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If you have a START Button, where is the key?

claycookiemonster

Well Known Member
I think it's primarily a cosmetic thing, but I'm going to have a START button for engine starting. However, I still want a modicum of security, so I'd like to have a turn key that must be inserted and turned before the aircraft can be started.

Those of you with a START Button, how'd you handle this?
 
You can get a key switch with is simply in series with your starter, or your master, or whatever. In my Subsonex, the key switch is essentially the master switch, and without the master on, you can’t do a thing, so it is a reasonable security (or safety) deterrent.
 
No key , but....

I put a hidden switch on the master circuit which I located in the RV 8 forward baggage area. This is in addition to the master switch on the instrument panel. The forward baggage is locked. So theoretically a thief could hand prop it but would not have a starter, EFIS, or any electrical system.
 
So, Paul; either the Key becomes the Master/Battery-on, or the key is wired in series with the above and it must be turned ON as well as Master-On to get the show on the road?
 
I used a simple key switch wired in series with a push button.

Key switch is labeled as "Starter Enable"

Push button is engraved "Start"

Both from Steinair.
 
No key but I have a lock that goes on the throttle. I use a Master hardened digital combination lock. I think I purchased the throttle lock from Sporty’s 25-years ago and sourced the pad lock at a local store.

13-18500.jpg


Aircraft Spruce sells them now.
 
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So, Paul; either the Key becomes the Master/Battery-on, or the key is wired in series with the above and it must be turned ON as well as Master-On to get the show on the road?

Correct - you can do it any way you wish. In the jet, the key energizes the master relay, so it actually IS the master switch.
 
I did my RV7a just like the Grumman Tiger as shown on this picture.

View attachment 25329

That’s what the guy who built my RV-9A did. Just that simple. Just like the certified planes I’ve been flying for 50+ years. Works great. Style points aside, can’t think of a functional reason to re-think.
 

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As suggested by Paul, I wired a key switch in line with the starter circuit (key on - starter enabled, key off - starter dead). My logic was that a key switch added in the master circuit added another single point failure on the master circuit (undesirable in flight). While the switch is also a single point of failure in the start circuit, that is a risk only on the ground. In practice, I only use the switch at overnight stops, or less secure airports.
One of my fears was flying to a faraway destination and losing the key. So I located the switch in a removable panel and wired the switch with blade connectors (I know - another failure point) with opposite connectors on each lead (male to female on one, female to male on the other). If I lost the key, I can remove the panel (a dozen #6 Philips screws), unplug the key switch, connect the leads bypassing the switch and I’m back in business.
 
I’m setting mine up for a start button with no key. Just like every bonanza and piston twin I’ve ever flown.

The only key will be for the canopy lock.
 
Key Switch

Cole Hersee makes a good 2 position switch and I carry an extra key "hidden" in the airframe just in case. Don't cheap out on this part, there are many out there that I would not trust.
 
Key on the door (modified JD Air Latch) that we haven‘t used so far, but no key in the plane… just the Starter button…
We only have 30 hours and no big trips yet…
 
With a push button starter I’ve used two different methods. This keyed inline switch on my RV8:

https://www.steinair.com/product/mini-keyswitch-2/

And a hidden inline guarded toggle on my RV4:

https://www.steinair.com/product/toggle-switch-guard-red-plastic-spring-loaded/

On my current build, I’m also using two DPDT switches for ignition:

https://www.steinair.com/product/toggle-switch-dpdt-onon/

For start the left mag (SureFly) has to be on (up - mag hot and 12v power complete to the start button), and the right mag (Slick) has to be off (down - mag grounded and start circuit complete through the switch), or the start circuit won’t be complete from the start button. From there the start circuitry then goes through the hidden guarded switch to the start solenoid. Lots of switches I know, but if one of them fails, you don’t get to go flying until you fix it. A loose connection shouldn’t affect anything once the engine is running.
 
As others have done, I have no key, just the start button and a hidden starter enable kit
 
I think it's primarily a cosmetic thing, but I'm going to have a START button for engine starting. However, I still want a modicum of security, so I'd like to have a turn key that must be inserted and turned before the aircraft can be started.

Those of you with a START Button, how'd you handle this?

Just like you said...the keyswitch is the "green tag item" (Insert Before Flight) that *enables* the starter AND the mags. No key, no start, not even if the mag switches are on and the prop is pulled by hand.

I consider a keyswitch a *safety* issue, not a theft deterrent. And I think "hidden switches" are gimmicky and silly. They make keyed switches for a reason...this is one of them.
View attachment 25364
 
https://photos.app.goo.gl/bk39n6A6pWYCPECo8

I just replaced my keyed ACS ignition switch with 2 DPDT switches and a push button, both purchased from Stein. I used Nuckolls wiring diagram. The 2 DPDT switches are partially hidden by the switch guards.
My key is in the ACS switch which is packed up to sell at Oshkosh Aeromart.
 
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Starter "Cut-out"...

...switch in the locked forward baggage compartment. This lets me leave the canopy open, yet turn my back/walk away without fear of anyone reaching in and turning the prop.
 
This is how I did it.

Screenshot%202022-05-02%20THIS%20ONE-M.jpg


The key switch on the top left is installed in series before the master battery switch. Without the key switched "on", the master battery switch remains dead. The keyed switch adds nothing for security (it could literally be bypassed with a paperclip), but simply adds a bit of safety if used properly.
 
...switch in the locked forward baggage compartment. This lets me leave the canopy open, yet turn my back/walk away without fear of anyone reaching in and turning the prop.

Until the time you forget to throw the switch, but you've satisfied yourself that you did because you *locked the baggage compartment*. Your system is actually *less* safe than a keyswitch, because the key is only marginally related to the safety of the switch (on or off). In addition, you've not solved the problem of a mag being switched on and the prop rotated by hand.

I honestly don't understand the aversion that people have to a keyswitch as a safety interlock. It's WHAT THEY WERE DESIGNED FOR, and yet people seem to go to great lengths to avoid them by putting in cutesy little "hidden switches", or schemes like this, or leaving them out altogether. Ever seen a curious kid digging around in something cool? Think they can't find your cleverly hidden switch? Willing to bet someone's life on it?
 
Just like you said...the keyswitch is the "green tag item" (Insert Before Flight) that *enables* the starter AND the mags. No key, no start, not even if the mag switches are on and the prop is pulled by hand.

I consider a keyswitch a *safety* issue, not a theft deterrent. And I think "hidden switches" are gimmicky and silly. They make keyed switches for a reason...this is one of them.
View attachment 25364

Ha ha…. “gimmicky and silly”……. made me laugh. Especially considering the hidden switch does exactly the same thing as the keyed enable switch - except with my hidden switch I can’t lose or misplace my key(s). I use my hidden switch as a safety device primarily, like it sounds you do with your key. I’ve never actually thought of it as a theft deterrent. When my grandkids are sitting in grandpa’s airplane they are given specific instructions not to push any buttons or flip any switches……. but what if they had a brain fart and turned back into a kid? I don’t want a prop to spin. I would challenge anyone to actually find my hidden switch. It would be easier for them to find my key when I had the keyed enable switch in my last airplane. They key is a good safety feature, but a hidden switch that does the same thing is at least as good. Definitely not a gimmick.
 
They key is a good safety feature, but a hidden switch that does the same thing is at least as good.

That's debatable, but the "hidden switch" guys all seem to convince themselves that their system is unbeatable...oh, well, to each his own, I guess.
 
That's debatable, but the "hidden switch" guys all seem to convince themselves that their system is unbeatable...oh, well, to each his own, I guess.

Well, it’s a pretty lame debate. I don’t believe that either system is “unbeatable” as you say. Either system has possible weak points, but both answer the same question about push button start safety. Both systems are “safe”, if properly implemented.

In terms of anti-theft protection, neither is better than the other. A determined thief won’t be deterred by either system. Both are easily overcome in the same way (involves “jumping” the start circuit). They would have to have some “system knowledge”, and that is key in theft protection. It would be easier to do in a keyed example, because you can see it has a key, and you can see the the keyed switch, so easily “jumped”. Try to find my guarded switch, which you have no knowledge that I even have. You won’t find it, and I can reach it from where I am seated in the cockpit. If you go searching, you’d better make sure you aren’t touching anything ‘metal’….. might be one of those ‘non-habit forming’ experiences.
 
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You did notice that I said the keyswitch is NOT, in my aircraft, for any kind of theft protection, but for safety only?

So you've rigged up a hidden switch which is hot, so that if you're monkeying around, you get a jolt of electricity. Yep, sounds like a good plan for safe electrical design to me.

But no, that's not "gimmicky" or "silly"... LOL!
 
I'm gonna put facial recognition in my next one. Nobody will be ugly enough to steal my airplane.
 
You did notice that I said the keyswitch is NOT, in my aircraft, for any kind of theft protection, but for safety only?

So you've rigged up a hidden switch which is hot, so that if you're monkeying around, you get a jolt of electricity. Yep, sounds like a good plan for safe electrical design to me.

But no, that's not "gimmicky" or "silly"... LOL!

Yes, that would be silly I agree. You won’t get a poke if you go looking for a hidden switch in my airplane - I was joking about the non habit forming experience. There are some areas behind the panel on the sub panel with exposed conductors on the fuse block that would be hot with the master switch on, like any airplane, but nothing near the switch that I’m talking about. The thing I didn’t like about that keyed switch I had from Stein was that you could take the key out in either the on or off position, in fact it would sometimes just fall out if left in while in flight. Taking the key out with it switched on, it wasn’t that noticeable if it was on or off. I wouldn’t use that switch again. With my guarded switch it’s easy to tell it’s position. Guard up, switch is hot. Snap the guard down, switch is open. It’s on my shutdown and cockpit secure checklist, just like the key switch was.
 
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The thing I didn’t like about that keyed switch I had from Stein was that you could take the key out in either the on or off position, in fact it would sometimes just fall out if left in while in flight. Taking the key out with it switched on, it wasn’t that noticeable if it was on or off. I wouldn’t use that switch again.

Yeah, that wouldn't be a good solution. I got mine from McMaster, and specifically chose the option for key removal only in the Off position. They have a wide selection, so I was able to get exactly what was required (DPDT, Normally open, key removal only when Off, etc.). Being able to remove it in the On position would be a potential hazard.
 
I simply use a very tight-fitting collar on the "starter" circuit breaker when I want to ensure nobody is going to crank the engine. (That includes when the aircraft is undergoing maintenance.) No power to the starter solenoid means no cranking, even if the guarded "Start" pushbutton switch is activated. Simple and reliable.
 
Blowing dust off this thread a bit. For some reason, I find that I really DON'T want a key. Irrational, but why stop now? Along this thread, someone said they put a lock on the throttle quadrant and I'm curious about that. How'd you do that? Did you make any special modifications to the quadrant?
 
Doing the Fastback kit, I plan to have a key for the canopy and none in the plane.
 
Blowing dust off this thread a bit. For some reason, I find that I really DON'T want a key. Irrational, but why stop now? Along this thread, someone said they put a lock on the throttle quadrant and I'm curious about that. How'd you do that? Did you make any special modifications to the quadrant?

Agree, don't need or want a key, just toggles for me :eek:
 
For those who want a push button starter and a modicum of additional security, how about mounting a simple magnetic interrupt in the center console or kick panel, away from anything that could be negativity influenced by a magnet?

Magnet in place, starter circuit energized. Magnet removed, starter circuit disabled. It's obviously easy to defeat, but only if you know it's there.

Here's an inexpensive version intended for motorcycle handlebars, but anything similar could be adapted.

There may be reasons using a magnetic interrupt isn't a good idea, but it's just a thought.

kuberg-notaus-magnetschalter-magnetic-kill-switch-freerider-1_1800x1800.jpg
 
I'm wiring mine up now. I'm installing Vertical Power's PPS, so I have a keyed "ON-OFF" switch that will be labeled "Master Key". It'll be located in a spot inside the front cockpit that is easily accessible, but unobtrusive (kind of like the keys they put in the Hueys after the 1974 Whitehouse incident). It retains the key in the "ON" position, so no worries that it will fall out. The Master/Alt switches will be located on the row at bottom of instrument panel. And, the starter switch will be on the Pilot's stick grip. PPS has an internal starter cut-out feature, so no need for a "Start-Enable" switch.
 
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When’s the last time you’ve heard of an RV being stolen?

I think most of us that are considering a keyed or hidden start enable switch aren’t worried about the airplane being stolen. For me it’s about worrying about somebody spinning a prop unintentionally.
 
I’ve got a start button and NO Key on my plane - instead I am using the Intellikey system (by Midwest Panels)… it’s got a remote key fob (like a car) that has a button on it and a start button on the panel… you must press the button on the key fob to activate the start button on the panel - so no key is needed… on the flip side, in case of an emergency start needed (like midair), the system Keeps the start button ‘available’ after the engine turns off for a certain amount of time (adjustable)…
 
When’s the last time you’ve heard of an RV being stolen?
I think most of us that are considering a keyed or hidden start enable switch aren’t worried about the airplane being stolen. For me it’s about worrying about somebody spinning a prop unintentionally.


Or even just flicking the battery switch on when I'm not looking.

I did too many "static displays" back in the day to trust anyone around my ride home.
 
Or even just flicking the battery switch on when I'm not looking.

I did too many "static displays" back in the day to trust anyone around my ride home.

My solution to that problem is a 10mm wrench in my bag that I use to remove the negative terminal on my EarthX battery, which is easily accessible from the oil door.
 
My L-39 Jet has a keyed battery disconnect, mounted under an external door in the nose cone. That goes straight to the source of the issue.

My Rocket has a toggle on the master. The toggle is from Honeywell and requires you to lift the knob to move the switch (two discrete actions). I dont allow the airplane out of my sight on the rare ocasions it is at a public display, and kids are not allowed near the cockpit without my extreme supervision.

"Security" is handled with a canopy lock and insurance premiums.
 
My solution to that problem is a 10mm wrench in my bag that I use to remove the negative terminal on my EarthX battery, which is easily accessible from the oil door.

For me (RV-8 w/battery in back), that's too much work. And, the way the Vertical Power system works, with the battery/master switch not carrying any current, the keyed switch is a no-brainer.
 
Key switch?

Key switches are only good enough for honest people, those who wouldn't steal your aircraft even if the keys were in it.
If you are seriously concerned about locking up your RV, a solid canopy lock will serve you better and protect your avionics (somewhat) from thieves.
A throttle lock seems like a good idea as well in that it would take some destructive efforts, time and special tools to make the engine come to live.
My Rv-10 doors lock from the inside with a hairpin through the unlock lever.
I would exit through the baggage compartment and lock the baggage door.
I have never stayed anywhere where I felt I needed to lock up tight and even if my 10 was all locked, a thieve could pry the baggage door open in 20 seconds.
Anyone who plans to steal your aircraft probably knows how to get around a key switch, mechanical lock or other device. An aircraft is a very soft target for
criminals to steal but not nearly as easily unloaded as are cars, electronics, etc.
 
When I was building my house some years back, I needed to leave a Kubota tractor on site unattended for a good length of time. I cleverly hid an interrupt switch under the hood, behind a panel, where only one finger could reach it to turn it on. "There, perfectly secure I said to myself" in a satisfying way.

I came over a few days later to see my general contractor driving the tractor over to pick up some material, like he owned the thing ... !! :eek:

When I asked him if it started right up (thinking I had forgotten to activate the cut out), he said "No, I just looked around for a good place to put a cut out and found the switch. Nice job hiding it tho!"

Hmmm ... No fancy stuff on my plane, Push To Start Device (PTSD) only for me. Enjoy the ride!
 
I think it's most important to be thinking about someone getting inside the cabin with access to all the avionics.
 
I think it's most important to be thinking about someone getting inside the cabin with access to all the avionics.

That's why you design your instrument panel to allow you to quickly and easily remove your $$$ avionics and radios. Put them in your flight bag and take them to the motel with you.
 
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