What If Machine: Kalinin K-7

The Kalinin K-7 was a Russian Bomber built in the 1930s, and it was a beast of a plane. With 7-8 engines (the actual number is thought to be 7, but it is unknown which is true) bomber which had a wingspan close to that of the B-52, and with a greater wing area. It was unsuccessful due to instability and vibrations caused by the engine frequency resonating with the structure of the air frame.

I ask this: What if the K-7 was built by a different country (which would have different engines which would have different frequencies?)

Considering that the Civilian model was to carry 120 passengers, this aircraft would have had great potential as both an airliner and a heavy bomber, and with the experience gain from this aircraft and the continued evolution of the ideas behind it, I think that this aircraft would have led to great things.

How about you guys?
 
I wonder if it could have worked with licence built Hispano-Suiza 12Ys rather than those Mikulin AM-34s it ended up with.
 
Well, if you could replace the Wright R-1820s on a B-17 with Allison V-1710s, I don't see how it would be possible.

Heck, the Russians even had them, the Klimov M-100.

I don't know how much horsepower the M-100 supplied, I admit that all the facts I've looked up are from a brief search, but it is late.

However, from what I have found, even the weakest of the Y12-series had 10 horsepower more than the AM-34s. Power, I do not think, would have been an issue.

However, Hispano-Suiza has a good pedigree.
 
Altering the length of the engine mounts and/or using metalastic bushings or other similar gimmicks would have got rid of the bad harmonics. Lockheed Electra turbo-props suffered as well. I'm sure the designer would have fixed it had he not been executed by Stalin.
 
WOW:eek:
I found this http://www.aviation.ru/k7/k7giant.html
Its a bit hard to understand but it looks like it suffered from 'flutter' where the trim tabs on your control surfaces are adversely affected by the airflow going over them .it is simple to mitigate, you just hang lumps of heavy metal forward of the hinge point and make sure that the airflow is as smooth as possible. Resonance was poorly understood then [try reading No Highway by Neville Shute] Mounting the engines on better Vibration dampers may help there but Russian aero engines in this era were frankly bloody awful
Building it out of steel tube with Aluminium alloy sheet skins would have made it a flying battery ,dissimilar metal corrosion is the curse of aircraft. With all that parasitice drag and all those engines its fuel consumption is not going to be good
If you can cure these and a whole lot of other problems maybe, just maybe it has a chance as a niche a/c rather like the 'super guppy' has today with a short prodution run I can't see it setting a trend ,it tries to be inovative in too many areas at the same time I cant see the Americans taking it ,similar sized country yes but they were going the Boeing 247 route smaller ,faster, The UK took the HP 42 ,slower but known technology or the ultra high speed DH Albatross road.
If anyone would build it it would be the French .As has been mentioned French engines were very good and a large a/c could possibly help knit the French empire together but thats a long shot as France was a bit of a mess in the 30's and the aircraft industry was not imune to that malaise.
 
Heck, the Russians even had them, the Klimov M-100.
Which was kind of why I chose them, Russia already had license to build them, and they were more powerful for their weight eventually, but slightly less powerful initially (the first production model only had 760hp, compared to the 800hp for the Mikulin, although it was lighter).
 
What about competition from the Maxim Gorki? It had eight engines and was just as ugly. It also showed movies.
 
You mean the Tupolev ANT-20? Well I suppose looking at it, you have to ask yourself what use would they have been?
 
The K-7 had almost twice the passenger capacity and was an early example of a large-scale lifting body.

It is a shame that Kalinin was executed. Who knows what would have come from the K-7 had he survived.

My first question was whether or not the problem with resonance could be remedied with different engines. I think that it could be so, since different engines should operate a different frequencies.

My next question is a bit more complicated, and quite possibly a bit more fun. My interest in the K-7 is not merely in what is was, or even what it could have been, but rather what it could have led to. The K-7, to my knowledge, was the first large-scale attempt at a blended wing body and might have led to production of either a blended-wing-body aircraft, or even a flying wing.

As an added incentive, let us say that the Stalinist purges never happened. That way, there'd actually be enough engineers to build the darn things, and they wouldn't die the same death as the ANT-20.
 
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The problem with BWBs in the pre-jet age was that you had to keep the wing pretty straight due to the diameter of the propeller, which, combined with the large depth, makes them quite slow.
 
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My next question is a bit more complicated, and quite possibly a bit more fun. My interest in the K-7 is not merely in what is was, or even what it could have been, but rather what it could have led to.
Well the first thing that springs to mind is engine development. Lets say different engines are built under licence ,It does'nt matter where they come from even the worst of them are much better than the local ones. from this will come an local industry born from the knowledge gained .Think precsion engineering, metalurgy fabrication techniques etc
Next is a must. A dedicated and massivly funded programme into aerodynamics particulary fluid flow a sort of Russian NACA . Bandaid solutions to this aircrafts many problems are only going to take the Russians so far
As a test bed this aircraft is waaaay too big and has waaaay too many problems ,from what I have read there was pressure to achieve results too soon.
If you are suggesting that this political pressure is gone or at least reduced then there will be a more measured progression to a pre production a/c [Look at any history of say the Avro Vulcan which has a wing form like you have suggested]
Also think about concrete technology big a/c need big airfields with long runways with deep well drained foundations and all the services that go with that.
From an engineering point of view to build this sort of thing you will need a well trained, Skilled workforce, and a vigorious, powerful independent quality control department .This has always been a problem in Russia.
Some sort of servo actuators of flying controls is another must... thats a big a/c :D Flying/blended wings are harder to control so they will be needed unless you have reaaaly strong pilots!
All of the above is true no matter what a/c type we use as a start point
 
Kalinin built a perfectly viable conventional transport, the K-5. The development of flying wings and lifting bodies for transport aircraft has been pioneered in the past by Northrop, Burnelli, poor Kalinin, and others, without significant support. The Soviet NACA was called TsAGI, and Tupolev's influence probably made it averse to helping Kalinin. One comes across Euler/Navier-Stokes flow solvers, and finite element structural models inside an optimization loop, when attempting to determine a viable aircraft, and Kalinin's full-scale model beyond the scope of available power plants was unlikely to meet success without modifications, also full scale, and failures, also full scale. The mathematically advantageous method of design seems to have met historical resistance. Computer modelling may be a benefit, but market acceptance isn't mathematically definable. It's a PR problem.

kalinin_k-5.jpg
 
Kalinin built a perfectly viable conventional transport, the K-5. The development of flying wings and lifting bodies for transport aircraft has been pioneered in the past by Northrop, Burnelli, poor Kalinin, and others, without significant support. The Soviet NACA was called TsAGI, and Tupolev's influence probably made it averse to helping Kalinin. One comes across Euler/Navier-Stokes flow solvers, and finite element structural models inside an optimization loop, when attempting to determine a viable aircraft, and Kalinin's full-scale model beyond the scope of available power plants was unlikely to meet success without modifications, also full scale, and failures, also full scale. The mathematically advantageous method of design seems to have met historical resistance. Computer modelling may be a benefit, but market acceptance isn't mathematically definable. It's a PR problem.

Yes i once met a graduate of TsAGI very clever guy:) Flow solvers and the like are just what is needed. You make the relevent point that the orginisation at this time is highly influenced by vested interests so for this POD to work we remove them and we follow the NACA model and let it concentrate on science and ignore politics .There is at this time no computer modeling and market acceptance as we understand it did not exist as the Soviet Union was a command economy.
If we follow Psyden's 'Stalinism with a human face' POD Kalinin may have time and resources to pursue his ideas more slowly through lab work, small scale models and pre production a/c
 
I don't believe Stalin would allow a human face, but the K-7 could have 8 engines and a revised boom with cantilever vertical empennages, for a start. Warm up the AH wind tunnel. The flight control system reminds me of the Beardmore Inflexible, another WI.

K-7bis.png
 
Now that sir is a fine drawing ,where did it come from?
I agree that Stalin is incapable of change in this time line But this is alternative history where the only things that are imutable are the laws of phsics and the certainty that sealion will fail!
maybe a time line can be contructed by Psyden and we can work in that?
 
The miracle of cut and paste, blended with the magic of MS paint. The above aircraft has limited room for engine enlargement because the engines have been moved closer, limiting the size of the propellors. The original allowed much room for great expansion, but didn't have the available powerplants, like the Wright R-2600, or equivalent Shvetsov M-82. The undercarriage was another area that needs work, but that's another drawing.
 
The miracle of cut and paste, blended with the magic of MS paint. The above aircraft has limited room for engine enlargement because the engines have been moved closer, limiting the size of the propellors. The original allowed much room for great expansion, but didn't have the available powerplants, like the Wright R-2600, or equivalent Shvetsov M-82. The undercarriage was another area that needs work, but that's another drawing.

Still a good dwg though. The two engines you mentioned are both good and a lot of work was done on the R series engines in the late 40's. I have seen pictures of versions with multiple props and even contra rotating props. Both of these solutions work and if I had my choice I would go for more blades. Contra rotating props in engines that close together will have adverse effects on the props next to them
The undercarriage looks like it has two school buses bolted underneath:D
It must have been a bitch to land in any sort of cross wind and as for the drag factor:p
Why not have a multi bogie in pods? with out riggers at the wing tips for those long wings [and maybe at the end of the booms sacrificial skids for those nose up landing situations.
There is a method in my madness here, regardless of the political situation in Russia the military are always a good place for funding with such an undercarriage [and some other major mods] Kalinin may have the beginings
of a battlefield supply aircraft
These a/c IOTL first appeared in any great numbers in the 50's Fairchild, and Lockheed did a lot of work on them for example
Russia is a large country and is about to become involved in a rather bitter war having that capability, and in such a large a/c maybe useful?
Aerodynamics wise a large nod in the direction of streamlining via fairings maybe a step in the direction of a blended wing as will leading edge slats and maybe some full fowler flaps. that wing has a lot of lift, killing that lift in a controlled way is a challenge.
 
Battlefield transport could be better met with a conventional configuration, using a high wing, drive-on/off fuselage, and adjustable suspension. The Kalinin would not be adaptable for vehicular ingress/egress due to several factors such as fuselage height and lateral cargo displacement.

Hamilton.png
 
Battlefield transport could be better met with a conventional configuration, using a high wing, drive-on/off fuselage, and adjustable suspension. The Kalinin would not be adaptable for vehicular ingress/egress due to several factors such as fuselage height and lateral cargo displacement.

The proposed upgrade upgrade to the Bristol frieghter ?A very popular a/c here in NZ .Fuselage height will be a problem I agree . The same problem was encountered with the Comet/ Nimrod conversion. Maybe use the same solution? This would tie in nicely with the u/c pod solution, especialy if we use another Russian speciality 'kneeling' bogies This way we have sufficient ground clearence for that large wing and remove problems during loading /unloading.
Lateral cargo movement ought not be a problem, any half way competent design engineer could solve it ,indeed the Russians themselves came up with an elegant solution with that Giant helicopter they tried out in the seventies .I saw an example at Farnborough back then.[Can't remember the name though]
The problem is thatwe have to find Kalinin a direction to mould his ideas to. At the moment in this time line that has'nt happened and if he doesnt do that soon he's going to end up shot again:D
 
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