The test aircraft is actually still on the German register and featured a number of curious anomalies. I was intrigued by the glider towing hook and absolutely fascinated by the tiny TV camera mounted next to it – more on this later. The test aircraft also featured a Ballistic Recovery System, though this will not be an option for aircraft registered in the UK as its installation just pushes the all-up weight over the 450kg limit.
During the pre-flight inspection, I was impressed both by the actual design of the aircraft and the construction techniques and materials. The airframe is constructed primarily of aircraft grade aluminium and is covered with composite sheets, which are non-structural. All the strength is in the aluminium boom. The strut-braced wings use tubular spars both front and rear, with the modified NACA 2412 aerofoil section covered by Mylar. An excellent feature is that the wings can be folded back by one person for ease of storage and transportation. I’ve always been a big fan of folding wings as they can greatly reduce hangarage charges. The tailplane is also a very neat unit and features a single bracing strut on either side.
Entry to the cockpit is excellent. The large gull-wing doors are well supported by gas struts and the doors themselves open good and wide. Settling myself into the cockpit, the first thing that struck me was the width of the cabin. At 48in, it is incredibly wide – slightly wider, in fact, than a Cessna 182. Although there is no provision for adjusting either the seat or the pedals, I found the seating arrangement perfectly satisfactory, although shorter pilots would probably find an additional seat back beneficial. The control layout featured some slightly unusual features. Pitch and roll control is via a single control column mounted between the seats, and each pilot has his own throttle. If the aircraft is being used for instruction, a second stick top can be mounted onto the central control column to provide each pilot with access to the stick. The throttle levers are also worthy of comment, being arranged in such a way that they hinge flat, making access to the cockpit very easy. Once the pilot is strapped in, it is a simple matter to rotate the throttle lever to the vertical, and you’re all set. The trim lever and three position flap lever are both located in the roof, although aircraft destined for the UK market will also be offered with electric trim. Initially I found the flap lever a bit awkward, although I soon got used to it. Barrie said that it is easier to use from the left-hand seat. The instrument panel is very wide and provides more than enough space for a fairly comprehensive instrumentation fit. The test aircraft featured one of the worst altimeters I have ever seen, and Barrie was quick to assure me that it would not be a feature of the UK version. Another point that did not impress me was that the knobs for the choke lever and fresh air vent are exactly the same colour, although slightly different shapes. This is poor ergonomics – they should really be different in both colour and shape, and I really don’t think that this would be especially difficult to achieve.
In common with many other SLA’s, the C-42 is powered by the ubiquitous Rotax 912. This turns a three-bladed ground – adjustable Warpdrive prop via the usual Rotax 2.27:1 reduction gearbox. It is intended that most of the aircraft imported into the UK will be powered by the 80hp 912UL, although as the test aircraft is cleared (in Germany) for towing gliders up to 600kg, it is fitted with a 100hp 912S.
The Rotax started readily and we trundled purposefully towards the active. The engine tick-over had been set slightly higher than normal on the test aircraft, resulting in a fairly high residual thrust. This meant that the C-42 was eager to taxi faster than I was prepared to allow it, and regular and numerous squeezes on the control column-mounted brake lever were necessary to keep the taxi speed down to an acceptable level. Although I prefer toe-mounted differential brakes, I found the single lever system perfectly adequate. A neat little catch on the control column locks the lever ‘on’ for use as a parking brake. The aircraft rolls on a well-spatted and sturdy-looking hydro-pneumatic tricycle undercarriage, while the nosewheel steering has a nice, positive feel to it. Floats and skis are available as options. Out at the run-up point I waited patiently for the engine coolant temperature gauge to rise above 50 degrees before starting the power checks.
The C-42 features a dual magneto ignition system, although, interestingly, there is no carb heat control despite it having a carburettor-based induction system. Apparently, the carb is located where it stays warm enough from residual engine heat to preclude the possibility of carb icing. With such simple systems, the rest of the pre-take-off checks were completed quickly, and having received clearance from Cranfield’s very busy tower I rolled out onto the runway and smoothly opened the Rotax up to full power. With a power-to-weight ratio of less than 10lb per horsepower, acceleration was distinctly brisk and after what seemed a ridiculously short ground roll, the Ikarus literally leapt off the runway and clawed itself skyward at an impressively steep angle. With the VSI indicating in excess of 1,000 fpm and a relatively low forward speed, I would say that we crossed the airfield boundary well in excess of 1,000ft agl. It is interesting to note that the flap limiting speed is quite low, and Barrie pointed out that on the odd occasion that the aircraft is taken off with the flaps down, care must be taken not to exceed the limiting speed. I do feel though, that with such impressive performance a flapped take-off would probably be quite a rare event.
Having rocketed up to 3,000ft in just under three minutes I reduced power, retrimmed, and began to feel the aircraft out. For a high wing aircraft the visibility is quite good, although as is a feature of practically all-high wing aircraft, it is a tiny bit blind in the turn. Another nice touch is the transparent panel in the roof, as if the aircraft is rolled into a very tight turn it is possible to look through the roof. The controls all seemed quite nicely harmonised and authoritative. The roll rate in particular is distinctly sprightly, while both pitch and yaw control were equally effective. The trimmer, although effective, always seemed to be either side of one of the notches. This was vaguely irritating, although the electric trim offered on UK aircraft should offer a wider range. By now, conditions were becoming quite thermic and as some of the bumps were, well, quite bumpy, I decided against diving the Ikarus to its 120kt Vne. However, even at speeds of around 90kts I was well impressed by both the handling and the ambient cockpit noise levels. It was also interesting to note that at this speed the Rotax was sipping less than three gallons an hour. Slowing down to explore the low speed side of the flight envelope revealed no unpleasant traits. Indeed, with flaps down and carrying a reasonable amount of power the Ikarus showed no desire to stall at all. This may be in part because, when extended, the flaps are very close to the fuselage. As the spiralling slipstream moves back over the fuselage, I think the net result may well be enhanced lift via a crude form of ‘upper surface blowing’ and part of the prop slipstream being deflected downwards by the extended flaps. A more vigorous approach to the stall with the engine off produced a more positive G-break at about 34 knots, combined with a slight wing drop which was easily controlled by the rudder. Full flap is 40 degrees, and this causes a fairly major change in pitch trim, although it is easily trimmed out. As the Ikarus seemed to possess very good flying manners, I also decided to investigate its spin characteristics with a couple of two-turn spins. As expected, these produced no nasty surprises, both spin entry and recovery demonstrating perfectly predictable behaviour.
The claimed glide angle is a reasonable 11:1, while minimum sink rate is around 400 fpm. A couple of minutes with the throttle pulled back appeared to confirm both these figures, although again the high residual thrust produced by the too-high tick-over may well have exerted some influence.

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