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Flying the Ravin 500
- Scully Levin
South Africa is a land that often surprises with
the world-beaters that it produces. From its loins
have come famous golfers, tennis players, sprinters,
medium and long distance runners, swimmers, actors,
authors, musicians, businessmen and entrepreneurs.
Talent in one field after another abounds in this
beautiful country, and often from the most unlikely
of sources.
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Add to the above list "aircraft designers and
manufacturers", for out of a garage in a homestead
North of Wonderboom Airport, has come one of the most
exciting and lovely aircraft I have ever flown, a
Comanche look-alike, simply called, the "Ravin".
This aircraft is the brainchild of one Jan Troskie,
a long time Comanche owner, who figured that he was
going to take a great design and a great aircraft
and make it even better. This he did, in under two
and a half years, with no fuss, no fan-fare and no
razz-a-ma-tazz. Combining huge latent talent with
enthusiasm, passion for the Piper Comanche, commonsense
and liberal doses of "Boere manier" know-how,
he has produced a truly phenomenal aircraft.
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Sunday 6th April,
2003 was certainly a red letter day for me, for on this
day Dirk de Vos of Wonderboom Airport organized an
invitation from Jan to fly the Ravin. Dirk is another
pilot that has a passion for Comanches, and having been
one of the first to fly the Ravin, he called me to say
that I just had to fly this machine. There was a
double bonus associated with the invitation, as Jeremy
Woods, a long time friend, said that he would fly me
back to Rand Airport in his 1959 Comanche 250, the very
same aircraft that I had owned and then co-owned over a
period of 16 years.
I would thus have the
opportunity of comparing the new with the old on the
very same morning……
Standing in isolation, one
would be excused for mistaking the Ravin with a late
model Comanche. The two aircraft look almost identical
However, the original machine is of all metallic
construction, whereas the Ravin is all-composite. Closer
inspection of the aircraft reveals that there is not a
single rivet on the airframe and that the entire machine
is as clean as a whistle. Jan tells everyone with great
pride that the total number of composite parts in the
entire airframe amounts to only one hundred and fifty.
This is as opposed to the many thousands of parts in the
original Comanche, where screw heads and rivets stand
proud all over the airframe.
Nor is
there an antenna to be found anywhere on the aircraft.
These are moulded into the airframe during construction
so that they will not produce any drag.
The aircraft is powered by a
stock-standard 260 h.p.Lycoming IO 540 engine driving a
three bladed Hartzell propeller. Great attention has
been paid to the placement and design of the engine’s
air intake so that the propeller, which has extensions
added to the trailing edge of each blade, is able
to transmit pulses of higher pressure air directly into
it. By so doing the manifold pressure
is raised by up to 1.5 inches Hg in cruise flight, thus
further enhancing the performance of the aircraft.
The all-composite wing is
immensely strong, being good for well over 5 “g”. This
was constructed by Francois Jordaan, who is rapidly
developing an excellent reputation for the composite
wings he has built for many other aircraft.
The Ravin is in fact
slightly smaller that the Comanche all-round. The entire
aircraft has been scaled down some 6% to 7%, but the
cabin is still roomy enough to be very comfortable.
There is more than enough shoulder room for two medium
to large sized men in the front, and the two back seats
certainly look comfortable and roomy enough.
There are other differences
that become immediately obvious as one prepares to fly
the aircraft. Entrance to the cabin is via a smallish
door on the left hand side of the aircraft adjacent to
the pilot’s seat. Jan works on the principle that the
pilot should be “last in, first out”. There is no
catwalk material, as this would produce some drag,
however small. Once everyone is seated, the pilot being
last, the cockpit door is pulled down and into position
and then firmly latched into position.
The windows are made of
thick plexiglass and are also moulded into the
structure, thereby contributing to the overall strength
of the entire machine. The prototype Ravin has no
interior upholstery, and yet the cabin does not look
Spartan at all. The composite material had its own
colour-speckled pattern built into it and this certainly
does not look unattractive. The floor carpeting and four
luxuriously covered and comfortable leather seats give
the cabin an air of simple and unaffected functionality.
The second aircraft and third aircraft, which are
already in the advanced production stage, will both have
fully upholstered interiors.
The instrument panel has
been laid out very neatly indeed and is more than
adequate for any use that the aircraft may be put to.
The radio’s in this, the prototype, were mixed and
varied, but the entire avionics package can be fitted to
order and depends on what the purchaser ultimately
requires.
Jan accompanied me on my
first flight in the Ravin and simply let me get on with
the job with operating the machine. He merely stated
that if I had flown the Comanche before, then there was
nothing that he could really add. The start up and taxi
out was entirely conventional although it felt that one
was slightly closer to the ground. The steering was
positive and the braking was good.
It was
on the take-off that the first manifestation of what was
to come presented itself. The aircraft fairly leapt
forward out of the starting blocks as the throttle was
advanced and tore down the runway
with a huge sense of urgency. We were airborne and
climbing away in no time at all.
In spite of the lack of
interior upholstery, the noise level with headsets on
was not really high and we were able to converse with
ease through the intercom. A few gentle manoeuvres followed, an I do
believe that within the first two or three minutes of
being airborne, I turned to Jan and said “This aircraft
is a masterpiece!”
This is indeed so, for the
aircraft combines huge speed and performance with
delightful handling characteristics. The aircraft feels
very stable throughout its speed regime. The controls
are light and extremely responsive…….. but more about
this later!
Having spent some twenty
minutes in Pretoria’s general flying area, we cruised
back to Wonderboom at 195 m.p.h indicated in straight
and level flight and then joined the circuit for the
landing. The approach and landing was entirely straight
forward and not unlike the same exercise in a
conventional Comanche.
A second flight followed in
which Jeremy Woods, was given the opportunity to savour
the delights of this new machine. After our return we
thanked Jan and Dirk, and then flew back to Rand in
Jeremy’s 1959 Comanche 250, also a great performer, but
at a cruising speed some 40 m.p.h. slower than the
Ravin’s.
I could ramble on and on
about the aircraft’s handling characteristics and its
features ….. the trimmers, flaps,
operation of the undercarriage, stalling
characteristics, ventilation, noise levels, visibility
from the cockpit ets, etc.. This is all stuff that would
bore the reader and that the aspirant purchaser would
find out for himself in any event.
For me, the greatest
excitement associated with the flying of this aircraft
came when Jan asked me to demonstrate the aircraft at
the Ermelo, EAA and Rand Airshows. Given the incredible
strength of the aircraft, its control responsiveness and
its performance, and also the fact that the machine is
an experimental prototype, permission was obtained to
perform rolling manoeuvres with the machine at these
airshows.
The Ravin is simply and
undoubtedly the most exciting and exhilarating cabin
class aircraft I have ever flown. It combines grace,
beauty, exceptional handling qualities and unusually
high cruising speeds with good load carrying capability
over long distances. The original Comanches were hard to
beat in all of these categories, those being the
qualities that endeared the aircraft to me in the first
place. However, the Ravin 500 goes many steps better and
makes a “great aircraft, even greater”!
Suffice it to say that this
aircraft proved to be a sheer delight to demonstrate.
There was a huge surfeit of performance through one
wingover after another, and at no stage did the aircraft
ever become energy deficient. The aircraft showed off
its capability in the rolling plane by flying fast,
super-slow and hesitation rolls. All of this in a four-seater
cabin class machine!
Since the aircraft has not
been spin tested yet, no pitching manoeuvres such as
loops and stall turns have been approved. Not would Jan
in fact want anyone flying any such manoeuvres. He
stresses that the aircraft has not been designed as an
aerobatic aircraft and does not want any buyer of the
machine going out and doing aerobatics in it. He
requested permission for the limited aerobatic
manoeuvres to be flown in order to demonstrate the
aircraft’s strength and agility.
THE RAVIN 500 Trevor Merton, Vice
President, Precision Aero Engineering, LLC
As a teenager learning to fly in the '60s I at last had
opportunities for hands-on experience in several of the
aircraft that had long captured my fevered imagination.
My initiation into the mystery of aviation and the magic
of aeroplanes was paralleled by my early experiences with
the fair sex. At Saturday night dances I soon learned that
the sleek, sexy appearance of the young ladies that I fancied
gave no clue about their abilities on the dance floor. Alas,
many of those great-looking girls lacked grace in movement
and a sense of rhythm and timing. My anticipated dancing
pleasure was too often transformed into a humdrum callisthenics
exercise set to music.
So it was with Mr. Piper's PA24 Comanche. Several Comanches
were based at my local airport in the '60s and I had watched
their comings and goings with intense interest. Surely such
a fast, fine-looking, fire-breathing steed would repay its
pilot with excitement and pleasure galore! Sadly, it was
not to be. While the Comanche is an efficient aircraft and
economical to operate, knowledgeable, widely-experienced
pilots do not regard it as a paragon of handling pleasure.
The Comanche's fine performance is not equalled by its control
harmony and handling qualities. Pilots hoping for a dancing
session with a tango expert will have to settle for a shuffle
with an aunt at the local barn dance. Don't get me wrong;
the Comanche meets all of the FAA Part 23 criteria that
ensure that the aircraft is safe to fly in Normal Category.
It's just that I feel it's rather stodgy in manoeuvre and
suffers from mediocre control harmonisation; an opinion
generated through several hundred hours of Comanche flying
in the 180HP, 250HP, and 400HP models in the '60s and a
few more hours in a 260C in the '90s. In comparison with
over 50 other types of aircraft that I have flown from single-engine
biplanes through piston and jet fighters to four-engine
jet transports, the Comanche is ranked low on my flying
pleasure totem pole.
On a recent visit to Wonderboom airport near Pretoria,
South Africa, I was shown a truly modern version of the
venerable Comanche. Constructed in epoxy resin/glass fibre/carbon
fibre composite material the look-alike Comanche is around
94% of the Comanche's size and proudly wears the name 'Ravin
500'. I was immediately struck by an impression of sleek
beauty and gem-quality perfect, mirror-smooth finish. A
curvaceous Hartzell scimitar propeller and a nose cowl featuring
a flush NACA air intake duct in place of the external scoop
worn by early model Comanches enhanced the flowing lines
of the Ravin. You can appreciate though, that my admiration
of this bird was tempered by my memories of Comanches. Would
the promise of this gorgeous appearance lead to another
humdrum flight experience? I wasn't exactly aching to find
out and was prepared to move on after a brief, distant glance.
My companion was more than impressed by the Ravin's beauty
and insisted on a closer inspection. As we walked around
her it soon became apparent that the Ravin differs from
the Comanche in a number of significant ways. The aerofoil
is based on the original, familiar NACA 64-series section
but features modern Harry Riblett enhancements for improved
efficiency through a wider range of the flight envelope.
Drag-reducing tips also add a modern touch to the wing.
In place of the familiar Piper horizontal, all-moving "stabilator"
the Ravin features a conventional arrangement of fixed horizontal
tailplane and hinged elevator. The ailerons have an approximate
2:1 differential action and are remarkable for the perfection
of fit between the ailerons and the wing trailing edge.
Less obvious is the slight Frise projection on the lower
leading edge of each aileron. This becomes visible below
the wing when the aileron trailing edge is deflected upwards.
My interest in the Ravin having been considerably raised,
I was pleased to be introduced to her creator, Jan Troskie.
A long time Comanche owner and enthusiast, Jan believed
that the basic Comanche design had many virtues and deserved
preservation in a rejuvenated form. Having previous experience
of composite aircraft construction he was undaunted by the
prospect of constructing the Ravin from scratch.
With Jan as my guide, I inspected the Ravin workshop and
was struck by the obvious professionalism exhibited in all
aspects of the aircraft's construction. The Ravin team possesses
impressive engineering credentials and the Ravin crystallises
their combined experience in a very emphatic manner. I quizzed
Jan with some of my favourite awkward questions about design
and construction issues and he fired answers back to me
in a forthright manner that spoke volumes about his knowledge,
ability, enthusiasm, dedication and commitment. I was shown
samples of spar sections and landing gear components that
were fabricated and tested in-house. The workmanship, fit
and finish were first class and the test results indicated
that all components substantially exceeded their design
specification. When Jan invited me to fly the Ravin I accepted
without reservation and with a much-heightened sense of
anticipation.
Back at the airport, I was introduced to local pilot Lourens
Kotze' who filled in lots of gaps in my knowledge of the
Ravin and patiently assisted me to explore her flight characteristics.
The Ravin 500 employs a retractable landing gear that utilises
similar components to the original Comanche but the operating
system has been improved to ensure that the alternate landing
gear extension system is easier for the pilot to operate
than the original. Unlike the Comanche, if the landing gear
is manually extended it's not necessary for a subsequent
workshop visit to reset the landing gear for electrical
operation. The gear is mounted on a steel torsion-resistant
framework that also serves to stiffen the wing spars.
In place of the forward-opening door on the right hand
side of the Comanche, an upward-opening gull wing door is
fitted on the left side next to the pilot's seat of the
Ravin. I was initially dubious about this arrangement but
found that access to the aircraft was readily accomplished
by sitting on the front of the wing then swinging one's
legs into the cockpit. It was surprisingly easy, offering
easier ingress and egress than many low-slung sports cars.
Ladies need not fear ungraceful entry and exit with this
bird. The Ravin is fitted with four seats and there is a
considerable volume behind the seats for baggage, golf clubs
and the usual bric-a-brac hauled around in light touring
aircraft. As with the main cabin door, the baggage door
opens upwards from top hinges.
The cabin of the prototype Ravin is nicely furnished with
four comfortable seats but otherwise looks a little Spartan.
I was concerned that there wasn't much in the way of sound
insulation and thought that the interior noise level would
be high. My fears proved groundless, however, and in-flight
conversation proved easy via the intercom system set to
fairly low volume. The cabin size does not suffer in comparison
to the Comanche, no doubt because the composite construction
does not need internal framing like the original metal aircraft.
The comfort level for four full-size adults is very good.
Cockpit layout is conventional with the prototype sporting
a full array of IFR instrumentation plus a nav-comm stack
featuring a moving map GPS. Another appealing feature was
an integrated electronic engine display. The engine controls
are levers mounted on a centre quadrant at the lower line
of the instrument panel. I much prefer this arrangement
to the Comanche layout, especially as the levers fell naturally
to hand for pilots in both front seats.
The 260-HP Lycoming IO-540 engine nestling comfortably under
the shark-nose cowling is the same powerplant seen in the
Comanche 260C. Feeding the very modest thirst of this well-respected
powerplant are leading edge fuel tanks with the amazing
capacity of 160 US gallons. At a typical cruise power setting
of 65%, this provides flight endurance in excess of eleven
hours! The tanks are baffled to inhibit slosh and also fitted
with non-return valves to prevent unwanted fuel transference
between the wings.
Flying the Ravin 500 was a memorable, revelatory experience.
Wonderboom airport elevation is 4100 feet and the temperature
was 250C giving a density altitude of approximately 6000
feet at the prevailing barometric pressure. A crosswind
of about 6 knots was blowing across the runway. There were
three adults on board, including yours truly, miscellaneous
kit and cameras and enough oil and fuel to fly across half
of Africa.
Taxying the Ravin was utterly conventional with tight turns
easily accomplished. Takeoff was initiated by fully opening
the quadrant-mounted centre throttle whereupon the Ravin
responded with Comanche-like acceleration. Reaching liftoff
speed I gingerly raised the nose a little and waited for
the Ravin to fly off. After gear retraction, the aircraft
was accelerated to 130 kts IAS for a cruise climb. Setting
up 22.5 inches MAP and 2450RPM, the rate of climb was checked
by altimeter and stopwatch and found to be around 800 feet
per minute at about 7500 feet density altitude. Very impressive.
Under direction from Loureus, I set out for the local training
area and performed a standard series of handling and performance
checks learned at test pilot school.
As the checks progressed it dawned on me that flying the
Ravin was great fun. It was difficult for me to maintain
my professional, reserved demeanour and not grin like a
fool. Because the Ravin wasn't fitted with specialist flight
test equipment my assessment was somewhat subjective. It
was fairly obvious, however, that the Ravin easily met the
FAA requirements for flying qualities and performance characteristics.
Nowhere in the FAA Regulations does it say that an aircraft
must delight its pilot so there is no such box to tick on
my flight test report page; so I wrote in longhand "Sheer
delight!" The Ravin's controls are light to manipulate,
stability is good around all three axes and importantly
for enthusiast aviators, control harmony is superb. The
accepted ideal control force ratio is expressed as A1:E2:R4
[for aileron, elevator, rudder] and the Ravin closely adheres
to this standard. There aren't many aircraft that seemingly
respond to the pilot's thoughts without conscious muscle
inputs but the Ravin does. The ailerons are especially light
to manipulate, thanks to their differential action and Frise-type
projections.
As far as its performance goes, it's hard to comprehend
just how far the Ravin is ahead of standard Comanches. We
had spent most of our flight at mid-range speeds while conducting
handling and stability checks. As we turned back towards
Wonderboom airport, power was again set to 75% in level
flight at a density altitude around 7000 feet. Although
we were bumping along in light turbulence, the airspeed
settled within a minute and a computer check revealed the
astonishing true airspeed of 195 knots! The 400-HP Comanche
was hard pressed to reach that kind of speed as I recall.
Consider that the Ravin can turn out this sparkling performance
while virtually doubling the Comanche's range and it will
be obvious that this is a remarkably capable aircraft. When
one considers that the Ravin is more than twice as structurally
strong as the Comanche, the realisation of the magnitude
of the Ravin team's accomplishments is truly awesome.
Turning onto final approach and fully extending the wing
flaps, indicated airspeed was reduced to 75-80 knots. Memories
of the Comanche flooded back. I recalled "notchy"
stabilator response during landing flares and little ability
to prevent the nosewheel thudding down shortly after main
gear touchdown. Flaring for landing, I held the Ravin about
a foot above the runway until it stopped flying and settled
lightly to earth. It was easy to hold the nose up for a
considerable period after touchdown, and then gently ground
the nosewheel. That's a considerable improvement on the
Comanche.
It was a very enjoyable experience to fly the Ravin. Such
a mix of high performance and high pleasure is rare in a
light aircraft and I told Jan Troskie that it had been a
privilege to fly his creation. He smiled, knowing that I
would say that very thing, as had all the Ravin's previous
pilots.
Leaving Jan's workshop, I mused that I had virtually taken
the Belle of the Ball to a dance, and what a dancer she
was! She had given me indelible happy memories of the occasion.
I had learned something too of her Olympian qualities (Marathon
runner and sprinter!) and am eagerly anticipating our next
date.
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