Struts in windshield area?

[cowman57]

Just curious. Why do I see braces/struts above the dash board/behind the windshield in some 170 videos? Is this a modification, and for what purpose?

[edbooth]

This is a fuselage strengthening modification for aircraft that are used on floats and skies.

[pdb]

Ed is right.

The struts are known as V-Braces and are used to stiffen up the fuselage in the cockpit area to deal with the added stress of rough field, floats, and ski operations.

[cowman57]

Thanks for the answer. Is this modification precautionary, or is there slight inherent weakness in the 170 cabin design?

[pdb]

I don't think its precautionary or indicative of a design weakness, I think it just reflects a modification for extra heavy duty service.

[mit]

Everything has a weak spot somewhere and when that is strengthened you move it somewhere else. Although over all might be stronger. Another example on a Cessna, is p-ponk.

[pdb]

Just remember that the goal of aeronautical engineers is to make every part as weak as possible.

If planes were built like locomotives, they would never fly.

[GAHorn]

The pounding of waves/water really stresses (downward) the engine and it's mount, which transfers to the firewall/cabin area/windshield. The V-Brace stiffens that area up to avoid cracks. (not something the ordinary 170 will suffer even tho' 60-plus years of operations.)

[Blue4]

V-braces are still available as a special order from F. Atlee Dodge. They require a field approval to be installed in a 170. There are other good forum threads on the topic.

Personally, I was surprised at how much a V-brace stiffened the fuselage solely from the evidence of eliminating the windshield squeak. The difference was amazing.

I run floats, skis, and bush gear (but seldom all at the same time). If my bird was an airport-to-airport flier, the V-brace would not be necessary.

-S