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 backBack to Set Manoeuvres List    The Slapper

The Slapper

Description
This manoeuvre is based on stationary metronomes with the inclusion of a half aileron roll between the stop points. The half roll may be in either direction, but should be centred at the mid-point of the metronome. Six pitch reversals are required. The model should retain overall position and height during the manoeuvre and the tail-boom should retain constant orientation.

Preparation
This should begin with your model, as this manoeuvre is very demanding on the engine/servo performance of your machine. Check that your engine is in good condition and tuned for maximum power. Also check that your cyclic and pitch servos are suitably fast and powerful.

If you have not yet performed tail-down metronomes, these may be developed along the lines detailed in the November 2006 ‘Idling Up’ article, where we examined how a beginner may start some initial pitch exercises from the hover and develop the necessary elevator and pitch co-ordination to perform tail-down metronomes.

When you are able to perform consistent tail-down metronomes that retain position and height, you should then consider stretching your model to its limit, by carefully reducing the elevator inputs whilst increasing pitch inputs.

You will notice from the Judges’ notes that the manoeuvre is to be a series of ‘tail-boom - vertical metronomes’ and that ‘the model will retain constant tail-boom orientation.’ This means that to retain the tail-boom in the vertical will require an aggressive metronome with relatively small elevator inputs but large pitch and power requirements.

It is, of course, not possible to maintain the tail-boom perfectly vertical as the model metronomes, or it would begin to descend, but we must aim for something approaching this requirement. So, before proceedings further, practise plenty of metronomes ranging from relatively slow arcing (rainbow) examples to the most aggressive your model will allow without beginning to descend.

Finally, the half-roll must be considered. You should check that your model is capable of rolling as rapidly as possible. Practise half-rolls in normal level flight and make any model adjustments necessary to ensure a crisp but controlled half-roll can be consistently performed.

Flying the Manoeuvre
Following your practise of metronomes and half-rolls, try your first ‘Slapper’ by starting a relatively large arcing metronome at a safe height. Get the model established in a few reversals before introducing the half-roll. The half-roll, which may be in either direction, should be centred at the mid-point of each metronome, so begin aileron input just before the vertical position is reached. Full aileron control should be used to give a rapid half-roll. It is important to be fully aware that the collective pitch at the centre of the half-roll should be zero to ensure the model holds position.

From this it is apparent that the required pitch changes to fly the ‘Slapper’ must be accurate and fast changing. As the half-roll is completed, pitch must be quickly reinstated in the opposite direction to keep the model moving before full opposite pitch is applied to return the model into the next metronome. Six pitch reversals are required indicating that this manoeuvre may be described as fast and furious!

Possible Problems
The introduction of the half-roll dictates that the manoeuvre is somewhat more protracted than straightforward metronomes, and this in turn, adds to the difficulty in maintaining a tail-boom down attitude that is ‘constant.’

Inevitably, a compromise will be reached as you fly the ‘Slapper’ that offers a balance between a clear-cut manoeuvre and the best ‘tail-down’ attitude that can be achieved.

The pitch control requirements of this manoeuvre, coupled with the timing of the half-roll must be developed with practice to produce good results.

 

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