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Canopy OPEN Warning light, but HOW?

claycookiemonster

claycookiemonster

Well Known Member
Everyone seems to have one. But how is it done? And what EXACTLY are you sensing? Contact between canopy and rail? Handle fully closed? Handle locked? I know there is a world of micro switches out there Installing one, or even two to sense close proximity of canopy and rail isn't theoretically hard, but I couldn't find a thread on exactly how anyone did it. Also, no doubt air loads may alter the fit of a canopy in flight, so I'd guess certain locations around the canopy perimeter would be more reliable than others. Or, maybe those are the exact location to keep an eye on? A single sensor, or more than one? In series, so if any one of them loses contact, I get the light? Inquiring minds want to know.
 
claycookiemonster said:
Everyone seems to have one. But how is it done? And what EXACTLY are you sensing? Contact between canopy and rail? Handle fully closed? Handle locked? I know there is a world of micro switches out there Installing one, or even two to sense close proximity of canopy and rail isn't theoretically hard, but I couldn't find a thread on exactly how anyone did it. Also, no doubt air loads may alter the fit of a canopy in flight, so I'd guess certain locations around the canopy perimeter would be more reliable than others. Or, maybe those are the exact location to keep an eye on? A single sensor, or more than one? In series, so if any one of them loses contact, I get the light? Inquiring minds want to know.
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On the -14 it is a microswitch that is activated by the canopy locking pin.
 
The ones I've looked at are assuring the latch is engaged. (like what Mountainride said) So, you could have the canopy tipped uo and the latch closed and there would be no light. But you aren't going to take off like that.

The reminder is useful. I confess I took off unlatched., ONCE. I still don't have an indicator, but it's something your unlikely to do more than once. And that passenger will never let me live it down :(.
 
I think the only way it's of any value is to measure whether the latch is engaged or not. I ultimately decided it wasn't worth it for me, but how I would have done it on my 7 slider is a microswitch that got bumped by the latch hook when it was engaged.

Maybe your 8 is different, but couldn't really see any other location or method on a 7 slider that would show whether the canopy was actually latched or just slid closed, which I don't think I need a CAS message to tell me. I didn't like the idea of having to look at that micro switch front and center and so I decided to pass on it.
 
Not really needed in an RV-8. If you do somehow fail to look at the handle that is a few inches from your face and take off anyway with canopy shut but not latched, the airflow will hold the canopy down. If you take off with the canopy open all bets are off.

Carl
 
Magnetic reed switches are also an option. They are available both normally open and normally closed. But a pilot will soon get used to the warning light being on while taxiing around with the canopy open on a hot day. What is needed is both an audible and visual warning when the airspeed is higher than normal taxi speeds and the canopy is open. Some EFISs have that feature built in. If not, you can install an airspeed switch. Below is a circuit that will give a voice alarm if taking off with the canopy open. Mine says, "Canopy open. Abort. CANOPY CANOPY !" The circuit looks complicated but there are only 4 parts and 2 switches besides the ready made voice recorder that is available on eBay for $2 from China or $8 from the U.S.Canopy Alarm.png
 
I agree with most comments that, if you're paying attention, or using your CHECKLIST, this is not something to be worried about. My -8 is a Fastback, so the oddly tilted canopy should also be a dead give away. All of that being said, were we sitting around the hanger and telling war stories, I bet some of us have forgotten or overlooked even more obvious things.
 
Mel said:
CHECKLIST...CHECKLIST...CHECKLIST
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And I add to the list above is DO NOT let distractions get in the way. A canopy will let you know it is not latched right after take off. Then you will not ever not remember to check.
Been there done that!!!!!!!!!!!!!!!! WOW quite and experience. Sure made me laugh """after""" I got it latched in place
Wonder how I know that?????
My luck varies Fixit
 
claycookiemonster said:
Everyone seems to have one. But how is it done? And what EXACTLY are you sensing? Handle locked? I know there is a world of micro switches out there Installing one, or even two to sense close proximity of canopy and rail isn't theoretically hard, but I couldn't find a thread on exactly how anyone did it. A single sensor, or more than one?
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I can't answer for anything other than what I did on SuzieQ, an RV-4. There is a microswitch positioned so the canopy rail opens the microswitch (turning the RED light off) when the canopy is closed and locked. It is positioned to be pretty sensitive and the canopy has to be CLOSED to move the switch arm enough to open. It can be seen in the photograph in front of the nylon block that holds the canopy rail in the closed position. The canopy is in the TAXI position in the photo. The microswitch is held in place by a bracket that is bolted to the nylon block with the same bolts that hold the block in place. It has never failed and never turned on in flight. It is on my CHECK LIST in several places. The first line of my predeparture check list is CANOPY: DOWN AND LOCKED; SEAT BELTS: LOCKED (and the RED light is off!) BOOST PUMP: ON; FLAPS: SET 20 DEGREES; GAS: RIGHT TANK etc all of which I say out loud as I have done this so many times it is welded in my memory!.
 

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Many ways to do this--I think there is another thread with ideas. I did this on my -7A tip-up by attaching micro-switches to the steel latch "fingers" that engage with the WD-622 canopy latch lug. When the fingers are completely engaged with the lugs, both switches switch on, and they're wired in series so if one or both are not on, I get a CAS message.

Closing the canopy and double checking both latches are checklist items, too, of course.

 
On my fastback I mounted a microswitch on the forward side of the front locking block behind the instrument panel. I fabricated a simple bracket to hold the microswitch in the correct position. When the locking pin is in the latched position, the contact is tripped and the latched signal is achieved.

If your using a Dynon system just make sure your signal is ground, ask me how know! The beautiful part of integrating this feature into the Dynon system is you can set up an audio alert after your engine reaches a specific RPM and the locked contact has not yet been achieved.
 

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claycookiemonster said:
I agree with most comments that, if you're paying attention, or using your CHECKLIST, this is not something to be worried about. My -8 is a Fastback, so the oddly tilted canopy should also be a dead give away. All of that being said, were we sitting around the hanger and telling war stories, I bet some of us have forgotten or overlooked even more obvious things.
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OK, your non-standard canopy is a game changer. If it is anything like an RV-4 tilt canopy then yes, add whatever you can to alert you to it not being locked. I know of one RV-4 canopy that departed the plane because it was not locked.

Carl
 
claycookiemonster said:
what EXACTLY are you sensing? Contact between canopy and rail? Handle fully closed? Handle locked?
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Will be watching this thread with interest... Also a Fastback here. Thinking about putting a spring loaded normally open switch that goes against the canopy pin(s) in series with throttle position past halfway to trigger the alarm(I'm throttle by wire so it makes that part easy). Open to better ideas though...

Also, I painted the last 1/2" of the pin travel bright yellow but that paint starts rubbing off fairly quick cycling the latch handle.

Mich48041 said:
Below is a circuit that will give a voice alarm if taking off with the canopy open.
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Very elegant solution, thanks for sharing. Similarly, I'm planning on getting a PCB made up that has an Arduino on it to run a few lights/alarms for a few of the "what if" scenarios I want to have some protection against.
 

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If you don't have a "flopper" type canopy, this warning device may not be mandatory - but it doesn't hurt. If you knew anybody (I did) back in the day who lost the canopy of their -4, and died as a result, you might be more interested in developing something. Tip ups & sliders maybe not as critical as tip overs. In addition to the panel warning light, I would strongly suggest some sort of aural notification loud enough to be heard above the engine/propeller noise, doesn't need to be wired into your headset - just loud enough to be heard through it.

Case in point: Taking off one day from Bakersfield Muni, I got the aural warning, looked down (then) saw the warning light in the panel, and proceeded to lock the canopy lock arm to recover a safe condition. In the process of advancing the throttle and scanning the runway ahead on the takeoff roll I didn't do a good job of monitoring everything on my panel. My bad - but still had the secondary aural notification as a backup.

Now, here's the problem with this system if you don't have a way to disarm the aural part when you want to taxi with the canopy ajar. Now we're talking about the way, wayback machine before all the fancy electronic systems that would/could allow this integration - I just wired a second micro switch, in series, to respond to throttle movement. Below 1700 rpm, microswitch open, above that - closed. I also wired a "test" function (momentary off-on micro push button switch) under the cockpit rail that I can use to test system operation after being "armed". Comes in handy to give you comfort knowing that you have a working safety device for canopy security.

If you go to the trouble of installing a light, also install an aural warning.

I've known people that have had canopy's come open from this oversight - one even had a light and didn't see it (he lived through it - that's how I know), so do yourself a favor and at least consider it.

HFS
 
I found this a nice program that Vans wrote for both Garmin and Dynan. It gives you a CAS alarm when your avionics on and "check canopy". In addition, if you are like many and taxi with the canopy open when you do your run-up (over 1,700 RPM) you get an aural (Nice lady tell you "Warning canopy open") and visual red alarm in the CAS display if canopy open. I found it pretty well thought out and you can use it on all RV models.

 

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HFS said:
If you go to the trouble of installing a light, also install an aural warning.
I've known people that have had canopy's come open from this oversight - one even had a light and didn't see it (he lived through it - that's how I know), so do yourself a favor and at least consider it.

HFS
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Good thoughts all.

As in post #10 it is #1 on my oral call-out of my final predeparture check list. Then, if I happened to miss the BRIGHT RED LIGHT on the panel as I pull onto the runway, as I advance throttle and do my "GOOD ENGINE" scan, right above all those instruments I quickly check, and with it being right next to the ASI, if I miss all that, I think for me, anyway, the aural warning would just be annoying! If I missed all those warnings, I should probably just pull throttle and head back to the hangar. That would NOT be a day to go flying... 😊
 

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Roadjunkie1 said:
Good thoughts all.

As in post #10 it is #1 on my oral call-out of my final predeparture check list. Then, if I happened to miss the BRIGHT RED LIGHT on the panel as I pull onto the runway, as I advance throttle and do my "GOOD ENGINE" scan, right above all those instruments I quickly check, and with it being right next to the ASI, if I miss all that, I think for me, anyway, the aural warning would just be annoying! If I missed all those warnings, I should probably just pull throttle and head back to the hangar. That would NOT be a day to go flying... 😊
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You only get the "horn" if you have an emergency - how "annoying" could that be ...
 
I know a guy that had his -4 canopy come off at about 170mph because it was not latched completely, just enough that the locking pin was in the hole. Lived to see another day, luckily. My upcoming panel redo will absolutely have a warning light and a buzzer somehow hooked into throttle position.
 
climbak said:
I know a guy that had his -4 canopy come off at about 170mph because it was not latched completely, just enough that the locking pin was in the hole. Lived to see another day, luckily. My upcoming panel redo will absolutely have a warning light and a buzzer somehow hooked into throttle position.
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That's what I like about my setup: the microswitch is not opened until the locking pin is FULL FORWARD!
 
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