3. DESCRIPTIONS AND OPERATIONS
A heated Pitot tube is situated under the left wing. It is connected to both the analogue and the digital airspeed indicators. Prior to flight, it must be checked to make sure there are no blockages to the air inlet. Foreign particles can be prevented from entering the pitot system by the use of the “Remove Before Flight” cover when the aircraft is not flying. This protective cover MUST be removed during the pre-flight inspection. There are two static vents that provide the flight instruments with ambient pressure. These vents are “teed” at the source and are located on both sides of the fuselage, on the waterline, just behind the Station 139 bulkhead. Care must be taken not to block these vents, especially during washing or polishing the aircraft.
A rocker switch on the switch panel operates Pitot heat. This feature should be used in icing conditions to prevent ice blockage of the pitot inlet.
In addition to the standard Pitot / Static system, this aircraft also features a Lift Reserve Indicator. The probe is located under the right wing at between 15 % and 30% of the wing chord (just behind the aileron bellcrank access cover) and has two ports – a high pressure and a low pressure. The high pressure port on the probe is the top-most of the two ports, the bottom port being the low pressure feed. Two tubes connect the probe directly to the HP (high pressure) and LP (low pressure) inlets on the panel-mounted gauge. The gauge is clearly marked with red (stall), yellow (approach / climb) and green (normal) arcs. The probe angle is set correctly when the LRI needle matches the black line in the red arc at the moment of touchdown during a full stall landing.
A 14-volt, direct current system powered by an engine-driven alternator, supplies electrical energy. The 12-volt battery is located behind the rear baggage bulkhead. Power is supplied to all electrical circuits via a bus bar, located on the far right of the instrument panel.
A split-rocker type Master switch is located on the main switch panel. The right half of the switch (Battery) controls all electrical power to the aircraft via a master solenoid situated at the rear near the battery. The left half of the switch (Alternator) controls the Alternator field. Normally, both sides of the switch are used simultaneously, however, in the event of alternator failure, it is possible to switch off the alternator field, whilst leaving the battery switched on. This means that the entire aircraft’s electrical requirements are then placed upon the battery. Conversely, it is not possible to switch off the battery and leave the alternator in circuit.
The Rocky Mountain Micro-Monitor monitors the electrical buss current draw and voltage. It displays the current draw/load on the alternator as well as the main bus voltage. No current monitoring of the battery output is possible, should the alternator be switched off.
The aircraft is equipped with an automatic over-voltage protection system. In the event of an over-voltage condition, the LR-3 voltage regulator shuts down the alternator field and the warning light (on the circuit breaker panel) illuminates. If the bus voltage
drops below 12.5 volts, this same indicator will flash until the situation has been rectified.
The majority of the electrical circuits in the aircraft are protected by push-to-reset circuit breakers, situated on the far right panel of the instrument panel. Exceptions to this are the Hobbs meter, Micro-monitor clock and interior lighting. The circuit breaker for these is situated on the battery box. Always be sure that, in the event of a circuit breaker tripping, the problem is rectified before resetting the circuit breaker.
An external power socket is situated on the lower left part of the fuselage, just forward of the Station 139 bulkhead. This is permanently live and directly connected to the battery. Using the custom manufactured jumper leads, this socket can be used to assist in starting the engine in the event of the aircraft battery being flat. A battery charger could also be connected to this socket.
Forward of the main spar of each wing is a “wet wing” type fuel tank. Fuel exits the tanks through finger strainers and then flows to a LEFT-RIGHT-OFF-OFF selector valve situated in the cockpit. Depending upon the setting of the selector valve, fuel from the left or right tank flows through a firewall mounted filter, after which it either flows through a high pressure electric fuel pump, or a one-way check valve en-route to an engine mounted mechanical fuel pump. From here, fuel is distributed to the engine cylinders via a fuel control unit and manifold. Prior to take-off, it is wise to check that both the mechanical and electrical pumps are operational. During take-off and landing and whenever changing fuel tanks, the electric pump should be switched on to reduce the risk of fuel starvation in the event of a mechanical pump failure, or in the event of air getting into the fuel system.
Each tank has a capacity of 26 gallons, of which 25.5 gallons are usable. It is not practical to measure the time required to consume all the fuel in one tank, and, after switching to the opposite tank, expect equal duration from the remaining fuel. A vent line interconnects the airspace in both fuel tanks and, therefore, some sloshing of fuel between tanks can be expected when the tanks are nearly full and the wings are not level. Prolonged steep turns, with the low wing’s tank selected should be avoided due to the possibility of the fuel tank outlets being uncovered, especially during low fuel situations. Each tank has a vent line that exits the underside of the wing, at each wing tip. To prevent fuel starvation, it is vital that these vents are confirmed to be clear of blockages during the pre-flight inspection. The cross-vent line between tanks is a safety measure just in case one vent does get blocked. The tank with the blocked vent is then able to draw air from the opposite tanks vent.
Each filler cap is grounded to the firewall, which in turn is directly connected to the nose gear. This means that the ground wire that is attached to the nose gear upon re-fuelling, has a direct link to the filler cap, thus enabling the filler nozzle to ground itself against the filler cap housing, thereby reducing the risk of static buildup and sparking during re-fuelling.
Capacitance type fuel sender units situated in each tank operate the fuel gauge. Due to the nature of their installation, they will tend to indicate “FULL” even when the tanks are only two-thirds full. Only then will they start indicating the dropping fuel level in each tank. As a backup to this gauge and a more accurate method of monitoring fuel usage, the Rocky Mountain Micro-Monitor fuel flow indicator should be continuously monitored. Fuel pressure is also displayed by the Micro-Monitor and upper and lower alarm limits can be programmed into the unit. (See the Micro-monitor operations manual)
External lighting consists of 2 landing lights (one on each wing), wing tip navigation lights, a white tail light (on the rudder trailing edge) and a single strobe (on the top of the rudder). All the lights are operated via switches on the Instrument panel. The high intensity strobe light will enhance anti-collision protection, however, it should be turned off when taxiing in the vicinity of other aircraft, or during flight through cloud, fog or haze.
Interior lighting is controlled by an on/off switch and a dimmer, and consists of panel flood lights (in the overhead console) in addition to the integrated lighting of some instruments. For the rear passengers, map lights are situated in the overhead console.
Cabin Heating / Ventilation
Outside air is ducted into the cabin via 3 sources – eyeball vents on the pilot and the co-pilot side of the instrument panel, and eyeball vents positioned in the overhead console. The overhead vents are fed from a Naca duct on the right hand side of the vertical fin.
Cabin Heat is adjusted by a push/pull knob situated in the center of the instrument panel. The air enters the cabin via a vent in the firewall just to the left of the co-pilot’s feet. Due to the fact that hot air is sourced from a heat muff on the exhausts, there is the risk of Carbon Monoxide entering the cabin should a hole develop in the exhaust. It is therefore wise to keep an eye on the Carbon Monoxide detector and rectify any exhaust gas leakage problem as soon as it becomes apparent.
All 4 seats are equipped with adjustable 3-point lap and shoulder harnesses. Once the two parts of the seatbelts have been securely fastened (using the quick release buckles), the shoulder portions of the harnesses should be adjusted to permit the occupant to lean forward enough to sit completely erect, yet be tight enough to prevent excess forward movement and contact with objects during sudden deceleration. Also, the pilot will want the freedom to reach all the controls easily.
A 4-place intercom is incorporated into the RST audio panel. All 4 headsets can be plugged into the aircraft system via the jacks situated in the center support console between the front seats. This diagram shows the jack layout:
A Mini-Disk music player is situated in the small compartment under the Micro-Monitor. This comes up as “aux” on the audio panel and can be routed to all headphones or the speaker in the overhead console. Music is dimmed when the radios are active, and the pilot can isolate himself from the rest of the passengers.
The pilot’s control stick has a PTT button on the front. If headphones with integrated PTT buttons are used, they need to be plugged in to either the pilot’s or the co-pilot’s jack points to enable this option. The other jack points do not have PTT functionality.
The flaps are manually operated by means of the “handbrake” style lever between the front seats. The full down position is 0 degrees, the second position is 12 degrees and the third position is 28 degrees. It is not required to use flaps for take-off. Maximum flap deployment speed is 110 mph (white arc).
Electric elevator trim is controlled by either the buttons on the top of the pilot’s stick, or by the rocker switch situated on the Instrument panel. An indicator next to the rocker switch shows the trim tab position.
Brakes / steering/ landing gear
Ground steering is achieved by using differential braking to turn the aircraft. The castoring nose wheel simply follows the aircraft heading. It is important to check the castoring nose wheel friction nut on a regular basis to ensure that the pin holding the nut in place is not damaged or missing. This nut should always be tightened such that a force of about 20 lbs is required to move the nose wheel from side to side. The rod-end bearings on the “H” bracket at the lower mounting point should also be checked for security and for lubrication on a regular basis. There is very little maintenance possible on the main landing gear, with the exception of the brake pads, discs and brake lines. To operate the park brake – press hard on the toe brakes and pull park brake handle to lock brakes. To release, simply push handle back in again.
Rocky Mountain Instruments
The two digital instruments on the panel are the Micro-Encoder (flight instrument) and the Micro-Monitor (engine instruments). In the event of clarification of operation, or programming, refer to their respective operational manuals.
The Lycoming IO-360 A2B is a fuel injected, fixed pitch propeller, 4 cylinder, air cooled aircraft engine. Fuel is supplied by a Bendix fuel injection system and ignition is taken care of by dual Bendix 1200 series magnetos, firing 2 spark plugs per cylinder. The engine is rated at 200 HP at 2700 RPM.
EGT: At a maximum of 75% cruise power, best power cruise is at 100F rich of peak EGT and best economy is achieved when operating at peak EGT.
CHT: Normal CHT values are between 350F and 435F. It is best to try and keep the CHT below 400F. Never exceed 500F.
Oil Temps: Normal oil temps are between 165F and 220F.
Refer to the Lycoming IO360 A2B operator’s manual for further details on the engine description and operation.
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