|The Third First Flight|
Why is this called the Third First Flight?
The second-first flight, three years later was with the new untried downdraft plenums. That flight was actually approached with more apprehension than the airplane’s first flight because of the significant unknowns with the unique plenum cooling installation. Ground tests were good but then I somehow had to determine that it would also work at two thousand feet. I was well aware of what over-temping on climb-out could mean. But once in the air the summertime CHT’s were tamed on takeoff roll and then reduced nicely on downwind. It worked. Ha.
This Third First-Flight - with the 0-290
- is upcoming (This was written in summer of 05. It wasn’t yet
known that the development period would include a pesky leaking intake
valve fouling one cylinder occasionally, and a firing but bad plug).
The carb heat temp effectiveness was also tested last night. Ground runs have shown interesting intake cooling activity (condensation on the long, curved intake) so a considerable number of carb heat designs were scuffled through to come up with a robust system. This one feeds from the lower plenum next to the exhaust and travels only a few inches to the intake.
At the suggestion of Terry Schubert, a Radio Shack remote outdoor/indoor temp gauge temp sender was plugged into the gourd / carb intake for an actual temperature measurement, rather than just looking for the engine run-up drop in rpm. At a thousand rpm the carb heat lever was fully opened. I was looking for a 90 F degree increase. The gauge started at 62 degrees and in a few seconds went to 96, and then 119, and then blinked HHH, obviously still climbing. Robust enough.
Overall the throttle and engine response is what I would have expected from a normal intake setup. Scott Carter spent a day helping to trace proper engine operation. There was a hesitancy that he resolved by finding and tightening up one of the intake tube hose clamps. It had been tightened appropriately so someone must have snuck in and loosened it.
Four A&Ps have had their toes in the pie working on or checking the engine along the way. Fresh eyes are good and I like to learn from them. Each has contributed in his own way to accurate installation and adjustment of normal items, as well as sometimes offering comments on the implementation or expectations of the unique components.
Cowl Fire Warning System- At least one other person is installing the engine fire detection loop. I’ll look back in a few years to see if that simple dual wire element was ever used to advantage in the heat of battle.
For liftoff this third time, the alien-like entrails and repositioned elements of this “air pump” will have to orchestrate together in flight. The ground runs have helped to step normally through some areas. Of course I can only totally confirm the mutual cooperation of these creations at 12 K… when up there at 12 K. Oh, and eventually, Jackpot if possible.
Rolling onto 17L there is a slight left crosswind. There is six thousand feet ahead of me and the abort point is generous. Canopy latches have caught the bolts, and it’s locked. Could land back on the runway or the two parallel taxiways, or the cross taxiway; nope no one is on them right now.
Throttle up, good oil and fuel pressure,
good rpm, airspeeds moving, half-throttle matches the old acceleration,
elevators trimmed ¾ inch
TE down, nose lifting at 55, rpms still good, we’re off like a
Holding 140 mph up to 2500 feet. That didn’t take long. Let tower
know I’ll be up here a while and level and power back a little
for a minute. Winglets and everything still on and cooling inlets look…good
I guess; they’re still there.
Getting the feel of the old steed again,
it seems a little weird in a couple of ways maybe, but probably just
because I’m paying too
much attention. Leave her alone and she’ll be fine. This turn could
be better…wonder if I got the same aileron-throw back after the
I’m liking it here at 2500 feet. Nice that the sunset has stayed
about the same while I’ve been gone. What is that hissing noise?
Something’s hissing every few seconds. I don’t even have
anything pressurized but it sure is hissing. Let’s see, which of
the new items … Hey you’re not going to trick me into loosing
track of things here, oil’s good…good pressure but the temp
is still rising, no traffic coming over the top here…there’s
that hissing again…CHTs good, RPMs, speed, good, no one sneaking
up on me, what could be hissing?
Oil temp is not going to come down. Time to hit the showers. One guy entering on downwind on the other side. Let him know I’m descending over here, will probably beat him to calling base. Oil temp will need some attention. Aiming on touching down a third of the way down the runway, coming around nice with a little rudder, right there, settling in just like we knew what we were doing. Set that Eze attitude and… cool, on the ground with no bounce or joggle, hold the nose up here for some drag, cheated death again.
June 05. After thirteen flights now N95BJ has returned to shapely elegance
on the ground and in the air. But, she is adroitly evading oil cooling
advances with a flip of her winglets. Each short flight is a little longer
with more and more room for dalliances and power runs. The upholstery
finishes off the new look nicely.
This always-almost-there pilot has been in sunset withdrawal for some
time. But now the much needed airborne therapy is once again salving
the ravaging wounds of life. Of course this is part of living the Big
Life, right? Whatever, I am again ushering the sleek steed into the hangar
after sunset tinged outings, with both of us better for it.
Along the way the vernatherm operation was confirmed. On the next flight the oil temp stabilized with moderate power. The good cylinder temps continue to allow the engine and my stomach to be comfortable in the 98 degree OAT. After about 45 minutes of this longest yet flight the CHTs were happily observed to make a pretty uniform 35-45 degree reduction. With all the one-after-another delays this was a welcomed advance.
What do they call someone that tries the
same thing expecting different results? OK, that title fits, but what
about someone that tries half a dozen different things and gets the
same inglorious results…
At this point (summer 05) there is little time spent on one distraction. Once normal or acceptable operation in confirmed in that area, it is no longer a squeaky wheel and attention is turned to the next distracter.
Besides the still undetected leaking intake valve and sputtering spark
plug, the initial 0-290 flights were thwarted by two inaccurate oil temp
gauges in a row. The first gauge read way low, giving a false indication
of good temps. Fortunately keeping an eye; actually a hand, on the oil
sump caught the inaccuracy.
The oil cooler location will be moved. Several tweaks have stabilized the temp but didn’t appreciably reduce it. The old girl is back and just needs a little skirt straightening.
>>Summer 06 - Oil cooling is now good
even on hot days. Ha. Am selectively removing the little spoilers that
had helped to improve airflow in the cowl to see if they are still