The International Cessna^® 170 Association

There are some existing inserts in the floor of my '56 170-B that appear to be for cargo net tiedown rings that use a 10/32 thread. Does this type of tiedown ring actually exist, and if so, where can they be procured?

Thanks

MontanaBird

Does it look anything like whats on page 162, Fig. 103, Item 2, of the Illustrated Parts Catalog, PN 0511165, which can be purchased from Cessna?

Item 3 in that illustration is a An366F-428 nutplate. It's 1/4-28 rather than 10-32 threads.

One could buy a couple of these and attach them with adel clamp shaped stainless sheet metal.
http://www.uscargocontrol.com/1wiredring-p-78.html Check out this thread for other ideas: http://www.cessna170.org/forums/viewtop ... ngs#p54941

You could use an AN42BA Eye bolt. This has 10/32 threads. A -4 is about 1/2 long a -6 is 3/4 long which includes the grip and thread length. Then get some 3/16 steel rod and cut and bend your own rings and insert them into the eye bolts and weld the ends closed.

Here is a sample of what I'm talking about. This one is probably 1/4-28 or maybe a bit bigger and came from the cargo area of a UH-1H. What you would make would be a little smaller but I think usable. Your limit is the 10/32 threads or you could get a bigger eye bolt and thick ring.

So, if one wanted to install tie-down rings, wouldn't they have to be at least as big (1/4-28) as the hardware shown in the IPB, and be of similar design?

gahorn wrote:Does it look anything like whats on page 162, Fig. 103, Item 2, of the Illustrated Parts Catalog, PN 0511165, which can be purchased from Cessna?

Cargo Tie down PN 0511165.JPG

You can and they are about $100 each.

lowNslow wrote:

gahorn wrote:Does it look anything like whats on page 162, Fig. 103, Item 2, of the Illustrated Parts Catalog, PN 0511165, which can be purchased from Cessna?

Cargo Tie down PN 0511165.JPG

You can and they are about $100 each.

Yep. (I didn't want to go on-record as recommending a simple shopping-trip to a hardware store.)

ronjenx wrote:So, if one wanted to install tie-down rings, wouldn't they have to be at least as big (1/4-28) as the hardware shown in the IPB, and be of similar design?

Ron I think that would depend on how and what you were doing with your plane. Using the aircraft for pleasure and not for hire and as long as you didn't create a major alteration installing the sockets or rings, you are OK.

After all, for pleasure you can fill your airplane with all the unrestrained stuff you can fit. What difference does it make if you restrained it but restraint was inadequate. Anything would be better than nothing and no restraint is OK

Kind of similar to the FAA's position on shoulder harnesses in aircraft like our 170s. Their basic logic is the aircraft are safe as they were certified without shoulder harnesses. So the addition of all most any shoulder restraint system using practically any material can only make it safer so long as one doesn't create a major alteration will doing it. Installing the shoulder harness in itself is not a major alteration as long as you don't change the airframe to do so.

I think the same logic could be used with tie down rings.

I would agree with Bruce in that installing cargo rings, even if not FAA-approved, would be better than nothing.

Here's another alternative from your local Pick-N-Pull. There are four in the back of a Prius. One would have to grind off the little tab before installing them. I verified that the four nutplates in the baggage compartment floor of my '52 are 1/4X28 threads. The mounting holes in the Prius tiedown rings fit a 1/4" bolt (AN4) perfectly. It would be easy enough to do a static load test before installing them to verify their strength. The baggage compartment has a 120 lb. load limit. If the entire load was constrained by only one tiedown ring, that ring would only have to hold 1080 lbs. at 9 G's.

Aftermarket cargo rings can be found from various sources for Piper and Cessna seat tracks too. Most manufacturers are extremely proud of them, even the non-PMA ones.