Your not reading the drawing properly - the front is parallel, The side rails have a 4 degree taper but the 512 measurement is taken 530 mm from the front - whereas the angle change on the outide face of the frame is 580 mm back from the front. This is why your measurements are wrong.

so it is a optical illusion . If you look at the foto I did post , it looks like the front end opens to the front .

Photos only help in a relative way. Perspective can mess things up badly.

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Vive la Marque !!

It looks like Greg is wrong , there is no taper at the end of the Royale chassis . In the drawing it tapers from 65mm to 45mm , but only in the drawing .
Nobody has a Royale chassis at home ?

I don't even know what you are talking about now.

top view , Royale chassis drawing . End tapers from 65 mm to 45 mm .

perhaps just nip over to the museum and measure the schlumph ones...
are they real enough...

I allready did .

You are close enough to visit, well done.
what are your findings on measurements - related to drawings and questions arising regarding the Royale chassis?
[hopefully clear enough to avoid errors..]

about the small number , only 6 Royales , I think all are prototypes .