Mar. 14, 2002
Well, so much for flying it last fall! But I think summer
2002 is realistic. It's pretty much done except for the little tasks
that seem easy before you start. Then three weeks later you realize
there was more to it than you thought. There was one big job recently:
balancing, then refinishing the elevators and ailerons. They must
balance at a certain angle and be below specified weights for safe operation.
If they aren't balanced or weigh too much, they can flutter in flight and
cause structural failure. It's especially critical for the elevators
since they attach to the relatively small canard (front wing). Elevator
flutter could easily result in the failure of the canard, which would be
fatal. But before you get frightened for my safety, I should add
that they have to be
way out of balance
for something like that to happen. Mine balance perfectly, so rest
easy. The plans has always been very clear about the control surface
weight and balance requirements, and the issue has been revisited several
times over the years in the Canard Pushers newsletter. But it's back
in the news after a fatal
accident near Palm Springs, apparently caused by elevator flutter.
The right elevator was examined after the crash and found to be heavy and
out of balance. The theory is that strong turbulence triggered the
flutter (it's thought that the plane operated without incident for years
because it never encountered conditions extreme enough to exceed its reduced
safety margin). Air
& Space Magazine has some Quicktime
movies demonstrating the destructive power of flutter on their website
(fast internet connection recommended).
Feb. 17, 2001
Not much of a diarist, I guess. The good news is progress
is accelerating. The engine installation is nearly complete.
I started over with the electrical system and it's now complete.
There are just a bunch of small jobs to be finished before she can take
flight. I'm hoping for first flight this summer or fall.
June 5, 1999
I know, I know, it's been a long time since the last diary entry.
Work on the Vari-Eze hasn't stopped, however. The surface finishing
is pretty much complete and it could be painted with just a little more
preparation. I haven't gotten around to the control and electrical
systems though.
The big news is I bought an engine! It's a Lycoming O-235-C with -L2C pistons to give it 8.5:1 compression. It was completely rebuilt and run for a couple hours in a test cell. Very nice looking piece of hardware. She should really climb with 118HP. Most Vari-Ezes have 100HP Continental O-200s. I was concerned about weight but others have reassured me that it'll be fine as long as I don't put a starter on it. I also considered the Surburu and more seriously the Jabiru but finally settled on the Lycoming for reliability, cost, and ease of installation.
The last couple months have been spent modifying the lower engine cowling. I previously installed a streamlined NACA airscoop on the bottom of the fuselage, and now the cowling matches and tapers to a boat-tail shape. It has been a big job: the bottom of the cowling was cut off, a new shape was made with pour-in-place foam with a thick layer of Bondo to get the contour just right, mold-release was applied, four layers of fiberglass were layed up over the form, and after hardening the foam and Bondo were dug out from the inside. Then I discovered that the shape wasn't quite right so I cut off part of it, made a new form, and re-glassed. It looks great now, though it won't be as light as some cowlings out there. And it's been a real treat to get back into fiberglass work :->
I'm also putting together a carb airbox. It's a kit from Van's Aircraft, intended for an RV. I'm orienting it with the intake pointing to the rear. People who have done the same tell me the air pressure in the rear of the cowling is the same if not higher than that at the cowling opening.
April 22, 1998
The landing gear legs are done. They're quite wide now! But most
importantly they're aligned with the relative wind. That modification should
be good for a couple miles per hour and looks good too. I also made a small
fairing for the transponder antenna and installed a vent for the header
fuel tank.
I sprayed the entire airplane with Sterling and sanded it down with 220 grit paper. A smooth, unbroken layer of Sterling now awaits a coat of the hard final primer. On the canard I made the mistake of letting high spots come through the Sterling. When I sprayed the canard with the hard primer these spots were easily visible. Fixing it wasn't a problem; Evercoat spot putty fills the tiny irregularities nicely. But I'll have to spray the canard with another coat of hard primer.
I'm seeing light at the end of the tunnel. Just a few more weeks and the surfacing will be done! Then on to finishing the electrical system, control system, and installing an engine. That kind of work sounds like a welcome change at this point.
February 4, 1998
The fuselage, canard, elevators, and ailerons are all ready to be
painted with the sealing primer. The wings are about 2/3 done. Yes! The
sanding is nearly complete! Gordon Jones of the Livermore EAA chapter showed
me a great way to find the remaining contour imperfections: shine
a light across the surface at a low angle, looking back into the light.
Any bump or low spot is highlighted by an easily seen shadow.
I was using unacceptably large amounts of the Sterling, considering its cost. I think the culprit was the HVLP spray gun I've been using since tends to put the Sterling on with a course texture. Most of it would simply get sanded off without doing much good. So I experimented with the amount of thinner (reducer) and the distance from the sprayer to the surface to be painted. Eventually I found a combination that seems to work. The other major reason I've slowed down my Sterling consumption is that I now just spray the low spots: after sanding I look at the wing, for example, with a low angle light and mark the low spots on a drawing. When I spray I just look at the drawing to know exactly where spraying is needed.
The last modification to the structure is streamlining the landing gear legs. I'll install sleeves for the brake lines, so they can be replaced later, align the legs with the airflow at cruise, and give them a low-drag contour (NACA 664-021).
October 12, 1997
The Sterling sands nicely. I'm using 120 grit sandpaper to start
with since anything coarser tends to sand through it too quickly. Now is
when you see any problem areas that the Sterling can't even out. One section
near the air scoop had a bump so I sanded down into the micro balloons.
When I started sanding the wings with a four foot long block it became
obvious that this technique wouldn't work unless you have really straight
wings. Straight wings offer nothing aerodynamically while the airfoil shape
quite important. I've heard stories of people using 12 foot sanding blocks
on their wings to make them super flat. The best way to sand wings is to
first make sure the airfoil shape is correct (if it isn't sand it with
a flexible spline). Then use a two foot sanding block (with the paper attached
directly to the block: no pad between) and sand at a 45° angle to the
chord line, making long strokes between the leading and trailing edges.
Move the block over a quarter inch with each back and forth stroke as you
move across the wing. Your wing probably won't be as flat as a ruler but
the curve will be gentle and without ripples.
It's amazing how much reinventing the wheel people do. My advice is find an airplane that came out well. Ask the builder exactly how they did it, or would do it if they had to again.
My basic process is:
August 30, 1997
It's been a long time since the last entry. In the last year I finished
painting the cockpit, did a lot of work on the electrical system, installed
the NACA engine air intake (a big job!), and got the instrument panel into
shape.
The sanding goes on. All the contouring is done, I think. Using a squeegee, I put a thin layer of resin on the airframe to fill the pinholes. Now I'm sanding it down in preparation for the Sterling filler/primer. Once the Sterling is on I'll be happy since it'll feel like progress is being made. Then I'll start looking for an engine.
July 6, 1996
Endless sanding is starting to get me down. It seems like even the
simplest contours take days to get right. At least I'm better at this than
I was: no more carefully filling small depressions and then trying to blend
them into the surrounding area. Now I liberally spread micro all over the
area and then sand it down. Still, I decided I had to do something to give
me a sense of progress: paint! Now the instrument panel is "black granite"
and the arm rests "white granite". I used a splatter paint called Stonecraft
(made by Krylon and available at Home Depot, etc.). I'll paint the rest
of the cockpit later.
The vertical card compass I ordered arrived DOA. I'm not sure I want one now anyway, after reading in the instructions that it shouldn't be mounted in the panel due to vibration and magnetic fields from radios, etc.
June 29, 1996
The sanding continues. While I thought the fuselage was pretty
much done, I realized a few areas needed attention. I cut out a NACA air
scoop for back seat ventilation, and installed a prefab scoop on the canopy
frame for the front seat. The engine air scoop is on order from Klaus Savier,
who also gave me a lead on an engine.
June 21, 1996
More sanding. The fuselage is ready to be primed, except for
the bottom which I decided to modify for a NACA engine air scoop. The instrument
panel layout is finalized and for the most part all prepared. Still need
to determine the best way to provide ventilation for the back seat.
April 5, 1996
Lots of sanding this week. I'm chasing my tail a little: making
more problems by accidentally sanding depressions in the area around freshly
applied micro-balloons. I've been working on the fuselage and wing strakes.
I also planned out the instrument panel and made a list needed equipment.
It's going to be fairly simple since this will be a VFR-only airplane.
No vacuum-powered gyros; just altimeter, VSI, airspeed, turn coordinator,
and the misc. engine and electrical system gauges.
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