The Problem with Von Hippel's Wing Failure

[charles]

If you have been following my other post in the aircraft part of this forum, I am making a partial restoration of the wreckage of an Albatros D.V. I have come across a curious thing.

In the right-hand photos below, you can see the lower left wing spar attachment fitting from my D.V. wreckage. It's identical to the same fitting on the Albatros D.Va.s at the Smithsonian and in Canberra. The Lower left photo is the same fitting from the Albatros parts catalogue. The upper left photo is from the crash investigation of Von Hippel's D.V and the upper middle photo is an enlargement of the von Hippel fitting. Notice how it is curved? My point is that in this small way it's different than the three extant fittings, which are all alike. I can't see how a minor modification to the von Hippel fitting would have helped the wing failure problem. Notice also that they are all different in one respect from the drawing, too.


http://www.aeroconservancy.com/vonhippel/composite.jpg

[StephenLawson]

Greetings Charles; Here is my take. The real modification was not in the shape but in the retaining plate for the rigging cables running up to the top wing. (Seen with the tongue holding the two turnbuckles) In the D.V it appears that if this retainer was made from pot (soft or substandard) metal it would tear away from its sandwich mounting. Thus allowing for the twist of the structure under load and then the failure.

The modification may have been later included in the D.Va types as it appears to be a single unit in yours and the Smithsonian's example.

[R Pope]

It looks to me as if the curvature you mention is damage due to the crash.The lower flange is at a 90 degree angle to the bent part-- if it was built in. this flange would have been horizontal, would it not?