"Zveno-SPB" : Tupolev TB-3 carrying Polikarpov I-16 parasite fighters

[Stargazer]

An apparently undesignated project had an ANT-6 (TB-3) carry two Polikarpov I-16 SPB parasite fighters under the wings:

 

[redstar72]

An apparently undesignated project

Hi Stephane!

This is not a project - this combination was really built, even used operationally during WW2. And "SPB" is its designation (also known as "Zveno-SPB"). It is the definitive version of Vakhmistrov "Zveno" project. "SPB" stands for Sostavnoi Pikiruyuschiy Bombardirovschik - "composite dive bomber": the parasite I-16s were used as dive bombers, every of them carried two 100-kg or even 250-kg bombs with which they couldn't take off on their own account. Parasite I-16 could carry 5x larger bomb load than sole I-16, and its operational range increased by 80 %. The combination was tested successfully since July 1937 and was oficially approved for service in 1938. The first production one was made by Zavod No.207 in June 1940. Five SPB combinations were inducted by 2nd Special Squadron of 32nd Fighter Air Regiment (IAP), 62nd Air Brigade of Black Sea Naval Air Force based in Yevpatoria and commanded by Arseny Shubikov (therefore the squadron was nicknamed "Shubikov circus"). They were used in July-August 1941 to attack Constanţa oil depot, the King Carol I Bridge over Danube and other targets.

 

[Stargazer]

Awesome, redstar72! Thanks a lot for this information and accompanying pictures!

 

[Jemiba]

... and two aircarft carried just weren't enough !
Have to digg for that article, I once had somewhere, until then I'll just post this picture (http://www.grumlinas.lt/lektuvai/SPB_ver.jpg),
showing the configurations tested, with up to five (!) aircraft carried, although the fifth, carried beneath the centerline,
had to hook on after take off of the conglomeration. And, AFAIK, this stunt was regarded more or less as "circus performance",
without much practical means. But those two parasite I-16 dive bombers were quite succesful occasionally.

 

[piko1]

see in AiV there was a big article on the TB-3 with some info about the Carrier projects if i recall correctly

 

[Avimimus]

Any info on the last concepts? The Pe-8/Mig-3 combination?

 

[borovik]

Any info on the last concepts? The Pe-8/Mig-3 combination?

When the war came another idea: to develop a new version of the "Zveno", in which the carrier would act quite modern heavy bomber TB-7, and placed under the wing of his fighter LaGG-3 or MiG-3.
Estimated top speed 405-420 km / h is achieved at 6,000 meters in all six motors in the nominal mode, the range can reach 1320-1450 km, and its duration - 4.5-5 hours When uncoupling fighters midway battle radius level reached 850-950 km. For take-off is not required any special airfields: take-off run is estimated to be no more than 500-520 m
The option of a composite link TB-7 and two MiG-3 was quite promising. But not implemented.

 

[Stargazer]

More Zveno pics, from Modelist Konstruktor. Tthe bomber seems to be a different type (different tail fin and nose turret are immediately apparent) and the parasite fighters are not I-16 types. Artistic license, or another project altogether?

 

[Avimimus]

Very neat Borovik! Thank you!

 

[redstar72]

Tthe bomber seems to be a different type (different tail fin and nose turret are immediately apparent) and the parasite fighters are not I-16 types. Artistic license, or another project altogether?

Stephane, I'm a bit shocked... Don't you see that the bomber has only two engines? You can't recognize the TB-1?

This is the first Zveno-1, tested in 1931-32. The fighters are I-4 (specially modified, known as I-4Z). Actually there is an artist's mistake: I-4Z had its lower wing shortened, almost rudimentary but still present. Probably the artist confused it with another version, the I-4bis designed and tested by V. Shevchenko: this one actually had lower wing deleted, thus transformed from a sesquiplane into parasol-wing monoplane.

Here are some photos of the Zveno-1, taken from M. Maslov's TB-1 monograph in Aviatsiya i Vremya (Aviation & Time) magazine No.3/2007.

 

[Jemiba]

Stephane, I'm a bit shocked... Don't you see that the bomber has only two engines? You can't recognize the TB-1?

Come on ! Have a look at the hour Stéphane has posted it. Deep in the night, probably bone-tired and maybe ...
after some glasses of red wine ? It's excusable then to see things double , I think.

 

[Stargazer]

Ha ha!! Thanks a lot Jens for coming to my rescue! But redstar72 is right... I have no excuse. And, YES, though I recognized an early Tupolev bomber, I didn't even realize the "other" Zveno only had four engines... In my haste I concentrated on the name Zveno, not realizing there had been a Zveno-1 and a Zveno-2... Sorry for being so absent-minded! :-[ :-[ :-[

 

[redstar72]

There were not only Zveno-1 and -2...

Zveno-1: TB-1 + 2x I-4 (on the wings);
Zveno-1A: TB-1 + 2x I-5 (on the wings);
Zveno-2/2A: TB-3 + 3x I-5 (two on the wings, one above the fuselage);
Zveno-3: TB-3 + 2x I-Z (under the wings) - disaster during first flight: I-Z pilot Korotkov killed.
Zveno-5: TB-3 + I-Z (under the fuselage, joins in flight);
Zveno-6: TB-3 + 2x I-16 (under the wings) - pre-SPB.

Some ambiquity is with Zveno-7. Some autors (especially Kotelnikov) refer this designation to the "maximum" version of "Vakhmistrov circus" - TB-3 with two I-5 on the wings, two I-16 under the wings and one I-Z joining in flight under the fuselage. Other sources (Shavrov) call this combination only Aviamatka (Aircraft mothership), while Zveno-7 is referred to TB-3 with two or three I-16 joining in flight.

 

[Jemiba]

Ah, yes, thank you for helping my bad memory. Have looked up the Zveno article again
and carrying the fifth, the I-Z was ONLY possible with hooking up in flight. Judging the photos
and drawings, the under wing stations were for launch only, weren't they ?

 

[redstar72]

Yes, underwing I-16 stations in Zveno-6, Zveno-SPB, and Zveno-7 (Aviamatka) were for launch only. As well as I-Z underwing stations of the unlucky Zveno-3.

But there was also that "another" Zveno-7 (named as such in Shavrov book; Kotelnikov also mentions this version but without any specific designation), in which TB-3RN carried three I-16 fighters and all of them were joining in flight. The joining was controlled from special post in TB-3 fuselage, equipped by observation device and command console. According to Shavrov, this Zveno version was tested in November 1939 by renowned test pilots Mikhail Nyukhtikov, Stepan Suprun and Petr Stefanovsky. Unfortunately I don't have any photos of it.

 

[Stargazer]

Thanks a bunch for all the info on the Zveno series of projects. Never knew there were that many!

 

[Cy-27]

Following on from Reply #12 from redstar, here is a photograph of the loading process of I-5 biplanes onto the mothership TB-3.

The image has a caption of "Zveno-2" on a similar photograph on the same page, so I would guess the third fuselage aircraft has not yet been loaded.

Source:
Aviatsia & Kosmonautika (A+K) Magazine May/June 2003