Tuesday, September 08, 2009

Some major steps have been taking with the wiring, with a bunch of "lessons learned".

The approach I took was what seemed logical to my programmer mind. I took a look at each device, the inputs and the outputs and made a series of sub harnesses. Connectors ( D-Sub 9 ) are used where two harnesses would need to join together.

Rough distances were measured with approximate routing.

Each sub harness was made in relative isolation.

This worked fairly well. Some of the earlier harnesses are a little untidy. None of them match in size.

As I went to install the harnesses this weekend I realized that I needed more of an "integrative" approach to the wiring problem. Lots of single wires got tangled up with each other. Wires drooped all over. The whole thing was a rat's nest mess.

I took everything back apart. Slowly I added one sub-harness back in at a time. With each new addition I attempted to clean up the harness and wrapped the wires into more logical bundles.

As the harness was put in, those bundles were bundled with the other bundles. The ground terminals were grouped together and bundled. The power terminals for the two buses got a similar treatment.

While doing this the remaining amounts of wire were looped and tied off to further promote a clean installation.

I have a LED strobe with controller. The directions suggest placing the controller in the wingtip - but there is a problem. The controller has a built in fuse holder. To comply with FARs all fuses need to be replaceable easily, preferably in flight. So a bracket and mounting plate were made and installed on the passenger side. This plate extends from the bottom of the instrument panel to the "L" angle that runs along the passenger side to the firewall.

The strobe controller and buses were mounted to this.

A partial power up test was performed. The radio and lights were all working. The split bus was isolating and the terminal ground was fine. The trim indicator was working great and the trim rocker and joystick controls were all functional.

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.

Wednesday, May 27, 2009

More wiring components have been ordered and the wiring is in full swing.

This week the full wire harness for the strobes and position lights were made including a strobe pattern selector.

The harness for the landing lights was also made.

The buses are in hand and ready.

A few questions still remain, like how to properly tie in the Ducati voltage regulator and the split master switch.

Saturday, May 02, 2009

Progress visually has been slow, but much has been done.

The majority of the effort has been spent researching the wiring portion of the project.

Recently I flew down to Oregon and purchased an ICOM A210, Garmin GX327 and an ELT along with the matching antennas.

I also have ordered the Dynon D180 Rotax probe package and many small parts for the wiring.

A wiring diagram has been made an is almost finished. It will get posted here for the benefit of others. This diagram was used to generate the parts list. It even goes as far to include the pinouts for each piece of avionics.

Recently the ignition key was figured out using a 12V latern battery. The strobe wiring was also confirmed.

Tonight the ICOM A210 had a temp harness made and was rigged to a headphones speaker and the latern battery to power it on. The faint sound of BFI's ATIS was able to come through without the antenna attached.

Monday, April 13, 2009

This weekend the engine mount was reinstalled. It was realized that there are two steel angles that have not been drilled into place yet and need to.

The next steps of the controls will require pulling the fuselage out to mount the rudder hinge. Foul weather prevented this. The hinges were fabricated over the weekend.

The wiring diagram was started. The current plan is:

Dynon D180
Airgizmo / Garmin 496
Garmin GTX 327 Transponder
ICOM A210 Transceiver

I am using Visio to create a fully detailed diagram. The hope is that I can decide on color coding before hand and decide where additional connectors may be wanted to help with maintainability.

Tuesday, April 07, 2009

I recently moved. Packing a mostly finished airframe and a "used" workshop and then moving it across town is harder than you would think.

First the plane with the gear was about two inches wider than the trailer. This required removing one wheel. Next there is the organizational issue. The new garage is smaller and needs more organization. The plane needs to sit at a diagonal to fit. Once the engine is hung the door from the garage into the house will need to be removed to fit the plane.

Recent progress has included mounting the rudder pedals, brakes and nose steering. I also fabricated the rudder cable pulleys and some rudder mounting parts.

Here is the new workspace ( Requires Silverlight )

Friday, February 13, 2009

This picture illustrates that I placed the horizontal stabilizer mounts 10mm to far inside on both sides.

Two options exist in my mind for fixing this.

The first option is to create a custom mount from the fuselage side shaped to clear the flange of the stabilizer's mount. This would require a spacer and a much longer bolt. It also increases the chance of the mount cracking.

The second option is to open the stabilizer and move the mounts 10mm outside. This may require some work to the spar.

The controls are coming along nicely. The push rods and flaperon bellcranks are all connected. The flaperon mixer is also connected. The pushrods terminate where they will exit the fuselage.

I also figured out the wiring for the strobes and nav lights. They were pretty easy to deal with, but finding a suitable location for the control unit may be tricky.

Thursday, January 08, 2009

I have been very bad about posting recently, but this should not be construed as the project not being worked on.

The whole workbench was partially redone and lowered about half a foot. This is so the plane can sit on its wheels on the ground.

The engine mount holes were drilled out to their final size and bolted on.

Work has started on the controls. All three bell cranks have been fabricated. The lower torque tube bearing was un-riveted to allow for the torque tube to be placed. I then found an unacceptable amount of ply, so a new lower bushing was fabricated to raise the torque tube up and remove the wiggle.

In addition I have fabricated the flaperon mixer bearings and started placing the "L" angle that supports them.