Rusty,
Glad you're back on track. I spent part of the afternoon with
Turbo Tom at a soaring club (he was the tractor driver this weekend, and
I'm going to get into this stuff). We discussed turbos as some length.
He predicted that you'd be happier with 5-10 psi than with the 5" you started
with. He doesn't regard Mazda as an ideal turbo platform. The
exhaust is hotter, so the turbo is hotter so the intake charge is hotter
so you need even more intercooler than other folks. Also, since rotarys
aren't exactly torque factories, the benefits are not as great as with
recips. That said, he assured me that it CAN be done - but you will
need a SERIOUS intercooler for good results. No surprises here.
Rotarys are famous for heat rejection problems, and this is one more.
The secret is to be VERY careful around optimizing the plenum so as to
maximize flow through the heat exchanger while minimizing cooling drag.
Today's rendition of the gospel according to TT .... Jim S.
Russell Duffy wrote:
Greetings,I
took the plane out again today, and found it to be MUCH more satisfying
at 5 psi of boost. I ordered another excellent used 89-91 turbo off
Ebay today, and I'm going to pick up a crack free exhaust manifold to go
with it. Before I install the new turbo, I'll port the crap out of
the wastegate, to see if I can get down to something more reasonable, like
5 psi, rather than 10+ like I get now. If that works, I can actually
use full throttle, which will make me, and Lynn happy (see Lynn, I do pay
attention). I'm also trying to pick up an 87-88 turbo actuator,
which was only 5.5 psi I think. As
I mentioned before, the new cowl is on order, and I'm starting to work
out the details to get this all inside the stock cowl. I can't imagine
how nice it might fly without all the cowl and tire drag. Realistically,
it will probably be around the first of the year before this all happens,
but at least I'm back on track, and excited about doing it all.
Thanks for putting up with my earlier depression. This IS going to
work, and it IS going to be the hotrod I hoped for. Cheers,Rusty
(psyched again)
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Started
my climb out at 4 psi of boost, then modified to 5 psi around a thousand
feet or so.I couldn’t get any rational
VSI readings from the Anywhere map, but it sure did climb better than ever.The
oil and water both stayed right at 180 degrees, so no problems there.I
had the usual ceiling of about 2500 ft, so I couldn’t go higher for any
real testing.Here are the numbers
for 14 degrees of pitch:
Boost (over
ambient) / MAP / RPM / MPH
Climb
4 psi /
38” / 5600 / 100
5 psi /
40” / 5800 / 100
Cruise at
2000 ft
0 psi /
28” / 5600 / 130
3 psi /
34” / 6000 / 145
5 psi /
38” / 6300 / 155
Once I returned
(with another beautiful landing I might add), I planned to fill the tanks,
and increase the pitch of the prop to 16 degrees.
Unfortunately,
I found that my left brake line is leaking again.The
line was made of slightly softer aluminum than Van may have had in mind,
but I can’t figure out what was actually in the RV-8, and he doesn’t spec
the material for the RV-3 either, so I thought I’d give it a try.I
left a loop of brake line at the caliper, and I believe that vibration
is causing this to break at the flare.After
one of the early leaks, the brake on the left has been “chattering”, rather
than smoothly braking, so I figured it must have been soaked with fluid.To
make sure this never happens again, I will replace the pads (which are
22 years old) on both brakes, and replace the lines with stronger aluminum.I
will also get rid of the loop of line, since it could be part of the problem.It’ll
be nice weather tomorrow, but I won’t be flying.
I found
one other problem today, my air vent sucks, and I mean literally.Rather
than blowing air on me like it’s supposed to, it has a pretty large suction
on it.One way or another, air is
coming in, so I guess it’s still ventilation.
--
Jim Sower
Crossville, TN; Chapter 5
Long-EZ N83RT, Velocity N4095T
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