27 Apr 2019, 16:58

SpudmanWP wrote: The most likely reason that LM paid for Yak data was to see data related to the operational use of a 3BSD nozzle and verify it against their internal studies & projections.

1st a little background. When LM 1st decided to tender for the JSF they put forward plans for a smaller cunard foreplane aircraft (a la the Israeli Lavi, the Eurofighter, the Dassault Rafale etc). They even developed a Large Scale Powered Model (LSPM) to demonstrate their JAST concept. A number of Small Scale Powered Models (SSPMs) were also tested to develop a basic understanding of the hover and transition regions. But pretty quicky they realised they could not get the design sorted out within the timeframe, so they went & knocked on the door of the Yakovlev OKB in Russia. In 1992, Lockheed Martin signed an agreement with the Russian Yakovlev Design Bureau & Pratt & Whitney signed one with the Soyuz Aero Engine Company for information on the supersonic Yak-141 STOVL fighter and its three bearing swivel duct nozzle, etc. Yakovlev was paid 'several dozen million dollars', P&W also spent some small change on a license from the Soyuz Aero Engine Company . Its no big secret outside of the US.



Now lets see what AeroWorld Net has to say: [slashdot.org]



..In 1992/93 Lockheed contracted Yakovlev on some work pertaining to short take-off/vertical landing (STOVL) aircraft studies in reference to the JAST (JSF) project. Yakovlev shared its STOVL technologies with the US company for several dozen million dollars.



Former Yakovlev employees accuse Yakovlev heads of taking personal interest out of the deal with Lockheed, because the official sum of the contract did not correspond with the value of the information presented to the US company. The data was on the Yak-141 test program, aerodynamics and design features, including the design of the R-79 engine nozzles.



After a careful study of those materials, Lockheed - without much noise - changed its initial JSF proposal, including a design of the engine nozzles that is now very similar to those of the Yak-141...



Yakovlev, Lockheed Sign Pact

By Anton Zhigulsky

Sep. 12 1995 00:00



Moscow's Yakovlev aircraft design bureau has signed an agreement with the American aerospace giant Lockheed-Martin to help develop a new U.S. supersonic fighter capable of vertical takeoff and landing (VTOL), a company official said Monday.



The contract is the latest partnership between Russia's struggling aviation companies and their Western counterparts, all trying to make ends meet in the post-Cold War world.



Arkady Gurtovoy, Yakovlev's deputy general director, said Lockheed Martin wants to tap the "huge experience" of the Russian company in developing the supersonic VTOL jets.



"The Yak-141 is still the most advanced aircraft of its kind in the world," Gurtovoy said, referring to a mid-1980s program that was shelved after the Soviet Union's collapse in 1991. No other countries have developed similar aircraft, he said, "so no wonder the Americans needed us."



The British Harrier jet that saw activity in the 1983 Falklands war is the most famous similar model, but it is not capable of supersonic speed. VTOL enables military jets to be deployed to combat zones without full-length carrier decks.



Under the contract, signed at the end of August, Yakovlev is to offer technical advice on American-built technology, Gurtovoy said.



He would not specify the value of the six-month contract, calling it "mutually profitable," but Interfax reported that Lockheed-Martin would spend approximately $400 million on research and development of the fighter by 1998.



Lockheed officials could not be reached for comment Monday.



Gurtovoy said the contract will help to reopen the Yak-141 program and keep specialists from leaving the cash-strapped company.



Yakovlev engineers completed work on an early-form VSTOL aircraft through the Yak-104 during the 1960s. This, based on a modified Yak-30 jet-powered trainer, laid the framework for a more advanced form still to come. When development of the Yak-104 was abandoned due to its complex lift system, attention turned to a more condensed model.



An initial single-engine approach was dropped in favor of a twin-engine product and the primary propulsion units would be featured in a side-by-side arrangement aspirated at the nose of the aircraft through a bifurcated intake. The same engines, mounted forward in the design, would also provide the necessary lifting power by way of swiveling exhaust nozzles set about the underside of the airframe. The design held a single pilot under a bubble-style canopy with minimal framing. A single vertical fin was featured at the tail with high-mounted horizontal planes. The wing mainplanes themselves were mid-mounted, swept-back, cropped-delta elements showcasing 37-degree sweepback along their trailing edges and slight anhedral (downward angle) overall. The undercarriage was of particular note, arranged in a "bicycle" pattern in which the main legs were inline under the fuselage's centerline. Outriggers were added to the wingtips to prevent tipping when ground-running.



The initial prototype was reserved for static tests so the second prototype was used in actual hovering, landing, and take-off actions. The third prototype was a more evolved model based on experiences gained with the first and second prototypes. The fourth prototype became another flyable example. The third and fourth units eventually crashed during tests with only the third example being rebuilt to continue work.



As a fighter development, it was envisioned that the production-quality Yak-36 would carry underwing hardpoints for conventional drop bombs, rocket pods, or cannon pods. Provision for 1 x 23mm GSh-12L series cannon was also planned. However, these were never fitted due to the design's lack of power - which kept it forever as a test platform and nothing more.



A first flight, though tethered for pilot safety, was held on January 9th, 1963 and a completely untethered test flight was recorded on June 23rd of that year. A first vertical-to-horizontal action was finally had on September 16th and March 24th, 1966 marked the first vertical-to-horizontal launch with vertical landing action undertaken (successfully). In July of 1967, the aircraft was publically showcased during the celebrations surrounding the 50th anniversary of the October Revolution. When identified in the West, it received the NATO codename of "Freehand".



The Yak-36 never materialized beyond the test articles as it lacked useful-enough qualities to become a combat-worthy platform - mainly operational range and power. Thusly, the Yak-36M was designed as a separate entry influenced by experience gained in the Yak-36 program - though the two aircraft held few similarities on the whole. The Yak-38 went on to become one of the few frontline VSTOL aircraft to see operational service - joining the vaunted British "Harrier" strike fighter appearing during the Cold War.



Production of the Yak-38 Forger began in 1975 making it the world's second operational VSTOL aircraft, after the Harrier series. In the USSR, the first VTOL jet estimations were carried out in 1947, the idea was based on the use of the rotary nozzle. At the end of 1950 it was connected to the OKB-115 Design Bureau, which experts have proposed the Yak-104 project with two up-and-boosters (PMD) 1600 kg thrust and one lifting motor (PD) 600 kg thrust. Later vthe Yak-28VV fighter-bomber project with two jet engines, as well as attack aircraft with two jet engines and lift fan in the wing, equipped with a gas-dynamic drive system. Exotic solutions were dictated by the high proportion of the engines of the time, constituted the 0.2-0.25 kg / kg, whereas to ensure acceptable performance characteristics of the aircraft, this option had to be brought up to at least 0.08-0.1 kg / kg. In the end, it was decided to create a prototype single-seat fighter-bomber for the study of flight technical and operating issues, and in the future to move to more serious projects.



Four VTOL aircraft, the designation Yak-36 ("B", the Yak-B) were built at the end of 1962, which was preceded by a long-term testing of the individual systems and components, and flight studies on the experimental apparatus "Turbolet". Yak-36 was powered by two jet engines R27-300 thrust of 5,000 kg, with rotating nozzles in the area of the center of gravity. For transient and hovering Yak-36 was administered via jet rudders, nozzles which are in the rear fuselage, on the wingtips and the front bar. Yak-36 was the subject of numerous studies on the stability and controllability of the VTOL, the impact of the gas jet to the surface and the aircraft structure, the influence of the reflected streams on the behavior of the aircraft and the operation of the power plant, the efficiency of jet rudders, and more.

...

Application is not enough power would lead to the same problems, which were characteristic of the Yak-36:. the inevitable drop in thrust due to gas recirculation and air flow the jet control system, as well as the effect of the suction force becomes so great that it is not allowed to take off vertically, even with minimal combat load. The concept of the initiative group Mordovina eventually won, though it took a long time: the decision of the CC CPSU and the USSR on the establishment of the Yak-36M appeared immediately after the meeting of the NTS MAP in December 1967, and only 25 January 1969 Air Force Commander K .A.Vershinin approved TTT to a light attack aircraft Yak-36M vertical takeoff and landing with lifting and sustainer engine R-27B-300 and RD-lifting 36-35FV.



You're obviously selectively quoting (knowingly or not). If you track through enough articles you'll realise that Lockeed Martin JSF prototype design was changed after consulting data from Yakovlev. The total cost of the transaction was speculated to vary from between tens of millions of dollars to $400M USD for several protypes and an evolved version of the Yak-141 that has very similar specifications and looks to the current JSF. I'm reasonably certain that Lockheed Martin gained far more then just V/STOVL data.If you can not see similarities in specifications, drawings, between evolved designs of the Yak-141 and the JSF then you are lying to yourself, blind, etc...The only question I have is over what articles are authentic.Yak-36 and Yak-38Harrier Hover CapabilityI've worked with certain types of people before. They try to take credit even if it's not entirely deserved. In this case, I think you just need to give some credit to others. If the US were to suddenly weaken or disappear from the face of the Earth life would be a bit strange at first but it would go on, just in a different form.Your tone sometimes seems to imply that it's almost as though only US citizens have the ability to think which is ridiculous? Several countries were working on SVOTL aircraft in the 1960s at exactly the same time US and Soviet Union were. There have been experiments with been supersonic SVTOL aircraft since 1950s and we know that through history the US has tried to shut down advanced work which can rival that of the US. Other countries have to work on some stuff in secret.