Jenx Aviation - Flying Techniques

Rolls and rolling manouvres.

A roll is one of the most difficult manouvres and this section will try to cover some hints to help in Aeileron, Barrel, Slow, Snap (flick) and Hesitation rolls.

Aileron RollThis is a manouvre between a wing over and a barrel roll and was known as the Victory Roll. It is dangerous!

What could sound easier than applying full aileron until a 360o roll is completed? The problem stems from the rate of roll of the aircraft and where the lift vector is pointing. Most aircraft are designed to fly upright so, when the bank exceeds about 75o the nose will drop - the aircraft is behaving like a dart with the added issue of yaw into the dive (secondary effect of the ailerons) - and without corrective action the nose will be close to vertical by the inverted position. High 'g' is required to recover and the aircraft risks a spiral dive or overspeed (Vne).

One way we can improve matters is to raise the nose to, say, 20o nose up before starting the roll - this will work if the aircraft has a high rate of roll but any mistake, or loss in power, and the aircraft is going down big time... As high nose up entries, and lots of 'dish-out' can result these are best done at height.

Barrel RollThe Barrel Roll is effectively a relaxed and slow aileron roll. Pitch is used to prevent a spiral dive and to keep the axis horizontal. Lacking effective Gate or check heights and escaspe manouvres, it is the most dangerous low level manouvre.

Key high level hints are to:

  • Point at a feature on the horizon 10-15 kts below looping speed.
  • Dive off 30o to the left (if going right).
  • At speed, pitch and roll to achieve wings level through the horizon.
  • Vary rate of pitch and roll to achieve the inverted attitude
    NB if this cannot be achieved abandon the manouvre and roll and pitch to the nearest horizon.
  • Continue to roll and pitch (increasing pressure as the speed increases) until S&L attitude.

    Throughout, the roll rate should remain constant for varying speed and the point should be kept 30-45o off the nose into the centre of the barrel.

    Key Low Level hints are to:

  • Start at looping speed and at 45o to the line feature.
  • Pitch to approximately 45o before commencing any roll.
  • Roll slowly for the first 90o of bank.
  • Increase the rate of roll to complete at least 75o/o of the roll before the nose is below the horizon and the height, above base, required to pull out from a vertical dive.
  • Complete the roll with enough height above base to pitch out from 45o nose down.
  • Gently pitch to base height.

    Using this technique will ensure that you do not become a statistic like so many who have barrelled into the ground!

    • Slow RollPrior to starting slow rolls you should:

  • Identify the inverted S&L attitude - As the wings of most aircraft are bolted on at about 4o to the axis, then the inverted attitude will need to take this into account.
  • Identify the knife edge attitude - 90o straight.
  • Whether your aircraft has sufficient rudder authority to hold the nose up in a knife edge.
  • What the recommended speed and power settings for the roll are - in the Flight Manual.

    In most aircraft, a slight pitch up is required prior to starting the roll. If we consider a roll to the right, we will need increasing top rudder (to a maximum at 90o AOB) and increasing stick forward to the inverted attitude. This is represented diagramatically below.

    Remember, the slow roll will be easier 'with' the engine rather than 'against' it. Furthermore, the first half of the roll is assisted by the rudder whereas, the second half is resisted by the rudder - the adverse secondary effects of the rudder.

    In practice, it is best to start with slightly fast rolls and concentrate on getting them level and straight before slowing the roll rate down!

    • Snap RollThe Snap roll is nothing more than an autorotation in a given horizontal plane.

    The aircraft Flight Manual will provide max speeds as this manouvre places enormous asymmetric stresses on the main spar. The use of aileron to assist entry is common.

    The best hint for these manouvres is to follow the Flight Manual and be positive, near aggressive, in applying the techniques.

    Hesitation RollGiven that prior to the Slow roll practices we had learnt the attitudes for the 4 point hestitation roll, the only issue is how to get to the attitude.

    In a 2 Point then a snap roll may be possible whereas in 4 Point a slow roll will nearly always be better. Key is to fix the attitude, hold it and correct any errors in the rolling part of the manouvre. Small errors in line or height are best left until after the pause in the position.
    This page is maintained by Jenx
    Last updated on 8 Aug 2004