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Message
Greetings,
Well, I've confirmed a few
facts, and finalized the w&b for the rev-2 conversion. My old empty
weight was 895 with the turbo, huge radiator, and BUC (big ugly cowl for those
who were fortunate enough to miss that chapter of the story).
The new empty weight is
853, or 42 pounds lighter. This moved the typical flight CG back about
1.1", which is just dandy.
I ran the engine today, in
an attempt to tune it. While it runs fairly well with Tracy's defaults, I
thought I'd touch it up. Of course, there's no such thing as doing
something like this easily, so I didn't get much accomplished. In reality,
I screwed a few things up, and had to reset to Tracy's defaults a couple
times.
The only real problem I had
was that the O2 reading in the EM-2 seems erratic. Todd, did you ever
figure this out? Mine was so wishy washy that I couldn't confirm whether a
longer "bar" means richer, or leaner. I swear sometimes it would go one
way, and some times the other. Finally, it just went to no bar, and stayed
that way. I can't say that I can blame the EM-2, since my old
meter did the exact same thing once. It just refused to work one
day, then worked fine the next. Maybe everything will just work
perfectly tomorrow, and all will be well. I have to admit to being tempted
to take the FJO wideband O2 meter out of the RX-7 for use in the plane.
That would be sweet. Fast, reliable air fuel reading from 10 to
20.
In better news, the temps
were very well behaved, and I didn't have to worry about overheating at all,
even with the rad ducts in place (no cowl though). There were no new
leaks! The EM-2 worked perfectly, give or take my odd
O2 issues. Max static rpm was 4850, but unfortunately, I have no
good static rpm from this prop pitch before. Even more
unfortunately, I just noticed that I don't have any good climb rpm's
from the last flying setup. I have some numbers from the same prop
pitch, at 5 psi, but this was before I set the relief valve to dump
everything over 5 psi. Previously, at 5 psi of boost (not full throttle),
I was getting 5400 rpm at 100 mph in climb, and 5600 rpm at 120 mph. If
I'm really getting 4850 now (prop not stalled?), I should certainly be in the
same ballpark as before. I'll have to wait for the performance figures to
confirm. I think being 42 pounds lighter, and with the FAR more
aerodynamically clean (non-BUC) cowl, I'll probably break even on
performance.
As much as I'd love to find
out tomorrow, it's unlikely to fly until next weekend. I still have to
attach some heat shielding with RTV, and it won't have time to dry. My
airport is under the Navy flight area, and is limited to 900 ft during
the week. That means I'll probably end up waiting until next weekend to
fly.
Cheers,
Rusty (more good than bad
news)
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