The Kinder, Simpler, MORE Affordable Diamond Four Seater (Part
Three)
When last we left ANN's
Jim Campbell and the poor guy from Diamond Aircraft who got conned
into riding along with him (now undergoing intensive therapy that
shows great promise), they were all lined at the end of Winter
Haven, FL's Runway 11, ready to commit the unpardonable 'sin' of
aviation.
And 'sin,' they did…
Firewalling the FP's O-360 produced modest acceleration (that
improved significantly once we get a few knots under our belt and
gave that prop a chance to get an air-bite) and moderate torquing,
easily countered by what Diamond describes as an "enhanced" rudder.
Light pressures (barely a few pounds) were all that was required
and a slight stab of toe-brake kept things lined up well until
about 20-30 knots when the rudder and vertical stab got a taste of
the relative wind and were all that was needed from there on out.
One notch of flap was used, and following my experience with
previous generations of the DA40, I eased on a lot of aft stick
pressure early in the ground roll, until the nosewheel lightened
perceptibly. At that point, I started easing OFF the pitch to
assume a deck angle near 10-12 degrees until liftoff… and
then settled into a 65 knot attitude that produced a ready 1000 FPM
at the start, with a fairly decent deck angle that needed to be
lessened now and then to check the way ahead for interlopers
(especially the B1-RD variant) intent on playing mid-air roulette
off the departure end of RWY11. Cooling from the larger air vents
on either side of the cabin is excellent… a necessity
underneath that big beautiful canopy (literally, a virtually
unrestricted window to the world below).
With about 600 pounds of payload (fuel and pax), and 80-85
degrees in the kind of sky that Florida tourist bureaus love to
brag about; the FP was off and running in an easy 1200 feet.
Initial P-Factor issues were easily countered with light to
moderate rudder pressure, visibility over the nose was slightly
restricted by the Vx climb I selected in order to check the FP's
cooling prowess, and the delightful control harmonies I remembered
from the constant speed-equipped DA40-180 were as good as ever. A
climb to 5500 feet, taking 9 minutes from brake release to
nose-over, yielded excellent temps that peaked at 358 degrees and
started backing off by the time we reached the 4500 foot
mark… in apparent sympathy with the lowered ambient temps at
such lofty heights. For the busy flight school that does a lot of
hot and heavy taxiing and climbing enroute to the day's lesson, the
additional cooling in the FP would seem to be a good investment
against premature engine melt-down.
The DA40-180-FP flies much like its CS cousin. The short throw
control stick impresses one with little mechanical feedback and
requires light to moderate pressures throughout the approved flight
envelope. Of short stature, fingertip pressures can do most of the
work, and produces a fairly agile roll response, complete with a
noticeable adverse yaw and excellent pitch response. Aerodynamic
feedback is well pronounced with a noticeable (and fairly linear)
stick force gradient throughout the normal speed range of the
aircraft, despite the fairly modest pressures inherent in this
airplane. Pitch is particularly well defined in that it features a
slightly higher stick load than roll, sports virtually no breakaway
inhibitions (none of the mechanical persuasion... this thing is
SMOOOOOTH), and conforms obediently to the speed range in use.
Rudder pressures are modest, as well, and produce a lightly
separated response that will, with larger input, roll the aircraft
sympathetically with the chosen input. The power of the rudder,
though, is not to be underestimated… it has as much
authority as you may possibly need and seems to have benefited
nicely from some additional attention from Diamond's aerodynamic
aces. Coupled together and led slightly by rudder, the
coordinated rolling response of the FP is agile, but not sensitive,
and produces an obedient response at most any speed in the normal
envelope... And then some.
Stability and control issues with the FP are a delight. The
static pitch stability of this trainer bird is exceptionally well
defined and a look at its dynamic behavior reveals a pretty
obedient bird. In 10 degree, stick-free displacement at cruise
speeds and settings, the FP offers up a low frequency cycle of
modest amplitude (diminishing on the order of 50% per cycle) that
is pretty well damped out in about three excursions. Short period
pitch behavior is nearly deadbeat with virtually no oscillatory
belly-aching.
The roll/yaw scene is about as well defined… with
exceptional spiral tendencies. The usual steady heading/attitude
side-slip excursions saw obedient behavior in roll and yaw, upon
release to the trimmed configuration. Dutch roll investigations
were well damped in a few cycles and pretty much done in two.
Sweet.
Pitching over at 5500 feet, we leaned the O-360 back a bit,
watching the G1000 give us excellent feedback on each cylinder of
the Lycoming four-banger. A 2500 RPM run yielded a fuel flow of
slightly less than 10 GPH, and a power rating of a little over 75%.
After settling on "the step," the FP showed an unerring ability to
hold to a TAS of at least 135-137 knots… well within what
one might expect with a slightly nose-heavy load at a
fairly inefficient altitude, in a bird boasting 140 kts for a top
end cruise.
Particularly laudable is the in-flight visibility of the FP (as
well as the CS version of the DA40). Its sailplane heritage is
evident in the exceptional visibility offered up by the bird and
the surprisingly "nose-low" impression the airplane takes in
cruise, not to mention the fact that the high-aspect ratio wings
that muck up little of the lateral viz. If you can't see
what's in your way in a DA40, it's time to order a seeing eye dog.
For flight training, this is invaluable… and for just plain
"flight-seeing," you'll get no complaints from your
passengers… this is a very pretty way to fly.
To be continued...
(ANN will be publishing flight test data and research from
our flights in the new Diamond DA40-180-FP, the new Cirrus SR22-G2
and the recently certificated Lancair Columbia 400 over the next
several days… don't miss them!)