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Canopy locked indicator light

jamo002

I'm New Here
Please excuse me if this has already been covered in the Forum. I recently purchased a factory built RV-12. I've flying since 1978, but I'm not immune to mistakes. With the unseasonably hot, humid weather in Georgia this spring I've been taxiing with the canopy about 2" open, resting on the closed latch. An instructor friend of mine recently commented that taking off with a canopy unlatched is the primary cause of fatalities in an RV 12 and suggested that if I plan to keep doing this I should invest in adding a canopy lock indicator light. I think that's a great idea. Can any of you tell me if there is a system designed to be used with an RV 12, and where can I purchase it?
 
I’m not sure about the “primary cause of fatalities” but I haven’t followed the numbers. There is a Canopy Latch sensor (micro switch) and red/green lamp on my Dynon screen. The system also gives an audio alert when RPMs exceed 4000 if the canopy isn’t latched. The mod was made available to builders and Vans encouraged us LLC to install it. I’ll defer to the experts about how you get it installed on an SLSA.
 
One more thing, there is also a mod which secures the hatch from coming open while resting on the latch bar. The latch handle clips into a tab which gets installed in the forward face of the roll bar.
 
These mods are very worthwhile to do.

As for the canopy popping open as a potential cause of fatalities??? Aerodynamics are barely affected. If there are accidents and potential fatalities, it is virtually always pilot error. Unlatched doors on Cessnas don’t crash planes, the pilot’s overreaction may. I encourage you to educate your instructor.
 
These mods are very worthwhile to do.

As for the canopy popping open as a potential cause of fatalities??? Aerodynamics are barely affected. If there are accidents and potential fatalities, it is virtually always pilot error. Unlatched doors on Cessnas don’t crash planes, the pilot’s overreaction may. I encourage you to educate your instructor.

Unlatched doors in Cessnas don't crash planes, but this isn't a Cessna.

It's been widely reported that an unlatched tipup canopy on the various Vans models sometimes causes a significant nose down pitching moment. depending on a number of factors. I've never flown an rv12, so are you saying that's not the case?
 
...commented that taking off with a canopy unlatched is the primary cause of fatalities in an RV 12...

Out of the 6 I was able to find at NTSB:

  1. Canopy
  2. Exceeding op limits / health issues
  3. Engine problem on takeoff
  4. Canopy (possible incorrect installation of retrofit kit); Dynon D-180 without warning system
  5. Unknown yet
  6. Probably flight into IMC.

I suppose if you're wanting to fix ONE thing on the plane to avert a possible problem down the road.. sure, perform all the Canopy Latch notices/fixes. If you have the D-180 system, maybe even go as far as rigging up a buzzer to a microswitch.. or get into the habit of moving a placard every time you open the canopy. For example, a streamer with a suction cup that is either attached to the handle, or stuck to your EFIS screen as a warning.

I don't think its an automatic crash if it pops open.. but there is a startle factor to deal with, and a controllability/pitch-down problem to deal with.
 
Inflight canopy open

I departed field climb to 2000 ft when i transistion from climb to level flight canopy was showing signs of coming open so reached overhead to secure it know at level flight the canopy was really wanting to open all the while my right hand was trying to close really lot of force to keep it from opening about 3inches open pulled power back with left hand, made tower freq switch 1.5 miles away from tower airport asked for immediate landing, was cleared for 36 but option of any runway. With rt hand holding canopy latch still on short final canopy was coming more to close position yes flying with left hand only making power adjustments with left hand just over numbers into flare the canopy came closed twisted overhead latch all was then locked up. Whee what a adrenaline rush. Conclusion is go to slow flight at altitude until the canopy loses its lift due to speed then canopy will settle to close position.
 
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[/url]IMG_1730 by Brent Connelly, on Flickr[/IMG]
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[/url]IMG_1729 by Brent Connelly, on Flickr[/IMG]

Have had only one experience with open RV-12 canopy during flight. Passenger didn't fully close latch in our haste to roll onto runway at KOSH (I failed to supervise). All was good until climbing off shore over lake Michigan, when it popped open and jammed in partially open position. Startled the *** out of me, but had no noticeable effect on flight controls. Uneventful landing. Found that in normal flight, air pressure prevents one from pulling it closed. If it is open, or pops open in flight, ignore it, it won't open very much due to air flow and just fly the plane.

The above clips are great for ground taxing but might lull one into complacency in not checking that canopy is properly latched for takeoff.
 
Latch canopy should be on your pre flight checklist, right before run up to 4000 rpm to check functionality of both ignition systems.
 
Aerodynamics

From what I've been told, the "canopy open - pitch down" issue is caused first by the low pressure area above the canopy (think top surface of an airfoil) pulling the assembly upward. The resulting "board in the wind" blanks out the empennage. If you will recall aerodynamics theory from ground school, in level flight the horizonal stabilizer on a standard configuration aircraft produces downward force on the tail. With your tail blanked out by the dirty air coming off of the canopy that force goes away and you subsequently have a steady downward pitch.

I haven't tried it myself (and don't intend to!), but I imagine how far the canopy has been opened has a lot to do with the severity of the pitch moment.

Hope this helps!
 
Possible reasons that a RV-12 pitches down:
Because the pilot just stalled it while trying to close the canopy.
Because the pilot inadvertently pushed the stick forward while trying to close the canopy.
_
An open canopy will naturally assume the position with the least amount of drag.
My RV-12 did not pitch down when I took off with the canopy unlatched.
 
Early-on, I did a takeoff with canopy unlatched in the heat of summer. Just like Joe says in above post, it is a non-event. Loud noise, and startling for sure, but aerodynamics not changed very much, if even perceptible. No change in pitch.

Recall what happened to John Denver when reaching for awkwardly placed fuel valve and inadvertent control inputs were applied…
 
The above clips are great for ground taxing but might lull one into complacency in not checking that canopy is properly latched for takeoff.

If you retrofit the canopy catch, how do you make sure that the 3 LP rivets do not fall and remain in the rollover bar? Is there a safe method for drilling out those?
I would like to retrofit but would not like the shop heads remain loosely in there.
 
If you retrofit the canopy catch, how do you make sure that the 3 LP rivets do not fall and remain in the rollover bar? Is there a safe method for drilling out those?
I would like to retrofit but would not like the shop heads remain loosely in there.

Like any other safety of flight decision, you have to evaluate the risk vs. reward of doing the modification. In this case, loose rivet debris in the roll bar vs. the canopy flying open. Easy decision?
 
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