Yakovlev Yak 18T — yak18t_fltrep18 NOT FOR FLIGHT — source fidelity: unreviewed | operational review: none | completeness: full Source: Yakovlev/Yak 18T/yak18t_fltrep18.txt Rights: licensed Checklist hash: d554d9058dfbb6bdeae47891b2b6a24eae64f1377c6dfdcabd02cf5819a80e84 Verify against the aircraft's own approved documentation before use. ======================================================================== YAK 18T FLIGHT REPORT — GENERAL DESCRIPTION ------------------------------------------- GENERAL ** NOTE: A four-seat tourer-cum-aerobatic trainer, the 18T was designed by Yuri Yankyevich and first flew in 1967. ** NOTE: More than a thousand have been produced and delivered, mainly to Eastern Bloc countries. The manufacturing licence was subsequently bought by TechnoAvia in Moscow. ** NOTE: Nine-cylinder supercharged Vedeneyev 360hp M-14P radial engine. ** NOTE: At 27 1/2 feet long and 36 1/2 feet span, the Yak is nearly four feet longer and a foot wider than a Piper Warrior. CONSTRUCTION ** NOTE: Riveted alloy panels form the main structure. The rudder, double-braced tailplane and elevator are fabric covered. ** NOTE: The split elevator has an adjustable trim-tab on each side, while the rudder carries only a fixed tab. ** NOTE: The wing centre-section carries an oil radiator in the starboard wing-root and a large metal single-position plain flap-cum airbrake across its span, plus the inward-retracting main gear legs. ** NOTE: The battery is mounted on a hinged tray in the port wing-root, released by three Camlock fasteners, and may be dropped down for service. ** NOTE: External power connector behind a small access door near the port wing-root. WINGS AND FUEL ** NOTE: The wing dihedral starts at the break point just outboard of the main undercarriage. The outer wing panels are fabric-covered and can be removed. ** NOTE: The port wing carries a long barber's-pole-striped pitot tube, the stall warning vane, and a large-diameter landing light. The Frieze ailerons are also fabric-covered, while tie-down rings are provided near each wingtip. ** NOTE: Each wing contains a 95 litre (21 imperial gallon) fuel tank, of which four litres are unusable. UNDERCARRIAGE ** NOTE: On each of the three gear legs is a small, forward-facing white light for the benefit of the flight dispatcher to confirm undercarriage down at night. ** NOTE: Three small mechanical plungers protrude — one from the top surface of each wing and one just in front of the windscreen — to act as a belt-and-braces method of checking the undercarriage position. ** NOTE: Main wheels are 5.00 x 500. Long anti-static wicks trail from each main wheel assembly. COCKPIT AND EQUIPMENT ** NOTE: Each door is individually jettisonable via a prominent red handle below the panel. The aircraft can be flown with both doors removed. ** NOTE: The front seats are fore-and-aft adjustable. Four-point harness is fitted; no central fifth g-strap nor second aerobatic security strap is provided. ** NOTE: The hinged rudder pedals have leather stirrups but no brake pedals. The pedal assemblies are adjustable. ** NOTE: Rear passengers have a wide bench seat behind which sits a large yellow-painted auxiliary fuel tank holding 95 litres, which drains automatically into the wing-tanks. ** NOTE: The cockpit trim and rear seat materials are reminiscent of an early 1960s aeroplane. ** NOTE: The rear side windows boast sliding curtains, also fitted above the two front seats. Two smoked plastic sun visors hinge down from the top of the screens. ** NOTE: A pull-cord arrangement unrolls a miniature window-blind in front of the pilot's screen to facilitate IMC training. ** NOTE: A two-speed, self-parking windscreen wiper is fitted, but no washers. ** NOTE: The panel is dominated centre-stage by a huge electrically-driven and non-toppling artificial horizon. ** NOTE: A gyro-magnetic compass is adjustable for north or south hemispheres and individual latitudes. FUEL SYSTEM ** NOTE: A single fuel gauge with a selector switch shows total litres in both tanks on the outer scale, and the contents of the selected tank on the inner scale. ** NOTE: The fuel is controlled by a prominent red T-handle on the panel left of the quadrant. Push for On, pull for Off. ELECTRICAL SYSTEM ** NOTE: A combined single ammeter/voltmeter is fitted; press its switch for amps, release for volts. CONTROLS ** NOTE: Each yoke sports two PTT buttons; the left-hand one opens the air-ground transmission circuit, the right-hand one activates the cockpit intercom. ** NOTE: The pneumatically-operated brakes work through a pull-handle on the back of each yoke. The P2 position has an override button to allow the instructor to release the brakes. ** NOTE: The park brake is a small button under the yoke; pull the lever and press the button. ** NOTE: No nose-wheel steering: to turn on the ground, press the appropriate rudder pedal and squeeze the brake lever. ** NOTE: The pitch trimmer is a small handle on the left-hand cockpit wall, low-geared taking five turns from full aft to full nose-down trim. A light indicates neutral trim. ANNUNCIATION AND WARNING LIGHTS ** NOTE: Annunciation lights show Fuel low and Gen. fail. Two red lights flash Slow and Stall as the aircraft approaches stalling speed. UNDERCARRIAGE AND FLAP CONTROLS ** NOTE: The undercarriage lever is set low down on the left-hand end of the panel, pressed firmly before operation, with a slide-across safety bar. ** NOTE: The two-position (Up and Down) flap lever is on the central quadrant with the cowl gills control, carb heat, oil cooler selector and throttle friction lever. ** NOTE: The prop lever actuates a microswitch which, at anything less than full throttle in fully fine setting, illuminates the landing gear warning light. STARTING -------- ** NOTE: The big radial requires to be thoroughly warm before flight. ** NOTE: For really cold climates the engine oil can be diluted by a button next to the starter, feeding neat petrol into the sump, up to twelve per cent dilution. [ ] Primer ................................................ SEVERAL PUMPS [ ] Primer selection ................................... LINE OR CYLINDER [ ] Starter button outer ring ... UNLOCK — TURN UNTIL TWO RED DOTS ALIGNED [ ] Master switch and almost all the double row of switches .......... ON [ ] Starter ....................................................... PRESS [ ] After two or three blades have passed the vertical, magneto switch ... TURN ANTICLOCKWISE TO 1+2 [ ] Throttle (to get all nine cylinders on line) ....... JUDICIOUSLY PUMP [ ] Engine idle ...................................... AROUND 30 PER CENT TAXYING ------- ** NOTE: Taxying requires a degree of initial concentration, at least until the braking system is mastered for turning. ** NOTE: No nose-wheel steering: to initiate a turn requires differential braking by pressing the appropriate rudder pedal, then squeezing the brake lever. PRE-FLIGHT RUN-UP ----------------- ** NOTE: The pre-flight run-up only differs slightly from that of a Lycoming or Continental. TAKE-OFF -------- [ ] Initial pitch-up overcome by ... FIRM PUSH FORWARD IMMEDIATELY AFTER LIFT-OFF [ ] Lift-off speed .............................................. 130 kph CLIMB ----- [ ] Best climb speed ............................................ 170 kph [ ] Rudder ....... CONSIDERABLE BOOT REQUIRED AGAINST TORQUE AND P-FACTOR CRUISE ------ [ ] Cruise setting ......................... 59 PER CENT CRANKSHAFT SPEED [ ] Manifold pressure ...................... 6 ON DIAL (600mm OF MERCURY) ** NOTE: Fly at almost equal settings on the two gauges, e.g. 80/80, 60/6. Throttle and prop levers are well-matched and can be treated almost as one. ** NOTE: At 6,000 feet the 59 per cent setting produces 150hp and fuel consumption of eleven gallons an hour at 205kph (110 knots). ** NOTE: The M14 radial has a rather irritating harmonic in cruise; both prop and throttle levers vibrate sufficiently to blur their handles. AEROBATICS AND HANDLING ----------------------- ** NOTE: Ailerons and elevator are light and responsive, though the rudder is heavier. Full aileron requires only about forty degrees deflection either way. ** NOTE: The test aircraft had no inverted oil system, so no negative manoeuvres were permitted. An inverted oil system is an option. ** NOTE: G limits are +6.4/-3.2g. STALL AND SPIN -------------- [ ] Stall speed (depending on all-up weight and power settings) ... 100 kph (54 kt) TO 123 kph (65 kt) ** NOTE: The stall is signalled by a horn, flashing lights and a pre-stall buffet. Roll authority remains present throughout. ** NOTE: The Yak is cleared for spinning; a three-turn spin and recovery consumes about 2,300 feet loss of height. CIRCUIT AND APPROACH -------------------- [ ] Gear and flap extension ............................... BELOW 200 kph [ ] Approach speed .............................................. 150 kph [ ] Trim (with two occupants) .................................. FULL AFT [ ] Threshold speed ............................................. 140 kph [ ] Touch-down speed ..................................... AROUND 115 kph ** NOTE: In the last stages of final approach and flare, the airfield disappears under the nose; look peripherally to judge height and keep directionally straight. ** NOTE: There is little float; touchdown occurs about six inches before one expects it. Unless the yoke is right back at contact, the nose-wheel drops with a thump. TOUCH-AND-GO / BALKED LANDING ----------------------------- [ ] Aft trim .................................. UNWIND RAPIDLY TO NEUTRAL [ ] Prop and throttle ............................... PUSH FIRMLY FORWARD [ ] Flaps ............................................................ UP [ ] Undercarriage ............................................... RETRACT [ ] Shoulder harness (before going round) ........................ UNLOCK ** NOTE: Pitch-up is accentuated if flaps are still down or trim hasn't reached neutral by lift-off. LANDING ------- [ ] Brakes ................................ MUST NOT BE USED OVER 110 kph ** NOTE: Deceleration after landing is noticeable, even without brakes. DIMENSIONS ---------- [ ] Length ................................................... 27 ft 6 in [ ] Height ................................................... 11 ft 2 in [ ] Wing span ................................................ 36 ft 7 in [ ] Wing area .............................................. 202.36 sq ft WEIGHTS AND LOADINGS -------------------- [ ] Max AUW (utility) .......................................... 3,637 lb [ ] Max AUW (aerobatic) ........................................ 3,307 lb [ ] Empty weight ............................................... 2,683 lb [ ] Useful load (utility) ........................................ 954 lb [ ] Useful load (aerobatic) ...................................... 624 lb [ ] Fuel capacity (as tested) ............................. 62.7 imp gall [ ] Wing loading (utility) ............................... 17.97 lb/sq ft [ ] Wing loading (aerobatic) ............................. 16.34 lb/sq ft [ ] Power loading (utility) ................................. 10.10 lb/hp [ ] Power loading (aerobatic) ................................ 9.18 lb/hp PERFORMANCE ----------- [ ] Cruise at 59% crank speed .................................... 110 kt [ ] Max speed in level flight .................................... 156 kt [ ] Vne .......................................................... 161 kt [ ] Stall (clean) ................................................. 64 kt [ ] Stall (with flaps and gear) ................................... 55 kt [ ] Take-off roll (firm grass) .................................... 370 m [ ] Landing roll (firm grass) ..................................... 390 m [ ] Take-off (firm grass, to 50 ft) ............................... 690 m [ ] Landing (firm grass, from 50 ft) .............................. 790 m [ ] Range (as tested, with reserves) ............................. 485 nm [ ] Rate of climb at s/l ................................... 1,082 ft/min [ ] Service ceiling ........................................... 18,000 ft ENGINE AND PROPELLER -------------------- [ ] Engine ... Vedeneyev M-14P supercharged single-row air-cooled nine-cylinder radial, 360 hp at 99 per cent crankshaft speed (2,900 rpm) [ ] Propeller ... B530TA-A35 constant speed, two-bladed, wood, 94.5 inches diameter