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CarterCopter CC-RTW

For X-Plane 6.12

© Mark Fisher, 2002

Note: A Pilot’s Operating Handbook (POH) is a primer on the operation of a specific aircraft. This POH is intended as a primer on the operation of the X-Plane model of the CarterCopter Round-the-Wold attempt aircraft (CC-RTW). It is designed to run under the flight simulator X-Plane, available from www.x-plane.com. The X-Plane model is freeware; it may be freely modified, copied, and redistributed, provided a) it is not part of any for-profit package other than X-Plane itself, and b) credit for this design is given to Mark Fisher and Austin Meyer.

This model:

For a number of reasons, this model is not an exact replica of the real CCTD. "Flying" techniques discussed here should not be taken as a full and direct description of skills needed in the real CCTD.

Overview:

The CarterCopter is a hybrid aircraft. It operates in three modes: At all times, "steer small." Work to find the smallest input that will have the desired effect. Over control only masks the response of the aircraft.

As a general rule DON'T let forward speed drop below about 70knots (certainly keep above 50-60) unless you are coming in for a zero roll landing or at high altitude and experimenting.

Unique Controls:

There is an unfamiliar control on the throttle quadrant – the "Rotor Trim" lever. This does not directly control the rotor. Instead it controls the link between the elevator trim and the rotor pitch cyclic. In the "up" position, the rotor mirrors the pitch trim, allowing pitch control before the elevator is effective. In the "down" position, the rotor pitch cyclic is not affected by elevator trim.

There is also a "collective" control. This controls the pitch of the rotor blades. This is used as a lift control in helicopter mode, and as a rotor rpm control in autogiro and fixed wing modes. This control is vital. If necessary, transfer your throttle to joystick-button control, and set your throttle slider to operate as a collective.

Jump Take-Offs (zero roll take-off)

Principles:

The CC-RTW will be attempting to go around the world as a rotorcraft. Thus, it must take off without moving forward. At takeoff, the CCTD has two sources of energy: the thrust of the engine-prop unit, and lift from the inertia-rotor unit.

The CC-RTW will be acting as a helicopter for the first 10 vertical feet of flight, and then use JATO boost to transition to autogiro mode at 40 Ft. AGL, where it will accelerate in ground effect to high-Mu flight at 130 knots.

The period of time between takeoff and the establishment of flight speed is quite short. The entire period should be treated as a takeoff – if there is any delay in establishing flight, the aircraft should be landed again immediately.

The first step is to store sufficient takeoff energy in the rotor system. This is done via the "Pre-Rotate" buttons.

Procedure:

  1. Set up instruments:
  1. Set up weather and location: Las Vegas North Las Vegas, ~ 32° F.
  2. Start engine – throttle at idle – collective at zero pitch.
  3. Engage pre-rotator – apply full throttle. In reality, the spin up takes three minutes.
  4. At 250 rotor rpm, gently pull stick back to a spindle angle of 5.0.
  5. Commence steady but swift (not fast) pull on collective up to 100%. When the wheels leave ther ground, release pre-rotator.
  6. As the drive prop spins up, fire JATO.
  7. Keep nose level as the aircraft accelerates along runway to 70 kts. Immediately begin to reduce collective.
  8. Retract gear once flying speed is achieved (reduces drag and allows faster airspeed build up).
  9. Fly in ground effect – 100 feet AGL, ‘till high Mu flight is established.

Climb Out to Low Speed Cruise

Principles:

The CCTD will be operating as a conventional autogiro. The rotor will be tipped back around 5°, and will be supporting over half the weight. Rotor rpm will be around 160 rpm. (More rpm = greater drag and less forward speed and greater engine power is needed – the goal here is to minimize fuel consumption and avoid using excessive engine power.) Too little collective and the rotor rpm will go over 300 and this needs more power from the engine to keep up airspeed.

Don't drop below about 70 knots (certainly keep above 50-60 as it can be difficult to regain speed ESPECIALLY if flying at a low altitude).

Procedure:

  1. Retract wheels to reduce drag and gain forward speed.
  2. Climb out to about 1500 feet.
  3. Once at cruise altitude, ease back to about 2/3 – 1/2 throttle. Bring rotor trim to "min." Trim elevator to 130 knots.
  4. Adjust collective so that you have between 160 rotor rpm

High Speed Cruise

Principles:

The CCTD will be operating primarily as a fixed wing aircraft. As the aircraft is trimmed forward to balance increasing wing lift, the rotor will be almost completely aligned with the line of flight. Because it is not absorbing energy, 1) it will slow down to under 100 RPM, and 2) the reduced drag will allow the CCTD to continue to accelerate. This is that "High m " flight!

Procedure:

  1. In level flight, bring engine power to 80%.
  2. As speed builds, use forward elevator trim. "Steer small" – avoid jerky control inputs.
  3. Reduce collective to 0°. Click on "STAT" button on EFIS. Use rotor trim to minimize "F-A Spindle."
  4. In this model, try adding one notch flaps to make it past the drag hump.
  5. As speed builds, retract flaps.
  6. If rotor speed drops below 60, adjust with collective. "Less is more" – lower pitch allows the rotor to windmill.
  7. In X-Plane, you may see the lift vectors of each lifting surface – press <Ctrl – "/"> twice.

Descent from High Speed Cruise

The CCTD will be operating primarily as a fixed wing aircraft. As power is reduced and aircraft is trimmed forward to maintain speed, the rotor will be almost completely aligned with the line of flight. High m flight will continue.

Transition to Autogiro Mode

As power is reduced and trim is brought back to maintain altitude, the rotor disk will capture more airflow and gain energy, increasing its rpm. To build rpm more rapidly, reduce the collective to –2° until rotor speed is around 300 rpm, then increase collective to maintain that speed.

Run-On Landings

With rotor stabilized at 300 rpm, adjust engine power for desired rate of descent. Advance rotor trim to full. Fly a normal approach, but use collective to flare. Pulling back on the stick will tip rotor back, slowing the aircraft, but reducing braking effectiveness.

Vertical Landings (zero roll landing)

Principles:

The CCTD is now going to enter helicopter mode, using the stored energy of the rotor to control descent. Caution: at 250 rotor rpm, there is only enough energy for one descent – you can’t hover!

Procedure:

  1. Lower gear!
  2. Come in at about 500-750 ft AGL over the end of the runway.
  3. You need to be at 70-80 knots or less and with min collective. The trick is to lower engine power (but keep hand on the throttle) and do what ever it takes to spin the rotor up as fast as possible.
  4. As you head down the runway at about 400ft AGL pull back on the stick and go nose up – watch your airspeed closely, use light power and light forward stick if the sink rate becomes too fast or if airspeed slows too much.
  5. Be ready to pull steady collective if you need to slow descent but remember that this slows the rotor and you need as much rotor speed as you can get and keep.
  6. At about 100 ft allow CC to settle – apply light collective to ensure a slow last few feet down. You can hit the deck at up to 20 ft/sec. What ever you do, avoid flying backward just prior to reaching the runway.