Door latch design factors.
 

With the current interest in the RV 10 door safety latch, I wanted to start a separate thread to get a group consensus of the design elements that we, the users, find desirable.

There are at least 3 threads going right now with latch designs, and all have good and not so good features (IMHO).

http://www.vansairforce.com/communit...ad.php?t=53564

http://www.vansairforce.com/communit...ad.php?t=53151

http://www.vansairforce.com/communit...ad.php?t=53090

Here is what I have come up with so far.

I would like a latch that is totally automatic, and is tied into the existing door handle for operation. One point of operation, not two like the existing factory design.

I would like to see the safety latch located at the middle to rear of the door, this is where the problem is. The latch in Verns thread is simple and elegant, but I am concerned as to the fact it is at the front portion of the door. I do like that it resists upward movement of the door, not just outward. But, as far as I know, all door losses have come from a lack of rear pin engagement.

I would like a latch that can be retrofitted to an finished door, and not look like it is an afterthought/band aid fix.
And that it can be utilized in a door that is upholstered.

And I want to see factory support/approval for the design, so that there wont be any loophole for an insurance co to claim that the "mandatory factory approved" safety was not installed, therefore your claim is rejected.

Please jump in here, and add any design points I have missed.

I really like Vern's solution to this issue. im not really sure how the inside of the panel looks ( i havent even ordered a kit yet) but if there is enough room, im sure it could be setup with a push rod to the rear and have a secondary latch back there.

one size fits all latch system?
 

Mike,
The criteria listed seems to eliminate the ones listed except for Greg Hale's.
This solution can be retofitted into Hendricks, Coss or stock door latch designs. Impact to the builder is nominal since it's installed on the inside of the door making it easier to cover the modification up with a door panel or material.Gregg has provided a blueprint detailing the design including the geometry needed to make it work. He has a working unit so it's not just smoke here. Finally, after seeing the rest of his site concerning his RV-10 (his plane is off the hook!) I feel he has developed the simplest yet most universal solution. Just my opinion.

Don Orrick
N410JA
40010

I've been giving this quite a bit of thought recently, as well as others. While a solution that was internal to the door would be most aesthetically pleasing, I do have concerns.

The latch would require a hole in the cabin cover and/or middle cabin deck that is outside the door seal. My concern is that water would run down the door gutter into the opening. Just like the factory solution, water doesn't really have a place to go.

With all the brainstorming going on, I'm sure there will be a more elogant solution soon.

bob

That is EXACTLY why I started this thread.

The collective VAF mind can be pretty amazing when it comes to problem solving.

The criteria is strictly my opinion so far, I am asking for input and constructive criticism from the VAF group mind, so as to develop a true criteria for all, or at least most of us.

Is this the one from Greg Hale??

http://www.nwacaptain.com/door_center_latch.html

I agree that it fits my idea/criteria, but then so does this one.

http://www.vansairforce.com/communit...5&postcount=69.

Thanks for the input, keep it up.

Mike, Since we seem to both agree on what we would want in a redesign
I offer my first post as my "input and constructive criticism from the VAF group mind". Unfortunately, the fourth item on your criteria list is not obtainable since this issue is resolved as far as the factory is concerned.
But you need to add to the criteria that it can be retro fit to any style latching system.


Bob,
After reviewing the pictures of Greg's latch system it appears the center door pin is actually inside of the door seal, in fact it's inside of the canopy, basically inside the airplane.

Don

Don, you know the factory obviously used the latch developed by a builder shown in this thread.

They can and do respond to builder input, but as can be seen the response time may be a bit long----

I am hoping that the group can come up with a design that the factory will acknowledge as satisfactory at a minimum, and preferable substitute for the current "mandatory" unit.

Of the four factors I mentioned at the start, I suspect the buy-in from the factory may end up being the most critical in the long run.

Unfortunately, it will probably take a crash or two, and the almost inevitable lawsuit to prove if that is a correct assumption.

What about using Vern's system with two attach points per door???

We could use his standard position for the forward point...

For the rear point, we can mount another factory door handle mechanism (minus the door handle) near the aft edge of the door. Like I said, there won't be a handle.

It's primary purpose would be to convert the horizontal movement of the rear pin into an arc for the aft striker.

My airplane will only fly as far as I can throw it, so I don't know. But I think it's possible to do if we would use a toothed push rod to run through both the forward and aft mechanisms. It would operate both mechanisms in unison.

I probably did a lousy job describing that. (Well all except for the part about having an airplane that will only fly as far as I can throw it. That part was pretty clear.)

Phil