Greetings,
Here's my log from today. I'm not
too optimistic that the next climb will be all that
great.
Rusty (turbo
depression)
9-16-03
I tuned the engine today, after setting the timing to
the correct point. It’s now
running well on both controllers. Idle is 16-17 inches of vacuum (13-14
MAP). I had to cut the fuel
injector flow down by 4-5 steps to get in range, which seems odd, but maybe it
makes sense to someone. I set the
staging point to about 19-20 inches MAP (12 inches vacuum on the gauge, which
I know to actually be 10-11 because the gauge is crap). The staging transition is still ugly,
and will continue to be that way until I get matching injectors. I had to make the staging point a bit
on the rich side to keep it from surging. Once I got done with the A controller,
I copied A to B, and then had to touch up the mixture just a bit across the
board. It’s obvious that the copy
function is working, because the ugly transition is certainly where it should
be. I ran as high as 7 psi of boost
briefly, and it really seemed strong, which is more than I can say for 0
psi. I’m going to be surprised if
I picked up any significant performance with the timing change.
FWIW, the rpm at 30 inches MAP was 5000 static. I’m pretty sure that’s partially
stalled though, so it’s worthless if it is. If it happens to be correct, then it
will be an increase in power.
Only a climb will tell.
As a side note, the oil and water were both great
during all the ground running.
Water stayed rock solid on 180, and oil made it to maybe 190. This is running the absolute snot out
of the engine under boost.
Unfortunately, I’m still thinking that it will take
about 5 psi to get the engine back to what a healthy NA engine would run. That means I’d have to run that on
climb from sea level, and run as much as 11 psi to get the amount of
normalization that I want. This
is more boost than I will be comfortable running, so if the next climb doesn’t
change my mind, I’ll probably start working on removing the turbo. 190 HP is plenty for an RV-3, and if I
really feel the need to optimize climb and cruise, I’ll have to come up with a
variable pitch prop.
Sorry to hear you are
hitting so many bumps in the road. While there are some advantages to a turbo
(high altitude, etc), I myself keep wondering if they are worth all the time
and effort and fuel consumption. I kinda think that if we get our aircraft to
fly as well as say, Tracy and Ed Anderson, normally aspirated, and are able to
do so by the keep it simple method, that ain't all bad news. It would be
nice to just advance the throttle and just take off without worrying about
boost, map, sea level pressure, etc, etc. Plus you can knock off 35
pounds of turbo weight....possibly helping your CG.....I had the pleasure of
riding in Tracy's plane, and if my 13b powered canard flys anything like his
RV, I will consider that a true success story, especially with a bullet-proof,
smooth engine that runs on auto fuel. What more could one ask for in an
aircraft? Loosing the turbo might not be as bad as it sounds. I saw Fink fly
his RV as well.....good performance with the same bullet-proof smooth engine
that can burn auto fuel, and be rebuilt for less than the cost of one cylinder
on a Lycoming. Maybe we already HAVE that better mousetrap. For
what it's worth. Take care. Paul
Conner