[GuerraCivil]

Well, SB-2 is common mistake made by many professional aviation historians and it has been established in many publications. Maybe we ordinary aviation aficionados can be forgiven to use such, but thanks for correction. I try to remember from now on only SB - although there are people who know well what is SB 2, but may be confused with SB.

Also Polikarpov I-152 is often used to mean I-15 bis, although it originally was intended to another prototype than I-15 bis - it was almost the same aircraft, but had different exhaustion pipes and a three-panel windscreen. The whole I-152 designation was used only a short while and I-15 bis should be called I-15 bis and nothing else.

However, the designation I-152 has been used by many historians. Strictly speaking it meant I-15, version 2. The I-153 was I-15, version 3. All I-15, I-15bis and I-153 are called sometimes as "Chaika". In reality there are even visible differences between the three planes (different engines and front nose, strutted wing of I-15 bis, retractable landing gears of I-153 etc) . I-15 was not the same plane as I-15 bis, although the latter is often called also as a I-15.

There are of course a question of the different versions of same plane:
SB 2 M 100 - is this the Czech VB 7? - or is this: SB 2 M 103 etc.

I-16: are we talking of type 5, type 18 or type 29? - there were big differences between different types of I-16 when it came to technical performance and armament. The later series of I-16 were far away from the type 5 although the basic look of plane was superficially same. Also with type 5 there is some confusion: sometimes type 5 with open cockpit is called type 6. That is incorrect, it should be called I-16 later type 5. Also all colourplates showing I-16 type 5 with closed cockpit show rather theoretical situation - pilots almost always opened the cockpit and flew with the opened cockpit.