First use of REVI 3a

[Revi16]

The Revi 3 series includes the 3a, 3b, 3c, and 3d.
The Revi 3a & 3c were 12 volt units, the Revi 3b & 3d were 24 volt units.

The Revi 3 series also vary in the way the units mount to the instrument panel. I have seen Revi 3c's with two different Fl.#'s (Fl. 52085 & 52116) which I am guessing indicates the different mount type.

Besides the aircraft you have listed I have seen pictures of Revi 3's installed in the Hs-126, Ju-87 and Bf-109. The early Bf-109 could use either the Revi 3 or C12. There are pictures of Bf-109B,C/D/E with Revi 3 or C12, not sure if there was any reason which model got which gun sight.
I have never seen a positively identified Revi 3a or 3b in pictures (other than the manual) or in any collection. There are a reasonable amount of 3c & 3d that have survived.

I believe the Swiss Revi 3's can be identified by an "A" that prefixes the serial number,e.g. Revi 3c A 446, Revi 3d A 731. I also have not seen any "A" prefixed Revi 3's that contained an Fl#.

The German Revi 3's will have an "Nr." that prefixes the serial number, e.g. Revi 3c Nr. 3500, Revi 3c Nr. 3841. The German Revi 3's normally have an Fl# applied as well.

The Finns also used the Revi 3 (possibly a locally produced copy).

In short I would guess the Revi 3 series was used in various aircraft starting around the 1935-1936 time period.

Regards,