina.  She bucked most of the rivets in the wings and it was she that climbed into the tail cone to buck the top skin.  She braved the hazards of Pro Seal fuel tank sealant, one of the most obnoxious substances ever concocted by man.  Carol assembled many of the PC boards for our home built avionics and she did a lot of the plane's wiring.  Carol endured many hardships without (much) complaint, not the least of which was having to listen to me bitch about the wrongheaded way the kit does this, or why that doesn't fit. Never-the-less, whenever I needed some help I could always count on her to come down to the shop. 

Is it worth it?  Time will tell, but even if I never flew it I would still have gained a wealth of technical knowledge related to aviation, metallurgy, mechanical processes, and an advanced degree in profanity.  And above all, I would still have the sublime satisfaction of completion.

It is said that even the longest journey begins with a first step. So here are a couple of pictures from 2012 that remind us where this adventure began: The first kit I received from Van's aircraft as I initially saw it, delivered to my porch.  And a few weeks later, the very first rivet.

Flying day, 4 July 2016 :

In my mind, I had been planning this day for years.  Long before I even started building the airplane. Even before I started building the shop, to build the airplane.  Hardly a day passed without my having imagined how this day would unfold.

Behind computer screens, dozens of white lab-coated technicians with headsets would be controlling the flight while still others with clipboards milled about mission control looking, well, important. You're cleared for takeoff crackles over my headset as I sit alone in my newly minted aircraft, a steely-eyed missile man at heart,  I coolly stare down the runway and slowly advance the throttle...

Well, needless to say, the reality of the first flight was nothing like that.  I arrived at the airport 30 minutes late because my first trip to the airport was sans hangar keys.  Then a quick preflight.  I find that I need to add a quart of oil.  Crap, the oil is still in Carol's car.  She went to let my parents through the airport gate.  Another delay.  I'm feeling rushed at this point.

Airport denizen and fellow EAA member Keith Pederson, has helpfully offered to fly chase during my flight.  We quickly brief the flight and the frequencies that we will use.  The flight plan is simple: Climb above the traffic pattern and then circle the airport (within gliding range) for 30 minutes. Return for a safe landing and celebrate.

Now I'm in the plane and setting the radios.  I go through the startup checklist and turn the key. The engine roars to life and then quickly dies. I recheck the mixture and re-prime. The second attempt same thing, the engine starts and then dies.  OK, here's my first problem and I'm not even off of the ground. Concentrate.  What does the engine need:  Air, fuel, spark.  I know I have air and spark.  It must be fuel. The mixture is full rich so that's OK.  Ah ha! The fuel selector valve is set to off.  I'll need to add that to my checklist.

With the engine started I taxi to the run up area.  Along the way, I test the brakes for the first time. They seem to mostly work, so I continue.  At the run up there are no surprises. Also, there is no discernible drop in RPM during the magneto check.  I saw this before during the previous engine tests (from internet research I know this is common with P-MAGs) so I move on.  The run up is complete, there is nothing left to do but fly.

Flaps 10 degrees.  Trim set for takeoff.  A quick radio call and I am rolling on to the runway.  I slowly advance the throttle and very quickly reach Vr, rotation speed. At this point I am not thinking about the significance of this moment:  I am finally about to achieve the penultimate experience I will ever have in this airplane or perhaps any other, the first lift off in the first plane I've ever built. But there's no time for that.  A little back pressure on the stick and I'm off the ground. 4 years, six months, and 3 days after setting the first rivet, I have an airplane -- that flies!

I make a shallow climb to the planned altitude of 5000' where Keith joins me and I begin a series of orbits about the field.  Keith maneuvers his plane above, below, and on either side of me as the flight unfolds.  Principally, the chase plane is there looking for anything coming loose. Keith reports that nothing is departing the aircraft or flapping in the breeze. Good to continue.  I am attempting to get the aircraft trimmed for level flight but, I find that it is a bit sensitive in pitch and I am having some difficulty finding the right pitch trim setting.

For the remainder of the flight, I am periodically reporting engine temperatures that are being recorded by another EAA member, Jim Braddock on the ground. And Keith was still there following behind and reminding me to fly the plane when my altitude deviated too far.  I found that it was a challenge to maintain the desired altitude and play with my Garmin avionics at the same time.  This is why I need to get the pitch trim figured out.

After about 25 minutes of circling it is apparent that the engine would continue to run without overheating and the first flight data had been collected. All of the goals for this flight had been met, save one: land safely.  Engine power is reduced and we descend back down to traffic pattern altitude. Flying left downwind for runway 25 the aircraft is slowed to 90kts.  Just before I am ready to turn on to the base leg of the pattern I find that my flaps will not deploy.  This is really no big deal, as I have made many no flap landings in other aircraft.  The trouble was actually on the ground.  Without thinking, I mentioned this to Keith on the radio and this was, of course, overheard by Carol on the ground.  Well, I found out later that this may have been somewhat concerning for her and my parents. In the meantime, I got the flaps working again and I continued my base leg descent.  The cool morning air was calm and the final approach was very smooth, without the breezes and mild turbulence that will buffet landing aircraft later in the day.

At 76 kts I was carrying a little more speed than I would have liked as I crossed the approach end of the runway. This is about 10kts faster than I was going for, but I did not float much in ground effect and was on the ground in the first thousand feet of runway.  It was a pretty good landing.

And so there it is, the much-heralded 'RV grin.'  I don't think it would be possible not to grin after flying this magnificent machine.  Like a master chef, Mr. Richard VanGrunsven who is the aircraft's designer has managed to combine the best aircraft ingredients in just the right proportions to make a near perfect flying experience.

So many thanks to all that helped along the way. Keith for his advice and flying chase today. Especially to my wife Carolina, who helped at every stage of the build.

And to other RV builders:  Keep pounding those rivets!  Some dreams do come true.

Step 14.3, Transition training

The purpose of transition training is to become familiar with the flying qualities of your aircraft before you actually attempt to fly your own plane for the first time.  The FAA allows a waiver to the rule against using an experimental airplane for commercial purposes in this case, so that builders can gain experience in the same type of aircraft that they have constructed while under the supervision of a Certified flight Instructor.  Prudence and your insurance company dictate that one under go the training,  especially for someone with relatively few flight hours such as myself.

I began looking for suitable training a few months ago. Since my airplane is an RV-7A I was looking for the same.  I also have a constant speed propeller and so my training needed to include that as well. I wanted to schedule the training to conclude as near as possible to the completion of my aircraft so the training would be fresh in my mind.  I was fortunate to locate Mr. Chris Droege of Nampa, Idaho whose qualification and aircraft seemed to be a perfect fit. And the location was ideal as I have a sister in nearby Eagle, a suburb of Boise.  The drive from Rough and Ready California to Nampa is a bit of a grind at 8 or 9 hours of mostly desert.  Even worse, half of that is two lane highway with all the drama that entails.

As it turns out, my first two attempts to get to Nampa failed.  The first, stymied by high winds in Idaho and then by my poorly timed case of the flu.  Chris was understanding and cheerfully rescheduled -- both times.

The third time is the charm, as they say, and since the training would occur much later than originally scheduled it has worked out even better for me since my airplane has only just been completed.

Chris Droege's RV-7A

Day 1:

Chris likes to start early and still being on Pacific time didn't help.  Never-the-less, I managed to arrive at his hangar at 7:30 am, MDT.  The hangar was quite large, spotless, well organised and finished. By finished I mean epoxy floors and painted walls and ceiling.  One corner was devoted to a small apartment and in the center of this impressive space sat two aircraft.  A Glassair Sportsman and the RV-7A.

After a few minutes of pleasantries and a look around the hangar we settled down to business. First off, there was a look at my log book, my pilot license and my current medical certificate. Then there were was a waiver to sign.  Chris has a easy going style and a colorful vernacular. He often referred to me as "dude" which I found amusing and it fits his laid back demeanor.

Normally the ground school portion would go on for a couple of hours, but since high winds were forecast for the next day we decided to keep it short on this first day.  The first hour of ground covered the basics of getting into the air:  Getting into and out of the aircraft, taxiing the castering nose wheeled 7A, engine start, and finally, the takeoff roll in detail.

I really liked Chris' teaching style.  He first tells you what he is going to do.  Then he shows it to you slowly as he does it.  He will then ask you to repeat what you just saw and heard.  Good so far.  Here is the key thing -- He tells you that he understands that you will forget what you just did and that's OK, because he is going to repeat it a million times.  And so he did, at least with me, without the slightest bit of frustration being apparent.

The flying on day 1 was focused on getting familiar with the RV-7A.  There was an emphasis on the characteristics of a short winged aircraft, particularly in turns.  We did a lot of exercises that stress the fundamentals -- turns around a point and S-turns across a road.  And, of course, what check out would be complete without slow flight and stalls.

In all I had about 3 hours in the air on day one, but it went by fast because I was having such a good time.

Day 2:
The foretasted wind arrived right on schedule, so on day two we met for only an hour or so while we finished up the ground school and we put off the flying until day three.  This section focused a lot on how to organize your aircraft records and Chris showed examples from his RV that illustrate his point: That good records will increase the value of your aircraft.  I never really thought much about this aspect of aircraft ownership while I was building, and being a first time aircraft owner, I simply didn't know what I didn't know.  I appreciated the information and the application of that information. Another requirement of building an airplane is the production of the Pilot Operating Handbook or aircraft manual.  Since the aircraft builder is considered to be its manufacturer as well, it is his responsibility to produce the aircraft's POH.  Chris used his POH as an example of what data must be collected and recorded during the aircraft's test phase and how the proper presentation can become a resource for the pilot and any future owner of the aircraft.

Ground school, Chris on left.

Day 3:
Fortunately the windy conditions subsided and day three began still and warm.  Day 3 would be all about landings.  We departed Nampa Id, for nearby Ontario Or.  The airport at Ontario would be a little less busy.  Along the way we practiced power changes for ascents and descents. The point being to arrive at the desired altitude and simultaneously with the desired airspeed.  After that, it was just one landing after another.  I could see incremental improvement as I improved my ability to begin each landing with a stabilized approach.  It is Chris's habit to debrief each landing as soon as we are off  the runway.  Stopped on the taxiway, Chris offers a constructive critique of the landing while the details are fresh in your mind  Since this occurs while stopped it is possible to fully concentrate on the advice being given. I liked this approach, but it does take more time, so fewer landings will be possible.

As the number of landings increased, I could feel the proper sight picture of the approaching runway getting locked in.  My muscle memory is progressively tuned and Chris is getting happier and happier with the results.  After about ten landings or so, Chris decided I was ready. I would have liked to continue all day, but realistically, Chris's job isn't to make me the best RV-7A pilot ever, it is simply to make me safe enough to fly my own aircraft.  I can build my expertise in my own plane, but if I should I need a tuneup in the future, I wouldn't hesitate to fly to Nampa to get some more excellent instruction from Chris.

Taxiing at Nampa

So in the end, I'm returning home with the certain knowledge that I will be able to safely fly my new airplane.  That is why I went to Idaho, and that is exactly what happened.  Well done Chris!

Step 14.2, Airworthiness Inspection

I'm in the home stretch now.  All that separates me from flying my plane are the airworthiness inspection and my transition training.  It turns out that "airplane" is a legal term to the Federal Aviation Administration.  Before a successful airworthiness inspection your airplane is not actually an airplane to the FAA.  I don't know what they think the thing with the wings and the big fan on the front is, but is definitely not an airplane.  So to become an airplane it needs to be inspected by the FAA or a designated examiner (DAR).  If one can get their local FAA examiner to do the inspection then the cost of the inspection is zero. Awesome!  Not every Flight Standards District Office will send out an inspector though, and in that case, a Designated Airworthiness Representative is required. If a DAR is employed one can expect to part with a handful of Franklin's for their time and expertise.

The last rivet goes in attaching the aircraft data plate.

My experience with the Sacramento FSDO was painless, and quite pleasant, actually.  Not at all what I was expecting.  On the internet, the FAA moto is mockingly, "We're not happy until you're unhappy." Perhaps it's because most people that are happy don't take the time to post their experience online. Whatever the reason, I didn't actually have anything to worry about.

To get my thing with the wings and a big fan inspected, I needed to file the appropriate applications. The EAA has a helpful guide in preparing the forms.  This is one area where the FAA's reputation is actually well deserved.  The forms must be filled out perfectly without the slightest deviation permitted.  One might draw a parallel with the Soup Nazi from the Seinfeld TV show.  Make a mistake on the form and go to the back of the line.  But I had the sizable advantage of seeing a filled out application from our local EAA chapter's president, Frank Jackson.  The ability to see how he answered some of the more obscure questions was a very big help.  This is where I should also confess that it was Carol who did all of the forms.  Because as it turns out, although I am capable of building an airplane, I am helpless at filling out forms. 

Once I thought all of the forms were ready, I called the FSDO and was put in touch with Richard Dilbeck who would be my inspector.  I just wanted to be certain that I had all of the information required for a successful airworthiness inspection.  Richard was helpful and pleasant on the phone and I learned that he prefers to be called "Dilly."  Following our phone conversation, he emailed me a bunch of documentation and some checklists to follow.  I completed the checklist's and looked over the other documents and was satisfied that I was ready to send in my packet.

It turns out that Dilly was already going to do an inspection for someone in my area and was willing to add mine on that day, so I didn't have long to wait.  The time from first contact to the inspection was only about 2 and a half weeks in the future.  OMG!  I'm not ready.  My plane was fully assembled in my shop and I only just arranged for a hangar at the airport.  Well, needless to say, I was able to finish the fuel testing, disassemble the plane, and move it to the airport by the day of the inspection.  But only just.  I was still tightening the wing attach bolts minutes before Dilly arrived at my hangar.

The inspection process consisted of a detailed discussion of the operating limitations for this airplane. Dilly was quite thorough and highlighted each point with an anecdote from his extensive experience that explains the rule or otherwise highlights it's application. I appreciated the opportunity to benefit from his aviation knowledge.  At some point in the future, Dilly plans to retire from the FAA and become a DAR.

The operating limitations, among other things, establishes that this aircraft will be operated in two distinct phases, 1 and 2.  In phase 1, I will be doing the basic flight testing where I verify the performance envelope of the aircraft.  This phase will last for a minimum of 40 hours. During this time I am not allowed to take passengers and I must stay within a predefined area.  Once the 40 hours are flown, I will make a notation to that effect in the aircraft log book that indicates that the aircraft is now moving to phase 2.  Phase 2 is the normal operation phase were I am allowed to treat the aircraft just as I would for any similar certified aircraft.  Meaning, that I can basically go where I want and carry passengers.

Once Dilly had finished with the discussion on the operating limitations, he moved on to the physical examination of the aircraft.  Here is Dilly and I going over the engine.  I'm taking notes as he checks each connection.  

The inspection continued around the plane and focused mainly on the linkages where we had the opportunity to discuss ball end joints and possible failure modes at some length.  I was happy that Dilly was willing to take his time during this phase of the inspection stopping frequently to discuss not only the structural element in question, but also what I should be looking for in the future to help keep this aircraft safe.

In the end, Dilly found a jam nut loose on the aileron linkage which I corrected on the spot. He made several other recommendations that I plan to implement.  Although no show stoppers were discovered (thankfully), I feel that the inspection was a great learning experience all the same.  It really is  a relief to get another pair of eyes on the project as I know how very easy it is to not "see" things when one is so intimately familiar with a project.  After the inspection we moved on to the log book notations.

And finally, the Special Airworthiness Certificate.  Ta Da!

It was a long day for me, and a much longer one for Dilly who completed two inspections.  With hindsight, I can see that I was unnecessarily stressed going in.  Dilly was calm and easy to work with. I know that in the future I will not hesitate to give him a call as the need arises.  And if I should build another plane, I wouldn't hesitate to hire him as a DAR.

Before I will be ready to fly this airplane I still have two steps to complete.  I need to get training with this model aircraft and I need to fully re-assemble the plane after having it mostly apart for the inspection.

Step 14.1 The big move

After 4 and a half years, the day of the big move has finally arrived.  One might suppose that an auspicious day such as this might bring more excitement, but to be honest, my feelings lie closer to the bitter sweet end of the emotional spectrum.  On the one hand I am inching ever closer to the big day -- the day I actually fly her.  But on the other, I look at my empty shop and I am struck by how big it looks, and how empty it is.  I guess you can't have your cake and, blah, blah, blah. 

Before I moved the plane to the airport I still had one test to perform.  A test to verify that the plane would continue to run while inclined at a climb attitude.  It's simple enough, just jack up the nose wheel and crank her up.

While it's going, I switch tanks and check the fuel flow the the boost pump on and off.  No trouble feeding from either tank and we're good to go...

This is the last photo I took with my plane in the shop I built, to build it.

Now, I take the tail feathers and wings off.  I moved the vertical and horizontal stabilizers in the back of my pickup.  I made some supports to span the bed for the wings to ride on.

The actual move was a non event.  The fuselage went on the back of flat bed auto tow truck.  This might be the smartest $150 I spent all year.  In five minutes the driver had the fuselage safely loaded and we were on our way the the airport.

The trip lasted all of 15 minutes and covered about 7.5 miles.

And so here we are at the airport.  Everything intact, no new damage.  Whew!

At this point I only have a few days to get ready for my FAA air worthiness inspection.  There is not much time in my schedule to think about the great big hole left in my shop where an airplane used to be.

Step 14.0, Engine first start

Holy smokes that thing is loud!  That was the second thing that went through my mind when I saw the propeller turning on its own for the first time.  The first thing was just the surprise that it happened so quickly.  In retrospect, I guess there is no real reason to be surprised, but it seems that few things ever come along this easily and this was a glittering counter-example to everyday experience.

The one remaining task to perform before starting the engine was to check the fuel flow rate.  I wanted to be confident that when I finally turned the key, there would be fuel ready to ignite.  But in order to get fuel to the engine, I first had to have a place to store the fuel.  The fuel tanks are in the wings so I needed to put the wings back on temporarily.  I say temporarily because I can not transport the plane to the airport with the wings on. But on the other hand, I can't start the plane without the wings.  So on they go, for now.

I built a couple of saw horses that are at different heights to comp-ensate for the wing dihedral. This time around, and with the help of my new saw horses, I found the wing installation much easier.  After the wings were on I could move on to the fuel flow tests.  

To better understand what happens next, I'll explain the path that the fuel takes on its way to the engine cylinders.

The aviation fuel, 100LL, is held in the aforementioned wing tanks, each holding 21 US gallons.

The fuel pickup in each tank begins the fuel's journey to the engine.  The first stop is the fuel selector valve where the pilot chooses from which tank to feed the go-juice.  After the fuel selector the gas goes through the auxiliary electric fuel pump and through a maze of check valves, bypasses, and a filter.  It then goes on to the engine mounted mechanical fuel pump.  Either of these pumps is sufficient to power the engine, we have two for redundancy.  After the mechanical pump, the fuel travels to the fuel servo where it is metered using the mixture control and the manifold pressure. Following the fuel servo, the fuel then travels through the fuel flow transducer and then on to the flow divider, also called a spider.  The spider is so named because of its physical appearance is similar to its namesake.  The spider divides the fuel flow among the four cylinders.  The last stop on the fuel highway is the injector where the 100LL is atomized and inserted directly into each cylinder just ahead of the intake valve.

Center:  Fuel spider

The purpose of the fuel flow tests are to verify that the fuel pumps can supply enough fuel to the engine to sustain flight at high power and with a generous safety margin.  For my plane that number would be 125% of max flow at rated horsepower or about 21.35 gallons per hour.

Fuel test 1.

I broke the connection between the fuel servo and the spider and routed the fuel through a hose to a quart sized graduated container.  I then measured the amount of fuel delivered to the container over a period of 1 minute.  Simple, right?  Well, the fuel was just dribbling out and the fuel pump sounded like it was sucking air along with fuel.  This was troubling to say the least.  The amount of fuel collected after a minute was no where near that which would be required to sustain the motor under full power.

To trouble shoot the low flow rate , I started at the aux fuel pump because that is where I thought I could hear the sound of air being sucked into the lines.  There were no loose connections and no leaking fuel.  I then thought that perhaps the fuel pickup in the tank was sucking air.  But before I could test that I decided to move my attention to the output side of the aux fuel pump and check the flow there.

Fuel test 2.

The flow coming out of the aux fuel pump was quite robust.  In excess of 50 gallons per hour.  So the problem wasn't in the tank, fuel selector, or aux fuel pump after all.

Fuel test 3.  

I moved the collection point to after the mechanical pump, but before the fuel servo.  The flow here was awesome as well.  So now I was back to where I started, the problem was in the fuel servo.

This is when I had to change my operational method, and only as a last resort;  I would take a new tack, going forward, I decided to think a little before I tried stuff.  So it occurred to me that the fuel servo could not provide the flow I was hoping to see because its job is to provide fuel at the optimum ratio of air to fuel.  In my test there was no air component since the engine was not running and consequently, that meant that the servo was doing exactly what it should do -- provide only enough fuel to get the engine started.  Woo hoo! this thinking stuff was starting to pay dividends.

Well, a lot of hours were wasted chasing a phantom problem, but it's better than having a real one.  It was now time to actually start the motor.  After pulling the plane out of the shop, I removed the plugs and poured a small quantity of oil into each cylinder.

Then I rotated the prop by hand for a few minutes to try to get the engine's oil pump primed.  The plugs were then replaced and I positioned my pickup behind the plane to give me something to tie it to because I haven't been able to test the plane's brakes yet.

I have read many accounts of people having a great deal of trouble getting their engine going so I wasn't expecting much on my first try.   I even informed Carol that I would only let it turn for 20 seconds without starting before we would have to abort and let the starter motor cool down.   Carol's job was to video the event and check for leaks with fire extinguisher at the ready.

So as you can see, the engine started quite easily.  The white smoke at the beginning was just the oil that I had previously poured in to the cylinders.  There were no leaks observed and I was able the check the P-Mags.  In addition, the various sensors seemed to all be indicating correctly: oil pressure, fuel pressure, fuel flow rate, RPM, exhaust temperature, cylinder head temperature.  I cycled the prop control and verified the propeller governor was working.  After I looked at everything I could think of I shut it off.  Total run time was about 6 minutes.  So what kind of fuel flow did I actually measure?  I only let the RPM go to 2700 at which point I saw 16.9 GPH.  That is very close to the estimated value using HP*BSFC/6 = 17.03GPH.  More testing will be required and I will need to adjust the stops on the prop governor to limit the RPM.

Since I had the carpet out of the cockpit and since I had the canopy cracked open, my overall impression is that this thing is loud.  Crazy loud.  Like, dragster loud.  With four short pipes and no muffler it is not entirely unexpected, but jeez, this thing is scary powerful.  I was thankful that I thought to tie it to the truck because it was difficult to stop it from rolling. 

Finally, I'll wrap it up with another video that answers the question:

"Yeah it's an airplane, but what else is it good for?"

Answer:  Automatic tailgate lifter and bed liner extractor.

Step 13.9, Cowling

The cowling is the fiberglass enclosure around the engine.  It is analogous to the front quarter panels and hood of an automobile.  Theoretically, this cowling was made using molds taken from a perfectly fitting cowl from yesteryear.  If this cowl ever fit anything, it would be surprising indeed.  More on the fitment later.

The cowling is split laterally and each piece is supposed to be over sized such that careful trimming would result in one's own perfectly fitting cowl.  The first difficulty, though, is that no exact reference point exists in any dimension that would allow one to know where to trim.  However, I do know three things: first, that the back of the spinner must be about a 1/4" from the front face of the cowl. Second, that the opening for the prop shaft and the front is supposed to be 13" in diameter, and third, that the cowling is longitudinally symmetrical.

Since I didn't have the prop installed when I was fitting the cowl, my first datum, the back of the spinner, didn't exist.  No problem, I'll just mount the spinner back plate without the prop.  Now how thick is the prop hub.  Hmm, this could be trouble.

Here is the beginning of the fitment problems.  The upper and lower cowl halfs do not meet along the horizontal parting line.

No problemo, I'll just add more "side"to the lower front cowl.

Doesn't fit along the side either.  More cowl, please!

The upper front guides are glassed in.  These smooth the transition into the plenum.

A bit of spot putty fixes most of the unevenness.

I made these clips to hold the heater hose away from the exhaust pipes.

Now to cut the openings in the lower cowl for cowl flaps.  These openings allow additional air to flow, providing better cooling under high load or elevated ambient temperatures.

Now on to more sanding.  The reddish power is spot putty being sanded off.  The spot putty is primarily being used to fill the trillions of pin holes in the fiber glass cowl.

With the pin holes filled its time to apply the primer.

As it turns out, not all of the pin holes got filled.  I still have 150 billion to go.  I'm going to need more spot putty.

After one more round of primer, the cowl is finally ready for paint.

The next step is to install and test the cowl flaps.

Getting near the end now.  Adding the heat reflective foil to the inside of the cowl.  Hopefully, this will prevent the paint from bubbling on the outside.

Shush!  Sleeping puppy.

I'm not real happy with the final fitment of the cowling.  It seems that the fit is now different since the cowl has been painted.  Since that doesn't make a lot of sense I think I'll blame it on tolerance build up with the quarter turn fasteners.  Either way, the cowl doesn't fit as well now as it did before when it was just attached with clecos.  It's not obvious in the pictures, but there are some areas that will require additional work.

Also, the spinner is too close to the cowling so I will need to address that before first engine start. There are a lot of details to wrap up as I inch ever closer to finishing.  The old adage that 90% of the work occurs in the last 10% of the project applies here.

It seems that I am testing the Greek philosopher Xeno's paradox who noted some 2500 years ago that before one can finish his airplane he must first finish half of his airplane,  And before he can do that he must finish a quarter of his airplane -- and so on, in an infinite number of ever smaller steps that seem to prove that it is impossible to finish an airplane.  

Xeno was clearly ahead of his time!

Step 13.8, Spinner

The spinner is the little nose cone that covers the propeller hub.  It is not just ornamental, it plays an important part in smoothing the air flow over the cowling and guiding the air into the intakes on either side.  The construction is fairly simple:  A fiberglass party hat reinforced by a rear bulkhead and a forward bulkhead that sits about midway within the spinner.  How it got the name spinner shall remain forever a mystery :)

The rear bulkhead is delivered by Vans without the cutout.  Airplanes with fixed pitch props don't need the cutout, but for those of us with constant speed propellers -- well, we have more work to do. Cut a hole in the bulkhead to allow the propeller hub to protrude into the spinner cavity.   

                                   

Rivet on the bulkhead doubler.

Now test fit the spinner and bulkhead and drill out the mounting screw locations.  This takes a bit of measurement and calculation to get even spacing, but this step has gotten a lot easier since PI was discovered.

The next step is to cut out the openings for the propeller.

This is the front bulkhead bolted to the prop hub.

On a constant speed propeller, the blades twist to change their pitch during normal operation. Internally, hydraulic pressure moves the blades in one direction, while a big spring pushes the blades back.  Without the engine running, there is no hydraulic pressure so the spring pushes the blades back against their stops.  In the this step I will need to twist the prop blades to do the final fitting of the blade cutouts on the spinner, but the spring is really strong so I need some kind of leverage.  A couple of pieces of wood and two C clamps later I have a big lever.  The last part of the fitting is iterative: twist the blade until it contacts the spinner cutout, then make the cutout bigger. Repeat.

Here is where I run into the first problem with the propeller installation.  I get the prop mounted on the enginge and the prop bolts are lightly seated.  Great. Now I realize that these prop bolts need to be torqued to 65ft/lbs.  There's barely enough room for a thin wrench between the rear of the spinner and the flywheel/ring gear.  There is just no way that my torque wrench was going to fit in there.  There are probably expensive torque wrench extenders that I could buy, but I didn't find anything suitable after a quick look online.  This is where cheap tools are really valuable -- there is no need to feel bad about re-purposing them.  Carol found a $3 dollar combination wrench in some kind of bargain bin and I was able to cut off the end I needed and weld on a 3/8" socket adapter.  A new tool is born! Carefully measuring the extension allows an appropriate adjustment to be made to the final torque value using a ratio of total torque arm length to extension length.

So here we are with the propeller mounted and torqued.  Next, the prop bolts were safety wired.

It's a little bit hard to see what is going on here, but after the prop was mounted I wanted to see how the propeller tracked blade to blade.  A dial indicator is set up to measure the relative position of one blade and then the prop is turned 180 degrees to compare it to the other.  The two blades were virtually identical in their track, but one of the blades was .01" longer than the other.  I think I can live with that.

Almost finished now, the final step is to paint the spinner and then put it on your head.  Check.

All assembled, including a whole bunch of painted screws.