[LyleM]

I'm getting ready to cut holes for the avionics in my -8 panel. they are all Garmin. Audio Panel, GPS Comm, Transponder. The bottom surface of the open end of the tray/box that each one slides into sticks out 1/8" more than the sides or top. Does this bottom surface stick through the hole even with the face of the instrument panel? Or what?
On an IO-360 180HP, The boost pump is used for starting I'm sure. Is it on for take off and landing, or is it on all the time?

 

[islandmonkey]

Snip

On an IO-360 180HP, The boost pump is used for starting I'm sure. Is it on for take off and landing, or is it on all the time?

On low wing aircraft with tanks below the engine and fitted with a mechanical pump in the engine bay and an electric pump somewhere in the vicinity of the wing root, it can spoil your day if the mechanical pump decides go on strike in the take off or landing phase. Hence electric pump should be turned on. In the cruise, the electric pump can be turned off. All fuel pumps work better when they are pushing fuel as opposed to sucking fuel as then there no possibility of a vapour lock. The further the distance the fuel pump is from the tank then the greater the likelyhood of vapour locks.

 

[gear1]

Cutting panal holes

Lyle,
Your observaton is correct; some garmin trays have a lip that goes to the pilot side of the panal. It is very critical that it do so, as the install manual specifies that if the lip is behind the panal, insufficient engagement of the pins and plugs will result. The install manuals have excellent drawings of the trays. The install manuals are available online. The manuals for the certified units (GNS-430, etc.) are not available from Garmin directly, but I Googled them and found them on other sites. I used the Garmin tray drawings when I designed my panal in AutoCad, and when everything was cnc machined and rivited/bolted together, the trays and radios fit perfectly. Also note that the installation manual calls for a .040" vertical clearance between each of the trays to allow for cooling air flow. My radio stack consists of a GNS 430, SL-40, GTX-327, and a GMA-240. If your stack will be similar, I would be happy to share the drawings.
Craig

 

[cfiidon]

Hence electric pump should be turned on. In the cruise, the electric pump can be turned off.

Not always the case. I have an ECi IO-360. The electric boost pump is there as a backup only in normal operation. Energizing the boost pump when the mechanical is operating will cause on over pressurization/over rich condition. You must consult your engine manual to be certain.

Don

 

[LyleM]

Cooling fans?

Thanks guy's for the input. Another question does come to mind now. I will have a 1/4" space between the avionics units. Would a cooling fan be needed?

 

[cfiidon]

Thanks guy's for the input. Another question does come to mind now. I will have a 1/4" space between the avionics units. Would a cooling fan be needed?

The definitive answer is "maybe". I think the answer is "why not" so I plan to put one in, I bought it cheap on sleezebay. If you didn't put one in and provided some vent holes up top, it would probably be fine.

Don