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Message
Hi
Rusty;
You're probably not as curious now about this since you've been out
wrangling up some extra ponies, but here it is anyways...
Just
how much below your expectations was you climb
performance?
Lots. I had dreams
of 2000fpm, but was expecting 1200fpm without using boost, but managed a dismal
500fpm. However aircraft weight was approx 1700 lbs, as there was two of us on
board and I was carrying more fuel than necessary.
How much boost were you running?
Full throttle, or part throttle to lower boost?
We were
running 0psi boost, which is less than 3/4 throttle. At one point it
creeped up to 2 psi but I throttled back. I had been running under the idea that
0 boost would equal an NA, even though in the back of my mind I remembered
someone speculating that it would require at least 2 psi to overcome the
backpressure caused by the turbo. Leon has confirmed this for
me.
You're initial speculation of being over
propped might put you in the same boat I'm in, that is, having less power
than you should.
I spoke with
Dave Atkins as I knew he was also using an IVO Magnum. His is also a 76"
3-blade, so maybe I'm as overpropped as I had thought. He has reprofiled his
blades, but he says that only helped at the top end. Apparently some NASA
engineer helped him with it and it allowed him to get the top end numbers that
are otherwise elusive for IVO props. I can't tell you what pitch I'm running as
mine is cockpit adjustable, so I've cycled through a few times. A big priority
will be to calibrate the electronic constant speed governor so then I should be
able to dial it in for the climb RPM. This has to be done under flight
conditions.
I know you've run as much as 6 psi
on the ground, so I'm guessing that you were probably running more than I was
for these flights, so you may not be as far behind the curve as I
am.
The plan for
flight #5 was to "press the go button":-), and use all available boost on
take-off, just to see what she really had in her, unfortunately the EWP seizing
moments before we taxied onto the active runway put a halt on that idea.
The weather
here has really cooled off in the last week, this evening as I was riding my
motorbike home, it was downright freezing, so by the time I get going again I'll
do some air density calcs before I pour all the coals on the
fire.
I'm also
considering removing my wings and bringing my plane home, but for different
reasons. In less than a week I have to go to the bush to work as a hunting guide
for a few weeks, then when I return I have less than three weeks before I return
to tech school. Since we have an incoming exam that is worth 25% of final mark,
I'd best get my nose in the books. I don't return from school till Christmas, so
realistically I'm looking at January before I can resume flight testing. As a
rookie pilot, flight testing in the winter might not be the best idea, so it may
even be spring before I can get really serious about again. Right now I pay a
pretty reasonable rate for hangar space, but it goes up substantially in the
winter, so bringing it home may be the best option. I can't say that I'm very
happy about this, in fact I'm downright pissed off :-(, but as everyday goes by
with an empty mailbox and no EWP, I'm running out of
options.
This is not
to say that I regret trying the EWP. It was really promising right up until it
quit working :-). As even the best products can fail, I'm willing to give it the
benefit and try a replacement. Leon has helped by sending a replacement right
away, but somewhere it got lost, so he has sent yet another, but I'm beginning
to lose faith in our mail system. I'm really hoping I can get another chance to
try this pump before I'm forced to bring it home, as if it is not successful it
would be allot easier to convert to a mechanical pump here in my own
shop.
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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