Poor Man's Helichair

Bruce Burdekin is now the proud owner of my old Exec and he is rebuilding it in New Zealand. He sent the following project for those who want to get a jump start on their flight training. I have found that students who can fly a remote controlled helicopter adapt very quickly to learning to fly their Rotorways.

Hi Orv,

No photos from my re-build yet, as I'm having a sort-out - there are hundreds of them

On another subject, the 'heli-chair', I have built a (very) poor man's one using a cheap 'Honey-bee' r/c electric heli, and it certainly is challenging practice. I have just written to a member of the R/Fun forum who asked me about it, and thought you might be interested. I will also post it on the ROG forum, but you should have first go, for all the help you give us. From seeing someone flying the more advanced Honeybee, that has full rotor pitch control and can do autos, I can see it being a very good starter for quick-stops and autos as well as hover practice. I would appreciate your opinion/experience.

Attached are some pictures of how I made my 'poor man's heli-chair'. I do not know if you have electronic experience, but it's very simple in any case. All I did was to add another socket in the controller, that connects to the chair controls, and a switch to switch the controls for the throttle and tail to the chair. This means that the controller can be used normally as well, just take it out of the chair and switch to normal control.

Remove the back of the controller, and identify the control for throttle (up/down on the left joystick for Mode 2) and left-right for the rudder control, which will become the pedals. Cut the track to the middle leg of the control, and solder a wire to each side of the cut. (see photo 1 and 2) This brings the feed from the control and to the electronics out on 2 wires. I used the same color as the wires already there, but anything will do. Do the same with the other control, and as well, add to the red and black wires off one control.

Now, the control (blue and yellow) wires go to the selector switch which is a 2-pole changeover mini toggle switch, with the wire that goes to the electronics soldered to the center (common) pin of the switch Blue to one pole, yellow to the other. The wire that goes back to the control in the main unit goes to one of the end contacts. Now, add a wire from each of the the remaining end contacts (one blue and one yellow) to the new plug. The switch now acts as a changeover from internal to external control.

I used a 6-pin mini-DIN plug and socket, as I had it lying around, but almost any plug with 4 or more contacts will do. The plug is wired with the red and black wires which are the reference voltage and ground, and the blue and yellow wires from the selector switch. I used a length of 4-wire security cable to wire the chair up with, but again almost any flexible wire will do.

The controls on the actual chair are two 5Ohm linear potentiometers (available from any hobby electronics store) with ordinary cheap plastic knobs on. Wire up as shown in the photos. The red and black wires go to the outside contacts on both, and the control wire goes to the center pin. The yellow wire to the tail-rotor pedal, the blue (which is green in the
alarm cable) to the collective. I joined the wire in a tee-junction at the end of the seat, with all wires joined. That's why there is a spare strand at each control. I have drawn a very rough circuit diagram for each part, see the last 2 photos.

Now for the mechanical part, ...... Again, I used whatever was around to make the chair up. I started with a bit of 300 x 600mm custom-wood (MDF)for the base, and built a pocket on to the front of it to hold the controller so the joystick for the direction (now the cyclic!) is centered in front of the seat base. I made a strip on the left side to mount the pot on, made a 'collective' lever out of a length of 20mm plastic pipe, added a bit of wire that goes from the collective, twice round the control's knob, and back to the collective, via a large rubber band to keep tension on the wire. (I used wire because I didn't have anything else; light braided nylon cord would be better) I hinged a length of wood on to the front of the controller pocket, and made a very crude pedal cross-bar out of another length of custom-wood, pivoted on a single screw with a washer either side. I then made a control drive set-up similar to the collective, with a bit of wire round the control knob that is anchored to each end of the pedal bar. Another bit of plastic pipe to extend the joystick into a cyclic, and that's about it.

The hinge on the length of wood that supports the pedal bar is to allow the whole thing to fold up a bit smaller for travel or putting away, allows for any height chair to be used, ..... and it's an easy way to join the two pieces!

Now, plug in the controller, switch to external, sit down and go. The 3rd-last picture shows my friend Don trying to fly the simulator on my laptop. I have set myself the goal of mastering the simulator before trying the model. Certainly from my experience so far trying to fly the simulator from the heli-chair, it is a lot like the real thing, and good practice to get the reactions working right. I find myself making all the same errors that I made when trying to hover an R22, and hopefully
will overcome them in time.

Any questions, just e-mail me and I'll answer as best I can.

Have fun, Bruce.

Bruce Burdekin,
1 / 31 Heywood Terrace,
Christchurch, 8013,
New Zealand.
T: +64 3 942 2154
M: +64 21 341 820
E: bwburdekin@clear.net.nz