170A Cowl Latch

indymoor · Post by **indymoor** » Sun Nov 28, 2004 10:56 pm

I had a problem with the right front cowl latch popping open on me. We put 2 new cowl latches on the right side and still have a problem with the right front popping open. Any ideas? Is there some kind of safety that can be field installed to keep the latches from moving?

Thanks in Advance,
Rick

3958v · Post by **3958v** » Mon Nov 29, 2004 1:25 am

Mine are secured with a camloc fastener thru the latch handle. I have seen others secured with a hairpin clip. The camlock has worked well for me in 1000 hours of flying and is less obvious then the hairpin clip but probably is a little more dificult to engineer. Bill

Post by **Bruce Fenstermacher** » Mon Nov 29, 2004 1:37 am

Do a search for "'51 C170 Cowl Latch Backup". In the thread besides other examples posted I described the types of safetys I've seen. There is other good info also.

The one I described that my airplane has which uses Fillister styel screws in one of the easiest I've seen. I you need I could send you a picture at the end of this week.

The following will take you directly to the thread I just told you about.

http://www.cessna170.org/phpBB2/viewtopic.php?t=1411

doug8082a · Post by **doug8082a** » Mon Nov 29, 2004 2:28 am

When you say you replaced two cowl latches, what EXACTLY did you replace? The entire cowl latch assembly? The little latch lever clips that hold the latch closed? other?

The reason I ask is that the problem on mine turned out to be the cowl latch levers. The back side of these actually have a turned edge that creates a lip that catches the cowl latch clip and holds the latch closed. After 50 years of riding back and forth over the latch clip, a groove is worn on the aforementioned lips and they no longer engage properly.

Next time you are at the plane take a look at the cowl latch levers from underneath. You'll likely see where is't been worn away from years of use. New levers can be had from A/C Spruce for a LOT less than the entire latch assembly.

N73087 · Post by **N73087** » Mon Nov 29, 2004 9:42 am

I installed an STC'd latch. Dip Davis of the C-140 association holds it. All 4 of his latches cost less than one original replacement. $189 per set, shipping included. They go on with a few rivets, and look nice, and best of all, they work well.
STC # SA01139CH
W.D. "Dip" Davis
411 Pawnee Trail
Marengo, IS 60152
815-568-6811

indymoor · Post by **indymoor** » Mon Nov 29, 2004 6:42 pm

Thanks for all the input. I think we found what the problem was. One arm of the little clip was bent out of alingment and was riding on the outside of the lower latch. We got it stright and now the clips are on the inside of the lower latch were they belong, nice and snug now!!

Thanks

doug8082a · Post by **doug8082a** » Mon Nov 29, 2004 7:04 pm

Yup, that'll do it. But I'd still look at the underside of your latch levers and check for wear. Mine need replacing for that very reason and I would imagine that any latch of this type that has seen 50+ years of use would likely need attention as well.

zero.one.victor · Post by **zero.one.victor** » Mon Nov 29, 2004 7:37 pm

Even if my cowl latches were in perfect condition (which they are not), I'd feel better f they were safetied--either with a screw, a camloc, or a hitchpin- or hairpin-clip. FWIW

Eric

doug8082a · Post by **doug8082a** » Mon Nov 29, 2004 7:48 pm

True, Eric. But to rely on a latch that is NOT secured and has NOT been serviced in any way in it's 50+ years of service is surely asking for trouble. If at least the latches are in good condition, then the likelihood of an in-flight failure of the latch is reduced - but admittedly, not entirely removed.

Jeff Matthews · Post by **Jeff Matthews** » Mon Dec 06, 2004 11:14 pm

So how does one go about peening over the long rivet that hinges the lever and latch together? I've attempted the job with a set of progressively blunter center punches, and it ain't gonna come apart, but it doesn't look as good as the other three. I suppose I could duplicate a brake rivet tool in miniature, but if there's a quicker way I'm interested.

JM

blueldr · Post by **blueldr** » Tue Dec 07, 2004 4:37 am

I believe those long drilled tip rivits are set with a tool similar to your brake rivit set and it is used in a drill press while rotating.

russfarris · Post by **russfarris** » Tue Dec 07, 2004 5:06 am

Since the subject is cowl latches, I thought you guys might like to know what happens if the side cowl (1948 to 1952) is unlatched in flight.

I was pre-flighting my airplane when I first got it, about five years ago. I had opened up the right cowl when a friend of mine drove up and wanted me to look at something on his airplane. You guessed it - the distraction
made me forget to latch the cowl. 30 years of flying and 15,000 hours doesn't rule out doing something dumb!

Take-off, climb and cruise were absolutely normal. But when I slowed to about 70 mph in the pattern, that thing start flapping at about a two second cycle! I was startled, to say the least. I shoved the nose down, and
it closed, at about 85. Well, I had to land the airplane, so I slowed down again to 70, it lifted up to about vertical and back down again. It didn't stop flapping until just before touchdown.

The only damage (except to my seat cushion) was a small wrinkle at the front of the cowl door. Apparently, the strong slope of the 170s nose allowed the relative wind to keep it closed. When I slowed down, the angle of attack was high enough to fly the cowl open.

I didn't intend to become a test pilot, but at least my experience showed that it didn't rip off the airplane. BTW, a 1949 170A based here at my field has exactly the same wrinkle on the front of the left cowl door that I now have in my airplane

Russ Farris

roger · Post by **roger** » Thu May 26, 2005 4:17 am

I have the hair pin clips on my latches and the only other aircraft that I ve seen with them is the bird dog.They appear to be the same ,at least ,they look the same. and they also have the hair pin clips. I'm glad some of you all have the hair pin locks too Thanks roger

doug8082a · Post by **doug8082a** » Thu May 26, 2005 1:29 pm

I've had a recent development I'd like to add here. My cowl latches have screws holding them closed and I STILL have one latch that comes undone. Since it is the front-copilot side latch, I can't see it from inside to determine when/how it comes loose, but my theory is that there is not enough tension on the cowl door to allow the latch to stay latched. If I put my hand on top of the cowl right above the latch and pull down on the cowling, the latch will simply fall open. I'm going to add a layer of chafe strip to the inside of the cowl around where it seals to the nose bowl to see if that will provide enough tension to keep the latch engaged.

Anyway, just because you have a positive means of securing the bottom of the latch, it doesn't mean that the top half still can't come open (although it may be a lot less likely).

Post by **GAHorn** » Fri May 27, 2005 9:39 pm

The nicest, cleanest, slickest modification to the original cowl latch system is covered by STC #SA01139CH, by W. D. Davis, 411 Pawnee Tr. Marengo IL 60152 (edit: PH (815) 568-6811)

It installs type "V.I.C.C.L." type cowl latches. (This completely removes the existing latches, and in their place, installs a solidly, smooth plate containing the female socket to a "Camloc" and an upper strap with the male, phillips-head Camloc. If the instructions are followed, (detailed drawing accompany the STC, as well as instructions, etc.) this will end up looking like Cessna should have made it to begin with. It does not preclude the airplane from being returned to the original configuration should it be desired in the future, with very little effort. (Merely drill out a few rivets and replace them. Last I checked, the entire STC costs about the same as ONE replacement latch from Univair. (About $225.) Contact W.D. Davis for latest prices and availability.