Desperate Rhapsodies— some fool aircraft design of the Soviet Air Force from 1970 to 1991

[trajan]

part1：
Lets start from su24

For a variety of reasons, mainly that the aviation industry was really not as advanced as that of the United States, the Soviet Union generally chose to copy the United States directly in its aviation industry.

For example, the original version of the early Su-24 prototype, the T-6-1, was actually of a completely different structure to the extant Su-24.



The T-6-1, which first flew in 1967, was a short take-off and landing fighter with four RD36-35 lift engines, quite different from today's Su-24.

So it is possible to answer that famous unsolved mystery in military fan circles: why does the F-111 have so much more range than the Su-24 when it also uses VG wings and is about the same size and weight?


（ As you can see. Even the Su-24M, which entered service only around 1983, has a radius of only about 390 km (without secondary fuel tanks) for full ultra-low altitude defence at 200 metres with 3 tonnes of ammunition. This is a poor radius compared to the F-111（more than 800 km）.）



（real serviced SU24 body same asT—6—1）

One of the main reasons for this was that the design of the Su-24, which was really in service, was changed after the F-111 structure was known, and the prototype T-6-2I only first flew in 1970. We can find many commonalities between the Su-24 and the T-6-1 prototype in terms of aerodynamic structure.

Due to hasty design changes, the VG wing of the T-6-2I/Su-24 was only used for short take-offs and landings with the lift engine of the T-6-1 removed, and was not optimised for subsonic and supersonic lift-to-drag ratios as was the case with the F-111.



AS you can see. The maximum subsonic lift-to-drag ratio of the F-111 is around 16, and any military aircraft with a higher subsonic lift-to-drag ratio would have to be the C-5/C-130.

While the maximum supersonic lift-to-drag ratio at Mach 2.5 is over 6.5 for the F-111, and any military aircraft with a higher supersonic lift-to-drag ratio than the F-111 would have to be the XB-70 or Concorde.(σ′▽‵)′▽‵)σ

The Su-24 was originally designed as a conventional wing with lift engines for short take-offs and landings, and the change to VG wings was too hasty, so the subsonic and supersonic lift-to-drag ratios were not excellent.

The maximum subsonic lift to drag ratio of the Su-24 is only about 9.5, and the maximum supersonic lift to drag ratio is less than 4. It is almost in the same league as the F-101/102.(ಡωಡ)hiahiahia

 

[CV12Hornet]

Well, there's also the fact that the F-111 carried way more fuel than the Su-24 (19,000+ liters versus 10,860 liters) due to the lack of wing fuel stowage in the Fencer, and the fact that the TF30 engine has better specific fuel consumption than the AL-21 in dry thrust (68 kg/(kNh) versus 87.7 kg/(h·kN)), though the AL-21 was more efficient in afterburner.

 

[trajan]

Part 2: The T60 bomber whose stupid design led to failure



Of course, it was not as if the Soviets were unaware of the problems with the SU24.



As mentioned earlier, the Soviets liked to follow the American lead in aviation design.



In the 1970s, after the Carter administration cancelled the B-1A project, General Dynamics offered a cheaper compromise to replace the B-1: the Advanced FB-111, or FB-111H





By stretching the existing FB-111A and replacing it with the B-1A's F101-GE-100 engine, it would have been a medium-range bomber comparable to the Backfire C (Tu-22M3, in Soviet scale service since 1983). This is the solution given by General Dynamics to replace the B-1A.



Seeing what the Americans had done, the Soviets naturally began to follow suit, and in the late 1970s and early 1980s the Soviets envisaged that the next-generation medium-range bomber project (expected to replace the Backfire) would be an enlarged version of the Su-24.



The Sukhoi T-6BM, or Su-24BM as it was called, the larger Su-24, was the next generation of medium bombers designed by the Soviets in the late 1970s and early 1980s, following in the footsteps of the larger American FB-111. the Su-24BM was to be fitted with the AL31F engine.

As we can see, the early Su-24BM design was still a simple single droop tail, VG wing, which was a simple enlargement of the Su-24 for a new engine. In 1983, however, the Su-24BM was changed to a conventional swept-back wing type, with the VG wing removed and a twin droop tail replaced.



The Su-24BM was a promising project, in line with Soviet aviation technology, and if development continued, it should have little problem replacing the Backfire as a cheaper medium bomb with similar performance to the Backfire. The project had already progressed to the full-scale model stage. However, it was at this point that a change occurred.

The Sukhoi Bureau's favourite project was the next-generation Medium Bomb, also known by the Soviet Ministry of Aviation as the B-90, so development of the Su-24BM had to be halted to prevent it from stealing the budget for the "1990s bomber".

The early design specifications for Sukhoi's B-90 project, internally designated the T-60, which began design in 1981, and which was expected to replace both the Backfire and the Su-24 as the next generation medium-range/frontline bomber, were as follows:

Empty weight: 32 tons (for comparison, the Su-24 has an empty weight of 21.2 tons, while the Tu-22M3 has an empty weight of 68 tons. Clearly, the T-60 is a bomber between the Su-24 and the Backfire, and is expected to replace both);

Length: 31.3 to 40 metres (Backfire at around 42.5 metres)

Maximum take-off weight: 85 tonnes (39.7 tonnes for the Su-24 and 126 tonnes for the Tu-22M3)

Maximum bomb load: 20 tonnes

Top speed: Mach 2 (same class as Tu-22M3, but faster than both Su-24M and Tu-22M2 in the Mach 1.6 class)

Maximum range: 6000km (Tu-22M3 is 7000km)

Operating radius (high-low-low-high, 2200 km, Tu-22M3 is 2410 km)

Overall, the Sukhoi T-60 is a medium-range bomber between the Su-24 and Tu-22M3, but with a similar payload range to the Tu-22M3, and is expected to replace both the front-line bomber Su-24 and the medium-range bomber Tu-16/22/22M in service with the Soviet Army.


Early design T-60, Sukhoi's responsibility for the next generation of Soviet front/medium range bombers, replacing the Su-24 and Backfire. Dorsal intake, VG wing and flat binary nozzle (which reduces the infra-red signature of the tail). Some stealth capability, with stealth performance probably up to the level of the B-1B.



We can see that the early Sukhoi T-60 programme clearly has many of the features of the T-4MS programme. For example, the VG wing and the twin drooping tails with very long distances on either side of the engine.
This may seem like a good idea, but the T-60 had two very distinctive designs, and it was these two stupid designs - especially the engine design - that ultimately put an end to the programme.

 

[trajan]

The first design is a simplified version of the VG wing.

As we know, the conventional VG wing requires a very bulky and difficult to machine titanium central wing box. This wing box was so difficult to machine that a new machining mode, vacuum electron beam welding, was also developed in the USA specifically for welding titanium wing boxes.
To solve the drawbacks of difficult machining, expensive, difficult maintenance and dead weight of the VG wing central wing box, Sukhoi's idea for the T-60 was to



Installing a variable swept wing directly under the wing, without a central wing box!(ﾟOﾟ)

As originally conceived, the T-60's VG wing did not require a central wing box and was fixed directly to the underside of the fuselage with fasteners, thus avoiding the drawbacks of the VG wing and having the advantages of the VG wing.

Of course, this is a very naive idea. There is no such strong fastener on the planet that can hold a VG wing in just one direction. And to confirm this, Sukhoi Design Bureau wasted four years ......

tips：

The vacuum electron beam titanium welding machine ЭЛУ-24-16 at the Soviet Union's own heavy bomber production site: the Kazan Aircraft Factory is the largest of its kind in the world and is specifically designed to weld the central titanium wing box of the Tu-160.

This machine consumes an extremely large amount of electricity, so it can only be started at staggered intervals in the latter part of the night, and working during the day could cause an overload of the circuits throughout the city.

 

[trajan]

The most brain-dead design of the T-60/T-60S is its engine

The engine of the T-60/60S is known as the "twin-tube engine", or the twin-tube variable cycle engine.



A sketch of the American variable cycle engine structure is shown below


The Soviets found this design too complex and had a much more cerebral and simpler variable culvert design:



The "twin-tube engine", a Soviet variable cycle design

The Soviet "twin-tube engine" was very simple and brutal, with two engine cores in effect.

If the intake ducts of the lower turbojet engine are closed, the engine will operate in pure turbofan mode. This is when fuel consumption is at its lowest;

If the lower turbojet inlet line is opened, both cores will operate in turbojet mode at the same time, where thrust is at its highest.

The 'twin-tube engine', designed by designer Kolesov, is expected to have a maximum boost thrust of around 23.5 tonnes, only slightly less than the Tu-22M3's NK25 three-rotor turbofan (25 tonnes maximum boost thrust).







It sounds good, and this "simple" twin-tube variable-cycle engine has passed bench tests. But the reality was bleak.



For one thing, the engine was too big and heavy to fit in the T-60/60S;

The so-called "data" in the T-106/112/113 models were all falsified.

heres the original file：
После внимательного изучения отчета ЦАГИ о продувках модели самолета в трубах Т-106, Т-112 и Т-113 я сумел отвергнуть эту компоновку. Оказалось, что результаты продувок, приведенные в итоговых отчетах, были сфальсифицированы: на графике изменения положения фокуса по числу М начальная точка отсчета положения центра тяжести самолета была сдвинута на 3% вверх. Я немедленно поехал к начальнику 10-го отделения ЦАГИ Л. М. Шкадову и указал ему на это несоответствие. В ответ Шкадов с усмешкой сказал: «Олег Сергеевич, 3% -это мелочь». Да, мелочь, если не учитывать, к чему она отнесена. А поскольку она была отнесена к полной длине самолета, равной 40 м, то эти три процента равнялись изменению положения центра тяжести самолета на 1200 мм. А это уже означало, что компоновка самолета должна быть проведена заново. Я официально, в письменном виде, вернул ЦАГИ их рекомендации и попросил уточнений. Ответа не последовало. Эпопея с Т-60 — не единственная подложенная Симоновым «свинья». По его инициативе нам в эти годы поручали разработку велосипеда, стиральной машины, машин для расфасовки сахарной пудры.

“After a careful study of the TsAGI report on the blowdowns of the model aircraft in tubes T-106, T-112 and T-113, I was able to reject this arrangement. It turned out that the results of the blowdowns given in the final reports had been falsified: on the graph of the change in the focus position according to the M number, the initial reference point for the position of the centre of gravity of the aircraft had been shifted upwards by 3%. I immediately went to the head of the 10th branch of TsAGI, L.M. Shkadov, and pointed out to him this discrepancy. In response, Shkadov said with a chuckle: "Oleg Sergeyevich, 3% is a trifle. Yes, a trifle if you don't take into account where it was attributed. And since it was related to the total length of the aircraft, equal to 40 m, these three percent were equal to a change in the centre of gravity of the aircraft by 1200 mm. And this already meant that the layout of the aircraft had to be redone. I officially returned their recommendations to TsAGI in writing and asked for clarification. There was no response. The T-60 epic was not the only "pig" laid by Simonov. At his initiative, during those years we were charged with developing a bicycle, a washing machine and a machine for packing icing sugar.”

(・●・)

In fact, the bullshit 'twin-tube engine' eventually led to the scrapping of the T-60/60S project.╮（﹀＿﹀）╭

Eventually Russia gradually replaced the Su-24 with the Su-34 "Defender" as a front-line bomber.


The Su-34, known in Soviet times as the T-10V or Su-27IB, was a low-end solution to complement the T-60/60S in those days. However, with the T-60 and Izd.54 failing to blossom, she is now the only aircraft that can hold up the Russian air force. With an empty weight of around 22.5 tonnes and a maximum take-off weight of around 45 tonnes, this aircraft is considerably smaller than both the T-60 and the Izd.54.ԅ(¯ㅂ¯ԅ)

 

[publiusr]

View attachment 702216
The vacuum electron beam titanium welding machine ЭЛУ-24-16 at the Soviet Union's own heavy bomber production site: the Kazan Aircraft Factory is the largest of its kind in the world and is specifically designed to weld the central titanium wing box of the Tu-160.

This machine consumes an extremely large amount of electricity, so it can only be started at staggered intervals in the latter part of the night, and working during the day could cause an overload of the circuits throughout the city.

Might that at least have other uses?

That looks like a magnificent tool---maybe to pump this thing?

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