Tuesday, August 11, 2009

The pilot and passenger grips are now wired and ready.

For the FlightGrips you need to trim 1" off the factory Y grips, use a bushing to allow for the 1" shaft and drill a 7/32" hole for a bolt that secures everything.

The grips are very sturdy and use aviation grade heavy duty buttons and switches.

In my configuration the pilot and passenger both have PTT and Flip/Flop.

The pilot has a memory set button, elevator trim up/down and an intercom isolate switch.

Wiring the passenger grip was easy. The PTT and F/F are both on an off center trigger. Pull on the bottom is PTT, pulling top is F/F. It is very hard to accidentally pull the wrong trigger. FlightGrip's trigger is removable from the shaft. The grip is designed to open up down the center with the trigger being removable. There was plenty of room for the wires and some heat shrink.

The pilot's grip was harder. The trim and mem set switches are on the top of the stick. These buttons are mounted on a removable disk, making wiring easier. The pilot has the same PTT/FF button config as the passenger.

The passenger intercom isolation toggle is mounted as a thumb shaft on the grip. Accessing the connection points was much harder for this one.

To get the wires down the stick some scotch tape was used to secure the various bundles together and then shoved down. Fitting 15 wires down the shaft ( each in sub bundles by function & destination ) was a little tricky due to the narrow passage where the "Y" forms and the pivot point at the base of the stick.

Once the wires were out I closed the grips and bolted them onto the stick. Closing the passenger grip was easy. The pilot's grip had the problem of heat shrink and wires made inflexible by solder. Some bending and finessing had to be done to get the stick to close with wires routed around the holes for the mounting bolt.

Almost all the connectors I have been placing are DSub 9s. The originally intention was to use a DSub 15 for the pilot's grip and a 9 for the passenger. Instead the pilot's grip has two 9 pins. One connector has the PTT,FF,MemSet and isolation buttons. The PTT and FF's pins are in the same location on the passenger's grip. You could interchange the two connectors with the only side effect being to disable two buttons. This seemed like a more resiliant configuration and also lets me have the option of disabling the trim in the field if I need to.

To use both the rocker switch in the panel and the switch on the joystick a relay had to be used. Ray allen sells one for this purpose. In addition to the relay a small circuit had to be made. This multiplexes the two switches. When the relay is used what the switches are really doing is selecting what ground is being closed.

Two IN4001 diodes are placed in line to the joystick ( DPDT ). These are split from lines that go to the rocker. From the rocker and joystick each a line is sent to the ground.

Sunday, August 09, 2009

Wiring update:

Most of the wiring harness is complete. Lights, radio and utilities are done. The transponder, Dynon and alternator wiring remain.

To help reduce the clutter on the kitchen and workbench tables I started cutting the panel and installing parts.

Many months ago I mocked up my panel using lifesized print outs. This worked well, but many details were simply left out. Some of the parts of changed, and a few unexpected things have been added. There are more switches and breakers than I had planned for.

One challenge has been trying to plan around the throttle handle. The exact position of the throttle can not be determined with out the throttle bellcrank installed. Based on the expected position from other builders I have moved the Dynon more towards the centerline. I would prefer that the Dynon be centered with the pilot's seat, but that may be impossible.

When laying out there were a few factors I kept in mind.

1) Anything flight and emergency critical should be close to aircraft center. This is to allow the passenger access to the starter, ELT, ect.

2) Try to logically group switches by function

3) Keep power away from the primer.

4) Do not stack any switch above or below another.

I have also received my grips. The final choice was for FlightGrips ( no website ). These are a solid grip that bolt onto the Y stick.

Internally the switch poles are easy to access as the stick splits apart and the top cap is removable. You do need to be careful with how much heat shrink is used as to keep the wire flexible enough to route around the grip.

On the pilot's side there is a elevator trim up/down, PTT, Radio Flip/Flop, Radio Mem Set and intercom isolation.

On the passenger's side there is PTT and Radio flip/flop.