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Aim:-
To teach the correct technique of taking off and landing into wind
Airmanship:-
Pre-Take-off Checks
 - Good lookout all around- Wind Direction & Velocity
- Surface type
- Temperatures & Pressures
- Awareness of Downwash
Take off to the Hover
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Pre-Take off checks |
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Fuel, T's & P's, Warning Lights, Card. Heat, Friction's off,
governor as required, all around
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Set the RPM at bottom of green (98%) |
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Gently raise collective - ready to reduce throttle as it will initially be over correlated
Aim to have the manifold pressure at 18" with the RPM in the middle of the green this will avoid an overspeed when lifting into the hover
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If aircraft move at any time - Get eyes outside |
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As aircraft becomes light on skids it will start to move
Must look out if aircraft moves
Correct Yaw with pedals
Correct pitch, roll and any tendency to skitter with cyclic |
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Raise collective some more - pedals & cyclic |
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As aircraft leaves the ground adjust with cyclic for attitude change |
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Establish 5ft Hover |
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Airmanship - After take-off checks |
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RPM & MP Checks
Carburettor Air Temperature (CAT)
T's & P's
Control responce
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Dynamic Rollover
| If incorrectly positioned the lift and thrust forces from the main rotor will cause the helicopter to roll about one skid. If not immediately corrected by the lowering of the collective lever these dynamic forces will cause the helicopter to roll over. If roll is rapid then the helicopter’s inertia can cause rollover to occur well before the 10º point
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| NOTE: |
Full right cyclic gives maximum main rotor disk displacement of 8°, full left cyclic gives maximum main rotor disk displacement of 10°
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Dynamic rollover can often occur when the aircraft is on sloping ground and rapid lifting of the collective lever causes a roll about one skid (pivot point)
Missed Take Off/Dynamic Rollover
Firmly lower the lever, re set-up and start again
Ground Resonance
Ground resonance generally only occurs in helicopters with fully articulated type rotors with lead/lag hinges. It has to all intents and purposes been designed out of modern day helicopters - but there is always a chance !! Ground resonance occurs when a series of ‘shocks’ between the landing gear and the ground cause an imbalance in the rotor head. If allowed to continue it will cause severe vibration and rocking, often resulting in structural failure and/or the aircraft to roll over. Recovery must be immediate, if the RPM is in the correct range the helicopter should be lifted into the hover and the vibrations allowed to cease otherwise the throttle should be closed and the collective fully lowered to take any pitch off the blades and the rotor brake applied
Although not prone to Ground Resonance the R22 is however subject to a sympathetic resonance between the tail rotor and the tail boom itself. This resonance can occur between 60% and 70% RPM and therefore prolonged periods within this range should be avoided, hence the yellow arc between this range on RPM gauge
Over Boosting(Piston), Overspeed & Over Pitching
‘Over boosting’ occurs when power settings over and above the maximum allowed limit occur due to excessive lifting of the collective lever. This situation will often lead to a low RPM condition (see below), as the correlator is not as effective in the higher power ranges as it is between 18" and 23", and throttle will need to be added manually in order to maintain the correct operating RPM. ‘Over boosting’ will cause unnecessary stress to both the engine and rotor system and is to be avoided
An overspeed will occur if too much throttle is applied over that required to maintain RPM within the normal operating green band causing both excessive rotor and engine RPM. An overspeed can place severe stress on both the engine and rotor system and may in turn cause damage to both, it is obviously therefore to be avoided. An overspeed is corrected by reducing the throttle thereby bringing the RPM back to its correct operating range
Over pitching (Low RPM condition) occurs when pitch is applied without the necessary power being added in order to maintain the correct RPM. In extreme cases this will cause a rapid decrease in RPM resulting in loss of lift and directional control. Low RPM during in-flight conditions, if not immediately corrected, is likely to result in a crash and again is to be avoided. Over pitching is corrected by immediately rolling on throttle and reducing the pitch setting with lever
Over boosting, overspeed and over pitching are likely to cause erratic fluctuations in RPM making control, especially heading and height, extremely difficult and are therefore to be avoided (especially low RPM). In order to avoid these situations RPM should be correctly stabilised in the middle of the green before lifting off and all control movements should be executed smoothly without any ‘jerkiness’
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Landing From the Hover
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Establish steady hover - into Wind with RPM in the green |
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Lower collective & 'Fly' the aircraft to the ground |
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Execute a firm Landing - with no sideways or rearward movement |
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On ground contact lower lever to avoid any bounce - nay need a bit of right pedal |
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Lower collective maintaining RPM in green using throttle |
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When collective fully down reduce RPM to 80% |
Mislanding
| It is essential that the helicopter is ‘flown’ to the ground and that there is no sideways or rearward movement when ground contact is made. If a skid were to dig in it is highly likely that the helicopter would tip over (dynamic rollover). If movement in either plane exists the landing should be immediately abandoned by raising the lever and returning to a stable 5 ft hover before a further landing is attempted
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Discussion Points
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Effect of concentrated ground cushion just before touchdown |
Air Exercises
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Landing into Wind |
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Take-off into Wind |
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Mislanding |
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