In this thread from Scalemodels.ru, there are links to two manuals for the I-15bis in pdf format:
http://scalemodels.ru/modules/forum/viewtopic_t_21878.htmlThe second one is the more useful from a modelbuilding perspective - it includes lots of detail drawings of various components of the aircraft. The first one is mostly text, but includes some good drawings of the OP-1 gunsight which should be helpful.
(1) To download, click on the link in the first post of the thread above.
(2) Enter the KAPTCHA code in the box at the bottom of the next page, then click on the green bar below it.
(3) On the next page, click on the active link on the upper left side of the page ("
http://narod.ru/disk/19816696000/И-15бис.Кн.1.pdf.html" for example).
(4) Next you will probably get a page offering you a yandex toolbar download; if so, click on your browser's "Back" arrow to return to the previous page, then click on the narod.ru/disc....И-15бис. Кн.1.pdf.html link again.
(5) At this point you'll get the usual questions regarding whether to view, save, or cancel the download; make your choice, and the download should begin. At a rate of about 30Kb/sec, each one of the two will take 15 - 20 minutes to download.
John