Lens scheme design Av-xenotar 250mm f4

[Xifoideus]

For the rollei AV66 slide projector a Av-xenotar 250mm f4 lens was made.

I have had the oppertunity to buy three of these lenses from a project to show slides around a city in Germany that never came about due to an illness of the photographer

However I'm adapting these lenses to copal 3 shutters to use on 4x5 and 5x7 (image circle of about 230mm). Have two of these lenses finished and started on no. 3.

The lens design is not a typical projector lens design [1] but I think resembles that of a xenotar 75mm f3.5 for rolleiflex.



I can't find a detailed scheme of a xenotar 210mm but I do think it resembles the xenotar 75mm f3.5 as a scheme can be found here.

What do you make of the Av-xenotar 250mm f4 lens scheme?

Note 1: I found that typical projector lens design are 5 element that resemble something of the Sonnar design. The Av-xenotar 150mm 2.8, s-heidosmat 150mm 2.8 and Lumagon 150mm 2.8 have such design. They all have an image circle of around 127mm, not covering 4x5.