As a dabbler in the obscure, strange, and oddball, of course I come across some weird stuff. This photo, though, actually made me do a double-take, if not for the most obvious reason.
This is one of the few photos of the only parasite aircraft program used operationally (and successfully, for that matter). It was a Russian project called “Zveno”, with several versions before the War, and one (this) during. A Tupolev TB-3 bomber served as the “mother ship” in most of the cases, and a combination of Polikarpov I-5s and I-16 were used as parasite fighters. A Grigorovitch I-Z was used, too, but that is even more obscure than the Zveno project itself.
An advanced version (Zveno SPB) was used in WWII, with 30 missions being flown, and they were overall successful. The I-16s were used as dive-bombers (hence the bombs in the photo), and the problem of reattaching was overcome by leaving it out. Thus, the range of the I-16s was basically doubled.
Now, what’s neat about it is one, the fact it’s a parasite aircraft. However, what I thought was kinda cool was the propeller. Take a close look to see what I mean. And if you have no idea what I’m talking about, I tell you later. Look close! It’s tough to see.
It is an odd aircraft, and believe it or not, ICM has this kit available in 1/72. From what I’ve read, the kit is not for the faint at heart. It’s said to be a difficult build.
Thinking about getting one?
If you’re talking about the prop on the TB-3, I think I’ve got a fair idea of what you’re talking about. That’s not a counter-rotating prop I spy is it? Knowing you and your fascination with them, I’m guessing that’s it. Another project to try to get working props on…
Yes the TB 3 kit is a bit of a challenge - the corregations make it rather difficult to rely upon filler and the U/c is very fragile. Over all though it is a good kit. I have nopt got round to setting up the facility for posting but Vintage Aircraft has a pic.of mine (for the Bomber GB) and he is welcome to post it if inclined,
I am not sure that the props can have been contra rotating?
I don’t think the props are contra rotating. They are just two props fixed on each other to make a four bladed prop. This was not unuseal (could some one give me the correct spelling?) at the time. For instance: the Handley-Page Hereford had the same prop construction.
It probably has more to do with the graining of the wood. If it would be a one piece prop, firstly you would need a gigantuan (really large) tree, and secondly it wouldn’t be strong enough. The grainin of the wood has to be in the length of the prop to be strong enough, I reckon.
BTW, there is no space at all between the two props, which makes it (seem) impossible to rotate counterwise. besides that it makes it seem to be attached to eachother. And that is unusual for counterrotating props…[;)]
I think that the counter twist on the 2 pairs of blades is actually an illusion. If you look at it hard, you can see that the two pairs are in fact twisting in the same direction. I imagine that they were made that way for speed of production, and for strength. Having to splice the blades together would have been time-consuming & possibly a source of weakness? Far quicker & cheaper to make 2 identical 2 bladed props & bolt them together at right-angles to eachother.
No, the props aren’t counter-rotating, but there is two two-bladed props bolted together to make a four-bladed one. As I said, not the most obvious thing in the world, but it’s something I haven’t see before. For a while this advanced version of the TB-3 only had the four-bladed prop on the inner engines, while the outer engines retained the two-bladed system.
Yes, I would really like to get the ICM Zveno SPB kit, but there is one problem. The TB-3 offered in the kit is this model:
What I would love to be able to do is attempt a conversion from the older model to the newer model, but as you can see, it will be difficult. Not only are the props different, the wheels are different, the nose/dorsal/tail turrets are different, which make the tail different, and (in my mind the most difficult of all) the engines are all totally different. It will be a challenge, to say the least. We’ll have to see what comes of it.
Lucien:
There where several versions of the Zveno concept, with all sorts of different configurations of aircraft. Maybe the ICM kit is an earlier version?
The kit can be built up as is and be a close approxamation of Zveno 6. Unfortunately, the I-16s would have to be backdated to make an accurate Zveno 6 model. Either way more work will have to be done. I’m honestly flip-flopping between the two, but I’d like to try the SPB.
by the way - there was an article on the construction of the kit in either an old copy of FSM, or the UK’s SAM. If you’re interested, I could look it out for you?
If this materializes, I’ll more than likely leave off the I-Z (the one on the bottom). I guess a kit exists, but it’s vacuform, and rarer than the Dodo bird. I’d just have to find some I-5 kits. Who knows? I HAVE been planning this for quite some time, now.
It is also possible that I might try the Zveno 7, the one right before the SPB. It was similar to Zveno 6 and SPB, but differed in the fact that the parasite I-16s were meant to re-attach. I’ll need to find photos of the mounting trapeze if I want to try this.
![http://members.jcom.home.ne.jp/mig_exp/z-spb.jpg[/image]](http://members.jcom.home.ne.jp/mig_exp/z-spb.jpg%5B/image%5D){kind=link}
![http://www.shift.sk/military/test_page_10/tb3/tb3_m17_motor_1934.jpg[/image]](http://www.shift.sk/military/test_page_10/tb3/tb3_m17_motor_1934.jpg%5B/image%5D){kind=link}
![http://www.shift.sk/military/test_page_10/tb3/tb3_m37frn_motor_1937.jpg[/image]](http://www.shift.sk/military/test_page_10/tb3/tb3_m37frn_motor_1937.jpg%5B/image%5D){kind=link}
![http://vvs.hobbyvista.com/ModelArticles/Duffy/Aviamatka/Aviamatka_01.jpg[/image]](http://vvs.hobbyvista.com/ModelArticles/Duffy/Aviamatka/Aviamatka_01.jpg%5B/image%5D){kind=link}