Talk:Blohm & Voss BV 246

Latest comment: 5 years ago by Steelpillow in topic Concrete wings?

Concrete wings?

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I suppose it's possible for it to work, if the lift is greater than the weight (and hopefully you use a thick, hollow metal core), but I have to say, the wings in the photo don't LOOK like concrete wings. Seems like concreete can be casted smoother than than that; that looks like dented metal to me. AnnaGoFast (talk) 00:06, 26 May 2016 (UTC)Reply

I very much doubt this (need to check Hogg). "Concrete" is distinguished from cement in that it contains aggregate, i.e. gravel of a significant size. Even if an ersatz wing moulding compound was based on cement, there's no way that an unsmoothable aggregate would be used. How was this applied? Was it trowelled to an aerodynamic surface, or was it sanded afterwards? A "putty" that needs to be sanded to a smooth aerofoil could be made from many of the contemporary ersatz fillers in use, far more easily than unsandable cement or concrete.
Looking at the Cosford example, the chipped leading edge looks more like it could be a wood fibre composite than cement.
Overall, I suspect this could stem from one of Cosford's display placards. It's a great museum, but they have some real howlers on those labels (the Firestreak "radar lock on" being another). Andy Dingley (talk) 12:33, 26 November 2018 (UTC)Reply
The construction is described in the Assistant Chief Designer, Hermann Pohlmann's account of the company, Chronik Eines Flugzeugwerkes 1932-1945 (Motorbuch, 1979, pp.199-201). Magnesite cement was the only suitable material. It was cast over a fabricated sheet-steel core and then finished to shape. So, several corrections/clarifications: Not concrete but cement, yes it was workable to a smooth and accurate finish, the caption to the cutaway piece has it back to front as it is the cement which is cut away to reveal the laminated steel core, and despite appearances no wood was used. — Cheers, Steelpillow (Talk) 14:58, 26 November 2018 (UTC)Reply
Why was magnesite cement used? Was that for its higher strength (compared to Portland), or because it was more easily available? Andy Dingley (talk) 15:22, 26 November 2018 (UTC)Reply
Pohlmann says it was the only material which met the performance criteria. Presumably that meant things like strength, adhesion to steel, workability and so on. I might glean a little more by feeding the German through a translator, but it is not a high priority for me. — Cheers, Steelpillow (Talk) 15:51, 26 November 2018 (UTC)Reply