57 SA Flyer Magazinevariables are interdependent. In other
words, you can compromise one for the
other to a degree, but at the end of the day
‘all are boiling with the same water’.
Of the helicopters in this particular
class, the JetRanger is the most numerous.
More than 7,300 JetRangers have been
built since it entered the market in the
1960s. There almost isn’t an airfield on
the planet where there isn’t one of these
helicopters – and there isn’t a child out
there that would not recognise one.
Then there is the Enstrom 480. It
entered the market nearly 25 years ago, yet
there are only around 200 operating world-
wide (if that). It’s a great machine, but some
helicopter pilots out there don’t even know
it exists.
It’s a different story for the Robinson
66 – the turbine follow-on model of the
abundant R44. More than 700 have entered
the market since 2007, 50 percent of which
have been exported all over the world. It
rides on the high recognition value of its
smaller piston brother, of which to date
close on 6,000 have been made since its
first flight in 1990.
Back to the MD500. Like the venerable
JetRanger, it was conceived in the ‘60s.
Close on 5,000 have been built. It’s still in
production – and, ask any chopper-pilot, it’s
considered legendary.
In terms of performance, the R66
comes out tops: best power-to-weight
ratio and most modern version of the Rolls
Royce engine. The light-weight construction
allows it to carry five people, plus luggage
and full tanks, at close to 120 knots (on
a calm day). None of the others can do
that up on the Highveld. However, it’s an
underslung two bladed rotor-head with all
the Vne, mast-bumping and ride discomfort
disadvantages. The lightweight construction
also comes at a high cost of ownership,
effectively necessitating a complete rebuilt
after 12 years, or 2,000 hours, and this
will set you back close on 50 percent of
the initial cost. Interestingly, the Robinson
Factory is the first manufacturer to copy the
MD500 design in mounting the turbine at a
45-degree angle.
The Enstrom is the exact opposite. It’s
a solid military spec design, and there are
only about nine life-limited components
that need replacement over time, so it has
a very high capital value retention. And
then it has a business class size cabin,
shock absorbing undercarriage, low centre
of gravity (the engine is mounted below
the cabin), fully articulated three-bladed
high inertia rotor-head and unobstructed
tail-rotor, allowing for 35 knot flight in any
direction. But, the power-to-weight ratio
only allows for an hour’s flight at 85 knots
with five people on board. It’s the perfect
initial turbine trainer and law-enforcement
platform. It’s the most stable machine in its
class, as easy to fly as a fixed-wing, with up
to four hours loitering capability and a zero
fatality track record – ahead of its time in
many ways, but maybe a bit bland to rock
anybody’s boat.
The Jetty fits in between the two above.
It can almost carry four adults and full fuel,
depending on age and quality of the turbine
and fitment of a higher performing tail
rotor. You can plan on close to 100 knots
in the cruise, but again, the two-bladed
system will affect Vne and ride comfort.
Furthermore, the engine and gearbox
are above the cabin, resulting in noise
levels that are higher than in the two more
modern machines discussed above. On
the other hand, capital retention is good,
and there is a vibrant second hand market,
since production stopped in 2010. It’s the
most affordable turbine step-up for private
operators.
The MD is smaller than the other
machines. Like the Jetty it can take four
people with full tanks, but zips them off at120 knots in the cruise, for about two hours
(or three with an extra tank). However,
there is no hiding its military heritage. The
only real space for luggage is under the
back seat, and the rear passengers can
hardly see each other, as their heads are
separated by the drive shaft and gearbox,
which is routed through the cabin between
them. It’s noisy and cramped.flight test
Simple instrument binnacle - some models
are fitted with a quasi-FADEC system, called
intellistart, for the start.Trim control via 'Chinese
hat’ that you swivel
around with your thumb
on top of the cyclic.Christoph Andrykowsky