The International Cessna^® 170 Association

I am trying to satisfy my curiosity more than anything else.

My 170B is a 54 model. Behind the baggage compartment, in the belly of the fuselage, there is a plate (aluminum skin) approximately 18” long and 12” wide in the shape of a tear drop. This plate is held in place with screws put in from the under side of the belly. Inside the fuselage I can see the plate, outside and under the belly I can only see the screws that hold it in place and outline the shape of this piece of aluminum. Within this piece is an inspection port where I can access and inspect the rigging. The piece is not shown in my parts book.



Is this put here for additional strength?

Why is it held with screws and not rivets? If it is to double the skin for strength, why didn’t Cessna rivet it in place?

The screws suggest that it can be removed, but why? There is nothing attached to it and it does not make the inspection hole any larger.

Bill

Check your logs and see if it had an old ADF installation sometime in the distant past. Mine has the same thing (except riveted in place). The old ADF antennas were housed in a fiberglass teardrop shaped housing - sometime on the belly, somtimes on the top of the fuse.

Here are a couple shots of an old Lear ADF unit:

It looks like some sort of pith/battle helmet worn by Spanish conquistadors. If many of our aircraft had these in the early days, we should have the hole patterns left behind, right? I have several mystery holes in the belly, all I assume were antennae of some sort, but nothing pokes out of them nowdays, they're just inlets for dirt to get sucked in.

tripslip38 wrote:It looks like some sort of pith/battle helmet worn by Spanish conquistadors.

I think the conquistadors used a different grade of phenolic.

Seriously though, my hypothesis as to the reason not many of us see the remnants of intallations such as this is that because of performance issues, 170's have never been a very popular IFR platform, and as such, not many would have been equipped with the heavy and draggy IFR gear of the day.

Miles