F-35B will have the most complex single engine for a jet

What's the difference between the F135-PW-100 and F135-PW-400?

..
TEG

LRIP 5 is about $3 million (10%?) difference on each $26 million (approx.) engine, navalized as Teg indicated.

btw, I have yet to locate the type cost for the Navy Dept. LRIP 4 engine purchase contract, if available?? Happy New Year

LRIP 5 is about $3 million (10%?) difference on each $26 million (approx.) engine, navalized as Teg indicated.

When looking at LRIP contracts or engine contracts as a whole don't forget this is not a completely accurate measurement of 'per engine' price...

When you read the contract it states; "This low rate initial production (LRIP) contract includes production, spare parts, sustainment and delivery of [this] lot of F135 engines."

So nobody knows (without seeing the contract's breakout) what 'spare parts, sustainment, and delivery' actually costs?

Ever purchased a spare parts for military jet engines? Tooling/support equipment isn't cheap either.

TEG

Some old words from Bevilaqua about the LiftFan/Engine concept for the F-35B - note the compromises taken overall.

Joint Strike Fighter PERSPECTIVES
Code One Magazine July 1996 Vol. 11 No. 3
Paul Bevilaqua, Lift-Fan System Inventor

Paul Bevilaqua could claim that he has been working on the Marine and Royal Navy variant of the Joint Strike Fighter since 1985, when he began researching short takeoff and vertical landing technologies on a NASA project at the Skunk Works. His subsequent work led to a patent in 1990 for the lift-fan concept used in the Lockheed Martin STOVL variant.

"The goal of those early studies was a supersonic STOVL aircraft," Bevilaqua explains, "but at that point, we were designing airplanes, not inventing propulsion systems. Several companies were conducting similar studies. Everyone was reworking old concepts or looking at new concepts that didn't provide any real advantage. NASA was disappointed in the lack of innovation."

As these studies ended, the Advanced Research Projects Agency asked the Skunk Works if it could come up with any new ideas. "We started from the beginning," Bevilaqua recounts. "First, we looked at all the old ideas that hadn't worked and tried to understand why they hadn't worked. From that study, we made a list of requirements for an ideal supersonic STOVL propulsion system.

"Then we used a variety of brainstorming and creativity exercises to come up with a new concept," Bevilaqua continues. " The technique that worked broke the problem down into its fundamental elements. Since modern fighters have a thrust-to-weight ratio greater than one, the basic problem is to get half of the thrust from the back of the airplane to the front. The simplest solution is to duct it there, but ducting makes the airplane too wide to go supersonic. So we looked for other ways to extract energy from the back, transfer it to the front, and produce lift.

"We generated a lot of wild ideas involving energy beams and superconductivity," Bevilaqua says. "but none worked out until we looked at a variable-pitch turbine to extract power from the jet exhaust. From that point, everything just started falling into place."

From these ARPA studies, the Skunk Works recommended two STOVL approaches: a gas-driven fan and a shaft-driven fan. ARPA liked both of them. "We thought the shaft-driven fan was the better concept," Bevilaqua says. "However, the gas-driven fan was perceived as being less risky. Propulsion engineers are familiar with ducting gases through an airplane. But the idea of shafting 25,000 horsepower was new. People were uncomfortable with the magnitude of the number. But there's really little to fear. The shaft inside a jet engine is already transferring around 75,000 horsepower."

A lift fan concept involves two STOVL-related problems at once. "The lift fan system efficiently transfers thrust from the back of the airplane to the front," Bevilaqua explains. "At the same time, it increases the total thrust of the engine because it increases the bypass ratio from a relatively low one associated with fighter engines to a high one for vertical flight. In other words, it makes the airplane more like a helicopter in the vertical mode.

"The Harrier makes a similar approach," Bevilaqua continues. "It has a large fan to augment the thrust of a small engine core. But the airplane has to live with that fan in the cruise mode. Because the fan is so large, the airplane can't go supersonic.

"Our lift fan approach is like taking that one large fan on the Harrier's engine, breaking it into two smaller fans, and turning off one of the smaller fans when the airplane converts to the cruise mode," he explains. "The concept doesn't compromise the other JSF variants. Our STOVL concept requires twin inlets, what we call bifurcated inlet ducts, to create the space needed for the lift fan. That is the only design requirement. And bifurcated ducts have low-observable and performance advantages that improve all of our JSF variants."

Source: http://www.codeonemagazine.com/images/C ... 8_7528.pdf (13.8Mb)

X-35B VLs & LiftFan Development

Rolls-Royce video for the Rolls-Royce LiftSystem

As recorded on previous page 2/3rds of way down the BEVILAQUA 5.5Mb DOC is no longer available at this URL:

http://www.dtic.mil/dticasd/sbir/sbir032/n184.doc

Through the miracle of MsOneDrive with native Word Viewer this DOC has been made into a small PDF corrected in next message. NOW only the original DOC file is attached here.

Attached is 8 page PDF with graphics ERRORS corrected (2 missing are on the end page now) & thankfully SMALL file size.

Now this same PDF is attached as a 2 page spread reprinted so only FOUR pages in this version but all correctevue also.

https://youtu.be/nnCQZ7GcYmA

Fantastic piece of engineering... masterful.

But really, do we care how complex it as so long as it works? And apparently it works very, very well. In fact I don't think China/Russia can come anywhere close and this is part of the reason you don't see a Chinese STOVL J-31 in the works. The Russians have been a bit more successful in their STOVL designs, but honestly - not anywhere close to the F-35.

The YAK-141 was a supersonic STOVL design going back to the 1980's. By it is infinitely less capable, certainly not stealthy and unlikely to be procured in any meaningful numbers. The question thus becomes, whatever became of the former Soviet's design?

https://www.youtube.com/watch?v=D3T9sA3Ymh0&t=591s

Well, parts of it made it into the F-35. In any case, the Russians seem to have re-kindled their interest in a like design. I just don't think the rubles are there, and perhaps no longer the expertise..

Oh dear, here we go around and around - this story is telling about said YAK-141 and NO BITS WERE BORROWED From it.

Search forum with 'RENSHAW' and four hits will be found citing this same story.

F-35B Lightning II Three-Bearing Swivel Nozzle
12 Aug 2014 Kevin Renshaw

"...Russian Swivel Nozzle Designs
A great deal of misinformation has appeared on the Internet regarding the relationship of the Soviet Yak-41 (later Yak-141), NATO reporting name Freestyle, to the X-35 and the rest of the JSF program. The Pratt & Whitney 3BSD nozzle design predates the Russian work. In fact the 3BSD was tested with a real engine almost twenty years before the first flight of the Yak.

Throughout the 1970s and 1980s, the Soviet Navy wanted a supersonic STOVL fighter to operate from its ski jump equipped carriers. At what point the Yakovlev Design Bureau became aware of the multi-swivel nozzle design is not known, but the Soyuz engine company created its own variant of it. The Yak-41 version of the nozzle, from published pictures, appears to be a three-bearing swivel duct with a significant offset “kink.” The Yak-141 also used two RKBM RD-41 lift engines – an almost identical arrangement to the Convair Model 200 design. The aircraft was also re-labeled as a Yak-141 to imply a production version, but no order for follow-on series came from the Russian Navy.

The Yak-141 was flown at the Paris Airshow in 1991. The flight displays of the Yak were suspended when the heat from the lift engines started to dislodge asphalt from the tarmac. At the 1992 Farnborough show, the Yak was limited to conventional takeoffs and landings with hovers performed 500 feet above the runway to avoid a repeat performance of asphalt damage. But the Yak-141 does deserve credit for being the first jet fighter to fly with a three-bearing swivel nozzle – twenty-five years after it was first designed in the United States.

During the early days of the JAST effort, Lockheed (accompanied by US government officials from the JAST program office) visited the Yakovlev Design Bureau along with several other suppliers of aviation equipment (notably also the Zvezda K-36 ejection seat) to examine the Yakovlev technologies and designs.

Yakovlev was looking for money to keep its VTOL program alive, not having received any orders for a production version of the Yak-141. Lockheed provided a small amount of funding in return for obtaining performance data and limited design data on the Yak-141. US government personnel were allowed to examine the aircraft. However, the 3BSN design was already in place on the X-35 before these visits.

The 3BSD was invented in America in the 1960s, proposed by Convair to the US Navy in the 1970s, first flown by the Russians in the late 1980s, re-engineered from the 1960 Pratt & Whitney design for the X-35 in the 1990s, and put into production for the F-35 in the 2000s. Sometimes a good idea has to wait for the right application and set of circumstances to come along. One moral of this story is not to throw out good work done in the past. It just might be needed later on.

Kevin Renshaw served as the ASTOVL Chief Engineer for General Dynamics and was later the deputy to Lockheed ASTOVL Chief Engineer Rick Rezabek in 1994 when the 3BSD concept was incorporated into the X-35B design. Renshaw continues to work in the Advanced System Development branch of Skunk Works where he is currently working on flight demonstration of the DARPA ARES VTOL UAV program.

Source: http://www.codeonemagazine.com/article.html?item_id=137

Oh dear, here we go around and around - this story is telling about said YAK-141 and NO BITS WERE BORROWED From it.

I also suspect they were interested in automatic ejection seat of the Freestyle, since that piece of tech was really unique and quite an achievement (or more likely the command logic behind that). The same family of seats were also used Buran and rated for M3.5 at 115000 feet ejections

Martin Baker makes the Mk.16 ejection seat with automatic ejection function for the F-35B in STOVL mode if engine fails.

Apologies: according to attached PDF (also found elsewhere this forum) LM makes the auto-eject function:

When All Else Fails
22 Dec 2013 Mark Ayton

"...The STOVL aircraft propulsion configuration results in unique failure mode conditions, which the pilot is not able to react to quickly enough to eject manually. This resulted in the US16E seat interfacing with Lockheed Martin’s auto-eject system which caters for low-altitude, low-speed and adverse pitch attitude escape conditions...."

2 page PDF attached below - ASLO: download/file.php?id=26489 (whatever)

Martin-Baker: Saving Lives in the Family Way
15 Jun 2015 Chris Pocock

"... the F-35B version of the Lightning II has an auto-eject mode. This is designed to function in the specific instance where the STOVL aircraft is in the hover, and the shaft-driven lift fan fails.

In that case, the jet is likely to pitch down sharply, quicker than the pilot can react to fire the seat manually. It will therefore fire automatically while the possibility of escape remains...."

Source: https://www.ainonline.com/aviation-news ... family-way

Martin Baker makes the Mk.16 ejection seat with automatic ejection function for the F-35B in STOVL mode if engine fails.

Apologies: according to attached PDF (also found elsewhere this forum) LM makes the auto-eject function:

When All Else Fails
22 Dec 2013 Mark Ayton

"...The STOVL aircraft propulsion configuration results in unique failure mode conditions, which the pilot is not able to react to quickly enough to eject manually. This resulted in the US16E seat interfacing with Lockheed Martin’s auto-eject system which caters for low-altitude, low-speed and adverse pitch attitude escape conditions...."

2 page PDF attached below - ASLO: download/file.php?id=26489 (whatever)

Martin-Baker: Saving Lives in the Family Way
15 Jun 2015 Chris Pocock

"... the F-35B version of the Lightning II has an auto-eject mode. This is designed to function in the specific instance where the STOVL aircraft is in the hover, and the shaft-driven lift fan fails.

In that case, the jet is likely to pitch down sharply, quicker than the pilot can react to fire the seat manually. It will therefore fire automatically while the possibility of escape remains...."

Source: https://www.ainonline.com/aviation-news ... family-way

There weren't that many Mk16s in 1994, were they? And were they auto-ejecting? My point is that it was unique at the time, Harrier does not have this function if I am not mistaken. The Soviets had an automatic ejectction seat already on the Forger since 1975 (auto-ejection function was tied to fly control computer and could detect if something goes bad during hover). I have not seen this info acknowledged anywhere, but IMO LM would be rightfuly interested in this, since it was a really nifty and unique feature which could be studied. Now that you confirm that auto-eject is developed by LM I am more inclined to believe so.

Not sure IF I want to go further into this Russian auto-eject feature on RUSSIAN AIRCRAFT, however I recall "...I have not seen this info acknowledged anywhere..." reading that certainly there was interest in the west for auto-eject but so what?

Not sure IF I want to go further into this Russian auto-eject feature on RUSSIAN AIRCRAFT, however I recall "...I have not seen this info acknowledged anywhere..." reading that certainly there was interest in the west for auto-eject but so what?

So what? Here-s what:

Lockheed provided a small amount of funding in return for obtaining performance data and limited design data on the Yak-141

You said yourself:

Oh dear, here we go around and around - this story is telling about said YAK-141 and NO BITS WERE BORROWED From it.

If, according to numerous documents provided, including by you, NO BITS WERE BORROWED, then what "performance data and limited design data" was purchased by Lockheed was analysed? I suggest that auto-eject feature was one candidate because that was the only part of Freestyle that was truly unique and of interest to LM.