Helitronix
Senior Heliman
Location: Marlborough, MA - USA
| Hi folks,
So I've been building helicopters, but I've been building a different part than most. I'm eventually going to build a Vario CH-47 with some sort of custom mechanics. Mine will be electric powered. Rather than start in on the mechanics, I chose to start building the electronics first. I decided to make my own custom tandem rotor mixer with all the features I could want in such a device. I built a first prototype over a year ago. Over the next year, I thought of some refinements and redesigned the whole thing. The result was a mixer that is 1/4 the size of the original prototype and has a better user interface. The original tandem rotor mixer was configured with 6 built in pushbuttons and 16 dip switches (3 buttons and 8 dips per rotor head). I simplified the design and now have no buttons or switches on the mixer itself. Instead, I created a display module with a nice green backlit LCD that connects to the mixer via a cable. When you want to configure the device, you plug in the display module and go through all the prompts on screen. When you are done, you just disconnect the cable from the mixer. It's quite clean this way.
You configure the swashplate type (3 servo CCPM, 4 servo CCPM, 3 servo standard, and 2 servo standard), phasing, Servo reverse, yaw sense, Differential Collective Pitch sense, aileron sense, elevator sense, servo centering, elevator mixing ratio (0 to 100%), DCP mix ratio (0 to 100%) individually for each rotor head or servo as applicable.
Some folks want a tandem with elevator mixing in addition to DCP. Some want it with just DCP. Because you can control how much mixing is applied for each, you can dial it in or out. It's your choice.
Here are a few pictures of the device. I haven't yet covered the mixer with heat shrink covering. It will normally be covered like the standard mixer is today.
Everything together:
A closeup of the mixer itself:
A closeup of the display unit:
The intended audience is those who are either scratch building their own tandem rotor helicopter, or those who have a mechanically mixed tandem rotor helicopter that they wish to upgrade with pure electronic mixing to reduce mechanical complexity and weight.
I'm going to try to find a few folks who want to beta test it and provide feedback. Once I confirm that all is well, I'll make them available for general sale for the other 6 people in the world who want one. 
Joel- |
