Tumper

Tumper

Well Known Member
Opening up the proverbial can of worms here, but who is still installing a keyed ignition switch on their plane (as opposed to two mag switches and a starter button)? Why and why not?
 
I am not

putting one in, but I go around with the issue in my head.

If someone wants to steal the airplane, a keyed ignition won't stop them.

On the other hand, needing a key would stop a kid who might climb in uninvited from accidently pushing the starter and hurting himself or others.

Course, to do that, he'd have to turn on the master, enable the starter button on the stick by flipping the enable switch on the instrument panel AND then push the start button on the stick. That's not likely to be done accidently.

So around and around I go. Still not putting one in.
 
What are the rules with regard to locking aircraft? I seem to recall some discussion about having to have at least one (if not two) keyed locks to prevent theft or unauthorized access and the keyed ignition switch could serve as one? Can't find that thread now, it was quite a while back...
 
No Key

-8A. Two ignition switches (LSI & Mag) and a start push-button switch. Fuze panes in locked fwd baggage compartment.

I have a canopy slider lock - and if uneasy about aircraft security, will pull the starter fuze.
 
The Cozy MKIV had a push button. I like keyed better so that's what I put in my -10.
 
Tumper said:
Opening up the proverbial can of worms here, but who is still installing a keyed ignition switch on their plane (as opposed to two mag switches and a starter button)? Why and why not?
Click to expand...

All factory type aircraft I have seen still use a keyed ignition, thats the look I wanted also. At least you have a choice.
 
Just a thought:
With a keyed ignition switch, you are stuck with only starting on the left mag.
I have a left impulse coupled mag and right, electronic ignition.
I have toggles for both.
I can start on either. I typically start on the lightspeed.
As an added benefit, I spin the prop for a couple of blades before I hit the ignition.
 
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Keyed vs. switch ignition

Above, Alton brought up a good point. Having the option to fire up on either mag/ignition. This seems like a good option in his example or if at a remote airstrip, having an option for a return flight if there is a failure on left mag.

It is understood that a keyed ignition is not going to prevent aircraft theft. I have a keyed ignition for a different reason. On my -6 the slider canopy could be locked partially open for hot day tie down. The keyed ignition allowed safety in regards to curious individuals. Kids can be very bold and love to play with switches. With my canopy locked partially open, a small arm could enter the cabin with dangerous potential.

The issues involved with making a plane safe and unable to start are known, although control settings can be manipulated. I have seen it with my kids. I don't ever want to be owner of the plane that caused damage to person and/or property from a unauthorized start. Even cranking the prop is extremely dangerous with people in the way. People have been seriously injured from doing a compression check, by prop contact.

I like Alton's point. I have a keyed ignition now on my -7 for reasons above.
 
AltonD said:
Just a thought:
With a keyed ignition switch, you are stuck with only starting on the left mag.
I have a left impulse coupled mag and right, electronic ignition.
I have toggles for both.
I can start on either. I typically start on the lightspeed.
As an added benefit, I spin the prop for a couple of blades before I hit the ignition.
Click to expand...

You can indeed start on both mags if you wish, there are jumpers on the switch that contol that function, no jumpers = start on both mags.

For my own aircraft I chose toggles and pushbutton starter.
 
Walt said:
You can indeed start on both mags if you wish, there are jumpers on the switch that contol that function, no jumpers = start on both mags.

For my own aircraft I chose toggles and pushbutton starter.
Click to expand...

Walt is the electronics Guru! If he said bubble gum would start it better I prob would do that. With that said if someone wants your plane they are going to get it. I once went for a ride in a golf cart with a "KEY switch" in it. (No key)

What? Dad didn't mind....:D
 
No one has mentioned a pushbutton starter, with an electronic passcode lock to enable it. :)

(This is something built into the Vertical Power VP-200.)
 
One option is a keyed ignition switch with a separate start button.

Its downside is that anyone who gained access to the cockpit and located the master switch and separate start switch could crank it over. But it wouldn't start.

The upside is that the starter circuitry is physically separated from the ignition circuitry.

Not saying it's particularly good or bad, just saying it's one way to do it. It's certainly functional - my Cessna 180 is set up this way as original equipment from back in 1955. The start switch is in a visible but fairly obscure location.

Dave
 
MAG SWITCHES

I used the push button start button & double action mag switches from Stein. Less chance of inadvertent action of switches by loose sleeves etc. My perception of simplicity vs the experience of worn keyed ignition switches

Good news: I cant lose/forget the ignition key.

Bad news: at my age there is an increasing risk of me forgetting the combo on the two numbered padlocks: one for the tip up, & one for the throttle lock. On second thought, if I forget how to unlock the padlocks, then I shouldn't go flying.

Regards.

Bob
 
Keyed switch, must be ON for starter (via START pushbutton) to even operate. Must be ON for Left Mag (impulse coupled) to be enabled.

START button grounds (disables) right (non-impulse coupled) mag during starting operation to prevent kickback.

No amount of messing with buttons and switches should be able to cause harm or damage unless the key is IN and ON.
 
I have a push button for my starter that I wired in series with another momentary push switch mounted under the edge if the panel just below the starter push button. The switch is hidden and faces down. It can be pushed with my index finger while I push the starter with my thumb. Works great!
 
I'm thinking of using a keyswitch, a starter enable switch, and a push button on the stick. I'm curious Steve if you were saying you used a 2 position keyswitch. Could you clarify what you did? A 5 position non-momentary switch could work if such a thing exists with the start position being start enable.
 
My reasoning....

My biggest objection to keyed switches is that it's not unusual for them to fail in the "off" position. Since we kill our engines with the mixture cut-off, unless you routinely check the "off" position, you won't know you have a failure.
With toggle switches, I routinely check the off position every time I do a mag check. With a keyed switch, the off position is not checked by using the "L" or "R" positions.

My starter circuit is back wired through the master switch and the avionics master. For the starter to function, the master must be on and the avionics master must be off.
 
Mel using the Avionics Master is something I hadn't thought of. I started counting up all of my switches and any reduction would be good.
 
When I was in flight school, I would often take the key for the wrong airplane and go flying. Wouldn't find out until after I got back. There were only 2 or 3 different keys for the fleet of 9 planes

I've also seen older key switches that didn't need the key to turn the switch. I'm assuming it was just worn out.

If somebody actually wants to steal your plane, a key switch won't slow them down much.
 
With a keyed ignition switch, you are stuck with only starting on the left mag.
Click to expand...

If I recall, there are jumpers on the back side of the switch that govern which (if any) sides ground in the start position. I think you can have a key switch with impulse couplings on both mags.

Dan
 
YEP!

DanBaier said:
If I recall, there are jumpers on the back side of the switch that govern which (if any) sides ground in the start position. I think you can have a key switch with impulse couplings on both mags.
Dan
Click to expand...

That is correct.
 
DanBaier said:
If I recall, there are jumpers on the back side of the switch that govern which (if any) sides ground in the start position. I think you can have a key switch with impulse couplings on both mags.

Dan
Click to expand...

Correct. I have a Bendix D2000 series dual mag, with an impulse coupler on the drive shaft. My switch does not have the jumper so both mags are retarded at start-up.
 
Mel,

I like the idea of the separate toggles for the mags as well, probably locking. it's just the total switch count. Especially if I have Pmag test switches.

Any concern about having what some might consider a non-standard configuration with your starter switch / Avionics Master dependency? I realize most people keep their Avionics Master off during start, but not all it appers from other threads.
 
There are many things I would change if I was to do it all over again, but that's part of the build.

No Key has never been one of them! I have a master start switch that protects against inadvertent start if someone hits the start button on top of the stick. I guess if you are afraid of someone stealing the airplane or a kid pushing buttons while you are not around you could always add a hinden master switch.

I have a AFS4500 with internal battery with a VP100. I use the AFS bat for engine instruments and the VP100 for Pmag power during start. Once the engine is started the Alternator is turned on followed by my avionics master.

I'd rather divert as much power to the starter as possible during start then have all the avionics on during it.
 
I will have two toggle switched in my new panel. One is an on/off switch for electronic ignition, the other a three position which grounds the mag, ungrounded the mag or, with a momentary, energizes the starter solenoid.

My airplane is always hangared unless I can't find space for it on the road. If its outside its locked. If someone gets into it and starts it what happens is their own lookout. I'll be upset if the plane is lost or damaged, but its insured.
 
walkman said:
I will have two toggle switched in my new panel. One is an on/off switch for electronic ignition, the other a three position which grounds the mag, ungrounded the mag or, with a momentary, energizes the starter solenoid.

My airplane is always hangared unless I can't find space for it on the road. If its outside its locked. If someone gets into it and starts it what happens is their own lookout. I'll be upset if the plane is lost or damaged, but its insured.
Click to expand...

+ 1... works flawlessly. :)
 
rapid_ascent said:
Mel,
I like the idea of the separate toggles for the mags as well, probably locking. it's just the total switch count. Especially if I have Pmag test switches.
Any concern about having what some might consider a non-standard configuration with your starter switch / Avionics Master dependency? I realize most people keep their Avionics Master off during start, but not all it appears from other threads.
Click to expand...

That's a personal choice. I want the avionics off during start, and my system disables the start switch during flight.
 
My first panel had toggles for everything but I used the special ones that allow you to group functions into them.

On the left I had a 3 pos with the up pos momentary for start...

(Start)
ON
OFF

On the right I had a 2 pos with the down pos interlocked with the starter (when I had a mag, I removed this interlock for the Pmag)

ON
OFF/START


The new panel has a key-switch and a separate power switch for the Pmag. All it does is keep the honest man honest and looks more normal to passengers and makes it easier for me to allow qualified pilots to fly my plane without having to go to school on how to start it.

There are pro's and con's to both key-switches and toggles. The failure modes around the safety aspects does not produce a clear winner. We all need to always treat the prop like a loaded gun no matter what system we are using....fully test each method during mag checks and during shutdown and your risk will go way down.
 
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Lessee.... where is my calculator? :D


Button switch from Stein $14

Keyed switch from Spruce $124

Difference $110 divided by 5 bucks per gallon equals 22 gallons. Nicely leaned translates close to 500 NM of distance... which brings me to Nova Scotia...


Of course if you don't want to go to Canada Dean you should install keyed switch. :D
 
Having a separate start button is very useful to crank the engine for oil pressure or other reason. I now have a keyed switch for ignition (with jumper removed) and a start button.

I write the next bit with some trepidation as I am not intending to slam any of the wise heads who post here regularly. My view is that putting addition switches/logic in the starter circuit can occasionally come back to bite. For example, I turn my airplane upside down - occasionally the motor stops, usually because the carb floods. Usually the prop keeps wind milling and the motor starts up when the float is in the right place. Very occasionally the prop stops - I hit the button and it starts again. In these circumstances I find I need simple stuff to do to recover. Brain power is reduced by the unusual attitude & situation. I don't want to have to make additional switch selections or press additional buttons, I just want the motor running again. Sure I have plenty of height, I could sit there and wait for things to calm down, find the right switch/button and then go for the starter - but because its a rather rare situation (on the two occasions it has happened) I don't have much spare brain power and am glad I can just hit the button.

Pete
 
Starting

I owned a Grumman Tiger before my "7A" it had a key switch to select L-R-Both (mags) and energise the start push button. Not a bad setup, but had to remember to select impulse mag to start then switch to both when running. My 7A has a key switch for all functions, = lower workload. When I installed P-Mags I just removed the jumper on the back of the key switch, use the ignition breakers to test the P-Mags. Simple and fool proof = win win.
 
Next panel makeover I'm considering two locking toggles on the panel:

OFF - ON - ARM (controls ignition and the starter button on the stick)

L- BOTH - R

I'm not in love with the circuit logic for the stick mounted stater button, but it does need to be an obvious and deliberate action to make the engine crank. I like the avionics master idea too... Going to have to think about that one.
 
I use a pushbutton ARM switch that enables the starter circuit for three minutes. This disables the START switch on the Infinity grip automatically.

A placard is essential to remind the pilot of the start procedure.... or the ARM switch can be hidden as a security feature but it must be easy to access in flight! It could even be combined with one of the mag switches.

If there is sufficient interest, I'll publish the design on the MakerPlane open source site.
 
I was going to do the "timed" enable switch on the -8 as well. Even bought the little programmable relay... Ultimately, I did not love the added complexity of the circuit. I think the concept is sound however, especially if coupled with the oil pressure switch to ensure the starter could never be engaged with the engine running.
 
Brantel said:
We all need to always treat the prop like a loaded gun no matter what system we are using....fully test each method during mag checks and during shutdown and your risk will go way down.
Click to expand...

Well said Brian. Here is a photo I took last week at our airport aviation day. The pilot stated he was "repositioning the prop" when it fired up, traveled across the ramp, a taxi way and across a ditch, which thankfully collapsed the landing gear producing a ground prop strike and engine stoppage. No one was in the airplane when the pilot positioned the prop. Luckily, the aircraft was facing out and not toward the spectators at aviation day.

No speculation please. Just wanted everyone to see the threat is real.

6z0u8p.jpg
 
I'd say that prop is repositioned.:D

Since someone brought it up I was curious about pmags and starting. Can someone explain this please? The emagair website doesn't really cover it well. I'm guessing there isn't a need for impulse type additions.
 
I was curious about pmags and starting. Can someone explain this please? The emagair website doesn't really cover it well. I'm guessing there isn't a need for impulse type additions.
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No. All an impulse unit does is crudely re-time the Mags at v low RPM, which the variable timing P-Mag does as part of it's design.

I prefer the keyed switch on an RV-8 since:
  1. It's pretty consistent across most GA types
  2. It's easy for me, and anyone else looking / working around / in the aircraft it is safe (Mags Off)
  3. Extension of above, if you ever get that nagging feeling "did I leave the Mags On?" answered if the keys are in your pocket. Aircraft with simple Mag switches seem to me vulnerable to leaving the Mags on - this by experience both mine and others... which of course is a human failing, not the switch design.
  4. It is impossible to fly away somewhere and discover you've forgotten the baggae door key
However, it is clearly only a personal preference issue...
 
rapid_ascent said:
I'd say that prop is repositioned.:D

Since someone brought it up I was curious about pmags and starting. Can someone explain this please? The emagair website doesn't really cover it well. I'm guessing there isn't a need for impulse type additions.
Click to expand...

The PMag does not require an impulse coupler and if you install it on the right side and you have a keyswitch, make sure to remove the shorting jumper that grounds the right mag during start.

You want the P-mag to fire during start.

The P-mag automatically retards the timing during start to prevent kickback and to assist in starting. Mine starts like a good car with the P-mag all the time...
 
Not Quite!

Andy Hill said:
[*]Extension of above, if you ever get that nagging feeling "did I leave the Mags On?" answered if the keys are in your pocket. Aircraft with simple Mag switches seem to me vulnerable to leaving the Mags on - this by experience both mine and others... which of course is a human failing, not the switch design.

[/LIST]However, it is clearly only a personal preference issue...
Click to expand...

This is exactly one of my reasons for NOT using a keyed mag switch.
I have seen on more than one occasion where the key came out of the switch with the left mag "on".

In one particular event a friend of mine went out to fly his Swift. He began to pull the prop through, and the engine started; even though it had bee killed with the mixture cut-off several days ago and the key was still in his pocket.
Fortunately he had treated the prop as if it were "hot", which it was, and no one was hurt.

Second reason, as I said before, it is not uncommon for keyed ignition switches to fail in the "off" mode, leaving the left mag hot.
 
I plan to test mine during mag checks. One quick move to the off position will let me know the ground is still working. This should cut the risk of this failure mode way down.
 
Brantel said:
I plan to test mine during mag checks. One quick move to the off position will let me know the ground is still working. This should cut the risk of this failure mode way down.
Click to expand...

Good idea! But do it at a low rpm. Switching the ignition off at high rpm can be very detrimental on the engine.
 
Toobuilder said:
I was going to do the "timed" enable switch on the -8 as well. Even bought the little programmable relay... Ultimately, I did not love the added complexity of the circuit. I think the concept is sound however, especially if coupled with the oil pressure switch to ensure the starter could never be engaged with the engine running.
Click to expand...


I looked into an oil pressure switch or a voltage switch (master bus voltage will be higher with engine running), but I am very suspicious of automatic systems that the pilot cannot override.

For example, if you use an engine pre-oiler, you'll have oil pressure even with the engine off. If you use a battery charger or jumper cables connected to your battery, you'll have a higher master bus voltage. Sometimes simpler is better.
 
I planned to use the timed relay to override the oil pressure switch during the start sequence. Pushing a momentary button gives you 30 seconds of cranking time (armed)...

...but yes, simpler is better. And that thought has ruled the day so far.
 
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I currently have a standard key switch in my panel. I like the key switch to help prevent accidental start/turning of the engine. For security, it is better than nothing, but not much.

After reading this thread I am considering installing two toggles for the mags and a keyed starter switch. The keyed switch will still give me some peace of mind while the toggles will allow me to pick my ignition system. I have mags, but plan to add EI one day.
 
Brian, give it some good wiggles while in the off position. AD 76-07-12 addresses this. Sometimes with wear, the key can go slightly beyond OFF. You can feel a little step when it does. This opens one of the mags and it wil keep running. If so, you need to pull it apart and fix. I've only seen it on switches that have some wear. Mel's comment about keys falling out is a good one. That's why you shouldn't have a big honking key fob or whatever. The extra weight and vibration wears out the keyswitch.
 
Brantel said:
I plan to test mine during mag checks. One quick move to the off position will let me know the ground is still working. This should cut the risk of this failure mode way down.
Click to expand...

I do a momentary mag grounding check the last thing before pulling the mixture for shutdown. That way I know I haven't had a switch or p-lead failure during the flight. On run up, if I get the requisite mag drop on both mags, I consider that a good grounding check.
 
longranger said:
I do a momentary mag grounding check the last thing before pulling the mixture for shutdown. That way I know I haven't had a switch or p-lead failure during the flight. On run up, if I get the requisite mag drop on both mags, I consider that a good grounding check.
Click to expand...

True enough for magnetos, but with dual electronic you may not get any drop at all. In this case you need to look for the EGT rise to verify the grounding function.
 
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