Comet 4 Flying Tips

Panel Manual VC extras Checklists Flying Tips General Tips Auto Coupled Approach

Takeoff

The elevator trim setting is important for takeoff.  The model needs around 3 degrees nose up trim on takeoff. If you do not set the nose up trim, it will not rotate at the correct Vr speed. The cockpit 'check list' gauge can be used to check if elevator trim is set within acceptable limits. 8000 - 8050 RPM is normal for takeoff. Flaps should always be set at 20 degrees. Click the 'Speed Reference Chinagraph' on the left of the main panel to get the correct rotate speed (Vr) for the aircraft's current weight.  The Comet has fairly low speeds. The 'check list' toggle button gives the essential settings needed for a takeoff.  Each setting is shown with a tick or a cross, making it easy to quickly check if your configuration is correct. After takeoff, the normal initial climb speed is just 150kt.  Holding this speed gave a greater climb angle so that the aircraft could get high quickly for reasons of noise abatement around airports. Normal speed for the main climb is 260 kts, but can be higher if desired.  Climb power is normally around 7400 RPM. IAS hold can be selected at the desired speed, leaving the autopilot to adjust your climb rate.

Cruise

Normal cruise altitudes range from 23,000 ft to 37,000 ft.  Operational ceiling is 40,000 ft The 4B was designed to fly slightly faster at lower altitudes, so the 4B would not normally go over 30,000 ft. Normal cruise speed is Mach 0.72 - 0.74 Mach 0.76 is the maximum cruise speed, with mach 0.8 the max mach number allowed.

Landing

The flaps do not cause much nose down attitude.  However some nose up trim will be needed to compensate for loss of speed.  It is normal for the model to need around 4-5 degrees of nose up trim with full flaps selected. Be aware of the maximum landing weights & their speeds.  While the aircraft can land safely at full weight, over weight landings were only done in an emergency. Normal landing weights will give Vat speeds of between 115 & 125 kts. Click the 'Speed Reference Chinagraph' on the left of the main panel to get the correct landing speed (Vat) for the aircraft's current weight.  The Comet has very low landing speeds. Once 20 degrees flaps are selected, adjust engine power to between 6500 - 6700 RPM, depending on your expected landing speed (Vat roughly between 115 - 125 kts).  You can keep the same engine power all the way down, using the flaps to lower your speed. As a rough guide 20 deg = 175 kts, 30 deg = 150 kts, 40 deg = 140 kts, 60 deg = 130 kts, 80 deg = 120 kts. When flying at the correct speed on the glide slope, the Comet should be level or slightly nose down, showing zero or 1 degree down on the attitude indicator. As a rough guide, 60 degree flaps should have been selected by the 1000 ft mark, or by 3 miles to run.  Only select full flaps (80 degrees) at 2 miles or less to run. At the higher landing speeds, full flaps were often not used as they could cause buffeting. The Comet does not use spoilers as lift dumpers on landing. Select reverse thrust when all wheels are down, reverse off at 60 kts.  Brakes are not normally needed until turnoff.

Range, Payload & Fuel

With a maximum payload, the amount of fuel must be limited to keep below the maximum takeoff weight (MTOW).  The difference between max payload & max fuel is much less for the 4B, as this was designed to carry high payloads over shorter distances. Maximum payload is around 24,000 lb. The models are all set up to be near their MTOW, with maximum fuel load by default.

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