The International Cessna 170 Association

Not sure what to call this piece, but it looks like a top windshield mount bracket?

1. Is it necessary to replace it? Structural to holding the glass on?

2. Anyone know what it's called or where to find it?

I couldn't locate it in the 170 illustrated parts catalog.

There's also a piece of wood in it, not sure what the deal is with that or what the metal protrusion up actually does.

Thanks

We are looking at two parts. That base at the very top of the aluminum strip is a base for a antenna mast. Your are missing the mast. The mast is made from the same material as pulleys but who's name escapes me at the moment. The antenna was a long wire that probably exited your boot cowl in front of the windshield and went up of the this mast and then back to the tail. The mast has nothing to do with the window strap other than the same mounting holes. This could be removed or left but since you will be doing some work here, why not remove it.

The strap, who's top section is riveted on, has cracked. This is not all that uncommon. The windshield floats in that top channel and puts a working side load on the strap. Yes you want to repair this part because it is all that holds the top part of the windshield into the fuselage securely. You do not want that windshield coming out though to be honest my 170A probably flew for 20 years with a broken strap and mast base just like yours and the windshield never attempted to come out.

Still your IA shouldn't overlook this and should require its repair for annual.

Mine got repaired when we removed the center strap all together under an STC for a new strapless windshield.

Bruce Fenstermacher wrote:We are looking at two parts. That base at the very top of the aluminum strip is a base for a antenna mast. Your are missing the mast. The mast is made from the same material as pulleys but who's name escapes me at the moment. The antenna was a long wire that probably exited your boot cowl in front of the windshield and went up of the this mast and then back to the tail. The mast has nothing to do with the window strap other than the same mounting holes. This could be removed or left but since you will be doing some work here, why not remove it.

The strap, who's top section is riveted on, has cracked. This is not all that uncommon. The windshield floats in that top channel and puts a working side load on the strap. Yes you want to repair this part because it is all that holds the top part of the windshield into the fuselage securely. You do not want that windshield coming out though to be honest my 170A probably flew for 20 years with a broken strap and mast base just like yours and the windshield never attempted to come out.

Still your IA shouldn't overlook this and should require its repair for annual.

Mine got repaired when we removed the center strap all together under an STC for a new strapless windshield.

When I replaced mine with the thicker, strapless windshield, it called for 4 screws at the top of the windshield (I think #6’s) to secure it.

The “wood” inside the “bracket-antenna-mast” (PN 0411670) is made of phenolic/linen resin (as Bruce points out, the same material pulleys are made).

Great discussions have transpired over the necessity of that bracket and mast…. some imaginative debates have occured over the need to have the mast installed to “prevent bugs and ice from entering the fuel vent” (gooseneck)…. pure B.S. in my opinion…but fun to debate.

It does have a modern day use: It is useful for “long-wire” HF antennas, and a few 170s that operate in the outback are possibly still equipped with HF radios.

If you do remove it, you might offer it for sale in the TradeMart because some “originality nuts” still have theirs installed complete with mast…. and copy-cat-wannabees may buy it. (Don’t hold your breath, however.).

Bruce Fenstermacher wrote:We are looking at two parts. That base at the very top of the aluminum strip is a base for a antenna mast. Your are missing the mast. The mast is made from the same material as pulleys but who's name escapes me at the moment. The antenna was a long wire that probably exited your boot cowl in front of the windshield and went up of the this mast and then back to the tail. The mast has nothing to do with the window strap other than the same mounting holes. This could be removed or left but since you will be doing some work here, why not remove it.

The strap, who's top section is riveted on, has cracked. This is not all that uncommon. The windshield floats in that top channel and puts a working side load on the strap. Yes you want to repair this part because it is all that holds the top part of the windshield into the fuselage securely. You do not want that windshield coming out though to be honest my 170A probably flew for 20 years with a broken strap and mast base just like yours and the windshield never attempted to come out.

Still your IA shouldn't overlook this and should require its repair for annual.

Mine got repaired when we removed the center strap all together under an STC for a new strapless windshield.

Thanks for all the information. You are correct, I do have a mount on my boot cowl in front of my windshield which I am planning to remove at some point too.

Is the strap a custom made piece, or do I order it from somewhere?

Haha—I thought the same thing with the antenna mast thinking it perhaps deflected debris/air around the vent.

I've not handled a windshield strap in some time. I seem to think it is stainless steel. Perhaps a hard aluminum. Others might remember. I think I still have my original strap in my garage and if so could study it tonight and give a better option. What ever it is determined to be, I'd order a small sheet of it and make my own replacement.

As for modern day use of the HF long wire, My good friend who is also an avid Ham operator and who's profession has had him designing antennas, just had one installed on his Cessna 210. He uses it with various radios to talk to his Ham buddies while he's flying.

I think the brand name for the mast material is Micarta.

I understood the long wire antenna to be the sense antenna for the old ADF.

When my upper strap broke in the same place, we replaced it with stainless steel which lasted until the strap was removed with the new windshield.

Cheers. I’ll trace it over stainless steel and make a replacement. I’ll post the photo once it’s done

That strap is not all that holds the windshield in place; the wing root fairings do most of that job, and the center bracket just keeps the windshield from bowing out as much. I noticed that bracket on my airplane cracked through in 1985. In 2010 the windshield cracked in the upper right corner at which point I installed a thicker Great Lakes windshield and did away with the center strap and bracket completely.