Mirror question

[JWS]

Have been thinking about the visuals for my single seat 737. Came across these discussions here. Interesting & daunting. Seen a lot of talk about Mylar. But wondered why nobody seems to have a look at highly polished metal sheets or acrylic mirrors. Too heavy, too expensive or not good enough??Best regards,JWS

[geneb]

Mylar is really only the practical choice for making the mirror cell of a collimated display. g.

[JWS]

Mylar is really only the practical choice for making the mirror cell of a collimated display. g.

Thanks for your response. Could you elaborate a bit on the 'practicallity' of that choice? I've seen how some people have managed to build a Mylar mirror, but to be honest, it seems to me a very demanding project, that involves lot's of calculations, correctly shaped woodwork or metal frame, vacuumcleaners, airflow regulation, etc. It seems to me that e.g. a polished metal mirror could be easier to handle (if not too big or too heavy), but then again I might be overlooking other problems. At least it is first surface by design.Best regards,JWS

[geneb]

Thanks for your response. Could you elaborate a bit on the 'practicallity' of that choice? I've seen how some people have managed to build a Mylar mirror, but to be honest, it seems to me a very demanding project, that involves lot's of calculations, correctly shaped woodwork or metal frame, vacuumcleaners, airflow regulation, etc. It seems to me that e.g. a polished metal mirror could be easier to handle (if not too big or too heavy), but then again I might be overlooking other problems. At least it is first surface by design.Best regards,JWS

When correctly used, silvered Mylar will create an optically perfect*, seamless, spherical section mirror. This is why all commercial full flight simulators use Mylar for their mirror cells. Bending a sheet of metal into a spherical section would likely involve some kind of custom made press at an astronomical cost. I also doubt it could be polished even "good enough". * A Mylar spherical section mirror created by a vacuum is as literally perfect a mirror as you can create without going to a multi-ton glass mirror. You can either build multiple single-channel Wide Angle Collimators, or you can build a mirror cell & screen combination using vacuum drawn Mylar. Trying to use other materials simply isn't practical. It's either not good enough (metal) or too expensive (metal or glass). g.

[JWS]

Thanks for your further explanation.BRJWS