Cowl Hood Assembly Situation

How to keep the Cessna 170 flying and airworthy.

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davidgrah
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Joined: Thu Oct 05, 2017 2:11 am

Cowl Hood Assembly Situation

Post by davidgrah »

Since I bought my 1950 Cessna 170A, serial 19821, in 1997, the rear latches on the cowl have been secured with lock pins over the rear latch lever and through a U bracket added under the lever in place of the clip that originally held the latch closed. The front latches haven't had pins, only the original clips.

My last flight, during decent, I noticed the front latch on the left side of the cowl had opened and soon after the left cowl hood assembly opened. Luckily its shape and hinging keeps it clear of the propellor. Even though I entered and tried to stay in a right slip to keep the cowl closed, it opened and flapped around a couple of times which was enough to bend the hood assembly and break some of its stiffeners.

I think I need a new hood assembly and need to improve how I secure the cowl latches and hoped this form could help me determine the best way to do these things. I'm not the best searcher and, although I thought I had seen more when I had searched related things in the past, haven't come up with much so far.

First, although I've not talked to my mechanic, I assume I am going to need or want a new hood assembly (I assume used would be fine too and maybe the only option), part 0552001-4. It looks like the hood assembly changed a serial 19200, before my serial. Some questions about this I'd appreciate any help answering:
1. Would a new hood assembly be available anywhere? If so, where could I check?
2. I contacted the only salvage yard I am aware of, Faeth, in Sacramento, but they didn't have the part. Any other salvage yards I should try or other methods to track the used part down?

Second, I need a better way to latch the cowl or at least add lock pins to the front latches. I think in the past I have seen a method of putting some quarter-turn fasteners through the latch levers to secure them in the latched position and I like this approach. I also see the Cessna 120/140/170 Replacement Cowl Latches sold by Taildragger Aviation, which look okay but I don't love them based just on the photos and the description.
1. Any opinions about which is the best approach. more lock pins, quarter-turn fasteners through the existing levers, Taildragger latches, or some other approach?
2. Any information on the best way to implement these approaches?

Although I have been an association member on and off during the time I've owned the plane, I have been sort of a deadbeat member and don't remember ever contributing to the forum before. I know I have very much appreciated the information I have received through the association in various channels in the past. Thanks in advance for any help with this.


David Grah
Bishop California
N5592C
Jr.CubBuilder
Posts: 517
Joined: Thu Aug 12, 2004 10:33 pm

Re: Cowl Hood Assembly Situation

Post by Jr.CubBuilder »

Hi David

I had a similar experience with my plane (a 52B with the early cowl style) my experience unfortunately happened in fast cruise and the resultant flapping quickly broke the other side loose. The whole upper cowl was a write off.

I made my own top cowl doors and the center piece, my IA approved them as an owner produced part and I believe he did a 337 on the repair. It took a lot of work and a few tries. I used the Dip Davis latch STC which basically replaces the stock spring latches with DZUS fasteners. That arrangement has been working for about 900hrs of flying.

I've never been completely happy with it because my cowl doors become a pressure cowl due to the engine conversion, but it works. Recently I've been mulling over the possibility of making a carbon fibre cowl to replace it, but I like flying more than building so I'll probably never get around to it.
Chris
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ghostflyer
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Re: Cowl Hood Assembly Situation

Post by ghostflyer »

Very earlier on when I had the continental fitted ,I had the R/H rear latch come undone in flight . While I was flying a 170a ,the cowl wasn’t pressurised ,it’s movement scared the hell out of me . Landing at the next available landing strip ,I resecured the latch. It appeared to be tight but on takeoff it came undone again. On returning to the strip This time it was secured and lock wired in the closed position. It was a band aid solution. Then reading a forum on Cessna 170s a photo was shown of a 170 with the cowl that come adrift in flight with damage showing. This aircraft had a shark teeth and mouth painted on the cowl. Maybe people will recall the forum blog.
The cowls of my aircraft were modified under a EO using 3 DZUS on the leading edge of the cowl and 3 DZUS on the horzontal edge of the cowl and 1 DZUS on the trailing edge of the cowl. It’s similar to the latest Cessna cowl attachments . It works well especially since it’s now a pressure cowl with a different engine . It’s now done 2200hrs since the mod
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