Guarded Switches for Important Systems?

[XenosN42]

If you kill the engine by shutting all the ignition off, like in the pattern, will it fire right back up when you turn everything back on? Will an Aerovee windmill at pattern airspeed? Honest question, I have no idea!

My AeroVees will start right back up if the ignition systems are turned off. My AeroVees wouldn't windmill or move at all.

[Spaceman]

I guess you have a starter to spin it right up if it's not already windmilling...

I'm just picturing the C-130's I fly at work, and I think just about every switch in there that isn't a light or pitot heat is one of these:


So I'm very used to using those. But they are expensive!

[DCASonex]

A guard for your master switch, if it has a cross hole drilled in it provides a place to put that little clip that locks the canopy slide while it also locks the switch off. Keeps the clip from getting lost, while insuring that the master does not get flipped on accidentally.

David A.

[N190YX]

switch guard3

Pull to unlock switch.png (17.71 KiB) Viewed 6616 times

switch guard

switch guard.jpg (14.6 KiB) Viewed 6616 times

Having inadvertently turned off the master switch when operating the gear retract switch to retract the gear in turbulence (then wondering why the gear was not retracting), I plan on switch covers or pull to switch type switches for the master and possibly ignition switches if not using the key off left right both start switch. Photos from Aircraft Spruce.

[Rynoth]

If you kill the engine by shutting all the ignition off, like in the pattern, will it fire right back up when you turn everything back on? Will an Aerovee windmill at pattern airspeed? Honest question, I have no idea!

Your question inspired me, so I tested it today (at a safe altitude next to a runway of course.)

https://youtu.be/CmnEc_UprfM?t=101

I was at 80KIAS when I pulled the mixture and 75KIAS when the prop stopped after about 8 seconds. Mixture in, then immediate restart using the starter motor. Aerovee Turbo with Sensinech climb prop.

[WesRagle]

HI Guys,

If you kill the engine by shutting all the ignition off, like in the pattern, will it fire right back up when you turn everything back on? Will an Aerovee windmill at pattern airspeed? Honest question, I have no idea!

I was at 80KIAS when I pulled the mixture and 75KIAS when the prop stopped after about 8 seconds. Mixture in, then immediate restart using the starter motor.

On my AeroVee pulling mixture and turning the ignition off had a totally different effect. In the early stages of my Sonex Phase One I had the idle set too low. The engine died on final and by the time I collected my wits and tried to restart the engine was flooded and would not restart. I glided to an uneventful landing. But, I learned that if the engine dies (ignition turned off) with mixture in on an AeroInjector it will continue to flow fuel and flood.

Wes

[Spaceman]

Good to know!! Impressive real world test... Although I don't know how else we'd have gotten an answer!

[WesRagle]

You can play with it on the ground. Just shut the ignition off and leave the mixture in and see how long it takes to flood.

I practiced a procedure that went something like this:

When the engine dies quickly pull mixture to idle cut off.
Engage the starter until either the engine fires (the flood is cleared) or 5 seconds passes (the engine wasn't flooded).
If the engine fires advance the mixture to full rich immediately.
If it doesn't fire advance the mixture to full rich and continue cranking.

Wes

[Rynoth]

When the engine dies quickly pull mixture to idle cut off.
Engage the starter until either the engine fires (the flood is cleared) or 5 seconds passes (the engine wasn't flooded).
If the engine fires advance the mixture to full rich immediately.
If it doesn't fire advance the mixture to full rich and continue cranking.

Wes

That's essentially what my emergency air restart procedure will be once I complete my flight testing and create a full flight manual. Anyone with an Aeroinjector should be acutely aware that if the mixture and fuel selector are open (and there's fuel in the tank), fuel IS flowing, regardless of whether or not the prop is turning or if the aircraft is sitting on the ground.

I'm not going to flight-test flooding my engine, I did think it was important to know how my engine windmills (or not) and could demonstrate it with appropriate safety margins. The flooding aspect is very relevant though, and I can recall a couple fairly recent topics on this forum where too much fuel has been an issue that stopped an engine, such as fuel leaks, aerobatics, inadvertent ignition cutoff or low idle.

[WesRagle]

I'm not going to flight-test flooding my engine,

Me neither. Once was one time too many.

Wes