Transmitter settings: Curves
This section explains throttle and pitch curves to program on transmitter.
In addition to do settings on heli, blades and servos; for RC heli we need to enter specific parameters into the transmitter.
To fly an heli we use one stick on transmitter to control two commands: throttle and pitch. To control these two commands we enter "curves" to define values of throttle and pitch for each stick position.
Also we set flight modes. We need different flight configurations when we do hovering, fast forward flight or aerobatics (3D).
This page presents 3 flight modes (Normal [starting / hovering], Idle-up 1 [fast flight], Idle-up 2 [3D flight]) and one more : Hold.
For each mode we will define a throttle curve and a pitch curve.
WARNING: pitch values (in degrees) written in this page must be adjusted depending on the helicopter model to set up.
Normal curves [starting / hovering]
These first curves are used to start, to take off, to hover and to land the helicopter.
- Stick at lowest position, engine needs to idle (for starting) and pitch needs to be close to 0°.
- When throttle/pitch stick is moved up, throttle and pitch must progressively increase.
- When stick is at the middle position, throttle is at 50% and pitch is equal to the specific hovering pitch of your heli (here 4.5°).
- For electric helis we use a different throttle curve which rises more quickly (having bigger slope) to speed up motor rpm.
For the normal flight mode pitch and throttle curves should look like this:
| Position (%) | Pitch (°) |
|---|
| 0 | -2 |
| 50 | 4.5 |
| 100 | 8 |
|
| Position (%) | Throttle (%) |
|---|
| 0 | 0 |
| 50 | 50 |
| 100 | 90 |
|
| Position (%) | Throttle (%) |
|---|
| 0 | 0 |
| 25 | 40 |
| 50 | 65 |
| 75 | 85 |
| 100 | 100 |
|
 |
 |
 |
Note: "Stick position" in percentage means: 0% = lowest position, 100% = highest position.
Idle-up 1 curves [fast flight]
The following curves allow to fly quickly in particular to come down quickly when the helicopter is high.
- Throttle/pitch stick at lowest position, we add negative pitch to make go down the helicopter.
- We keep some throttle to sustain and to maintain rotor speed when the stick is in lowest position as well.
- For electric helis we keep high rpm with a high throttle curve.
Here are the pitch and throttle curves for Idle-up 1 flight mode:
| Position (%) | Pitch (°) |
|---|
| 0 | -5 |
| 50 | 4.5 |
| 100 | 9 |
|
| Position (%) | Throttle (%) |
|---|
| 0 | 65 |
| 50 | 50 |
| 100 | 100 |
|
| Position (%) | Throttle (%) |
|---|
| 0 | 90 |
| 50 | 80 |
| 100 | 100 |
|
 |
 |
 |
Note: "Stick position" in percentage means: 0% = lowest position, 100% = highest position.
Idle-up 2 curves [3D]
3D curves are used to do aerobatics. These curves allow to do inverted flight.
- Pitch has a symmetrical curve, there is an equal amount of negative pitch as there is positive: -X° +X° with 0° at the middle position.
- Throttle is eaqual to 100% for full positive AND full negative pitch.
- throttle is never less than 50% when pitch is at 0° in order to maintain rotor speed.
- For electric helis throttle remains very high and is nearly constant.
Here are pitch and throttle curves for Idle-up 2 (3D) flight mode:
| Position (%) | Pitch (°) |
|---|
| 0 | -9 |
| 50 | 0 |
| 100 | 9 |
|
| Position (%) | Throttle (%) |
|---|
| 0 | 100 |
| 50 | 50 |
| 100 | 100 |
|
| Position (%) | Throttle (%) |
|---|
| 0 | 100 |
| 50 | 90 |
| 100 | 100 |
|
 |
 |
 |
Note: "Stick position" in percentage means: 0% = lowest position, 100% = highest position.
Hold Curve
Hold curve allows to land the helicopter when the engine stopped.
There is only one curve: pitch curve, throttle has no effect because engine is stopped.
- Hold curve needs to have negative pitch to speed up the rotor during the phase of descent.
- The positive pitch is set to maximum in order to slow down the heli just before to land.
Hold pitch curve:
| Position (%) | Pitch (°) |
|---|
| 0 | -5 |
| 50 | 0 |
| 100 | 12 |
|
 |
Note: "Stick position" in percentage means: 0% = lowest position, 100% = highest position.
