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Rolling Circles

Author: Mark Kiner

Since no one has tackled this one...I guess I will

Preaching first

Before you try a rolling circle I think it is important to be able to do multiple rolls from both directions. i.e. right to left and left to right. It is also important to use a moderate roll rate. Doing ballistic rolls at warp 9 cyclic do not really develop your timing for the collective.

Once you can do the rolls from left to right and from right to left with confidence at about 1 roll in 2 seconds or even a little slower it is time to do the rolls going away from you and coming back into you (looking at the tail and looking at the nose)

A helicopter with a little swashplate timing error will want to do a rolling circle on it's own when going from one corner or the sky to the other.

Rolling circles are a little easier with a standard gyro in my opinion. I personally feel that the HH gyros add an element of difficulty, but this could just be me.

Now that you can do the above let's talk about rolling circle technique:

Instructions below are for counter clockwise circle with right cyclic roll:

Start the roll from left end of the sky As heli hits show center push forward cyclic when the heli is on it's rh side (knive edge) and pull aft cyclic when it is on the left hand side (knife edge) Continue this and you will see the circle develop. If you get disoriented stop the roll and fly back and catch your breath.

By the way it is important to change your collective timing a little while in the roll.

I feel it works best to leave a little negative collective in when in the rh knife edge and a little positive when on the lh knife edge. Experiment with this collective timing as it will help maintain altitude during the rolling circle and will also help make the circle smaller.

Additionally it is necessary to give some steering with the rudder in HH modes to keep the circle smooth. Normal gyros don't really require the rudder steering in my opinion as they weathervane.

This tail rotor steering when the heli is upright and inverted is really a must with the backwards rolling circle.

Collective experiments:

Go back to your straight rolls and play with this collective exercise

When most people do a roll they are thinking right side up ...positive pitch

upside down....negative pitch.....at either knife edge....zero pitch and they transition the collective smoothly between pos and neg.

Try this exercise as a prelude to leering a rolling circle

Start your roll (for instance with right cyclic)...as soon as the heli passes knife edge pull negative pitch and hold it all the way through inverted and clear up to the other knife edge. (remember normally most people have zero at knife edge)

Now as the heli passes knife edge quickly go back to positive pitch but only hold until the other knife edge.

Essentially you are either holding positive pitch or negative pitch all the time and the only time you are at zero is the quick transition from positive to negative and back at the knife edge points....

You will see some interesting results.

This tends to push the machine back and forth laterally when in knife edge position, but it really gives some hang time.

Again never zero pitch either pos or neg....

Now this is not the way to do a perfect looking roll, but I think it will teach a few things relative to aerodynamics and the helicopter.

I beg the pardon of you experienced pilots for my long post.

Mark Kiner

The Colorado Rotor-Heads is a group of R/C helicopter pilots based in Denver, with members all along Colorado's Front Range.  Our members belong to many of the Front Range clubs from Colorado Springs to Fort Collins.  As a result, you may see our members at many of the local club fields and even the occasional cul-de-sac.  If you would like to learn more about the Colorado Rotor-Heads, or R/C helicopters in general, please visit our web site at www.coloradorotorheads.com.

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