Excellent work! I have not aware of historical references for proportions of parts but I think arms needed to be a little shorter. Otherwise fascinating. Eagerly waiting for a video featuring some shots with it. :-)
I agree that the arms are probably too long. At that length, if the scorpio is operated with any amount of tension, there may be a risk that the leverage created by the long arms could cause them to break. Also, I would recommend rivetting steel plates around the head unit like the originals from Ampurias and Caminrael, otherwise the tension of the rope springs could spoil your beautiful woodwork by producing cracks in it. Otherwise, I echo the other commentators in congratulating you on a very nice job so far.
Crispvs
Who is called \'\'Paul\'\' by no-one other than his wife, parents and brothers. :!: <img src="{SMILIES_PATH}/icon_exclaim.gif" alt=":!:" title="Exclamation" />:!:
It was planed as a 3 span Vitruvian - so dimension of the springs is about 74 mm. All other dimensions are calculated from this one of corse.
Arms are just something that we found in the garage to make first photos. Real ones should be 53 cm long and curved (1D curvature). Next will be the plating and most imortant thing - the washers. Seems if we wont have a iron or brass washers shooting distance will be poor.
Now it seems a lot of finishing work to make it good looking and good shooting. Honestly we thought that making such a machine is much easier, cheaper and faster