The wingtip lights were wired next:
All wires were tied with lacing cord. Adel clamps (rubber cushioned clamps)
were used to secure the wires, any place where they come through a lightening
hole. A local ground was created with a plate nut and screw. The
primer was cleaned off the rib at the point of contact for the ground wires.
Also note that all wires were attached to the lights with Molex connectors.
This will make things easier if the wingtip ever has to be removed.
Remote Compass and OAT Probe:
The Dynon D100 EFIS has a remote compass module, which sends magnetic compass
heading information to the unit. The compass must be mounted away from
any magnetic interference problems. I chose to mount mine out on the
wingtip to get it as far away from the steel fuselage frame (and the engine)
as possible. One of the concerns was whether or not the strobes and lights
on the wingtips would cause errors in the compass readings. To test
this, I bought a cheap compass from the local Walgreens and placed it in
my proposed compass location out in the wing:
The chosen location is in the last bay of the wing back close to the rear spar to keep it as far away from the strobes and lights as possible. With the above compass in place, the wingtip was re-installed. Using a flashlight, I could see the compass through the outboard aileron hinge location. With everything powered down, I took note of the compass reading. Then, each item was powered up one at a time (strobes, nav lights, landing light), checking the compass heading with each item. The compass never moved, so I am good to go with this location.
Now it's time to mount the remote compass sender unit. The instructions that came with the Dynon EFIS say that the compass module must be mounted so that it matches the pitch and bank attitude of the Dynon EFIS unit that is mounted in the instrument panel, within 1 degree. It must also be parallel with the wings.
Using a digital compass placed on the EFIS unit, the angle of the EFIS as its mounted in the instrument panel was determined and noted. The goal is to mount the compass module at this same angle (within 1 degree). The module was placed in the wing, and the digital compass was placed on top of it. Then using some washers, the module was shimmed up until the digital reading on the level was identical to the reading obtained when it was placed on the EFIS. For my application it took exactly 3 washers or about .189"
Using some .032 aluminum, a mounting bracket was made that lifted the aft
end of the compass module up approximately .189":
This bracket and compass module must be mounted using non-magnetic hardware.
The compass module was attached to the mounting bracket with some all
aluminum pop rivets. The bracket was then mounted to the wing skin using
some #6 stainless steel screws, washers and nylock nuts. (Note: When you
buy the stainless steel hardware, check them with a magnet as some stainless
is magnetic. Make sure yours is non-magnetic.) Here is the remote compass
sender mounted in the wing and wired up:
Also part of the EFIS system is an outside air temperature sensor. With this,
the EFIS will calculate density altitude, true airspeed, etc. The temp
probe is wired through the compass for some reason. The probe needs
to be mounted somewhere away from any engine heat and out of the sunlight.
It should be out in the air but in shade. The bottom of the wing
near the wingtip seemed like a good location so that's where I mounted it:
The wingtip was re-installed and stainless steel screws were used to secure
it to the wing. Finally a test of the lights was performed:
So far, so good. The compass heading read-out on the EFIS was checked with
the lights on and off. There was no variation in the compass reading either
way so it looks like everything is fine. I'll check it all again when the
engine is running. Also the OAT temp was checked against a thermometer
and it was only about 2 degrees off. That was re-calibrated on the
EFIS and it is now accurate.
As covered in the wings section, I made a simple Pitot tube system for the
airspeed indicator (EFIS). This was made by taking a simple brass elbow
and brazing on a flat piece of 4130 steel to use as mounting tabs. Here is
the fitting that was made to hold the 3/8' Pitot tube and Nylaflow tubing
connection to the airspeed indicator:
Here it is mounted on the wing spar:
And here is the Pitot tube sticking out from the leading edge of the wing:
The end of the Pitot tube was threaded with pipe threads to screw into the
elbow. There is a rubber grommet where the pitot tube enters the wing skin
to keep it from chaffing.
Come
back later for more . . . This page was last updated on January 19,
2008.