The International Cessna^® 170 Association

Just out of curiosity, I'm also interested in what the "hatch latch" looks like!

M

I don't have a pic of the hatch-latch, and even if I did, I don't know how to post it. I'll try to describe it:
The "skewer" is mounted on the wing on A & B models, and on the strut on ragwings. It looks like a white nylon penis (sorry, but it does!).
The reciever of the Hatchlatch mounts on the inboard side of the door,it looks like a rectangular piece of nylon with a hole in it, cut in half, wrapped with a spring. When the door is pushed all the way open, the head of the skewer is trapped by the reciever. The spring around the receiver lets the skewer snap in and/or out of the reciever as required. Works slick.
Williams Aircraft's ad in the Q3/05 170 News mentions the Hatchlatch, he might have some in stock. I believe they're out of production. There is a product called a Skycatch that I've seen used on 170's. It works similarly to the Hatchlatch but is not as elegant a solution IMHO. But it is servicable, more so than the tinnerman-looking stock Cessna item. I think Spruce and some other outfits sell that one, check TAP.

Eric

The gas/spring opener is an interesting addition to Cessna doors. Seems like a neat thing to hold that door open, especially on our conventional geared planes. Sure would ruin an "original" C-170 as being original if anyone had concerns. Some of the photos made it look like a bracket at the lower, forward door opening would/could impede one's feet getting in or out. Don't know if that was just my thoughts or if it indeed would/could.

I once observed a C-180 with what was probably an "owner produced part", which would work on any 120-180/185 series doors. It attached to the bottom of the wing where most of ours do. It had a simple hinged piece of metal that was longer on the aft side of the hinge point with a tapered end. When the door was opened to the fully open position the metal "bar" ( for lack of a better description) hinged up to allow the bar end to slide up over the top of the door top. It then dropped about 1/4 inch so that it held the door in the open position. To close the door all that was necessary was to flip the bar up. It was a positive holder that, if made correctly, would hold that door open in a strong wind. I realize this is a poor description of the device. I could draw a faxsimilie better than I could verbally describe it--although I am not able to draw engineering drawings either. I have the SkyCatch units on my plane. The ones that have two ball bearings, one on either side of the opening for the catch on the underside of the wing. The tension on the springs can be adjusted somewhat, but they will not withstand much of a wind and stay open. Someone with some "home building" expertise could design a set to these fairly easily. They are simple and work well. Unfortunately I didn't get a photo of the "device". If anyone comes up with a design, I sure would like a set as it is really aggravating to have a door suddenly slap you in the back or mash a finger when the wind slams a door on you.

The Steward actuator snugs up nicely to the door in the open position. I've never snagged my foot on it. They certainly help save the door hinges from getting bent when the wind catches the door and slams it into the skewer (or the hatch latch). They also keep the wing skin from getting oil canned and the door frame from getting marred up into a ragged hole above the window. All these items required repair before we painted our bird. Maybe next time we paint it (in 30 years ) we won't have to do those things!

Two cheap, quick, and easy solutions to holding the door open.
1) Have a small bungee handy to secure the open door to the strut. A friend of mine does this with his 180.
2) tie a string to the strut, when you want to hold the door open just open then close the window on the string. A charter operator on my airport did this with all their 172's, worked great.
Both methods are pretty much foolproof (depending on how big a fool is involved) and don't involve any shocks,skewers,bars,hinges, etc to mount to the airplane and/or be in the way. String method costs about one cent,bungee about two bucks a side. Spend the savings on gas.

Eric

OLE POKEY,

I'd sure be curious what that setup you described looked like. A photo would be best but maybe you could make a sketch?

I'm not a fan of the stock setup, nor of the SkyCatch or HatchLatch, which really aren't much different. I described the best setup I've seen when we discussed this about a year ago:

http://cessna170.org/phpBB2/viewtopic.php?t=2160

spiro wrote:
I saw a great setup on a 180 once: it replaced the whole shebang with a single rod of (1/8"-) stainless attached at each end to the bottom of the wing. This heavy wire was bent such that it provided a spring dedent for the top of the door frame when it was open. There was probably a SS rub strip on the door.

- paul

Paul I am sending you a PM. Let me know if you receive it. If not let me know if you have a fax number. If not I will resend the scanned item.

I can't find specific information on original latch spring replacement, but thought this would be a good place to start. The cam in my door rotates but no longer has spring pressure...so the door will not latch. Any hints from the "been there done that" crowd before I start to figure out how the interior panel is held on and start pulling on things

wa4jr wrote:I can't find specific information on original latch spring replacement, but thought this would be a good place to start. The cam in my door rotates but no longer has spring pressure...so the door will not latch. Any hints from the "been there done that" crowd before I start to figure out how the interior panel is held on and start pulling on things

It's fixable. Do you have the Service Related Articles Manual (SRAM)? If so, pages 3-14 and 3-17 have write ups on one fix for it. I believe Cessna had a repair kit for these springs back in the 60s or 70s. Anyway, you can take it apart and replace the spring (which will break again down the road) or you can perform the fix in the SRAM (my '52 had this as well) which involves getting a coil spring (sorry, don't know the exact length) and thread one end in through the gap between the cam and the plate that surrounds the cam. Attach one end to the plate and attach the other end to the portion of the door handle inside the door that actually moves the latch mechanism. This provides the same spring force as the original.

Sorry if I'm not describing this very well.

If I can figure out how to post a picture here, I can send one that I took when I had mine out and repaired it with coil springs. It's a lot better than the origial set-up.

Joe

Joe Moilanen wrote:If I can figure out how to post a picture here, I can send one that I took when I had mine out and repaired it with coil springs. It's a lot better than the origial set-up.

Joe

Joe,
you need to put the picture on a web-accessible server and then post a link to it here. If you don't have that capability, email it to me or Bruce and we can post it for you.

when my door handle didn't work,
this was the part that broke!!
i had it bronzed
iowa

That happened to me as well. I should have mentioned that - thanks Dave for posting the pic.

The problem I had was the Pull Bar (p/n 0411555) broke. There's a illustration in the 170B manual pg. 60, but if you happen to have a C140 manual the illustration is MUCH better. Anyway, the pull bar is a flat piece that connects the Catch (p/n 0411552) to the exterior door handle via Pin - Latch Pivot (p/n AN392-53). When you operate the door handle the Pull Bar pulls the catch, With the Pull Bar broken there is nothing to prevent the catch from flopping around. The Pull Bar can still be had from your typical Cessna parts sources for not "too" bad a price. The only way to replace it is to remove the door latch assembly. Of course, once you do that you quickly realize how badly worn the rest of the assembly is after 50+ years of use and start thinking "maybe I should rebuild this while it's out..."...

Well I have my crusty latching critter out of my left door Sure is dirty and really gummed up with whatever remains of the lube that someone put on it many years ago. Since Cessna decided not to put a window on the inside surface offering some access to this mechanism, it never got lubed. Someone also decided some years ago to fabricate another end plate, but made it a much larger piece that also turns 90 degrees and catches eight rivets from the outside door flange under the seal. So all these rivets had to be drilled out as well and now I'm going to have to learn to squeeze rivets. Any suggestions on a good rivet squeezer and the proper rivets to use The only other problem is that every spring in my latch is broken. I see remnants hanging everywhere. Does anyone have a good source for all the springs? Not only the ones that drive the quarter lobe latch, but also keep the outside handle faired in the recess? The SRAM mentions a special kit available from Cessna...then I read the date of the article...1964...good info but REALLY dated

I believe that service kit form Cessna ceased being available a long time ago. The original door springs are still available from most Cessna parts dealers (Yingling, Hill Aircraft, etc.). Ok, they'll break, but they DID last a few decades before doing so. Also, keep in mind that they break largely due to rust, so if your aircraft is in a hangar or you have a decent cockpit cover that covers the door latches and keeps the water from entering then you'll probably get a lot more life out of the new springs.