Yak-141 'Freestyle'
Comments
1 24 October 2013, 19:40
Michel HuijgheThat looks very nice 👍
So it's a very diffiuclt model to built.
I hope to see it in 1/48th scale to set it next to my Yak-38 and Yak-38U that I still need to build. 🙂
24 October 2013, 20:32
GlennNice job! The F-35 owes much of it's engine vectoring technology to this aircraft!
25 October 2013, 03:07
Sebastijan VidecThanks guys, I'm glad you like her!
Michel - I wouldn't hold my breath to see it someone release it in quarter scale. Although Chinese guys do release prototypes from time to time (like YF-23 just now)
Glenn - that's correct. Although Americans did patent similar nozzle before, Russians were the first to implement in a working aircraft.
Ville - I love Scandinavia - every time I go up North for a holiday, I learn a few basic words
25 October 2013, 07:41
Ville SiltanenHi sebastian.That´s great that you learn basic words. Maybe next when you come to finland you visit our museum.
25 October 2013, 14:42
Bill GilmanNice job! How was the kit to build? I've never built a kit from ART Model before. They do have a nice selection of subjects.
I have to disagree, though, with the comments that the Rolls Royce Lift System in the F-35 is similar to that in the Yak-141.
The Yak-141 uses three separate engines, one for thrust and two for lift. They are "connected" via electronic control systems that allow for all engines to be controlled automatically to maintain stability during transitioning from hover to forward flight. In addition, the Yak has reaction control jets at each wingtip, plus a yaw jet under the nose. This is a very clever system, but not at all like what is used in the F-35.
The Rolls Royce Lift System employs just one engine, the Pratt and Whitney F135. This has a swiveling nozzle in the rear and an axial shaft that protrudes from the front of the engine. This shaft is mechanically coupled to a vertical lift fan located behind the cockpit. When hovering, pitch is controlled by varying the thrust between the main engine and the lift fan. Roll is controlled by bleeding by-pass air through nozzles in the wingtips. Yaw is controlled by swiveling the engine's rear nozzle, and forward/backward movement is controlled by swiveling both the engine nozzle and the lift fan. All of this is done with one engine. Also a clever design, but mechanically very complex and it's had its share of development issues.
What is similar between the two designs is that the lift fan is behind the cockpit and the engine is located at the rear of the fuselage. Other than that, they are very different concepts.
I've read many times on the web that Lockheed "licensed" the engine technology from Yakolev. This is not true, what occurred was that Yakolev looked for foreign funding in 1991 to continue the development of the Yak-141 for export purposes, government money having stopped with the breakup of the USSR. Lockheed entered into a partnership with Yakolev and made an investment. This allowed for the Yak-141 to be exhibited at Farnborough in 1992. Nothing ever came of this partnership however. This is too bad, it would have been very interesting to see what would have happened.
I think that people have confused this partnership with the development of the F-35 (then X-35) which was already well underway. Here is a nice article on the development of the Rolls Royce Lift System:
designnews.com/docum..mp;dfpLayout=article
25 October 2013, 19:02
Sebastijan VidecBill everything you say is true. However Lockheed was struggling with the new technology at the time while the Russians already had it working - funding of the Yak-141 for a short time helped them get an insight of how it was done operationally which helped to boost the X-35 project considerably.
Speaking that Yak-141 didn't have much to do with the F-35B is simply ignoring the facts. Jane's reported that "In June 1994, Lockheed revealed that it had entered into a collaborative relationship with Yakovlev on their bid for the Joint Advanced Strike Technology competition, consisting of the purchase of design data from the Russian company; according to Jane's All the World's Aircraft 2000-2001 this was data from the cancelled Yak-141 program which employed a similar propulsion system."
Looking at the both aircraft from the top you can see Lockheed went for the same aerodynamic design as Yakovlev's engineers did more than a decade before...
26 October 2013, 08:03
Bill GilmanHi Sebastian, thanks for the reply.
If you read my comment again you'll see that I didn't say "the Yak-141 didn't have much to do with the F-35B." I said that the lift designs are not similar, which they are not relative to how they are executed. Hence my description of the hardware used in both aircraft.
The strongest connection between the two, in my opinion, is the swiveling nozzle on the rear of the engine. My understanding is that Rolls Royce studied the Yakovlev R-79 design (the concept of which was first patented by Convair for a USN project; interestingly Convair is one of the Lockheed heritage companies) in building the 3BSN (three bearing swiveling nozzle) unit for the X-35. The Rolls Royce nozzle was further developed into the VAVBN (variable area vane box nozzle) in use on the F-35B. VAVBN is quite different from the R-79, as it is actually part of the aircraft structure, and not just part of the engine.
The shaft driven lift fan (SDLF) on the F-35, since it develops much more thrust (hence lift) than the lift jets used on the Yak-141, solves a big problem that the Yak had, namely having to use afterburner for VTOL and hover. The F-35 does not, only having afterburner in horizontal flight. However USN carrier decks still need special coatings to handle the heat produced by the rear nozzle.
So how was the kit to build? You've done a great job on it, I may want to add one of these to my wish list!
Cheers,
Bill
26 October 2013, 17:44
Sebastijan Videcsorry, was in a bit of hurry and misread your post.
Wasn't a Convair 200 project that was supposed to use this kind of nozzle? [img1] it look really ahead of its time, considering it was '60s design.
Well I can't say much about it, due to the magazine article, but I can say she put up the fight but I managed to tame her 🙂
26 October 2013, 20:50
Bill GilmanYup, that's the one. Which magazine will your article be in? I'll be sure to pick up a copy. 🙂
27 October 2013, 00:26
Burkhard DIf you read the JANE's quote again, the collaboration was on the propulsion system. I seem to remember from similar articles in Aviation Week at the time that this referred to the main engine nozzle arrangement and how to integrate this into the overall design. Saying that the aerodynamic design of the F-35 is based on the Yak-141 is a bit of a stretch. 🙂
27 October 2013, 07:16
Sebastijan VidecNot really. Yak-43 project, which was largely based on Yak-41M (141) project compared with F-35B shape. One has to admit resemblance...
[img1]
27 October 2013, 09:28
Erik HoughtonMuch like the T-50 resembles the F-22; convergent design philosophies, that's all.
27 October 2013, 13:51
Bill GilmanIn my mind, the F-35 is very similar to the F-22 in planform, especially from above. And when you consider that the YF-22 first flew in 1990 it would be a bit of a stretch to claim it was based on Yak-141 data acquired by Lockheed in 1991. I think Erik's comment about convergent design philosophies is correct.
[img1]
27 October 2013, 20:14
