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Like everything in
aviation it's not usually one thing that gets you, but rather a culmination of
many little things.
The original plan for this flight was for my buddy (great pilot, shitty
mechanic) to fly the plane while I looked after the engine. First lesson...
stick with the plan. While taxi testing with me in the left seat (Dynon in front
of me, EM2 in front of buddy), all was good so we felt it was good to go and
asked for T/O clearance. Both agreed I might as well fly it.
Second factor; I have an electronic governor for my IVO prop which I have
previously calibrated on the ground, but while it works in flight it needs to
have some in-flight tweaking of the calibration to perform better, so I just
generally control it manually until I have more time to play with it. During
full power run-up, I briefly played with the auto settings, before switching
back to manual. While in auto it must have went full coarse and when I switched
back to manual it stayed there. Prop pitch is on my pre-T/O check list, but it
seems to have gotten by me. But this wasn't a problem yet...
During T/O roll I realized my RPM was low (4200) so with hand on throttle
I can manually adjust pitch with spare finger, so I began to do this and RPMs
began to climb just as I rotated into a nice climb. This is where the trouble
started. Suddenly the AOA system began to shout "ANGLE, ANGLE, PUSH, PUSH" into
my ears over & over again. What the ? We weren't climbing that steep, but
now I see that the Dynon is telling me I'm only going 90. It was feeling kinda
sluggish, but not that bad. Now the temps are beginning to climb over 200.
"ANGLE, ANGLE, PUSH, PUSH"!! OK, shut that damn thing up... No Go... Still
yelling at me... Still only 90 on the Dynon... The EM2 TAS doesn't agree?
neither does the old steam gauge (I never trusted that thing anyways)... Quick
look at EM2... 6300 rpm.... what the ? Shit, how long did I hold down the manual
prop pitch?... reverse switch to coarse pitch adjustment..... I can hear
the rattle of the boost pumps louder than normal... hmmmnnn, they're not on,
what the heck is that noise?... Turning downwind... Reduce power....
temps up to 210 (oil) & 220 (water) Prop doesn't seem to be going
coarse... screw it, just fly the damn plane.... "ANGLE, ANGLE, PUSH,
PUSH"!! AARRGHH! I'm about to call tower with request for a precautionary
landing when they cut in with instructions about staying east of blah,
blah, blah, due to chopper working west of blah, blah, blah, until reaching
blah, blah, blah, "ANGLE, ANGLE, PUSH, PUSH"!!, damn this thing is really
getting on my nerves but I'm hesitant to completely discount it as it could be
trying to save my life especially as I was seeing low and disagreeing
airspeeds... Now I have 230 & 220 for temps.... Tower finally shuts-up
and I request a precautionary landing for 33... granted..... Make base
turn a little early as I want to get over that runway... instructor/buddy points
out that I'm high & fast... Geeez, I almost forgot he was there.... I
explain that I don't want to discount the stall warning and low airspeed, so
would rather stay high and fast until right over the runway since it's almost
10,000' , I'm not worried about running out of runway.... at this point, I'm
just concerned with flying the plane and not worried about the EM2, but I do
hear him report 236 on the water as I chop the power and begin to slip a
little.... "ANGLE, ANGLE, PUSH, PUSH"!!.... I bring it in for a nice
gentle landing despite 20 kt winds with a 10 degree crosswind. About
then we feel an almost insignificant amount of the infamous RV nosewheel shimmy
and my instructor/buddy says just hold the nosewheel off, which he proceeds to
do before I can react.... noooooooo.... he doesn't realize that this RV-9
wing just doesn't want to quit flying and suddenly we're back up about 15' in
the air.... I add power... engine stumbles a little... but gives a little
more... he brings it back down for a not-so-gentle-landing.... and
another... geezz, that was ugly.... I get on the brakes hard to make
an upcoming taxiway... we're going allot faster than indicated, that's for
sure...... engine quietly takes its last gasp and quits....
tower asks "you guy's alright?".....
So we're down and safe, tow it back to my tiedown, a quick look
over everything then try to restart. It wants to start on a couple of faces but
just can't. So we secure it for the night and head to the pub for dinner and a
beer. Next morning I first decide to investigate the airspeed, AOA, and prop
pitch trim.
First I find that the breaker on the pitch trim motor is tripped. Seems
that with everything going on during climb-out I must have held my finger on the
trim until it reached full fine (30") and tripped the breaker. I could have
easily reset it to reverse pitch, but at the time I was making the decision to
just fly the damn plane. At 30" of pitch I wasn't producing enough thrust to fly
fast enough to cool an engine revving at 6200+. If I'd just switched the prop to
auto control on the T/O run (or set it properly prior) it would have controlled
the pitch well enough to avoid this.
I
feel that I would have had cooling problems at this point regardless of the
pump, but with 2 EWP's in an experimental parallel configuration which I knew
was putting out less flow than I could get in a single pump configuration, it
certainly couldn't have helped matters.
As boost increases exponentially with RPM, I was certainly over-boosting,
but every time I looked over at the EM2 I was focused on the RPM and the temps
and I really can't tell you what the MAP was. I was looking at everything but
with the sudden situation I seemed to not have absorbed it. This is where a data
recorder would be invaluable. If I could capture a serial stream from the EM2
and feed it into a TrendLink program on my laptop, then it would be a simple
matter to examine all this data at a later time (hint, hint, Tracy) for
troubleshooting.
Next I checked the Dynon. It seems that before flight my buddy was
scrolling through all of it's functions and had inadvertently changed the units
from mph to Kts, so at 90kts I was actually at 103mph. Still not stellar, but
with a prop pitched to 30", what else could I expect? Of course if I'd simply
looked below the airspeed figure the "Kts" was prominently displayed. Of
coarse I'd realized that the EM2 displays TAS so it would be higher, but at the
time I was more concerned with using the lowest reasonable reading as my
airspeed.
Next up was the AOA. During the addition of the EM2 & Dynon
to my panel, I required more static & pitot inputs so I reworked this part
to provide a header for each with several spares. During this I re-routed the
small 1/8" tubing for the AOA and when the panel was put into place it
kinked and pinched off the static source to the AOA only. So this allowed it to
pass it's self test, but during climb-out it was missing the rate of change that
it needed to see. I would have expected that to just cause it to give an error
message, but apparently not. I've got to read the instructions on that thing
again as I'm sure that there must be away to silence it.
While these last 2 items certainly didn't directly contribute to the
detonation of my engine, they did distract me enough that I was missing the key
clues that did cause it.
I
was burning marked premium bought from the cardlock, where it doesn't have the
octane rating on the pump, but I believe (almost certain) it is 92. I am using
the stock oil injection system, but I'd felt it had been injecting too much
judging from the engine oil consumption so I'd recently adjusted to flow less,
however to ensure that my butt was covered I'd added ~150:1 premix to the tanks
while I experimented with injection flow rates, so I'm certain that it had more
than sufficient lubrication.
When I originally built this engine I didn't have the turbo so it has the 9.4:1
rotors. As I originally intended to only use the turbo for normalization, this
wasn't a problem. I have the stock wastegate which is set to ~7-10psi. I ported
out the wastegate to reduce/eliminate? boost creep. I do have a custom built
bleed system to increase boost when at high altitudes only (works great), but
this has 2 safeties and definitely did not contribute here. I was using Atkins
2-piece, 2mm seals.
Fortunately during all this I never forgot to just "fly the damn
airplane", but I still feel extremely foolish as in the seat beside me was a
qualified pilot looking at an engine monitor for an engine that he didn't
understand, while I was more than able to comprehend everything on that monitor
but as a (very) low time pilot I was trying to do too much at once. If
he'd been in the left seat, I'd have been freed up to closely monitor and
control every aspect of the engine.
I
pretty much accept full responsibility for this little episode and consider it
"pilot error" and not the fault of the engine. I welcome any other opinions if
anybody has another take on it. (I already know that I was a dumbass, so
you can hold on to that one :-)
S. Todd Bartrim
Turbo 13B RV-9Endurance
C-FSTB
http://www3.telus.net/haywire/RV-9/C-FSTB.htm
"Whatever you vividly imagine, Ardently desire, Sincerely believe in,
Enthusiastically act upon, Must inevitably come to pass".
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