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Push button starter question

olyolson

Well Known Member
Friend
During the panel upgrade I’d like to use a push button starter and mag switches. I found one on Acft Spruce and the description says it’s for use as a start switch and only about $6. Is this what everyone is using that have a push button starter or is there a better one? See below.

https://www.aircraftspruce.com/catalog/elpages/pusbutswitch.php

”A quality momentary SPST switch, perfect as a starter button, Comes with a special boot that keeps out dust and weather.”

16kxh7d.jpg
 
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I have a starter button and 2 mag switches in the RV-8 I bought and I wondered why anyone would do that instead of using a more common keyed switch like you find in Cessnas. It must be that it's included in the kit already?
 
B&C has a nice one also.

I used the small button switch from B&C for primer solenoid from ACS. This was in addition to the Big starter button with bezel ring from B&C.
 
I have a starter button and 2 mag switches in the RV-8 I bought and I wondered why anyone would do that instead of using a more common keyed switch like you find in Cessnas. It must be that it's included in the kit already?

Keyed start switches are common in certified aircraft but not so much in experimentals. Not included in the kit. I too have the Steinair button and one in a box that the OP posted. I couldn't bring myself to install such an ugly thing in my panel :D
 
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be careful. Some of the starter switches are not rated high enough. The starter contactor will draw about 4 amps.

Larry
 
I used the start button out of a Honda S2000, but because of the amp draw had to add a secondary relay.
 
That is the button I have been using for 11+ years now with no issues.

It is stiff to push, so you aren't going to hit it accidently. I did not install the rubber boot but left the chrome button visible.

Ditto, and ditto.
 
That is the button I have been using for 11+ years now with no issues.

It is stiff to push, so you aren't going to hit it accidently. I did not install the rubber boot but left the chrome button visible.

Coming up on twenty years in my RV-6 but without the rubber cover...I didn't realize the switch was ugly...... ;)

Also have an orange "Starter Engaged" light above it to alert for a stuck solenoid.
 
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I have a starter button and 2 mag switches in the RV-8 I bought and I wondered why anyone would do that instead of using a more common keyed switch like you find in Cessnas. It must be that it's included in the kit already?

Cessnas are stuck with those antiquated key switches because that is what they were certificated with. ;)
 
Here?s what I used. Cole Hersey 9011, looks good, works great. I have E.I. so I keyed the master.
 
A couple of heads-up:

Since the Stein switch is giving good service, no doubt it's fine for the task. But it's always nice to have the current rating spec'd for a switch. As others have said, a start contactor can pull several amps (2 would be very optimistic for a start contactor; that's closer to a master).

A possible variation can change the equation significantly. There are starters out there that have a (real) solenoid built on the side, that acts as both a contactor for the high current and an engagement solenoid for the pinion. It's *possible* to wire that style starter's control terminal directly to a start pushbutton, with no external start contactor. But...a 15A-20A switch is advisable if wired that way. A small 3A-6A switch will work for a while, but may die at some inconvenient time in the future.

FWIW...
 
Good point Carl

Just a thougt from a gearhead, LOL. This is a good reason to buy coordnated components from a vendor like B&C. They sell buttons, contactors and starters. I dont know ( admitted laymen) but if Knuckles had anything to do with it, it would be coordinated. just sayin 😊
 
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I'm quite partial to the OTTO P1 - Sealed, MIL-PRF-8805/3 Momentary, Snap Action Pushbutton

https://www.otto-controls.com/p1-sealed-mil-prf-8805-3-momentary-snap-action-pushbutton

Sealed, rated 10A, small, lots of button colors, excellent snap action feel.

It is rated for 10 amps for resistive load only. For less in other applications. Has a life of 25k cycles — plenty for our purpose, but doesn’t compare favorably to ratings of 1 million cycles for some other quality switches. But at least it has the ratings posted, unlike the lack thereof for switches listed on other popular websites mentioned in this thread.

I think my point is that there is a good selection to choose from.
 
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I have a starter button and 2 mag switches in the RV-8 I bought and I wondered why anyone would do that instead of using a more common keyed switch like you find in Cessnas. It must be that it's included in the kit already?
There are a few reasons one may elect to use discrete switches rather than a keyed-style switch.

1. First and foremost, the keyed switches fail at an alarming rate.
2. When doing aerobatics, your keychain will swing around and around and scratch your panel.
2.a. If you take it off the keychain and just use the key, you risk losing the key and/or deciding to just leave the key in there all the time. If the key is in there all the time, the security value of a keyed switch is lost.
3. Checking your mags requires flipping a small key back and forth across the contacts accurately without going too far or not far enough.

Personally I removed a keyed switch from the RV-6 I bought, and installed two toggles for mags, and a momentary toggle with a flip-down cover for the starter.
 
ELECTROAIR IGNITION SWITCH PANELS

I opted for the Electroair Ignition Switch Panel for my 8a. It is a very nicely packaged design that includes the mag on/off switched and starter push button. It can be used with any magneto/pmag installation. Does not require that you use the Electroair electronic ignition. It is a little pricey at $255 from ACS.
 
I've always done push button starters because they're cheaper. Keyed sets seem to cost an arm and a leg. The button in my 8 was less than $10.
 
This could start another argument...well I think there is one on here already but my start is on the infinity grip with a relay. love it, no problems.
 
Probably a stupid question but with a starter button, what is the best way to secure the airplane against somebody jumping in and starting her up?
 
Funny you ask.

My plane is switches and a button. Theoretically someone cold jump in, grab the checklist off the glare shield, and fly her away.

So I have a lock on the canopy release. This is basically a $7 luggage lock on probably a $70,000 plane.

But it's worked just fine for 4 years. Knock on wood.
 
Probably a stupid question but with a starter button, what is the best way to secure the airplane against somebody jumping in and starting her up?
The easiest way is a hidden start permissive toggle switch in line with the power to the starter solenoid.

The other way is to use a simple key switch, but most do not have the current capacity for the solenoid so you need to add a relay.

Carl
 
I?ve used the red button starter from Stein with bezel on all 3 of my RV?s. On this latest one, I used a keyed enable switch (from Stein) to enable the starter push button. Turn off and remove the key when you aren?t there to prevent unauthorized use. Master switch on, won?t enable the start button without the keyed switch turned on.
 
I?ve used the red button starter from Stein with bezel on all 3 of my RV?s. On this latest one, I used a keyed enable switch (from Stein) to enable the starter push button. Turn off and remove the key when you aren?t there to prevent unauthorized use. Master switch on, won?t enable the start button without the keyed switch turned on.

What is the advantage of that setup over using an off/on/momentary start switch? You accomplish the same thing as far as I can tell with less panel space being taken up.
 
I've been thinking about putting a 7 amp automotive fuse inline with the starter switch and locating it somewhere inconspicuous. That would at least slow down any would be "barefoot bandits".

I'm actually more worried about somebody making off with my avionics.
 
What is the advantage of that setup over using an off/on/momentary start switch? You accomplish the same thing as far as I can tell with less panel space being taken up.

Largely personal preference, but the combined switch does run the risk of inadvertent starter activation, especially by someone not familiar with the system ('hmm; shouldn't the master go all the way up???'). Depending on architecture, a combo switch that can handle start solenoid current could cost quite a bit more than 2 separate switches (and be much harder to source, if it fails while 'on the road').

Everything's a compromise. :)
 
I've been thinking about putting a 7 amp automotive fuse inline with the starter switch and locating it somewhere inconspicuous. That would at least slow down any would be "barefoot bandits".

I'm actually more worried about somebody making off with my avionics.

Interesting as this is opposite of my priorities. I worry most about some kid getting in an hitting the start button. Not so much that the engine will start, but the prop hitting someone else. So steps taken to not let a push of the start button engaging the starter.

If someone wants to steal avionics, canopy security makes little difference. For this reason I did not put a lock on the canopy (other than a canopy cover when away from home and parked on the ramp). Insurance will pay for avionics, but repairing a broken canopy would be heartbreaking.

Carl
 
I've been thinking about putting a 7 amp automotive fuse inline with the starter switch and locating it somewhere inconspicuous. That would at least slow down any would be "barefoot bandits".

I'm actually more worried about somebody making off with my avionics.

Simplest thing is just a hidden switch in series with the start PB.

On 'wireless': one of the 'Popular' (either Sci or Mech) mags had an editor's page about hopping in his car with his kid, driving to the store, hitting the start/stop button, making his purchases, coming back out and discovering he didn't have his fob. He'd laid it on the roof of the car at home while he checked on something, and the car cranked up because the fob was close enough for communication. Continued to run when the fob fell off somewhere between home & store, but obviously wouldn't re-start with the fob many blocks away....

Charlie
 
Simplest thing is just a hidden switch in series with the start PB.
On 'wireless': one of the 'Popular' (either Sci or Mech) mags had an editor's page about hopping in his car with his kid, driving to the store, hitting the start/stop button, making his purchases, coming back out and discovering he didn't have his fob. He'd laid it on the roof of the car at home while he checked on something, and the car cranked up because the fob was close enough for communication. Continued to run when the fob fell off somewhere between home & store, but obviously wouldn't re-start with the fob many blocks away....
Charlie

Not sure what kind of car he had, but if this happens with my cars, when you try to turn the ignition off, the car will tell you, "There is no fob available. Are you sure you want to turn off?"
 
Largely personal preference, but the combined switch does run the risk of inadvertent starter activation, especially by someone not familiar with the system ('hmm; shouldn't the master go all the way up???'). Depending on architecture, a combo switch that can handle start solenoid current could cost quite a bit more than 2 separate switches (and be much harder to source, if it fails while 'on the road').

Everything's a compromise. :)

Thanks for piping in Charliie. I know from previous posts that you are quite knowledgeable about electrical stuff. There are a few Honeywell swithches in the Grainger link provided several posts up that handle 20 amps. How much current are the switches expected to handle? The solenoid does the heavy lifting for the most part does it not?
 
20A should be more than adequate. Only reason for the caution is that some have eliminated the separate contactor, when using a starter that has a built-in solenoid (that can on the side of the starter motor) that both moves the pinion out, and provides the high current connection for the starter. Those can stress a typical 10A switch.
 
Thanks for piping in Charliie. I know from previous posts that you are quite knowledgeable about electrical stuff. There are a few Honeywell swithches in the Grainger link provided several posts up that handle 20 amps. How much current are the switches expected to handle? The solenoid does the heavy lifting for the most part does it not?

What are those $400+ PMA'd Bendix keyed switches rated for? I bet you could look it up.
 
Interesting as this is opposite of my priorities. I worry most about some kid getting in an hitting the start button. Not so much that the engine will start, but the prop hitting someone else. So steps taken to not let a push of the start button engaging the starter.

If someone wants to steal avionics, canopy security makes little difference. For this reason I did not put a lock on the canopy (other than a canopy cover when away from home and parked on the ramp). Insurance will pay for avionics, but repairing a broken canopy would be heartbreaking.

Carl

Pulling out the fuse would serve to keep accidental starter engagement from a "kid getting in and hitting the start button" as well as slow down an airplane thief.
 
What are those $400+ PMA'd Bendix keyed switches rated for? I bet you could look it up.

5 amps according to the spec sheet provided on ACS.

https://m.grainger.com/mobile/produ...h-24M946?breadcrumbCatId=27646&fc=MWP2IDP2PCP

I think I might use one of these with the “momentary on” for the starter and the “on” position for the ECU master of the SDS EI. I will have to check if the “on” stays on while the starter is engaged though or that obviously won’t work.
 
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I wouldn't think the switch in the cockpit would see more than about 4 amps.

Looking at the wiring diagrams, it looks to me like the only current going through the start switch in the cockpit is from the 12vdc from the "Start" circuit breaker, through the switch, then coil of the starter contactor, and then to ground.

So, discounting any resistance of the wire, the switch, and the circuit breaker and their connections, the current in the circuit would only be 12vdc divided by the resistance of the coil.

I was looking at a popular starter contactor spec sheet today. It listed the coil resistance at ~3.5 ohms. That's less than 4 amps, nominal.
 
Keyed OFF/ON L/R

I've had a keyed switch in the -7 and kept it that way after the panel upgrade. I thought about going to a push button but that would have required 2 more switches for the Mags and possibly another solenoid. I'm not sure the "failure rate" on the Keyed Cessna type switches are that bad. The key is also the same key that opens my canopy so there is that. About the only complaint I have is that if you have too much "stuff" on your key ring it will flop around when you do aerobatics, so I do agree with that. I only have the 1 key on mine so it doesn't bother me. I did change the contacts at around 700 hours. I think it comes down to a personal preference again. I think the next plane will have a push button with e-Mag switches.
 
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I'm not sure the "failure rate" on the Keyed Cessna type switches are that bad.

It's not the "fail rate" so much that the failure may not be caught. When you do a mag check, you switch between both, right, and left. Few people check the "off" position. That's where the failure often occurs. And since you normally shut down the engine with the mixture, a failure of the "off" position is not obvious.
 
Thanks for piping in Charliie. I know from previous posts that you are quite knowledgeable about electrical stuff. There are a few Honeywell swithches in the Grainger link provided several posts up that handle 20 amps. How much current are the switches expected to handle? The solenoid does the heavy lifting for the most part does it not?

most external auto solenoids (i.e. ford style typically used in our planes) draw around 3-4 amps in my experience. As Charlie mentioned, those mounted on the starter that also pull the drive gear will draw more. I would expect those mounted solenoids that are only contactors would also draw the same 3-4.

Larry
 
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Is there a circuit diagram that shows how to modify a key-switch system to push button?

Thanks
 
Is there a circuit diagram that shows how to modify a key-switch system to push button?

Thanks

The easiest way is to buy the "Aeroelectric Connection" book or the "Aircraft Wiring Guide" that Vans sells.

How you do it in your aircraft is going to depend on a couple of different things.

If really want some help with it, PM me and I can give you some ideas.
 
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