The Slow Roll

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The Slow Roll

Post by Greg Russell-Brown on Mon Nov 21, 2016 8:43 am

The slow roll can be quite a challenging manoeuvre to execute as compared to a generic moderately fast aileron roll in that one MUST use both the rudder and the elevator to execute it successfully, whereas with the aileron roll the aircraft rolls through the 360 degrees of rotation along its longitudinal axis quite quickly so the extra inputs of rudder and elevator are not necessary.

As always ensure you are flying at a good altitude of (3 errors high) when attempting new manoeuvres!

We will practice this manoeuvre heading into wind to start with - (if one is attempting the gold wings accreditation this manoeuvre is done in both directions, i.e. from left to right and from right to left regardless of wind direction).

We start from upright level flight, heading into wind and commencing from a point roughly 50 Metres downwind from yourself - (this is done so the manoeuvre is balanced with half of the slow roll before or downwind of you and the other half after or upwind of yourself).

Throttle should be set at approximately 75-100%, when the aircraft is setup in the right area we commence by applying just the smallest amount of up elevator in order to nose the aircraft up by an almost imperceptible amount then release that small elevator input - enter the aileron input (in either direction of your choice) but only a little aileron - perhaps 20% of full stick travel and hold this on until the manoeuvre is complete.

The following is a lot easier to explain in person with a TX and with a whiteboard but nonetheless we will give it a try.
As the aircraft starts its slow roll, input a small to moderate amount of opposite rudder to the aileron input.

This rudder input gradually comes off as the aircraft rolls through sideways flight or knife edge and then all the way off as the aircraft approaches inverted, this is when a little down elevator is applied (quantity is dependent on the aircraft type and control throws available etc) and as the aircraft nowrolls from inverted through to the opposite sideways flight or knife edge, apply a little rudder again but obviously in the opposite direction from the initial input (when you first started the roll).

As the aircraft rolls back to upright flight the rudder comes off to zero input and then resume normal level upright flight.

The use of the rudder and elevator is the tricky bit here as correct usage of them results in a perfectly straight flight path whilst the aircraft is slow rolling.

On a mode 1 transmitter the left hand stick will appear to be moved through an elliptical motion in synch with the rotation of the aircraft.

For example and for a slow roll with right aileron the left stick will first go slightly down (up elevator) to point the nose of the aircraft up very slightly then to the left (left rudder) then slightly up (down elevator) and finally to the right (right rudder) then back to normal elevator for upright level flight.

On a mode 2 transmitter again with a slow roll to the right the right hand stick goes slightly down (up elevator) to point the nose of the aircraft up very slightly then this comes off and the left hand stick will then move left (left rudder) then it goes neutral and the right hand stick goes slightly up (down elevator) then neutral then the left hand stick goes right (right rudder) then neutral and finally we return back to normal elevator for upright level flight.

Manoeuvre complete.

It will take practice to find the sweet spot of exactly how much rudder and elevator to use (and it varies with the aircraft type and setup of course) in order to maintain a nice straight flight line whilst slow rolling.

After becoming used to and quite proficient with the slow roll you (may) want to try rolling circles and if you can slow roll pretty well guess what - a rolling circle is just a matter of changing the timings of the rudder and elevator inputs to induce a curve or turn as opposed to keeping the aircraft flying in a straight line.
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Greg Russell-Brown
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