These notes are for the information of Lasham Tug Pilots and give Lasham operating procedures with the aircraft type. They do not supersede the information in the Aircrew Manual for the type, a copy of which is held in the office and should be consulted from time to time as appropriate.
RALLYE 180T G-BTUG and G-BLGS. This mark of Rallye was built by SOCATA in France (now a subsidiary of the Aerospatiale Group) especially for towing. The aircraft weight was kept low by using the airframe previously only used for models up to 150 HP. It also has wing tip extensions to reduce induced drag and this also improves the rate of climb because more thrust is available for climbing. Both aircraft were bought new in 1978. Since new, one aircraft has had its engines replaced twice, and the other one three times. In 1993 when these notes were revised, both aircraft now have A4A engines with solid cranks that do not interact with the propeller and the red arc restriction does not apply.
Weights. The max AUW of the aircraft is 2095 lbs. The dry weight is around 1285 lbs, giving a disposable load of 810 lbs. Full fuel (37.4 gals) weighs 270 lb, giving a permissible cockpit load of 540 lbs. Note that the rear seat max is 310 lbs, and refer to the flight manual when planning a flight near the max AUW. A typical towing AUW is 1600-1650 lb (eg Pilot of 195 lb, fuel 120-170lb (40-60%) ).
Fuel and Weight. As part of keeping the weight down for towing the Flight Manual suggests that the aircraft should be restricted to half tanks for towing; this is not a mandatory safety regulation but a suggestion in order to ensure a reasonable rate of climb when towing. The aircraft holds 18.7 gallons per side (1 is unusable) and our normal practice is to fill to 10 gallons a side (about 5/8 full) from March to October but to completely fill the tanks each night during the winter to avoid condensation problems. In the winter, the lower temperatures balance the extra weight and rates of climb are still reasonable. In use the aircraft consumes about 1.1 gallons per 2000 ft tow.
Washing & Cleaning. Being sheet metal aeroplanes, some corrosion problems have been encountered, especially down the left side in the path of the exhaust gases. For this reason we expect our pilots to wash them down at the end of each days flying. In the winter, mud in the flap tracks causes problems and needs clearing out every 10 to 20 tows, failure to do this could force the flap rollers out of the guide or stall the flap motor.
Operations - General. In operation, the Rallye is pleasant to fly having reasonably responsive controls, a very docile stall, slats and powerful Fowler flaps, and an toe brake system to each main wheel that operates independently of the nose wheel or rudder positions. Be careful with the trimmer, it too is powerful and only requires small movements of the cockpit wheel. Ground steering is through differential brakes and a castoring nosewheel. The nosewheel assembly is rather fragile and the hydraulic damper is not very rigid, allowing the nose to bob up and down when taxying over undulating ground. Because there is no nosewheel steering, in strong winds on slippery ground, difficulty may be encountered in maintaining directional control when taxying crosswind.
PARTICULAR CARE MUST BE EXERCISED WHEN TAXYING WITH A TWO BLADE PROPELLER ON THE RALLYE, DUE TO LIMITED PROP CLEARANCE AND THE `SOFT' NOSE OLEO. TAKE ALL RUNWAY EDGES SLOWLY AT 45 DEGREES.
Stalling. The slats on the leading edge of the wing extend automatically below 69 knots and contribute to very safe handling at the stall. If the aircraft is held in the stall the controls remain effective and it is difficult to provoke a wing drop, but the sink rate will significantly increase, rate of descent increasing quickly to 900 fpm. The way the controls remain effective through the stall can tempt people to approach too slowly and unless a threshold speed of at least 50 knots is achieved, an unnecessarily positive arrival may result. With such powerful flaps, pilots new to Rallyes may find that they need to add power to compensate for the extra drag of full flap in order to stop the speed from decaying. If in doubt about stalling characteristics when you are flying a tug, stall it gently at a safe height, such as during a return from a tow. But bear in mind that later near the ground you have wind gradient, turbulence, and other control movements to contend with, all of which need a good increment over the stall to ensure safety. And if you fly it on another day, the stalling speeds may not be the same because ASIs are sometimes changed, ASI tubing can develop kinks, bugs or grit, and both speeds and characteristics will be different if the wing surface has mud on it, is wet, or a repair on the leading edge has been made.
Aerobatics and Spinning. The aircraft is non aerobatic and is not cleared for spins. The Flight Manual warns that recovery from an unintentional spin will need a 40 lb forward force on the stick to stop the spin.
Field Retrieves. These aircraft should not be used for field retrieves without the specific permission of the CFI or Tugmaster because the Super Cub is always our preferred field retrieve aircraft due to its low landing speed.
Opening the Canopy in Flight. The canopy can be open in flight provided the following speed restrictions are obeyed, up to 20 inches open max speed is 80 knots, over 20 inches 70 knots. Experience shows that a loop of strong cord from the handle to the catch is needed to prevent the canopy moving, and restricting the opening to 20 inches as it vibrates badly when further open.
Takeoff and Initial Climb. In glider towing, take off with half flap, expect 2450 rpm on the roll and be particularly careful to keep your feet clear of the brakes, the lightest touch delays the take off significantly. Make a point of initially holding the stick well back to ease the download on the nosewheel because we have had several cracked noselegs. Once off the ground, with a heavier glider do not rotate straight into the climb but build up speed first to just short of the correct climb speed for the glider, and then gradually pitch nose-up into the climb.
THE DI, COVERING ONLY POINTS PARTICULAR TO THE RALLYE
Include the other normal DI checks as you go around the aircraft.
RUN UP AT 1800 RPM. MAX MAG DROP 125 RPM. Avoid prolonged ground runs to prevent hot spots damaging cylinders. Typical carb heat drop 100 rpm.START UP CHECKS - RALLYE
NOSEWHEEL TOW BAR REMOVED RADIO................... OFF MASTER SWITCH.......... ON, fuel gauges read, low oil pressure light ON. FUEL.................... Select tank, note contents MIXTURE................. In for rich. CARB HEAT In for cold. ALTERNATOR.............. Off, switch down FUEL PUMP............... ON, prime engine, pressure in green then OFF BRAKES ON THROTTLE SET (1/2 inch open) MAGS ON (Both) *START* OIL PRESSURE Rising ALTERNATOR............. ON, check charging. RADIO.................. ON
PRE TAKE OFF CHECKS - RALLYE
Mnemonic: TT MM FF I HH C
Trim HALFWAY
Throttle friction SET
Mixture RICH
CARB HEAT COLD
Mags BOTH ON
Fuel SELECT L or R, CONTENTS
FUEL PUMP ON, PRESSURE OK
Flaps HALF
Instruments CORRECT
Hatches CLOSED & LOCKED
Harness TIGHT & LOCKED
Controls FULL & FREE
AT ABOUT 500 ft FLAPS UP
FUEL BOOSTER PUMP A/R
DURING THE CLIMB - Make sure the throttle friction adjuster at the panel end of the throttle lever is tight. If not, the throttle and therefore the rpm, can slip back during the climb.
TOWING SPEEDS - RALLYE, NO FLAP
MIN TOW SPEED .......... 54 Kts K13's................... 57 Kts ASTIRs and similar...... 65 Kts NORMAL GLASS 70 Kts Ballast add 5 Kts
ENGINE FAILURE - RALLYE `Fly the aircraft' as a first priority so that you do not, for instance, stall, or lose reference on a landing field. Only then, diagnose the fault and attempt remedial action.
LOWER THE NOSE
GET RID OF GLIDER
BEST GLIDE SPEED
FOR RANGE IN NIL WIND: 81 Kts (about 1:10 prop stopped, 1:9 prop rotating)
SELECT FIELD, TURN IF NECESSARY
R/T - MAYDAY TO LASHAM WITH POSITION & LIKELY LANDING AREA
Check:
FUEL CONTENTS & TANK SWITCH, SWITCH TANKS ANYWAY
FUEL BOOSTER PUMP - ON if not already on
MIXTURE LEVER - CHECK FULLY RICH
MAGS - TRY SWITCHING TO A SINGLE MAG
THROTTLE - EXERCISE TO TRY AND GET A RESPONSE
When committed to engine-off landing;
MAGS - OFF FUEL - OFF STRAPS - TIGHTDESCENT - RALLYE MAX MANOEUVRING SPEED (Vm) 113 Kt. Above this speed the aircraft is only cleared for use of one third of the available control surface deflection. This may not be enough for emergency collision avoidance action.
ROUGH AIR SPEED (Vra) 108 Kt - Use this as the normal descent speed. APPROACH - RALLYE FLAP LIMITING SPEED 80 Kt INITIAL APPROACH Strong Winds 70 Kt Slack Winds 60 Kt MIN THRESHOLD - FULL FLAP Vref, speed for round-out 50 Kt SHUT DOWN RADIO OFF Mags Dead Cut check at Idle FUEL PUMP OFF (if in use). MIXTURE FULLY LEAN. Engine Stopped MAGS OFF, remove Key ALTERNATOR OFF MASTER SWITCH OFF (3 switches all down) FLAPS HALF BRAKES A/R
TAKEOFF: Conditions, smooth hard surface, 2100 lb AUW, 20°C, no wind, no slope, pressure height 600 ft. Since a normal towing AUW will be about 1600 lbs, the figures for a weight of 2200 lb roughly equate to those towing a 500 lb glider
Unstick dist @ 1.1Vs = 870 ft
Dist Unstick to 15m/ 50ft @ 1.3Vs = 610 ft
Dist to 15 m / 50 ft @ 1.3Vs = 1480 ft
GRASS TAKEOFF
Short grass, add 10% to unstick, ie: Unstick = 960 ft
Dist Unstick to 15m/ 50ft = 610 ft
Dist to 15 m / 50 ft @ 1.3Vs = 1570 ft
Medium high grass, add 25 % to unstick, ie: Unstick = 1090 ft
Dist Unstick to 15m/ 50ft = 610 ft
Dist to 15 m / 50 ft @ 1.3Vs = 1700 ft
CRUISE: Depending on conditions, fuel consumption is between 9 and 11 imp gal per
hour, endurance on full fuel between 4-5 hours and range 500 - 600 NMl. For more
exact figures, consult the flight manual. Towing a draggy glider will degrade these
figures although modern glass gliders have very little drag, and towing a heavy glider
will cause substantially more fuel to be used in any climb.
LANDING Conditions: 1600 lb AUW, 20°C, no wind, no slope, pressure height 600 ft, moderate braking, runway or short grass
Distance from 15m / 50 ft = 1012 ft
50 ft to touchdown = 584 ft
Landing Roll = 428 ft
HEADWIND: Multiply Takeoff and Landing distances by:
10 kt headwind 0.79
15 " 0.72
20 " 0.64
Last updated by John Leibacher on Friday, September 8, 1995 at 21:21
| Dr. Günther Eichhorn | Springer 233 Spring Street New York, NY 10013 USA, email me |