THORP T-18 N10TK
OPERATORS MANUAL
Thomas R. Kerns, Builder
7033 Autumn Terrace
Eden Prairie MN 55346
(612) 934-6833
January 13, 2000
WARNING
This manual is specifically applicable to Kerns/Thorp T-18, S/N 71, N10TK with 135 HP Lycoming O-290 D-2 engine and Cassidy Pacesetter 68X63 propeller. Applicability of this manual to other T-18 aircraft and pilots is not assured due to variations in pilot experience and aptitude, and variations in aircraft configuration, equipment, manufacturing tolerances, and certification (See Section VIII). This manual is provided to others for educational purposes only, to be used as a model for preparing flight manuals for other T-18 Aircraft.
T-18 N10TK utilizes John Thorps original non-folding wing and NACA 63A-412 airfoil, electrical flaps limited to 30 degrees deflection, "standard" short length untapered main landing gear, standard short roll bar, plus pressure cowl, canopy, and wheel fairings. Numerous detail changes have been made for drag reduction on N10TK.
SUMMARY SPECIFICATIONS
DIMENSIONS
Wing Span 20'- 10"
Wing Chord 4'- 2"
Wing Aspect Ratio 5.0
Length Overall 18'- 11"
Height Overall 5'- 1"
Wheel Track 5'- 3"
Propeller Diameter 68"
AREAS
Wings (gross) 86.0 sq ft
Ailerons (total) 6.8 sq ft
Flaps (total) 6.0 sq ft
Fin 4.8 sq ft
Rudder 3.2 sq ft
Horizontal Tail 14.2 sq ft
Vertical Tail
Cruise, Sea Level @ 75% 170 mph
Cruise, 10,000 ft @ 75% 183 mph
Stall Speed, Flaps Down 60 mph
Rate Of Climb at Sea Level approx. 1200 fpm
Takeoff Roll 900 feet
Landing Roll 900 feet
Range, 30 Min Reserve 600 statute miles
INDEX
PAGE
I OPERATING LIMITATIONS------6
II EMERGENCY PROCEDURES------11
III NORMAL PROCEDURES------20
IV PERFORMANCE------32
V WEIGHT AND BALANCE------35
VI DESCRIPTION------37
VII SERVICING REQUIREMENTS------43
VIII APPLICABILITY TO OTHER T-18's------46
SECTION I
OPERATING LIMITATIONS
INDEX
PAGE
GENERAL------7
AIRSPEED LIMITATIONS------7
POWERPLANT LIMITS AND INSTRUMENT MARKINGS------8
WEIGHT AND BALANCE LIMITS------9
FLIGHT LOAD FACTORS------9
KINDS OF OPERATION------10
MANEUVERS------10
REQUIRED PLACARDS------10
SECTION I
OPERATING LIMITATIONS-NORMAL AND AEROBATIC
GENERAL
This section lists all powerplant and airframe operating limitations. These limitations are also indicated in the aircraft in the form of placards and instrument color markings.
AIRSPEED LIMITATIONS
NOTE
Limitations are applicable to both Normal and Aerobatic Category
except where designated as applying to only one category.
AIRSPEED
AIRSPEED DESIGNATION CAS MPH INDICATOR MARKING
Never Exceed (Vne) 210 Red Line
Caution Range 165-210 Yellow Arc
Maximum Structural Cruise (Vno) 165 End of Green Arc
Normal Operating Range 63-165 Green Arc
Maneuvering Speed (Va) 160 None
Maximum Flap Extension (Vfe) 110 End of White Arc
NOTE
CAS - Calibrated Airspeed: This is indicated airspeed
corrected for position and instrument error.
IAS - Indicated Airspeed assumes zero instrument error.
Vne - Maximum safe airspeed which is not to be exceeded at
any time.
Vno - Not to be exceeded except in smooth air only and then
with caution.
Va - No full or abrupt longitudinal control movements
allowed above this airspeed.
Vfe - No operation with flaps extended above this speed.
POWERPLANT LIMITATIONS AND INSTRUMENT MARKINGS
Engine
Lycoming O-290 D-2
Rated 135 BHP continuous and 140 HP
for 10 minute takeoff
290 cubic inches, 7.5:1 Compression ratio
Rated for 80/87 octane fuel
Marvel Schebler MA-3 SPA Carburetor
Slick 4370 and 4373 Magnetos
Propeller
Cassidy "Pacesetter 200", 68" diameter by 63" pitch.
Fuel, Minimum Octane Rating, Aviation Grade 80/87
Approved for continuous use--100/130 LL
Approved for limited use-- 100/130
Approved for limited use--Automotive Unleaded Regular. * See caution for hot weather operations in fuel system description*
Use of fuels with Ethanol is Prohibited.
Tachometer
Normal Range (Green Arc) 1800-2800 RPM
Maximum (Red Line) 2800 RPM
Cylinder Head Temperature
Normal Range (Green Arc) 280-420 Deg. F.
Maximum (Red Line) 500 Deg. F.
Oil Temperature
Caution (Yellow Arc) 100-160 Deg. F.
Normal Range (Green Arc) 160-220 Deg. F.
Maximum (Red Line) 245 Deg. F.
Oil Pressure
Normal Range (Green Arc) 65-85 PSI
Maximum (Red Line) 100 PSI
Minimum at Idle (Red Line) 25 PSI
WEIGHT AND BALANCE LIMITS
Maximum Gross Weight-- 1640 Lbs Standard Category
1250 Lbs Aerobatic Category
Center of Gravity Range-- Station 61.0 to 71.15
FLIGHT LOAD FACTORS
ACCELEROMETER
CATEGORY LOAD FACTOR LIMITS MARKING
Normal Positive 4.6 G Green Arc
Negative 2.3 G Green Arc
Aerobatic Positive 6.0 G Red Line
Negative 3.0 G Red Line
NOTE
Maximum load factors for Normal Category operations are shown by the ends of the green arc on the accelerometer. Load factors within the yellow arc up to the red radial lines are permitted only in the Aerobatic Category.
KINDS OF OPERATION
Only VFR Day operations are approved with all required equipment operating as specified in FAR Part 91.
Operation over densely populated areas is prohibited except for purposes of takeoff and landing.
Flight into known icing conditions is prohibited.
Crosswind landings have been demonstrated at 25 KTS.
INVERTED FLIGHT
Flight at negative "G" conditions is to be avoided due to lack of inverted fuel, oil, and battery systems.
REQUIRED PLACARDS
A placard must be in full view of the passengers seat reading:
WARNING
THIS AIRCRAFT IS AMATEUR BUILT AND MAY NOT
COMPLY WITH FEDERAL AIRWORTHINESS STANDARDS
SECTION II
EMERGENCY PROCEDURES
INDEX
PAGE
GENERAL------12
ENGINE FIRE DURING START------12
ENGINE FIRE IN FLIGHT------13
ELECTRICAL FIRE------13
ALTERNATOR/ELECTRICAL FAILURE------14
VACCUM SYSTEM FAILURE------14
ENGINE FAILURE ON TAKEOFF------14
ENGINE AIR RESTART------15
PARTIAL POWER LOSS/ROUGH RUNNING------16
ABNORMAL OIL PRESS/TEMP INDICATIONS------16
PRECAUTIONARY LANDING APPROACH------16
FORCED LANDING (COMPLETE POWER FAILURE)---17
DITCHING------18
SEVERE TURBULENCE------18
STALLS------18
EMERGENCY EXIT/BAIL OUT------19
EMERGENCY DESCENT------19
SECTION II
EMERGENCY PROCEDURES
GENERAL
This section covers the recommended procedures to follow during emergency and adverse flight conditions. As it is not possible to define every type of emergency that may occur, it is the pilots responsibility to use sound judgment based on experience and knowledge of the aircraft to determine the best course of action. It is mandatory that the pilot familiarize himself with the entire flight manual, particularly this section prior to flight.
NOTE
All airspeeds in this section are indicated airspeeds (IAS)
unless otherwise stated.
WARNING
These procedures are tailored specifically to T-18 N10TK, S/N 71.
ENGINE FIRE DURING START
If the fire is believed to be confined to intake or exhaust system (result of flooding engine):
(1) Continue cranking engine with starter.
(2) Mixture Control--IDLE CUT-OFF
(3) Throttle--DO NOT MOVE
(4) Inspect aircraft thoroughly for damage and cause prior
to restart.
If fire persists or is not limited to intake or exhaust system:
(1) Mixture Control--IDLE CUTOFF
(2) Fuel Shut-off Valve--OFF
(3) Electrical and Magneto Switches--OFF
(4) Remove fire extinguisher from cockpit floor
(5) Exit Aircraft
(6) Direct fire extinguisher through the cowling side air
vents.
ENGINE FIRE IN FLIGHT
(1) Mixture Control--IDLE CUT-OFF.
(2) Fuel Shut-Off Valve--OFF
(3) Electrical and Magneto Switches--OFF
(4) Cabin Heat--OFF
(5) Canopy Vent--CLOSE
(6) Land immediately using "Forced Landing Procedures"
WARNING
Do NOT attempt to restart engine.
NOTE
The floor vents may be used for cabin air in the event of an engine fire.
The floor vent intakes are 4 feet outboard from the fuselage,
providing smoke free air.
ELECTRICAL FIRE
An electrical fire is usually indicated by an acrid odor of hot or burning insulation and wisps of smoke.
(1) Electrical Switches--ALL OFF (Leave Magneto Switch ON).
(2) Cabin Heater--OFF
(3) Air Vents--OPEN only if absolutely necessary for smoke
removal and ventilation.
(3) Direct fire extinguisher to the smoke source (the
extinguisher is non-toxic HALON gas).
(4) If fire continues, land immediately.
If fire/smoke stops and electrical power is required for the remainder of the flight, pull all circuit breakers out, turn the battery switch on, then turn on the alternator switch and desired circuit breakers and/or switches. Allow a minute between turning on each switch or breaker in order to allow identification and isolation of the faulty circuit(s). Switch off any faulty circuits.
NOTE:
N10TK has an avionics / essential buss which may be powered directly from the battery, bypassing the master relay and main buss. To activate the avionics buss independently, turn on the backup radio switch and switch off the avionics master switch. Turning on both the avionics master switch and the backup radio switch will power the main buss from the avionics buss.
ALTERNATOR FAILURE
The ammeter displays current flow to and from the battery. Charge rates up to 60 amps will be observed after engine start, with rapid reduction to zero current flow. Indications of discharge will result from alternator failure, and the voltage warning light will glow a steady yellow.
In the event that buss voltage exceeds 15.5 volts the crow-bar overvoltage protection circuit will immediately toggle off the alternator circuit breaker switch, tripping the low voltage warning light which will glow steady yellow. In the event of high buss voltage and a malfunction of the crowbar, the voltage warning light will flash as a warning of excessive voltage.
(1) Alternator Switch--CYCLE to reset the overvoltage relay. If the switch immediately returns to the off position, an overvoltage condition is confirmed and activation of the alternator will not be possible.
(2) If alternator current is not restored, turn OFF all
non-essential electrical equipment to conserve battery
power and land as soon as practical. Switching on the alternate radio switch then turning off the master switch and avionics master switch will permit operation of the isolated avionics buss without the power drain of the master relay.
VACUUM SYSTEM FAILURE
Excess vacuum may be observed via the vacuum gauge provided. Low vacuum will be indicated by the vacuum gauge and by a steady yellow glow of the low vacuum warning light. Performance of the artificial horizon and directional gyro are suspect if vacuum is outside of the green arc. The turn coordinator is electrically powered and unaffected by vacuum system operation.
ENGINE FAILURE ON TAKE-OFF
If sufficient Runway Remains:
(1) Throttle--CLOSED
(2) Land using brakes as required.
If airborne and insufficient runway remains for landing:
(1) Select most favorable landing area straight ahead.
(2) If altitude permits, attempt engine restart:
* Carb Heat--FULL HOT
* Mixture Control--FULL RICH unless at high altitude.
* Fuel Shut-Off Valve--CHECK ON
* Magneto Switch--EXPERIMENT WITH LEFT, RIGHT, BOTH.
(3) If Engine restart is not possible, follow forced
landing procedures.
WARNING
Maintain flying speed at all times and do not attempt to turn back towards the runway unless sufficient altitude has been achieved. Altitude required for turnback with no margin is 600 feet. A 50 degree banked turn at 100 MPH is recommended for turnback. Builders preference is to use a 90 degree turn into the wind followed by a 270 degree turn in the opposite direction to provide runway line-up. Making the 90 degree turn first will minimize maneuvering at very low altitude near the runway.
ENGINE AIR RESTART
(1) Maintain Airspeed--100 MPH minimum recommended.
(2) Carb Heat--FULL HOT
(3) Magneto Switch--BOTH
(4) Mixture-- FULL RICH or LEANED as required at high
altitude.
(5) Fuel Shut-Off Valve--CHECK ON
(6) If restart does not occur, change throttle, mixture,
primer, and magneto settings in attempt to restart.
(7) Follow "Forced Landing Procedure" if unable to
restart.
NOTE
The engine starter may be engaged in flight if the
engine has stopped windmilling.
PARTIAL POWER LOSS/ROUGH RUNNING
(1) Follow the engine air restart procedures.
(2) Land as soon as practical using "Precautionary Landing
Approach" procedures.
Presence of carburetor ice may be indicated by a gradual power loss. Full carburetor heat should be applied for as long as the obstruction persists.
ABNORMAL OIL PRESSURE/TEMPERATURE INDICATIONS
Oil pressure and temperature problems are usually related with one affecting the other.
Before any action is taken, cross check the other engine instruments and control settings for possible clues. Open the oil cooler shutter fully if high oil temperatures are observed.
High oil temperature is generally the result of loss of oil, engine overheating (note CHT and EGT), or a malfunctioning oil cooler by-pass valve. If the situation remains unchecked, oil pressure usually drops resulting in possible engine damage. Power should be reduced while maintaining cruise airspeed. Place mixture in FULL RICH position and land as soon as practical.
Little or no oil pressure is usually caused by a failed pressure regulator valve, failed pump, loss of oil, clogged oil line, high oil temperature, or a defective gauge. A low pressure warning light is provided to alert the pilot to pressure loss when pressure drops below 15 PSI. A landing should be made as soon as practical using minimum RPM changes. Plan a "Precautionary Landing Approach" as engine failure may be imminent.
PRECAUTIONARY LANDING APPROACH
A precautionary landing approach should be used whenever power is still available, but a complete power failure is considered imminent.
Maintain a higher and closer pattern than normal to remain in gliding distance of the intended touch-down point. Recommended technique is to choose a point on the runway beyond which the aircraft could not be safely stopped, and to choose the earliest point at which a safe touchdown can be made (the earliest point may be before the runway threshold if the approach path is clear). Monitoring glide path relative to the two chosen touchdown limits will provide guidance for just how much reserve speed and altitude can be safely carried for the approach in progress.
Recommended setup is:
(1) Airspeed--85 MPH recommended on approach (80 minimum).
(2) Throttle--CLOSED when in gliding distance of the runway.
(3) Flaps--FULL DOWN when runway is assured.
NOTE
Full cross control slips may be used between 80 and 90
MPH to increase rate of descent.
FORCED LANDING (COMPLETE POWER FAILURE)
(1) Airspeed--Maintain 100 MPH
(2) Mixture--IDLE CUT-OFF
(3) Fuel Shut-Off Valve--OFF
(4) Radio--MAYDAY 121.5 MHZ
(5) Transponder--CODE 7700
(6) Attempt to position the aircraft 1000 ft. AGL when
downwind and abeam of the intended point of landing.
(7) All Electrical Switches--OFF (Except Battery)
(8) On Final Approach--Airspeed 85MPH (80 minimum). See
precautionary landing for technique.
(9) Canopy Latches--Released
(10) Flaps--Full when field is assured.
(11) Battery Switch--OFF
(12) Touchdown in 3-point or tail low wheel landing.