Vent window lock broken

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TwinStarScott
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Re: Vent window lock broken

Post by TwinStarScott »

The plastic ones I ordered were just installed and they worked perfectly right out of the box - huge improvement!
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Rich
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Re: Vent window lock broken

Post by Rich »

I have the bronze ones. Herewith some details:

Bore through the new part is 5.77 mm dia.
Original bushing is ~6 mm. It won't fit in that bore.
The screw on which it pivots is 4 mm, so there is 1.77 mm of slop if one does not use some kind of bushing. That is a lot.

It's conceivable there has been some variation in manufacture of the latch over the years. But my additional problems have to do with inconsistency in the location of that block above each vent window. In my case each of the two presents a different problem.
2002 DA40: MT, PF, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210.
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Boatguy
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Re: Vent window lock broken

Post by Boatguy »

Rich wrote:
Tue May 05, 2020 11:33 pm
I have the bronze ones. Herewith some details:

Bore through the new part is 5.77 mm dia.
Original bushing is ~6 mm. It won't fit in that bore.
The screw on which it pivots is 4 mm, so there is 1.77 mm of slop if one does not use some kind of bushing. That is a lot.
Assuming the bushing is 6mm OD, I guess we could take a 6mm drill and open up some room for the sleeve. But does it affect a performance difference?

I can see the need for a metal sleeve to contain a metal screw in a plastic part. But this is a metal screw through a metal part. 1.77mm is .07" of slop on the shaft on which the latch rotates. If the latch shifts side to side by .035", it really doesn't make much difference as it's held in place by the friction between the latch tongue and the block into which it rotates. The tongue is probably .5" and .07" of lateral movement doesn't have any material effect. Maybe the SS screw will eventually wear on the softer bronze latch, but probably not in the next 5-10yrs.

I appreciate the measurements you've taken and that we'd never want that sort of play in a lot of other places in our airplanes. But this is a window latch. The bottom line is whether or not it reliably holds the window closed and is less likely to snap off than the original plastic.

I installed the bronze in my plane and they work fine. I'm ok with the .07" of slop and would like to thank Kai for posting the part.
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Rich
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Re: Vent window lock broken

Post by Rich »

Ah, but you don't have a block that's excessively far from the vent window. That additional play means the latch won't stay in place. In any case, the nylon bushings I got takes it all out for the low, low price of $.25 each. And solves the base-washer thickness problem at the same time.
2002 DA40: MT, PF, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210.
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Rich
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Re: Vent window lock broken

Post by Rich »

After tedious Dremeling of the latches I got the bronze latches installed. This is not a criticism of the design of the new latches. It is something that has been required of all the Diamond-supplied latches on my plane. I've confirmed a subsequent design change of the canopy-bonded blocks would make this Dremel work unnecessary, but my old bird requires it.

Here's the Diamond part on the left window, before replacement. Note the tenuous hold of this latch (it was #3 mounted there), that somehow has held up for over 15 years:
N40XE Original Left Vent Window Latch.jpg
Here's the Bronze one in place on the same window.:
N40XE Bronze Left Vent Window Latch.jpg
2002 DA40: MT, PF, 530W/430W, KAP140, ext. baggage, 1090 ES out, 2646 MTOW, 40gal., Surefly, Flightstream 210.
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