Helitronix > Multi-Mixer Standard	Printable Version

HMIX02  Helitronix Multi-Mixer Standard for Flybar-Less Heads  $199.99 

Designed for: multi-blade & flybar-less rotor head models.

The complete Multi-Mixer Instruction Manual.

What is the purpose of the Multi-Mixer? The mixer fundamentally improves on three key problems that are not handled as well as they could be in many modern computer class transmitters. First, a transmitter that does not offer CCPM (cyclic collective pitch mixing) can now be used on a helicopter with this swashplate configuration. Secondly, the mixer is designed to work with gyro stabilizers for the pitch (elevator) and roll (aileron) control surfaces. Thirdly, the mixer generates swashplate phasing to precisely setup a multiple blade rotor head while keeping the mechanical pushrod setup perfectly linear.

New Features:

General Features:

The Multi-Mixer Standard is designed for a single rotor helicopters and will only use the R1 servo connections (S1R1 - roll (aileron), S2R1 - pitch (elevator) & S3R1 - collective pitch).

General Information
The LCD programming module is intended to be connected on the work bench during setup and is removed during flight, but can be used at the flying field to make any final trim adjustments. If you have been considering a mixer to assist you in flying your multi-rotor scale model, then the standard Mult-Mixer is the best money you can spend. The Helitronix mixer should be near the top of your list of must have accessories to change your scale project from an incredible scale model that you are afraid to fly into one that you want to fly all the time. It improves the flying characteristics of the model so much that it feels very close to our trainer flybar type models. You spend more time flying than correcting the model in forward flight.

The mixer doesn't look like much, but it is all in the programming. Any scale modeler considering a multi-rotor scale head should factor in the cost of this mixer. It attaches between the cyclic servos and the receiver and can be used with one or two rate gyros to stabilize the elevator and aileron in forward flight and while hovering in wind. The gyros you will be adding to the helicopter should be good quality rate gyros or dual heading hold/rate gyros that can be switched into rate mode. While single rate gyros will work just fine, spending that little extra for remote gain gyros is worth it (if your transmitter has enough spare channels) for adjusting the gain from the transmitter, or connect the gain channels together using a 'Y' harness. After installing the mixer, completing the detailed setup and flight testing, you will be able to comfortably fly your multi-rotor model just as much as if your were flying a flybar head on a sport model. It really works that well.

CCPM - Cyclic Collective Pitch Mixing
Modern radio control transmitters include both airplane and helicopter programming, but there are still a large number of transmitters that only have airplane programming, have limited functions for helicopters or are still analog (non-computer class) that are perfectly good radios but lack features to fly helicopters. The Multi-Mixer is designed to be connected to all radio systems in what is called single servo collective mode. In airplane terms, you simply connect the aileron, elevator, collective (channel 5) to the mixer and the programming and internal configuration is set to match the mechanical swashplate type on the model. If your transmitter has a swashplate mode feature, make sure it is NOT using CCPM. The mixer will only function correctly in single servo mode. The mixer provides both individual servo reversing, CCPM control surface reversing and digital servo trim to achieve a perfectly linear, mechanical setup on model.

Gyro Stabilization
Why do I need a mixer to use aileron and elevator gyros on my helicopter? If you are flying a mechanically mixed collective helicopter with a two blade rotor head, you do not need the mixer. But it is essential for helicopters with CCPM swashplate configurations because installing a gyro on say the elevator channel will not function as you think. The gyro will only assist the single servo connected to the elevator channel, resulting in an instant bind condition in the swashplate, possibly damaging the gyro, servos and the receiver. The Multi-Mixer applies the gyros response to each of the servos in the correct directions, magnitude of movement and in the correct phasing angle when configured. More importantly, installing elevator and optionally aileron control surface gyros on multi blade rotor systems vastly improves the models stability. It quite literally makes the multi blade model a pleasure to fly because the gyros dampen out or compensate for most of the flight characteristics that traditionally have made multi blade rotor heads very difficult to fly.

Swashplate Phasing - Multi Rotor Heads
Multiple rotor blades add an additional complexity to the helicopter setup that for many years was always compromised because of the programming limitations in transmitters. Currently only a select few high end transmitters offer phasing, but the benefit of phasing does not always justify the high cost of these transmitters. Traditionally, the inner race of the swashplate was physically rotated a number of degrees off center so that a pure forward cyclic (elevator) input would move the helicopter in the same direction. This was accomplished by loosening the swashplate driver and rotating a few degrees at a time. The actual angle and the direction of the phasing adjustment depends on the rotational direction of rotor head. However, each incremental move, the pushrod geometry would move away from vertical which introduced a pushrod angle and hence a control bias that was different for forward/left cyclic as compared to rear/right cyclic inputs. Models were still flyable, but an extraordinary amount of attention and concentration was needed during flight.

The Multi-Mixer offers electronic phasing adjustment in 1° increments which means that the swashplate is mechanically setup to achieve vertical pushrods and as close to 90° angles between the inner race control ball to pushrod and from the pushrod to the control ball lever on the blade grip, when the collective blade pitch is at 0°. This ensures a linear response from any input in any direction to the swashplate. The Multi-Mixer then takes the pure cyclic input and generates the correct angle to tilt the swashplate matching the programmed phasing value. The electronic adjustment is much easier to make at the field and eliminates costly wear on the swashplate driver and difficulties in making the mechanical adjustment.