Message forwarded for "Richard Holder" <rholder@avnet.co.uk>, who is having
Avnet-related posting problems.
I am doing the panel for G-OWWW which is kit 51 now being built in a garage
near Heathrow. My co-builder and I (he is doing most of it - I am doing the
panel and the electrics) bought this kit part-built. It had been untouched
for 7 years.
We have made an aluminium sheet for the left hand side. It covers the
'electrical' sub panel as well as the space for the T instruments. It is
flat, with a 90 degree bend at the bottom so that the bottom connects up
with the bottom of the plastic dash (above P1's feet). It also covers up
almost all the recess for the mono gear lever (ours is to be tri-gear).
After all the responses to my question about 3 1/8 hole saws I bought one
---From CPC for About 9. My co-builder has a pedestal drill and the holes were
drilled very easily. He also had a 2 inch hole saw so other holes were also
made. Needless to say there was lots of planning and many pilot holes were
drilled.
I have made some of the toggle switch holes but am frustrated now by the
lack of instruments. Many come with the engine. The T instruments could be
purchased now but they would be out of warranty (12 months) before the plane
even flew ! What have others done about this problem ? Have you just gone
ahead and bought the instruments (and the avionics come into the same Catch
22) and assumed that the warranty won't be needed or invoked ?
I have bought loads of Mil-spec cabling from Aircraft Spruce. It is strange
stuff to work with. The insulation can be melted off with a soldering iron,
but it is much more difficult that ordinary PVC insulation. 22 AWG is
amazingly thin, with thin insulation but is strong and retains the shape it
is bent into. I have bought 10 AWG for the main alternator cables and 4 AWG
for the battery cables. It solders up nicely and the insulation doesn't run
back when you heat up the copper core. All cabling will be mil-spec, which
leads to this question :
Can anyone tell me what comes with the Rotax 912S ? Do the screened mag
cables come with it ? Do the screened alternator cables come with it ? Do
the temp/pressure sender cables come with it ? What about the cables to the
RPM gauge ? If they come with it are they mil-spec ?
What display gauge is used for the new fuel gauge that Europa have announced
? Is it a round gauge or does it have 8 (?) LED segments like the latest
trim display ?
I have found a neat digital temp gauge which comes with an external sensor.
Bingo a suitable solution to another problem. It also has a clock mode.
Bingo another solution. It runs off an AA battery (12 months) so I am
putting in an AA battery holder so the battery can be changed from the front
of the panel. (This avoids another cable to the battery as the power to a
clock has to be live at all times). Cutting the rectangular hole in the ali
was interesting but I have succeeded.
Can anyone confirm that the Europa (Rotax) supplied RPM gauge is a standard
2 1/4 gauge mounted from the rear by four screws, whereas all the other
Rotax engine instruments as 2 inches and are mounted from the front ?
If anyone is interested I could probably do a photo as an attachment -
probably of-list (I dunno if attachments are allowed on this list).
I plan to use screened cable for most of the connections to the rear, with
the earth in the screen. That way the cabling for each device is kept tidily
together.
I also plan to make the whole panel easily removable by having multiway
connectors for the following :
battery, regulator and earth
magneto cables
firewall forward connections (sensors, CS prop, tacho)
rear compartment connections
audio panel connections
antenna connections
These are written like this as each line represents one connector (except
antennas).
I would be grateful if anyone has any comments, praise, criticism, warnings
in respect of any of these ideas.
As is often the case, the first one is the most difficult. All things being
equal I may be offering my services to do electrics at some time in the
future. Currently my offerings are restricted to conversion of standard
headsets to ANR (Active Noise Reduction). I do this with a kit, replacing
the 'Y' piece with the battery box, and inserting a 'turn the ANR off if the
mike bias voltage is zero' circuit which saves PP3 batteries. I have done 38
conversions so far. If anyone is interested contact me again. The Europa
will go one step further and will use XLR plugs (5 way - standard on a 777)
for audio connections. One pin will have the 9v required for the ANR. Presto
- no battery box required.
Richard Holder
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