MANUAL I > II CONTROLS > III > IV
Pilot's manual for the Curtiss Tomahawk (cont'd)Stuff in brackets [like this] has been added. Comments beginning DF are by the webmaster; those beginning ES are by Erik Shilling, a pilot with the AVG 3rd Squadron.
Pilot's Controls and Equipment
This section gives the location and, where necessary, explains the function of the controls and equipment in the pilot's cockpit.
NOTE: On aircraft Nos. A.H. 741 to A.H. 970 inclusive certain of the electrical switches are "on" when in the "Up" position and care should be taken to identify these. All switches are clearly marked "Off" and "On".
1. Cockpit - The cockpit is fully equipped and has the normal stick and rudder pedal controls which are dealt with individually in the following paragraphs. The sliding hood can be pushed right back from the cockpit and is operated by a crank mounted on the upper right longeron. A pin on the crank engages hole sin the drum and locks the cabin in the full back, full forward and intermediate positions.
An emergency hood release is also fitted and is a lever painted red, located at the top forward frame of the cabin roof. In case of an emergency, while in flight, the entire enclosure may be released from the fuselage by pulling on this lever. In the event of turnover on the ground, pull the panel release handle and push open the emergency exit on the left hand side of the cabin enclosure. This emergency exit may be operated from the outside by means of a handle located on the lower rear left hand cabin frame.
An emergency release which disengages the catches from the crank is located at the top of the windshield and consists of a turnbuckle and wire painted red. This eliminates winding the crank for rapid opening but the enclosure must then be pushed back by hand.
A ventilator for the cockpit is operated by a push-pull control located below the instrument board on the port side. When the control is pulled out hot air is admitted to two vents,: one permitting hot air to enter directly into the cockpit, the other deflects the hot air between the windscreen and bulletproof safety glass, acting as a defroster, before passing into the cockpit.
2. The seat is adjusted vertically by a lever on the starboard side of the seat. The lever is moved upward and to the rear permitting the seat to be raised manually. A release lever controlling the position of the pilot's harness belt is provided at the port side of the seat. To operate, push button on top of lever and move lever to rear locking position. This permits free movement of the pilot in a fore and aft direction. A pilot's relief tube is suspended from the bottom of the seat.
3. Control Column - The control column is of the conventional design. The control column hand grip has two switches; the one on the top of the grip is a push button and operates the landing gear; the other is a trigger switch and operates the firing of the guns. [ES: Ours did not have the top button. The hydraulic switch was a light weight switch just below the pistol type control handle, and operated by the little finger.]
4. Rudder Pedals - The rudder pedals are of conventional design and they are adjustable for leg reach by releasing a pin by means of the lever on the inboard side of the pedal, and moving forward or aft as required.
5. Brakes - Brakes are operated by toe pedals and the parking brake lever is located below the instrument board and may be engaged by being pulled back when the pedals are depressed. It is automatically disengaged when the pedals are depressed.
6. Trim Tabs - The adjustable trim tabs for the rudder and elevators [sic] controls are located at the port side of the cockpit near the pilot's seat, and work in the same plane as the controls concerned. The elevator wheel has a crank handle for rapid adjustment. Dials at the hand wheels indicate the positions of the tabs. [ES: the ailerons [also had] a cockpit trim control which was located in front and just below the rudder trim vertical to the rudder trim.]
7. Retractable Landing Gear - The retractable landing gear is operated hydraulically by either the emergency hand pump or the electric pump. An operating instructions plate is locate don the left hand side of the cockpit. On aircraft Nos. A.H. 741 to A.H. 999 and A.K. 100 to A.K. 155 inclusive, a selector lever extends forward along the port side of the cockpit and has a push button on the end which must be depressed to move the handle from neutral. (The handle may be returned to neutral without depressing the button.)
To retract the landing gear depress the button on the end of the handle, and raise the handle to the "Up" position. Then operation the electrical pump by pressing the switch button on the top of the control column. As a precaution the gun selector switch should be "Off" in case the trigger switch is squeezed by mistake. The switch must be held "On" during the period required for the retraction of the landing gear. To lower landing gear move handle to down position and operate switch button as before. [DF: Note what Erik says above, that on the AVG Tomahawks the button on top of the stick was replaced by a toggle below the pistol grip.]
NOTE: - On aircraft A.K. 156 and onwards the push button on the undercarriage selector lever is replaced by a safety latch bolt which must be pulled forward before the lever can be moved.
To ensure positive engagements [sic] of the locks, the switch should be held on for a few seconds after the indicator and the warning horn show that they are down. As a final check the pilot should try and move the hand pump lever on the right hand side of the cockpit. If this lever cannot be moved, except by a high load which brings the hydraulic bypass valve into operation, the pilot can be sure that the landing gear is locked down. The selector lever should then be raised to its neutral position. This hydraulic valve control lever should be in neutral when taking off or landing.
An indicator on the instrument board indicates the position of the landing gear whenever the battery switch is turned "On." A warning klaxon which operates when the throttle is closed with the wheels retracted, is only connected to the locks and consequently will sound when the wheels are down if the locks are not engaged.
This klaxon circuit is controlled through a toggle switch which is mounted just ahead of the throttle quadrant and is actuated by a cam mounted on the throttle rod. This came may be pulled out to turn the klaxon off temporarily during a throttled dive with the wheels retracted. It engages automatically when the throttle is opened to the stop.
Emergency operation: In the event of the electrical system failing, select the required position for the undercarriage on the selector lever and operate hand pump on right hand side of the cockpit.
Warning - Never operate pump with selector lever in "Up" position when airplane is resting on its wheels.
[ES: In the event of electric failure the gear was dropped by operating the emergency hydraulic hand pump. In the event of a hydraulic failure, the handle was removed from its normal position, and placed on a second position outboard of the normal position. In this position, would direct pressure to the main gear and lower the mains, but it would not lower the tail wheel which was left retracted.]
Before starting engine or taxiing, check landing gear lock by shifting selector to "down" position and operating the hand pump until it is solid to fore and aft movement. Return valve lever to neutral position.
8. Wing Flaps - The wing flaps are operated hydraulically by either the hand pump or an electrically operated pump. The selector handle is located on the port side of the cockpit beside the pilot's seat and moves fore and after; - forward for "Down" and after for "Up" and neutral for "Off". The hand operated hydraulic pump (see para. 7) may be worked back and forth to raise or lower the flaps after the up or down position has been selected on the handle. The flaps may be operated manually in order that partial setting may be obtained more easily. With aid loads on the flaps they will close automatically as soon as the selector switch is moved to the "Up" position.
[ES: our flap control lever had a push button on the end which had to be depressed in order to move the flap handle out of the neutral position. When placed in the up position, the little finger was used to turn on the electric hydraulic pump. The same switch was used to acctuate the hydraulic pump both for the Flaps and Gear.]
NOTE: - Flap selector lever cannot be set to "Up" position until undercarriage lever has been returned to neutral. [ES: We did not have this type of flap control.]
9. Undercarriage and Flap Position Indicator - The position indicator is located on the lower port side of the instrument board. The wheel and flap images simulate the actual position of the landing wheels, tail wheel and flaps. The images disappear from view when the electrical power is off, thereby indicating failure of the instrument, or open battery or generator circuit. The batter switch must be "On" to maintain operation of the indicator. The battery switch should be "Off" before leaving the airplane.
10. Throttle Quadrant - The throttle, automatic mixture and propeller controls are located on the throttle quadrant. The mixture control locates the automatic rich and automatic lean positions. Approximately the last 10° movement of the "lean" mixture on the quadrant is the engine "idle cut-off" position. There is a spring stop included to prevent mixture control from entering the "idle cut-off" position when normal pressure is applied.
11. Airscrew Operating - This may be either "Automatic or "Manual Selective". When on automatic control, a selected engine speed is held constant by an engine driven governor. Speed selection is accomplished by adjustment of the propeller control on the throttle quadrant, and the toggle switch on the propeller control panel is in the "down" or "on" position.
When on manual selective control, that is with switch in "Hand control" position, the propeller acts as a controllable pitch propeller by the operation of the "Increase R.P.M.", or "Decrease R.P.M." switch. Circuits are independent of the governor so that if the governor fails the propeller can be used as a multi-position controllable propeller.
Since the markings on the propeller control are for approximate settings, the tachometer should be relied up to obtain the desired R.P.M.
General Operation: Automatic Control - Set toggle safety switch which is of the circuit breaker type to "On" (Down) (automatic control) position at all times that constant speed control by C.P. lever on throttle quadrant is desired. (If the switch throws out it may be reset by turning to "Off" then to "On". Successive throwing out will probably be an indication of short circuit or overload and the switch should be left off, in this event, the pitch should be changed only if absolutely necessary.)
The desired R.P.M. can then be obtained by moving the constant speed control lever on the throttle quadrant.
Manual Control - Set switch from "on" (automatic control) to "Hand Control". The throttle quadrant lever is then cut out and any change in R.P.M. must be made by operating the manual switch over to "Increase" or "Decrease" until the desired changed in engine revs has been made.
[ES: The propeller control was a four position toggle switch. Up was automatic, down and left was manual decrease, down to the right was in increase rpm, and center was off.]
12. The Fuel Cock is located on the port side of the cockpit below the hand fuel pump and marked to show the tanks and capacities. [DF: See the diagram above. Measurements are in Imperial gallons, the equivalent of five U.S. quarts. In the manual this is Figure 4. All other figures omitted because too difficult to read.]
13. Fuel Quantity Gauge for the auxiliary tank is located on the instrument board and the front and rear main tanks on the floor of the cockpit.
[ES: Fuel tanks were not as shown. The fuel selector had five positions. 1. Res. 2. Main. 3. Aux. 4. Fuse. 5. Off. The reserve and main tanks were one and the same tank . The main tank was feed by a stand pipe in the main tank and the reserve fed from the bottom of the same main tank. The reserve was used for all take offs and landings. When reserve was selected, fuel was taken from the bottom of the main tank and fed fuel to the engine. In other words the stand pipe used all of the fuel in the main tank, but when the main was selected, it used all, except I believe, a positive amount of fuel giving 20 minutes at METO power. This was a positive indication of exactly how much fuel remained, eliminating the pilot having to rely upon a fuel gage which at best was an unreliable.]
14. Carburetor Air Heat Control - is located on the same bracket as the rounds indicator on the starboard side. The carburetor air intake is a scoop built into the top of the engine cowl. A butterfly valve, controlled from the cockpit, is located immediately above the carburetor air screen and permits either cold or warm air or a mixture of both to enter. Warm air for the carburetor is taken from inside the engine compartment. The carburetor air screen is installed to prevent the passage of any foreign matter into the carburetor. The carburetor air control should always be in the cold position when starting the engine.
15. The Engine Primer is located on the starboard side of the cockpit, just below the instrument panel.
16. Starter - A foot operated electric inertia starter is provided. A foot treadle on the cockpit floor is pushed back to operate a starter switch which allows a direct flow of current from the battery to the starter motor. When the starter has reached the desired speed, the foot treadle is pushed forward actuating a starter meshing solenoid and a booster coil; also by the same movement of the foot treadle the start switch contact is broken. The first few impulses of the engine in starting will automatically disengage the starter. On aircraft A.H. 971 and subsequent the foot operated starter is replaced by a two way toggle switch located on the switch panel on the port side of the cockpit. This is depressed to energize the starter and raised to engage it, and the switch automatically returns to the off position when released.
[ES: Starter had the foot treadle starter. DF: This strikes me as particularly significant. All AVG aircraft were taken from blocks higher than AH and therefore should have had the toggle switch. I don't see how Erik could possibly be wrong on this, which leaves only two possibilities: that the manual is in error, or that the planes diverted to China were not equipped the same as those sent to North Africa for the RAF.]
In case of battery failure, the started may be cranked by hand with crank and extension provided for this purpose, both being located in rear access compartment. The starter is operated by turning the crank handle which is inserted in the spiral slot provided in the end of the crank extension, on right hand side of engine cowl. Turn the crank with gradually increasing speed until a fairly good rate of speed is obtained. Remove the crank handle and extension. The engagement of the started will then be accomplished by a pull on the hand starter button located immediately above the crank. Caution: Starter crank and extension must be removed immediately after cranking and before actuating starter pull.
17. Oil Dilution Control is located on the switch panel on the port side of the cockpit.
(a) Before stopping the engine when a cold weather start is anticipated, hold the oil dilution control switch "On" for approximately four minutes at 800 RPM and stop the engine with the ignition switch, continuing to hold the dilution control switch "On" until the engine stops. Then turn the standard fuel cock to the off position.
(b) In starting the engine a normal start should be made. After starting the engine, if a heavy viscous oil is indicated by oil pressure that is too high or by oil pressure that fluctuates or falls back when the engine RPM is increased, the dilution valve should be held "On" to dilute the oil and correct this condition. Over dilution will result in a steady low oil pressure and should be avoided if possible.
(c) If the engine heat is excessive when operating the oil dilution control, the heat may evaporate the fuel out of the oil and leave the normal high viscosity oil in the engine. When this condition is encountered, the engine should first be shut off and allowed to cool for fifteen minutes, then re-started and the instructions outlined in paragraph "a" followed in preparing the engine for cold weather starting.
(d) Take-off may be made four minutes after starting the engine if there has been enough rise in oil temperature (40°c. minimum), if the engine holds its oil pressure and if the engine runs smoothly, or, the take-off may be made as soon after four minutes as these conditions are obtained.
18. Hand Fuel Pump Control is located on the port side of the cockpit forward of the throttle quadrant.
19. Radiator Flap Control is located on the starboard side of the cockpit near the floor. It consists of a long lever and a rack. The latter is provided with a stop at each end and may be set for "full open" (handle fully down), "Full closed" (handle fully up), or any intermediate position.
NOTE: Filling points for:
Wing fuel tanks through left hand wing fillet.
20. Gun Firing Switch - See Section 1, paragraph 1 [DF: should be para. 3]
21. Switches and Rheostats are located on panel on the left, below the throttle quadrant. Care must be taken to insure that all rheostats are in the extreme "Off" position when not in use, as they are equipped with integral switches.
22. Oxygen - Two oxygen bottles are carried in supports in the aft part of the fuselage, and accessible through the fuselage access door. The oxygen regulator and bayonet outlet are located on the starboard side of the cockpit. (Aircraft Nos. A.H. 741 to A.H. 990 have one bottle only) [ES: We did not have the oxygen as shown since it was a high pressure system, not the low pressure demand system.]
23. Aircraft Flares - Two M-8 type flares are carried in the flush type built-in wing flare racks. Flare release handles are located on the starboard side of the pilot's seat.
24. Recognition Device - A bracket for mounting the damped rate control is provided on the starboard side of the cockpit which actuates the recognition device mounted on brackets near the top of fuselage accessible through fuselage access door.
25. Landing Lamp - A landing light is fitted to the underside of the port wing and is operated by a switch on the main switch box.
26. Formation Lights - for lighting the upper surface of the wing are located in the fuselage aft of the cockpit. These are controlled through a rheostat on the port side electrical boxes. (Aircraft A.H. 971 onwards)
27. Identification Lights - Provisions are made in top of the fuselage aft of cockpit enclosure and starboard rear wing fillet for upward and downward identification lights. The identification light switch box is locate don starboard side of cockpit.
28. Wireless Controls - [DF: This section omitted. The AVG Tomahawks had after-market radios designed for civilian use.]
29. Dalton Computer - Provision is made for the Dalton computer to be inserted in a stowage on the port side of the cockpit. [ES: no Dalton computer.]
30. Shield - An instrument light shield is provided to prevent reflections on the windshield.
31. Fire Extinguisher - is located in brackets on port side of cockpit floor.
32. Map Case - is fastened to the starboard side of the cockpit.
33. Life Preserver - The back cushion of the pilot's seat may be used as a life preserver. [ES: no life preserver.]