Airtest – ARV Super 2

Put another way, the GA ab initio training industry, together with PPL aircraft owner-pilots want a different product: for a variety of reasons, but principally economic, the trainers that have been the mainstay of the industry for going on 30 years are no longer good enough. The word that a new product was coming from a number of companies probably held customers back from re-equipping.

Unquestionably the advances in trainer development have shifted across the Atlantic – Western Europe has a number of new conventional categories and very light training aircraft. Chronologically the ARV Super 2 is one of the front runners.

The ARV has some specifications that are typical of the new generation of very light aircraft – AUW about 500kg, side by side seating for two, etc. It is atypical as well; most significant, it can be argued, is the fact that it is being Type certificated to meet in full BCAR Section K, the British equivalent of the US FAR 23 – airworthiness requirements that cover ‘light’ aircraft up to and including for example the Beech King Air and Piper Cheyenne.

The decision to develop the Super 2 to meet requirements in full can be viewed from a bi-level – on the one hand, for a CofA it was necessary in the aircraft’s country of origin because the UK has no lesser set of requirements and on the other hand it can be thought of as a market investment, demonstrating the aircraft’s airworthiness to other aviation authorities and potential customers alike. However, Australia does have somewhat of a different regulatory situation because of its approval system for ‘heavyweight’ ultralights and this may force the question to be asked, “is it necessary or worth it for such a small and simple aircraft to meet rules normally applied to larger aircraft?”

It can be argued that there are practical as well as probably safety advantages associated with this path, bearing in mind that the training environment is one of high cycle utilization, firm landings and a share of mishandling. Thus the landing gear design is one example. Super 2’s gear is designed to a full set of loadings and is proven by drop tests and static load tests on the LG attachment structure. On the safety side, the DofA no doubt will bear in mind that the statistical safety trend for aircraft with concessioned airworthiness aspects, such as for example single ignition or flight handling items, is quite unknown because of lack of operational hours and once again it could be a problem in the training environment.

The Super 2’s structure is conventional semi-monocoque aluminium alloy, with frames, bulkheads, longerons, stringers, ribs, spars and skins fastened by a combination of cold-bonding adhesive and rivetting. The bonding distributes structural loads, enabling skins to be dimpled and flush-riveted with little likelihood of cracking around the rivets. Skin gauges are for the most part of 22/24 gauge. The aileron, flap, elevator and rudder trailing edge skins are folded into¼ inch base height blunt edges for ease of construction. It also gives a superior surface finish. The forward fuselage is moulded using a unique super plastically formed aluminium technique, by Supaform.

All this adds up to a relatively rigid surface, compared with other light aircraft structures and my guess is that it will result in a comparative reduction in gross skin friction drag.

Flight controls are conventional 3-axis. The aircraft’s ailerons and elevator are driven via torque tubes and push rods. The rudder is cable operated. The aileron torque tubes travel from the drive rods to the ailerons inside the flap leading edges. The plain flaps are mechanically operated. The wings, strutted and routinely removable, are swept forward 5. 2 degrees for centre of gravity placement.

The ARV is to an extent designed around its powerplant, a new Hewland Engineering (from Maidenhead, UK) inverted inline 3 cylinders two stroke. The engine has a single-piece crankcase and three individual carburettors for charging the cylinders. The firewall end of the crankshaft drives the ignition triggers and alternator. The front end drives the fixed pitch Hoffmann propeller through helical gears of ratio 2. 68 to 1. A note about the electronic ignition design is warranted. The engine is standard – 2 plugs per cylinder. The other end of the leads has 3 coils, amplifiers and triggers, controlled by separate ignition switches on the instrument panel. In fact, this system gives ‘dual and a half’ capability- insofar as, if 2 amps or coils go out, part power (2 cylinders) will still be developed; not enough to maintain height, but enough to assist a controlled descent.

The ignition, being electronic, must have the electrical busbar energised for normal operation, unlike magneto-equipped engines. If the alternator goes out the battery is sparking the engine (and will for about 2 hours before being drained). Thus a careful preflight of the battery charge condition on the voltmeter is warranted and during operation periodic checks on the alternator for normal operation are advisable (there is an alternator fail warning light). In flight test work to date the system has demonstrated good reliability, the only failure being one of the diodes on the alternator rectifying bridge.

The engine was Type Certificated along with the aircraft. ARV Aviation did the 150 hour type test programme at Sandown. Firstly three shakedown engines went through the test to bear out any design or reliability faults. The test rig was out in the weather and despite the customary British rains, its electronic ignition starting prowess each Monday morning was, according to staff, legend. The opportunity to flight test the ARV 1 Super 2 from the hot seat came after a couple of flights observing engine, climb and glide performance from the right hand_seat. After a frostx – 3°C night, the morning was sunny, with a mild southeasterly wind and scattered stratocumulus at 4000 feet.

A Super 2 preflight is standard with a few differences – the coolant pipes on the fuselage underside from the engine to the radiator should be checked for damage; likewise for the radiator; the coolant level in the header tank should be checked using the quick fastening access panel on the right side of the rear fuselage; the 12 volt 16 amp per hour battery is located alongside the header tank and has its access panel on the left side of the fuselage. The fuel tank is located in the fuselage behind the cockpit – the cap is between the wings and while it is easily accessible for refuelling, a ladder is required for the visual inspection of contents. Finally, don’t look for the oil dipstick that isn’t there.

As well as checking fuel sample from the tank drain for water and sediment the oil content of the fuel must be checked (following engine run-in the fuel to oil mix must be 40:1). It is intended that the mix is checked by using a dye in the oil and examining the stain colour on a special blotter comparator. Castro! A545 is the recommended oil. It is self-miscible, so premixing is not required. For refuelling, simply determine the fuel uplift and oil quantity (a marked measuring bottle is provided), add fuel to the tank up to 2 Imp gal, add the oil to the tank and then the remaining fuel. Fuel can be either avgas or mogas.

For entry, the cockpit is opened upwards from the front. It is supported in the open position by a pair of gas struts. Entry is assisted by a fixed step on each side of the aircraft. Settling oneself into the fixed position seat is straightforward. During the process, maps, headphones etc can be left on the cowling top where they are within easy reach. However, it is advisable for two people to enter sequentially to make it easier.

The cockpit has a large glove box on the right side of the panel and large map pockets on each side. Behind the cockpit there is intended to be a small but no doubt useful baggage compartment. The fuselage underside constitutes the cockpit floor. The dual control columns together form a U-shape and are each bolted to the control column torque tube assembly housed in a tunnel between the seats. Despite the asymmetric lateral movement of the stick about aileron neutral – the grip goes down and up slightly with left and right movement of the stick respectively – it is neither an awkward nor noticeably different feeling in flight.

Above the tunnel are the engine controls quadrant and pedestal to the panel. Brake and trim levers are on the pedestal. The flap lever is between the seats and the fuel selector 1s on the cockpit bulkhead, mid-height between the seats. The panel layout consists of, from left to right: fuel gauge, flight instruments, with electronic switches and fuses below, engine instruments, radio and glove box. Wet compass and OAT gauge are conveniently located centrally in the canopy roof. Of the general layout, I found the fuel selector to be ill-positioned. To check it requires a mild contortion. Relocating it on the pedestal requires the fuel line to be re-routed, but it would be worth it and may in fact be done in the future. Also, the carb heat lever on the rear face of the engine controls quadrant is a bit tucked away. Ease of operation would be enhanced if the lever was moved to the top of the quadrant, adjacent to and operating in the same sense as the throttle. With two on board the flap lever can be lost down the middle, leading to possible oversight of the flap position. A toughie – any alteration is a major re-design; perhaps extend the length of the handle forward so that it pokes its nose higher when the flaps are lowered and nudges a gentle reminder, on the pilot’s forearm as well.

Once seated and canopy shut I found the excellent and unobstructed visibility out of the aircraft provides a sense of spaciousness that belies the width of the cockpit.

Pre-start checks place some emphasis on assessing the electrical system integrity and in particular battery serviceability. The alternator output powers the main busbar through a diode which blocks the drain of charge in the event of an alternator short circuit. This diode must be checked using a diode test switch, which when depressed, contracts the voltmeter to the alternator side of the diode and should give an indication of zero volts with the engine stopped.

Engine start consists of opening the throttle a¼ inch, fully pulling out the choke and pressing the start switch. Following start, revs are set to 3500, with a choke in. The aircraft has dual electronic fuel pumps which are both switched on for start, takeoff, climb and landing (pump No. 1 is wired through IGN 3 switch and so is on continuously). After start the alternator master is switched on the charge checked. Because of the electronic ignition, it is vital not to overlook this selection and split rocker CB switch – with both batt and alt being switched on prior to start – would be preferable to the present separate switches.

The airfield we flew from, at Sandown, Isle of Wight, has a 3500 feet grass strip. The ground was frozen, hard and considerably rough. Taxiing over this ground, the aircraft tended to rock laterally somewhat; longitudinal oscillations were well damp. Steering forces were firm but responsive. Minimum turn radius 1s good. Feedback through the pedals from the rough ground was insignificant (a shimmy damper on the noseleg 1s standard). Brake power and effectiveness was excellent, as may be expected for such a small aeroplane. The aircraft does not have toe brakes: instead they are applied by pulling the lever on the pedestal above the throttle. As the engine, which of course has no spark retard, has a restricted RPM range below 2000 (because of possible rough running), Don Ellis, ARV’s Deputy Chief Test Pilot, showed me a single handed method of operating the brake lever and throttle simultaneously, to keep above the limit. I found after some adjustment that it is a usable technique.

Pre-takeoff checks are standard. Setting 4500rpm, I observed 150rpm drop on each of the three ignition switches. A failed spark plug would be indicated by a drop of about 600rpm on one of the switches off; a similar drop on any two of the switches off indicates a tailed coil or amplifier.

The takeoff into a quartering wind with a 10 knot crosswind component was fast but uneventful. Engine handling is very easy; RPM acceleration in response to a smart throttle advance was next to instantaneous. Takeoff technique advocated by Ellis was to maintain full back stick to raise the nosewheel as soon as possible and let the aircraft fly off. On the hard and rough strip it was the best technique. The nosewheel can be lifted off at about 30 knots IAS; the stick then needs to be checked to stop the aircraft over rotating when the elevator bites. On the rough strip the aircraft became skittish on the main wheels at about 50 knots and on this flight I invariably lifted off around this speed. On a smoother runway I would guess the nosewheel could remain on or near the ground with no problem and a positive rotation effected at a designated speed.

Nil significant trim change with flaps to up and normal climb at 70 knots. The nose of the aircraft was just above the horizon – slight turns to clear ahead which, in my opinion is a good habit to learn. Timed rate of climb through 2500 feet (in ISA-10°C) was about 700fpm (our weight being about 50Ib below the MTOWof 1100Ib). This aircraft, the prototype G-OARV, was at the time fitted with a non-standard coarser propeller, giving a full throttle rpm at a climb speed of 92% of max rpm. Climbing away, I checked longitudinal stability: elevator stick forces tor speed displacements away from the trimmed speed were quite positive.

Control force harmony was good. The rudder is very effective and overly sensitive and I wonder whether reducing the circuit gearing would have an effect. As it is, a delicate and constant feel on the pedals must be learned. Good tor a trainer? Most definitely yes. “Just like another British trainer, the everlasting Tiger Moth”, says Ellis.

Static lateral and directional stability with full throttle were found to be positive. In the cruise configuration (5500rpm, 81 knots IAS), following a 1o knot speed displacement, the phugoid damped out in a couple of cycles. Response to rudder doublets was more or less deadbeat, indicating strong Dutch roll damping; instead a particular asymmetric effect was observed, with both throttle full and closed. A right then left doublet saw the aircraft return to heading deadbeat; from a left to right doublet, the aircraft remained in a right bank and very slowly diverged into a spiral Secondary effects of controls are well demonstrated. The plain ailerons evince noticeable, but not awkward, adverse yaw and the aircraft can be rolled with rudder alone. The change in directional trim with power and speed is significant. Rpm variation with speed was quite marked, because of the propeller gearing. I found some close attention to rpm setting is needed following any speed change. The aircraft is happy to be sideslipped, although due to the strong roll effect from rudder it felt more comfortable to enter the sideslip by leading with aileron first. Roll response of the aircraft is most pleasant; at 70 knots a 60 degree roll reversal took about 2. 5 seconds, without really trying.

We carried out straight stalls, power off/approx 75% max and flaps up and set for landing (40 deg). The stall warning horn activated 3-5 knots above the stall speed. There is no noticeable buffet warning. First indication of the stall was a fluctuating wing heavying, controllable with an aileron. The minimum speed with full back stick was a further 1-3 knots lower; throttle closed, the aircraft exhibited ho pitch break, simply settling into a steady descent. With about 5500rpm set the aircraft gently nosed down and exhibited considerably less damping of the fluctuating wing heavying – maintaining full back stick saw the nose and speed oscillate, 5-8 knots up and down. Stall speeds: flaps up 51 knots IAS, flaps (land) 48. 5 knots IAS.

Cruising at 4000 feet with 5500rpm set gave about 81 knots IAS on the clock, although it showed some wandering in localised wave on this windy day. All-round visibility is excellent, making visual navigation not at all arduous. The ARV is type certificated in the Normal Type and Public Transport Category (a British classification) initially. Even so, SCAR K (and FAR 23) require that a one-turn (or 3 sec) spin be demonstrated with recovery within one additional turn. ARV have put the Super 2 through a rather comprehensive spin programme, to the tune of 250 spins, give or take a few, in four days by test pilot John Davies. No real problems were encountered. On this flight we investigated left and right incipient spins. With throttle closed, I applied full rudder and back stick at 60 knots. In both cases the aircraft rolled, tucked under and commenced a gentle and smooth auto rotation. Centralising controls after ½ turn stopped the rotation immediately. In the ensuing recovery from the dive, the stick forces felt to be somewhat lighter than in turning flight – the g built up quickly, as did the airspeed on this slippery craft.

Spiralling down from altitude with the throttle closed I tried left and right turning flight stalls. With stick fully back, the aircraft did not want to do a thing and could still be rolled with the aileron as normally.

We then rejoined for a few circuits. The circuit is definitely the best place for assessment of cockpit visibility; lookout is paramount in the busy patterns of airports like Bankstown and Moorabbin. The visibility from Super 2 is superb and is probably best appreciated most of all when clearing the airspace prior to a turn.

Rejoining downwind, 5500rpm was set, the speed being an average 80. Standard checks. Turning onto base – carb heat hot, 3500-4000rpm, lower the nose and flaps to approach (25 deg) below 80 knots. As advised, target speed for the approach is 70 knots. A lower speed could be applied in smooth air. With the power set and trimmed, the aircraft maintained its glide path easily and well stabilised. Over the threshold with landing flap and decelerating from 70, Super 2 had no tricks up its sleeve for the flare. On the four normal circuits we did, touchdown speed averaged about 53 KIAS. Ground roll was quite small, attributable to the effectiveness of the Super 2’s excellent brakes. The aircraft also handled the 12 knot crosswind with ease.

Our final circuit was a flapless, for which I extended downwind and used the same power and speed on final. The threshold remained well visible above the nose and the airplane settled easily on the ground.

The ARV exhibits qualities that should make it a good trainer.

But perhaps more importantly it has pleasant engine and flight handling that make it sheer and in a way, unexpected fun to fly for the recreational and even personal commuter pilot. Not only is its capital cost low, but at a mere 14 litres an hour of fuel and low maintenance costs (the engine has for example a minimum of moving parts), its running costs must be attractive to a school or private pilot.

To date ARV Aviation Ltd has been busy with development engineering and production establishment. Without a dedicated sales department, the aircraft has been selling itself to the tune of an average 4 per month, two-thirds of which are to private owners, the remainder being destined for training organizations. Originally uttered both in kit form and as completed aircraft, the market tor kits (in the UK) turned out to be quite shallow; on the contrary, the demand has been tor CotA aircraft (a kit plane can only ever fly under a Permit, as it is a homebuilt and thus could never be used for aerial work).

So what of the Super 2 in Australia? The design is not suited solely to the UK and Europe, the cost advantage must also be beneficial to the local training industry. It will be argued that the reduction in DOC will be offset to some extent by greater fixed costs caused by re-equipment financing: in which case however, the profitability will increase with time in service.

Australian interest started with Sir Jack Brabham ordering a couple of Super 2’s, one a kit. Noble’s policy, however, is one of worldwide •market penetration through licenced production. While several Australian groups have been interested in the licence rights. Selection of the licensee is a matter of some consideration by ARV. Building in Australia should present no difficulty because of the Super 2’s conventional metal construction. When arrangements are finalised we should soon see a demo plane flying. It is certainly worth taking a close look at the machine.