Air Test

Yes, that was 38 metres to get a tonne and a half of aircraft into the air!

Technoavia was formed in 1991, operating from the Smolensk Aircraft Factory. Its first design was the SM-92 Finist, a general purpose six/eight-seat all-metal utility aircraft with a strut-braced high wing and fixed tailwheel undercarriage. It was powered by a single Vedeneyev M-14P radial piston engine producing 360hp (268kW).

First flown on December 28 1991, it was intended for use in Russia’s remote areas with a single pilot and up to six passengers.

The aircraft featured a large sliding double door on the port side to load bulky freight, while it could carry two stretchers and a medical attendant in ambulance configuration.

Technoavia also produced a prototype of the military SM-92P version, featuring two rocket launchers and two machine guns fitted to the lower fuselage with another mounted in the open doorway. It is thought that five development aircraft and 10 production examples were constructed before output was suspended when the Smolensk factory closed.

The prototype Finist was converted to SM-92 Turbo Finist standard with the installation of a turboprop engine, before the conversion work was switched to Aerotech Slovakia, which converted HA‑DF as the SMG-92 Turbo Finist with a Walter M. 601 D-2 turboprop of 536shp (400kW), and this aircraft made its first flight on November 7 2000. At least six aircraft were subsequently converted to Turbo Finist standard.

The Finist was also intended for production in the Czech Republic by Moravan as the Zlin Z400 Rhino with a 485hp (360kW) Orenda diesel engine, and one airframe was converted as a prototype.

However, Moravan’s financial difficulties resulted in this activity being suspended.

Other conversions have meant that the aircraft has flown with a range of engine configurations, including the Walther range of engines and the ubiquitous Pratt & Whitney Canada PT6A and Allison 250 turboprops.

Apart from its fixed tail wheel undercarriage, it has also been operated on standard floats, amphibious floats and skis. In addition to its general purpose design, it has been used in both military and civilian air survey and scientific work, air rescue operations, air taxi work, medevac, glider towing and crop spraying roles.

First Impressions

Walking up to the aircraft, the first thing you notice is the size. With a wing span of 15m and an overall length touching 10m, and standing over 3m high in the three point attitude, this is a big aeroplane. Coupled to the engine is a huge three blade Avia propeller with a 2. 5m arc. Standing on a pair of gangly looking main legs with the longnose accommodating the turbine engine it reminds me of a daddy long leg spider. With an empty weight of 1507kg and a MTOW in parachute configuration of 2700kg, the aircraft has a useful load of 1207kg. In passenger configuration as a seven-seater it has a basic empty weight of 1544kg, which reduces the available load slightly.

The walk around is a pretty simple affair, inspecting the airframe and control surfaces.

The engine checks are a simple oil check ensuring that we have 5. 5 to seven litres.

The engine uses Aero Shell Turbine 500 as a norm and generally it’s not permitted to mix other brands. One thing you do notice is how clean the oil is –a pale clear purple –unlike the black sludge we are used to on piston engines. Refuelling is carried out with Jet A1 through standard filler caps located on the wings. At 3m it is a mountaineering expedition to get up to them! The long climb up to the front door (there are doors on both sides as well as the side entry cargo door), is accomplished by climbing onto the front wheel, then onto a step on the main leg, allowing access to a spacious flightdeck containing the throttle, propeller control and condition lever, as well as engine starting and override systems and the avionics stack. An overhead panel contains switches and circuit breakers for engine and avionics operations. The main panel contains a standard ‘six pack’ replicated onto the copilot’s side as well. In front of you is a standard yoke.

Both the seats and the rudder pedals are adjustable and it is quite easy for even a tall person like me to get comfortable.

The width of the airplane is such that the shoulder distance between the front seats is around 60cm, leaving the cabin feeling very spacious and bright.

Technoavia/Aerotech
SMG-92 Turbo Finist
Technical specifications
Performance
Max speed (SL) 170kt
Economy cruise (low level) 156kt
Stall speed clean 62kt
Takeoff run 38m
Weights
Max takeoff weight 2350kg
Load 850kg
Fuel capacity 296kg (270 litres)
Dimensions
Wing span 14.60m
Length 7.80m
Height 1.38m
Manufacturer
Technoavia
www.technoavia.ru

Strapping yourself in you notice just how high you are above the ground and how the nose of the aircraft seems to stretch ahead of you for an eternity, the two jet pipes clearly visible either side of the long sharp nose.

Engine start

Engine startup is a fairly simple process.

Generally a start is performed using a ground power unit as the internal batteries are easily drained and a constant voltage is critical for a good start. Starting a turbine engine is quite different to starting a piston engine – we need to spin the gas generator up prior to adding fuel and igniting it.

Once ignited, the engine should continue to spin up to operating speed and become self-sustaining. To do this we use a starter generator unit that sits on the back of the pg62-65. turbine shaft. During starting it turns the turbine shaft to bring the gas generator up to ignition speed, and once the engine is running it then becomes an AC generator.

To start we switch on the master, and the annunciator panel will give us a min fuel pressure warning. Switch on the boost pumps and check the voltage, which must be no less than 24v or the start will fail. We push the start button and wait for the gas generator speed (Ng) to rise to 15 per cent and push the condition lever to interlock – this feeds fuel into the combustion chamber and the igniters do the rest. Keep an eye on the ITT gauge to ensure that it does not exceed 735⁰C. The engine then accelerates and settles at the idling RPM of 60-63 per cent Ng, and as the oil pressure rises the min oil pressure light should go out.

On the Walter engine, start is protected by the IELU system – integrated electronic limiting unit. This intervenes through the fuel control unit to help prevent hot starts by reducing the fuel flow to prevent overheating of the turbine. The IELUs cut out after 40 seconds when the start cycle is complete.

Once the start is complete the ground power unit is disconnected, the generators turned on, and we are ready for taxi.

Fun taxiing!

This is where the fun begins! The gas generators produce 60 per cent power while still at idle, which leaves us with a large amount of residual thrust from the jet pipes as well as the reaction from the propeller.

Coupled with being a tailwheel configuration with its natural tendency to weather cock, this is a real handful of an aircraft to control on the ground. Taxiing on the brakes just overheats them and they fade to useless very quickly. So to taxi we use the beta range, ‘fly beta’ allows the prop to disc, and we move largely on residual thrust when empty. When at max weight we move in and out of ‘flight idle’ and ‘fly beta’ and to brake, bring back the prop lever to ‘ground beta’ which gives us reverse thrust.

This requires you to keep your wits about you as the change from forward to reverse thrust causes the aircraft to swing back and forwards –it takes some practice to react correctly and not overcook it and end up in a ground loop! At the hold, a check on the propeller feather and making sure we have strobes as well as full and free movement completes the preflight checks. No magnetos or carburettor heat to check here! Lining up with 20 degrees of flap and a 10kt headwind we allow a little power and wait for the turbine to spool up. This takes the gas generator to about 90 per cent and the torque to around 50 per cent, and we get very busy with our feet keeping it straight down the runway. On an ISA day at basic weight this sees a ground roll of 38 metres. Yes, that was 38 metres to get a tonne and a half of aircraft into the air! The Turbo Finist lifts off in the threepoint attitude at about 59kt and climbs at around 1800ft/min, needing a leg-aching amount of right rudder to keep the ball in the centre.

Climbing to 2000ft I set the torque to 50 per cent, which leaves the gas generators running at about 95 per cent, and settle into an economy cruise of approx 170kt TAS. We are burning about 150kg (187 litres) of jet fuel an hour in this configuration.

It is worth dwelling for a moment on the climb performance in this aircraft, which is one of the primary reasons it is used in parachute configuration. It will climb to FL150 in 11 minutes and back again in around four minutes, giving approximately a 15 minute lift time. In the high pressure world of parachute dropping, this reaps huge dividends.

In cruise flight the aircraft handles very conventionally. Steep turns are easy, requiring no power changes but a careful eye on the altimeter. It’s easy with this much power on tap and at these speeds for it to run away from you.

The glide performance in a PFL has to be seen to be believed. From 2000ft with the prop feathered and at best glide, the descent rate is under 300ft/min –it takes a very long time to come down!

Slow flight

Stalling the Finist when empty is an interesting experience. Bringing the power back to flight idle leaves a considerable amount of residual thrust, so the amount of pitch up required to actually get the aircraft to stall in the first place is considerable.

Once the wing finally does stall, the nose just gently pitches down and the aircraft slowly wallows its way downward.

Remove the back pressure and the aircraft quickly recovers.

Returning to the circuit for a downwind join sees the power brought back to flight idle and the speed starts to come back to 81kt, the residual thrust being enough to keep us in the air. Turning onto base leg I put out first stage of flap, then on final I go to full flap and set the airspeed for 75kt. I have to use ‘fly beta’ to maintain the airspeed and correct rate of descent in order to get to the threshold and not overshoot.

Coming over the hedge I maintain the airspeed, and in the flair bring the speed back to 54kt and touch down in a three-point attitude. As I touch down I progressively bring in full ground beta, ready to catch any swing from the suddenly reversed airflow and come to a stop in about 50m. The taxi back is a reverse of the taxi out, ever mindful of the weather cocking effect and the poor brakes.

Overall this is a very nice aircraft to fly.

It has powerful controls, and for such a large aircraft it is very responsive. Due to the enormous power on tap it does require constant flying –a moment’s inattention can see height changes of several hundred feet. It is hard work in the climb, requiring constant significant rudder input, although the second Finist that I fly does have a rudder trim, that while not completely trimming out the rudder forces, is a significant improvement. It has a huge load carrying capacity and breathtaking performance, and it is clear to see why it makes such a great parachute aircraft.

Not to mention that sitting behind a turbine engine does bring a smile to your face! n