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Tip: Tip Up Safety Latch Mod

db1yg

Well Known Member
Tip: Tip Up Safety and Main Latch Mods

Shortly after ordering my RV9a tail kit back in 2003 I witnessed an RV6a owner struggle to get his tip up canopy open. It seems the canopy slipped out of his hand on closure and the safety latch had pivoted and partially engaged under the roll bar when the canopy slammed shut. After about an hour of working accompanied by much colorful language he was able to get it unlocked without damage.

Hmmmm--how to avoid this as well as keep the latch from continuously scratching the high dollar jet flex paint I intended to use on the interior??

After much head scratching I tossed the stock mounting block and replaced it with some white UHMW plastic. The new block is the same thickness as the old but it is about 1" shorter and 1" wider. I drilled this block for the safety latch shaft handle, purchased a SS compression spring (aviation section of my local Lowes), and mounted the stock stop washer and cotter pin. The block was mounted whereby the safety latch is high of the roll bar when not in use therefore it can not pivot and lock with me on the outside of the plane. When you need to latch simply pull down on the handle (compress the spring), pivot, and release. It also will not rattle as it wears as the spring will remove any slack. You will note from the pic that I also mounted a thin strip (1/8th thick) of the UHMW plastic under the canopy bow--the latch rides on this when engaged. The angled white metal above the latch shaft is simply there to contain the spring in the event the cotter pin gave up--it is probably overkill but I did not want the spring releasing into my plexi.

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I also modified the primary canopy latch but will save that for a future post if anyone is interested.

Cheers,

db
 
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Neat

db1yg said:
...I witnessed an RV6a owner struggle to get his tip up canopy open...
I've had nightmares about this same exact thing! Did you happen to see how they got it unlatched?

I could get a coat hangar underneath my side skirts but it would but it would be worth knowing what he did (or anyone else).

db1yg said:
...I also modified the primary canopy latch but will save that for a future post if anyone is interested...
I'm interested, post away!
 
Last edited:
I simply added and squished a small silicone o-ring between the handle and delrin block to keep it from freely rotating.

-Jeff
 
Rescue from Outside?

Has anyone modified their tip up latch to have an outside latch such as on the slider? If a person inside were incapacitated it would take canopy destruction to get him/her out with the safety latch engaged.
 
Steve,

The 6a driver got his unlatched by having someone on each side of the plane at the canopy lift point push and pull alternately while placing upward pressure on the canopy---it was not pretty and I expected his "targa strip" to be destroyed but he got away with it. I don't want to see it again.

Cheers,

db
 
Canopy Latch

Thats funney, I was just working today on my handel mechanisim and as I was looking at it, I thought, this should have a spring on it to prevent a lock out. I really looked close at the plans but couldn't find any. :(

Thaks for the post. It was timley for me.

Carl Nank
RV7A canopy is cut.
 
Tip Up Latch Mod PII

Although the external blade style main latch for Vans tip up canopy is functional, simple, and reliable I was never really happy with the way it looked. I think it was the two blades sticking out of the side of the plane that concerned me and therefore more deviant builder behavior was coming to the surface. I found an aftermarket latch that mounted flush on the outside at Attaway Air:

http://www.attawayair.com/rv6_products.htm

It was very close to what I wanted but it did have a couple of features that I wanted to change. If you go to Robbie's site, a very nice/helpful guy by the way, you can see the stock latch and how it operates. He even has a video showing the latch action. The features I wanted to change were the use of a large external spring that mounted on the bottom of the inside portion of the latch and the attach point for the actuator arm which was on top of the latch mechanism. The instructions have you mount the large spring on the bottom of the mechanism spanning from the back portion of the latch to the front portion. This keeps locking pressure on the engaging teeth.

Deviant behavior: I took the back portion of the latch just aft of the teeth and drilled a horizontal hole into the vertical flat face, tapped it with a course tap, and threaded a small diameter compression spring into this point. If you do this be sure to make the hole slightly larger for the first 1/8th inch to allow the spring to compress into the face of the latch. When the latch is closed this spring applies inboard force on the locking teeth by pushing against inside surface of the side skin. This keeps the latch from disengaging, eliminates the need for the external spring, and allowed me to mount the actuating arm to the bottom of the latch for a clean look that pleased me.

You will also notice that I used an3 domed/slotted hardware/castle nuts for the pivot bolts as opposed to Vans an3 hex bolts/castle nuts---again to provide what I thought was a cleaner look. Yea, I know, I am a little "fussy" about this sort of thing.

The following are a couple of pics of the inside and outside of the latch. Click on the pic for a larger view.

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Sorry I don't have a pic of the hidden spring install but I bet you get the idea.

Cheers,

db
 
Frank,

Neat!!! Is the key the only thing showing on the outside??

Just takes a little imagination!!!!

Cheers,

db
 
Canopy latch

07-31-2007, 01:14 PM
db1yg Join Date: Mar 2006
Posts: 164

Tip: Tip Up Safety and Main Latch Mods

--------------------------------------------------------------------------------

Shortly after ordering my RV9a tail kit back in 2003 I witnessed an RV6a owner struggle to get his tip up canopy open. It seems the canopy slipped out of his hand on closure and the safety latch had pivoted and partially engaged under the roll bar when the canopy slammed shut. After about an hour of working accompanied by much colorful language he was able to get it unlocked without damage.

Hmmmm--how to avoid this as well as keep the latch from continuously scratching the high dollar jet flex paint I intended to use on the interior??

After much head scratching I tossed the stock mounting block and replaced it with some white UHMW plastic. The new block is the same thickness as the old but it is about 1" shorter and 1" wider. I drilled this block for the safety latch shaft handle, purchased a SS compression spring (aviation section of my local Lowes), and mounted the stock stop washer and cotter pin. The block was mounted whereby the safety latch is high of the roll bar when not in use therefore it can not pivot and lock with me on the outside of the plane. When you need to latch simply pull down on the handle (compress the spring), pivot, and release. It also will not rattle as it wears as the spring will remove any slack. You will note from the pic that I also mounted a thin strip (1/8th thick) of the UHMW plastic under the canopy bow--the latch rides on this when engaged. The angled white metal above the latch shaft is simply there to contain the spring in the event the cotter pin gave up--it is probably overkill but I did not want the spring releasing into my plexi.




Where did you purchase the white plastic & what size is the UMHW block.

Thanks,

Carl Nank
RV-7A - Canopy
 
Carl,

The UHMW plastic can be purchased from Aircraft Spruce or from McMaster Carr (great internet supply house). I actually bought mine as surplus from a local plastics supply in San Antonio. BTW, the initials stand for Ultra High Molecular Weight.

I am going to the hangar today and will get you the actual dimension of the block--pretty sure it is 3/4" in thickness.

Cheers,

db
 
Carl,

The dimensions of the UHMW block are:

3/4" thick
1 1/2" high
2" wide

Cheers,

db
 
Thanks Dave. I could only find round or flat stock in Aircraft Spruce & Wicks in their catalogues. I will try the other place you mentioned.

I also appreciate the dimensions. Your setup looks very clean & nice. I am going to install it.

Thanks again & happy flying. :)

Carl Nank
RV7A, Canopy fiberglassing
 
A variation on the original idea

I worked out a way to spring load my handle and not have to crush the spring down to solid height when the handle is locked. The two small coil springs are pocketed into the UHMW and the aluminum spring pressure plate. This allows the pressure plate to close completely against the UHMW and it also keeps the plate from rotating (no scratching the canopy bow).

3281787184c1ecf569d19d.jpg


The assembly will be mounted with the UHMW approximately 1/8" above the bottom of the canopy bow. Travel is 3/16".

Some may notice the buggered lower left mounting hole. I had this block fully clamped in a vice and the drill bit yanked it right out of the vice jaws.
It was my own fault. I did not use proper "pecking" technique on that hole. I plunged the bit too fast.
Fortunately, they are undersize so that hole will clean up a little when sized.
 
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