Av-87m

[Bellifortis]

Hallo,
attached you see a dummy classroom russian AV-87M fuze, about which I know nothing. May be somebody here has some additional info. I do not know its age, but it must have been produced before the 1970-80s. Above the standard russian booster there is a sheet-metal cup with No.s from 1 to 6 engraved. I suppose that this means Seconds. Depending on how you turn this cup (before assembly to a munition) a fire-channel is closed or opened. 1 to 6 second delay is quite long. The thread of the fuze is covered by a metal ring that seems to be locked so there is no thread to screw the fuze into something. My questions are :
1.) What air-Force munition was this fuze used with ?
2.) Does anybody have technical drawings he can share ?
3.) When was this fuze introduced ?
Thanking you in advance for your consideration, I remain, yours
Bellifortis.

 

[strakv]

It is used for the PLAB-250-120 anti-submarine bomb.

 

[Bellifortis]

Hallo @strakv,
i just had a look in the Bazalt 08 catalog. There the PLAB-250-120 is depicted with more modern head-and tailfuzes, with electric-pyrotechnical arming. In the russian book about bomb development in the soviet-union up till 1945,which I have as a digital copy, on page 685 the AV-87, apparently introduced in 1941, is described. This looks the same as the AV-87M (I can not read russian). So, it seems as if this fuze was used for earlier model bombs. Hoping for clarification, I remain,
Bellifortis.
P.S.: I noticed that it is possible to copy the pages of the book one by one. So here now are the 3 pages concerning the AV-87. If somebody can read russian, he please may extract the info wanted.QUOTE=strakv;302149]It is used for the PLAB-250-120 anti-submarine bomb.[/QUOTE]

 

[Ivashkin]

Belifors, information from Your pages about AV-87. Noothing special, but maybe will help.
Fuze AV-87 developed by I.S. Fedorov and A.Ya. Eremenko and came to service in 1941 (before 22 of June).
АВ-87 - Авиационный взрыватель 87-й модели, Aviation fuze model No. 87. It means, that 87 doesn`t mean anything special.
Diameter of the tread on the tail - 38 mm. Minimum height of bombing - 300 m. Was using in marine air forces, but could be used and for sea surface and for ground.
Delay - from 0 to 7,4 sec; short segment - 0,2 sec, long segment - 1 sec. "O" - immidiate action, when bomb uses as fragmentation (probably "O" - Осколочная). "Б" - safety position (probably, "Б" - Безопасно).
Installs in head and tail part of bomb. On plant fuzes prepeared for installation in head, but if installs in tail, you have to turn vane by special key to arrow "Д".
After dropping, fuze in ar position after 22 turning of vane.
Noticed few disadvantages:
1) large number of failures,
2) depending time of delay according storage circumstances (moisture, temperature etc.).
I was searching information about AV-87M, but found complitely nothing! No information from sources what I can trust.

 

[Bellifortis]

Hallo Ivashkin,
thank you very much for your translation. Yours is the only one. One thing about this fuze puzzles me. The narrow, rounded metal ring that is screwed onto the outer thread, completely covering it. So now this fuze can not be screwed into something. How was it fastened in a munition and for what purpose ? Questions, questions and more questions.
Regards,
Bellifortis.