Polikarpov I-16 types 5 and 6?

[GuerraCivil]

Unfortunately my Russian is limited to the knowledge of cyrillic alphabet and to very few words. IIRC, the book of Yefimov/Gordon "Soviet Combat Aircraft" did have quite a lot about the I-16 but the "type 6" was not mentioned - IIRC, they jumped from the type 5 directly to the type 10. The type 5/6 question seems a confusing matter. What I have found from the web gives contradictory and confusing info about "tip 6" (for example the powerplant is mentioned to be "M-25A" with 730 hp or "M-25B" with 750 hp).

About the existence of "type 6" I found this source from the web claiming that about 700 were built and some of these saw action in Spanish Civil War and in China: http://www.ctrl-c.liu.se/misc/ram/i-16-t6.html

Some model kit manufacturers have made "type 6" kits: A-model, Novo, Hasegawa.

So the "type 6" exists in the mind of many people interested in I-16 and is often used in various sources nowadays, but how long it has been around?

From various sources I have read the claim that "type 6" exists only in the literature and has been used by some researchers and authors of books to make a difference between the original type 5 and its later modifications. If such authority as Maslov does not mention such spesification as "tip 6" he must have a good reason to ignore it.

So I guess that when the "type 6" planes were manufactured they were actually labelled as "type 5" in serial production numbers. Thus back in late 1930´s the Soviets did not know and use such spesification as "type 6"...

Thus the "type 6" is a artificial creation or myth which is actually more misleading than clarifying for those interested in the history of I-16. It would be interesting to know who first used the "type 6" spesification and is the original source of its existence.

The Chinese seem to have considered the modification of type 5 as a new separate model of I-16 - labelling the modified type 5 as "I-16II" between the the "I-16I" (early type 5) and the "I-16III" (type 10 and later types). However I find it hard to believe that the Chinese would be responsible of the creation of the "type 6" spesification which is so often used in (Western) literature and web sources.