Bis?

[bonesvf103]

What does the “bis” mean in MiG-21bis?

[r4y30n]

Literally "second" or "twice" in Latin.  Basically just means improved.

[bonesvf103]

Thanks

[corn322]

In my limited informal studying of the Russian language, I was expecting a Greek prefix word. But it turns out Latin dis/bis and Greek dis stem from a common Proto Indo European word "dwis" which means "twice" or "in two."

https://en.wiktionary.org/wiki/bis#Latin

https://en.wiktionary.org/wiki/δίς

https://en.wiktionary.org/wiki/Reconstruction:Proto-Indo-European/dwís

 

[=475FG= Dawger]

It is rarely found in Russian. My resident Russian expert only encountered it once in a book, Master and Margarita by Bolgakov, as part of Satan's address.

 

It means two or second.

 

 

[rossmum]

It was used multiple times for aircraft variants, but of those, few actually made it to service (e.g. MiG-15bis, MiG-21bis). Others didn't - Su-15bis for instance was to be a Su-15TM re-engined with two R-25-300s, but those engines were needed for MiG-21 production, so it was cancelled.

It possibly came to them via loanwording from the French (who did have habit of using 'bis' to denote an improved variant of a tank or aircraft, and who the nascent USSR obtained many of its aircraft from).

Edited August 13, 2021 by rossmum

[Ala13_ManOWar]

I-15bis aircraft was the second variant of the model (also called I-152), and I-15ter was the third one (also called I-153). Not an expert on Russian names, but I guess they preferred that to other notating systems, like plain A, B, C, etc (also used anyway). In MiG-21 apparently that somewhat "last" variant was changed enough to be considered a somewhat "new" aircraft so they called it accordingly. In the MiG-15 that was literally, a second model of the aircraft, a new one with all the newly developed refinements. In MiG-21 I don't really know what was changed so much to use that name.

 

S!

Edited August 16, 2021 by Ala13_ManOWar

[TLTeo]

"bis" and "ter" are both Latin words. What I find ironic is that of all people, afaik that nomenclature was first introduced by the Italian fascist regime to label some aircraft variants (the CR32 and SM79 being the most common aircraft with bis/ter variants) due to their ideological link with Imperial Rome.

Edited August 16, 2021 by TLTeo

[Ala13_ManOWar]

I don't speak Russian or am specially acquainted to it, but the few words I could know show me that Indoeuropean roots, structures and everything makes it closer to other European languages than one could think at first making it rarer that it actually is only due to the Cyrillic alphabet we all see. Latin root words, coming from French influence I guess, are more common in Russian than it seems, so not that weird they use those Bis and Ter names. Anyway, perhaps some Russian fella here at the forums could enlighten us, are they occidental names to Russian models or they also use those terms and names? In wikipedia in Russian I see the Bis term used in several of those aircraft mentioned here, MiG-21Bis is one of them, not the Ter name as far as I could find, but maybe it is or was used. Anyway one has to be careful with sources since many, many, soooo many aviation related books only re-write once and again the same mistakes from decades ago and names is one of those things one has to be really careful about. But apparently in MiG-21 it was used for sure.

 

S!

[rossmum]

It was more common in earlier aircraft, but as I said, was also used through the Cold War for major or 'ultimate' upgrades of existing aircraft. The more common Cold War system was what Russia still uses - suffices that speak to what was actually changed, e.g. F - uprated, M - modernised, U - training (or sometimes strengthened/improved), K - shipborne or export, T - additional fuel, P - interceptor, etc.