72724063fec855cdfc319465613054c67fdc12445136a42ad32760c202c98b88 Section "Aircraft Description" item count differs between passes (25 vs 24); verify nothing was dropped. Section "Cruise" item count differs between passes (4 vs 6); verify nothing was dropped.

General The Yak 50 is an all-metal tail dragger designed solely for advanced aerobatics training and competition. The fuselage is semi monocoque, a combination of stressed skin and steel re-enforcement. The strong but simple main gear is semi-retractable, the lockable tailwheel permanently extended. The Yak 50 has no flaps. Flying controls are conventional and operated by control cables for the elevator and rudder, push rods for the ailerons. Only the elevator trim is adjustable in flight, the rudder and ailerons served by fixed tabs which are manipulated on the ground. Engine Power Powerplant: Ivchenko M14 radial, supercharged nine cylinder radial, 360hp at max rpm. Propeller: variable pitched two-bladed paddle via a simple gearbox. Fuel capacity on the basic aircraft is 11.4 imperial gallons contained in a single tank mounted aft of the firewall. Maximum flight endurance is quoted as 50 minutes and this figure can be halved during advanced aerobatic flights. A welcome mod fitted to the vast majority of Yak 50s is the installation of a cruise tank which more than doubles the fuel capacity, although the G limits are reduced when full fuel is carried. The Yak 50 uses pneumatics for engine starting, gear and brake operation. The aircraft's air bottle will give around 12 start attempts before a recharge is necessary and a reserve bottle is also installed for emergency gear extension. The main bottle gets recharged automatically once the engine has started. Cockpit The undercarriage lever is positioned on the left of the main panel, two green lights confirming that the gear is down and locked when the aircraft is on the ground. The throttle, rpm and lock lever form a meaty quadrant on the left shelf with another panel ahead comprising levers for the engine cooling gills and oil cooler flap. For most of the year the cooling levers will reside in the fully forward (open) position. The big red lever is the fuel shut off, replacing the emergency function of a mixture lever. Fuel mixture control is fully automatic. The instrument panel uses metric units. Most owners replace the altimeter since it reads in meters. The airspeed indicator reads in km/h. The engine has two main control indicators: an rpm gauge reading from 0 to 100%, and a manifold pressure gauge reading in mm of mercury. The Yak 50's electrics are in the centre of the panel and the fuel primer is located to the top right. The mag switch is mounted on the left of the panel next to the engine starter button.

Climbing into the cockpit and strapping into the chunky five point harness, one is immediately aware of the ruggedness of the Yak 50. Visibility from the cockpit is excellent in every direction except forwards.

Battery master OFF Ignition and mags OFF Primer lever TURN LEFT Primer pump PUMP 5 TIMES Primer lever TURN RIGHT Primer pump while helper turns prop PUMP SIMULTANEOUSLY Prop blades past windscreen 9 BLADES Prop turner CLEAR Battery, ignition and generator ON Throttle OPEN 2 INCHES Starter switch HIT As engine fires, mags BOTH Keep engine going with primer pumps LIBERAL PUMPS Don't bother pumping the throttle – no accelerator pump is fitted and this will have zero effect. After start, leave the primer centralised, not turned to the right. Result of leaving it right: rough running engine, excessive fuel burn and early engine overhaul.

After a few seconds the engine settles down CHECK Switches SET Radio ADJUST Straps RETIGHTEN A cold Ivchenko does not warm up to taxying temperature in less than five minutes, with ten minutes being more typical on a standard UK day. Oil temperature reaches 40 degree point WAIT Engine run DO

Differential braking is applied by a stick-mounted hand lever and controlled by the amount of rudder applied away from its neutral position. With the stick in the aft position, the Yak 50's tailwheel will lock straight. To turn, push the stick forward; taxying with the stick aft locks the tailwheel straight.

Throttle and rpm levers FULLY FORWARD Left rudder (prop goes round the 'wrong' way) PUSH Throttle ADVANCE FULL FORWARD

Once aircraft is underway, stick FORWARD TO RAISE TAIL Take-off roll is around 100 metres at MTOW. Climbs at 3,000 feet per minute.

Gear RAISE BEFORE 200 KM/H Prop rpm REDUCE TO MAX 82% A more modest '70%, 70mm' setting conserves engine life.

In the cruise any 'square' setting will do, for example, for 70 on the manifold gauge set 70% rpm, for 60 manifold set 60%. Cruise speed UP TO 280 KM/H (151 KT) Full throttle and 82% are the quoted maximum continuous power setting, giving max level speed of 300 km/h (162 Kt). Major engine overhaul every 500 hours.

In the circuit the Yak is easy to operate. The sum total of good all-round visibility, draggy aeroplane and high power results in a slick approach every time.

Undercarriage LOWER AT 200 KM/H OR LESS Approach speed 150 KM/H Threshold speed 100 KM/H The speed reduction on finals requires the throttle to be closed early and the aircraft held off until the speed bleeds back.

The Yak's large wing and short undercarriage can cause an excessive float if the airspeed is too high on landing. With repeated practise the Yak can be brought to a halt in 150 metres on a dry surface.

Control harmony is typically 3.2.3 for ailerons, elevator and rudder instead of the classical 1,2,3. Spades are an option on the Yak 50, recommended for serious aerobatic pilots. In pitch the Yak 50's stick force per G is very light; pulling up to the nine G maximum does not require excessive strength. During advanced aerobatics many pilots release the throttle to fly with two hands on the stick. With the aircraft wound up to its Vno of 400 km/h (226kt) the Yak 50 can perform huge lazy loops, barrel rolls and wing overs with low G forces. Stalls and spins are surprisingly docile. Stall and spin recovery are predictable and standard. Some advanced aerobats have to be positively wrestled out of an established spin; the Yak 50 is one of the exceptions.

With a standard 55 litre fuel tank fitted, an airfield will be needed every 60nm when cruising at 162kt. A more sedate 200 km/h (108kt) improves the range to 85nm. With a cruise tank fitted the aircraft's best range jumps to 250nm at economy cruise. Given such a short range, a GPS is a very desirable installation for a Yak 50.

External Dimensions Span 31 FT 3 IN Length 24 FT 5 IN Wing area 161 SQ FT Weights and Loadings Empty weight 1,624 LB Useful load 496 LB* / 377 LB Gross weight 2,120 LB / 2,001 LB Power loading 5.9 LB/HP Wing loading 13.1 LB/SQ FT Fuel capacity 26.2 IMP GALLONS G limits +9G / -6.6G Number of seats 1 (*denotes aerobatic figures) Power Engine manufacturer/type IVCHENKO (VEDENEYEV) M14P Max power 360 HP @ 2,900 PROP RPM Propeller type and diameter 2-BLADE VP 94.2 IN Performance Vne 232 KT Maximum level speed 162 KT Cruise speed @ 75% 151 KT Stall speed, power off 48 KT Stall speed, power on 45 KT Rate of climb (sea level) 3,000 FT/MIN Ceiling (oxygen limited) 10,000 FT Take off run 328 FT Landing run 492 FT Range (cruise tank, 45 min reserve) 200 NM Endurance 2.5 HR Price Price £35,000-£45,000 UK suppliers MARK AND JOHN JEFFERIES AT YAK UK, LITTLE GRANSDEN AIRFIELD, BEDFORDSHIRE. TELEPHONE (01767) 651156