Pitch & Throttle Experiments

Revised Setup Ideas and Practical Testing

Most Helicopter kit Manufacturers give you at least two mechanical setups, sometimes three.

This is very unhelpful, as every time you progress from Hover(Norm) to Circuits, to 3D, you have to set the machine up again. (This assumes you are not an "expert" where you actually need different mechanical settings)

What I really wanted was one mechanical setting that would suit all three, and 3 Tx modes to suit the above 3 requirements.

It is then easy to switch modes on the Tx.

Mechanical Setting (Head)

Mechanically, you are trying to get all servo arms in mid travel and 90degrees to the rods. Start with the manufacturer's recommended rod lengths, and adjust until 0 degrees shows on the pitch guage at the throttle stick mid-point. Note that the throttle should be adjusted for 1/2 power at the stick mid point also.

Mechanical Setting (Tail)

Set without Gyro in circuit, making sure you have full movement without binding. If any binding or over driving, adjust EPA to eliminate it. Either set as mid point or offset 6 to 8 degrees, depending on preference. Re-connect Gyro and power up to get Gyro to store end points.

The Beginner (in the Hover)

The left-hand vertical column (see diagram below) shows the Beginner's setup ((Hover(norm)) , as advised by most books / Manuals.

In this case the pitch curve is limited to +7 to -2 degrees.

Throttle and pitch curves are set to hover at the 5-6 degree point at mid-stick.

This is done for the following reasons ;

a) The Heli. does not gain height too fast (if positive pitch is limited)

b) The Heli. comes down slowly from height due to minimal negative pitch.

The more Experienced Flier (out of the Hover)

The second column show this these modes (Circuits(idle-1)) and (3D(idle-2)).

If using a mechanical pitch range of +10 to –10 and 0 at mid-stick, then the upright hover point will be at 60 -75% stick depending on ;

a)       Head speed.

b)       Positive pitch amount at the take-off point.

c)       The weight of the Heli. (AUW)

Setting up the Hover

Firstly, the hover point has to be found (it will be somewhere between 0 and 6 degrees and somewhere between

mid and ¾ stick position). This is assuming that the throttle has been mechanically set up so that ½ movement

on the servo is at mid-point on the throttle stick (1/2 power approximately).

Initially set the Tx norm for both Throttle and Pitch curves to straight lines (usually the default (or INH (inhibit)).

Ideally, the Hover point should be between 1400-1600rpm but differs for each engine/power combination.

In essence, there must be enough head speed to keep the Heli. stable in the Hover and keep the Gyro gain high

without tail oscillations. This can only be done by flying and testing.

Once the Hover point is set, the curves can be used as a basis for setting up idle-1.

Setting up Circuits/Aerobatics (idle-1)

Set up the Pitch curve exactly the same as the Hover set up.

Set up the Throttle curve from mid-point (50%) the same as the Hover. Set up the lower points to 50% (1/2 power).

This ensures that when switching from Norm to Idle-1 there is no drop/gain in the Heli’s height.

This has the following attributes ;

a)       The cyclic is constant response at around mid stick or lower which is ideal for circuits.

b)       Takes away throttle and replaces it with pitch only for most of the usable range, making it easier to adjust

       circuit height.

c)       Tail is more positive, especially noticeable losing height quickly.

d)       Nose does not fly up into wind due to no throttle increase under 50%.

Setting up 3D (idle-2)

(see diagram). The throttle is again set to 50% at the mid point and graduated upwards to

75%, then 100%. This gives maximum power (when necessary) both in normal flight and inverted and the

advantages above in idle-1. Height is controlled by pitch in both cases under 50% throttle. 

Setting up Autorotation (idle-3)

I have not shown this on the diagram due to it's simplicity. The pitch curve is a straight line.

It is important that the throttle is set to somewhere between 5 and10 % so that the engine idles reliably and most

importantly, the clutch is disengaged at this point. This is to make sure there is no interaction or drag while using

maximum negative pitch to spin up the blades.

My Currently Used Settings

I am currently using these settings on both of my .30 size Helicopters and am very happy with them. They are unlikely to ever change.

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