Sequoia Aircraft Corporation F.8L Falco, Construction Manual

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F.8L Falco Construction Manual 14–10 Revision 4, March 1, 2002
A partial list of things to be grounded: the firewall, all control cables, aileron pushrods, elevator
pushrod, seat tracks, flap torque tube, firewall, landing gear retraction system, the engine mount,
main landing gear, nose gear, all metal access doors and all metal fairings. Many parts of the
Falco are already grounded as part of the electrical system design. These include the fuel tanks,
the landing gear motor, the flap motor, the instrument panel and the engine. In addition to
eliminating noise from the signal that the Loran receiver uses, this grounding also extends the
ground plane for the antenna. The upper hinges for the rudder should
not be grounded as this
would put a ground plane in line with the antenna.
When grounding metal parts, literally any wire size or type will do.
Noise Suppression
The Loran depends on decoding a low-frequency noise-sensitive pulse in the midst of a lot of
crackles and pops. These come from lightning and from the devices installed in the airframe.
The Falco’s electrical system is extremely quiet and generates no audible noise, but there could be
some inaudible noise that the Loran will detect. We already use a solid-state voltage regulator,
and we have a shielded ignition system, so those two requirements are met. Digital devices can
generate some noise which will also affect the Loran. This is the big unknown for the Falco.
Potential sources would be the digital clocks, digital fuel flow analyser and digital OAT. Until we
know if we have a problem, we will not be able to offer any advice on this subject.
Materials required:
1 Apollo II Loran receiver (includes antenna coupler)
2 UG88 (male) BNC Connector
2 UG89 (female) BNC Connector
20’ RG58 Coaxial Cable (includes 3’ extra)
BNC Assembly Instructions
In the process of installing the antenna system, you will have to assemble a number of BNC
connectors. To assemble one of these connectors:
Figure 3
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Strip the outer cable insulation for a length of 9/32” (7.1 mm).
Figure 4