The last few days of maintenance paid off
today. The engine ran *much* smoother in
flight (prop balancing). There's still a
fairly pronounced vibration at certain RPMs,
but they're easy to avoid and have been reported
by other RV-drivers with similar prop/engine
combinations. Engine temps are much closer
across cylinders (small air dams in front of 1&2)
and a full throttle climb on a 90 deg day
showed temps within acceptable limits.
Now that I can run it harder I definitely
see the possibility of overspeeding the prop
(2700 RPM max) in a shallow descent at high power.
OTOH, at least from 3 to 5K, full throttle results
in something close to 2700 RPM after airspeed stabilizes,
so I guess the prop is pitched about right. We'll
see after I get weather to do it higher.

Rather than approach spins as originally planned,
since I wanted to keep the power up I changed the
plan and did some speed runs. The fairings
obviously need some cleaning up, but I indicate
150 KIAS at 3000 ft and 2600 RPM. It'll do better
with better fiberglass work, but that will come
later. It still feels smokin' to me. Of course
I had to do some pretty aggressive maneuvering
to stay within the 'measured course', so I got
up to 4.5g's. An interesting aside, I can definitely
tell how dehydration affects g tolerance. If I drink
a bottle of water and wait about 10 minutes my
g-tolerance increases by about 1g. Since the time
is so short some of it *may* be psychological, but
I understand the physiology behind it as well and
now make sure I'm well hydrated before flying.

I finished up the flight with mild acro: 1g rolls
and 'weenie wingovers'. RV's definitely have some
aileron buffet at full deflection. Not objectionable,
just noticeable. It feels a lot like the stall buffet
I get too, but only in the stick, not the whole airframe.
I guess I'm feeling separation over the ailerons prior to
stall - works for me. It certainly is easy to roll. I
tend to dish out the bottom, though, which probably means
I'm holding a little too much aft stick either all the
way or at the end. Who cares for now, they're fun
as all get out. Full-blown wingovers (90 deg out in heading
at inverted key, 90 deg nose up and down) and other overhead
maneuvers will wait until the engine is broken in and I spin it.
I'd much rather have the first spins be intentional rather than
out of blown acro. In the meantime, what little I'm willing to
do is a nice break from converting old dead dinosaurs into speed
with nowhere to go.

I'll have more time to fly in the upcoming weeks, I hope
to take a huge bite out of the flight test requirements
and my test plan. We'll see.

Dave 'dinner roll' Hyde

RV-4 in flight test, EAA tech counselor