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

Unread postPosted: 29 Dec 2011, 19:48
by hcobb
Raise your hand if you think the F-35B will have the most reliable engine for a single engine jet fighter, as promised.

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

Unread postPosted: 29 Dec 2011, 20:42
by alloycowboy
Reliability relative to what?

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

Unread postPosted: 29 Dec 2011, 20:51
by Shaken
So what single engine fighter do you believe is blessed with the most reliable engine? The MiG-21 perhaps?
The early F-16/F100 years weren't marked by stellar reliability and I don't imagine the JF-17 and J-10 are setting any records. I don't know how the various Dassault products fare, but I honestly suspect the current F-16 versions are somewhat more reliable than the M2000 (because they get a lot more debugging and overall investment due to the larger number in service and successive growth).

I predict there will be several engine-related incidents over the first ten years of service and much hyperbolic press coverage will accompany them. (Twin-engine advocates will crow that the predicted doom has arrived across many a forum.) Then we WILL see the most reliable single-engine fighter engine deliver on its promise reliability. Any new engine takes a little bit of time to get the last kinks worked out, but both Pratt and GE have delivered successively more reliable engines year after year. I see no reason to think the F135 will break that trend.

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

Unread postPosted: 29 Dec 2011, 20:57
by neptune
What matrix, no other jet driven lift fan system in production?

-Single engine jet?
-Compared to recent (modern manufacturing) or ever?

Please provide more definition for your question.

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

Unread postPosted: 29 Dec 2011, 21:27
by hcobb
I meant in relation to other single engine jet fighters. The F-35B adds lots of lovely complexity:
* All that gearing and ductwork.
* Highly weight constrained.
* Using all sorts of brand new processes and materials.

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

Unread postPosted: 29 Dec 2011, 21:31
by tacf-x
It will be far more reliable than the XFV-12A for sure! ;)

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

Unread postPosted: 29 Dec 2011, 21:49
by thestealthfighterguy
hcobb wrote:Raise your hand if you think the F-35B will have the most reliable engine for a single engine jet fighter, as promised.

Your poll dosn't have a yes so I guess it can't be. TSFG

RE: Re: F-35B will have the most complex single engine for a

Unread postPosted: 29 Dec 2011, 23:27
by velocityvector
It depends. How good are the engine maintainers in service with your particular country?

Re: RE: F-35B will have the most complex single engine for a

Unread postPosted: 29 Dec 2011, 23:44
by neptune
hcobb wrote:I meant in relation to other single engine jet fighters. The F-35B adds lots of lovely complexity:
* All that gearing and ductwork.
* Highly weight constrained.
* Using all sorts of brand new processes and materials.


After the development is completed about Block 3.0? The steady-state production should be optimised. Those planes, at that time, will experience IHMO greater reliability than previous single engine fighters. This is enhanced by the new maintenance system "Autonomic Logistics Information System" (ALIS) and Computerized Maintenance Management System which can download and analyze the inflight records from each system. Those A-799 "gripes" (nothing found) can now be identified as "which" loose connection that only occurs above 7gs, etc.

RE: Re: RE: F-35B will have the most complex single engine f

Unread postPosted: 30 Dec 2011, 01:33
by alloycowboy
hcobb is right, we should stop developing all new technology!


Image

RE: Re: RE: F-35B will have the most complex single engine f

Unread postPosted: 30 Dec 2011, 05:44
by Code3
hcobb...is there a reason you won't let anybody vote "yes"?

RE: Re: RE: F-35B will have the most complex single engine f

Unread postPosted: 30 Dec 2011, 06:49
by hcobb
hcobb...is there a reason you won't let anybody vote "yes"?
The absence is tongue in cheek, really.

I personally have grave doubts about how well the F-35B will work, once the Marines get it down in the mud and the gravel.

Surely the same service can not be proudly stating both of these things:

The Marines are planning to use the F-35B from "unimproved surfaces at austere bases" and are preparing landing spots with "special, high-temperature concrete designed to handle the heat from the JSF".

RE: Re: RE: F-35B will have the most complex single engine f

Unread postPosted: 30 Dec 2011, 08:06
by spazsinbad
Some of the issues described by hcobb above are overstated. There are quite a few threads on this forum describing how USMC intend to use their F-35Bs both ashore and afloat. Simply put no aircraft does well down in the mud and gravel. So what gives there? The reporter suggesting 'heat issues' for concrete was repeating the self praise of the concreter. That heat issue has been covered in the vertical landing threads. The F-35B heat/exhaust environment is similar to the AV-8b, which is well known to the Marines. They know how to deal with it - even if some find that difficult to understand.

RE: Re: RE: F-35B will have the most complex single engine f

Unread postPosted: 30 Dec 2011, 08:43
by alloycowboy
@ hcobb... Because the F-35B has a 450 NM combat radius vs the AV-8B's 300 NM combat radius it is not going to need as austere basing very often. Their aren't very many places in the world that are more then 800 KM away from a paved runway.

RE: Re: RE: F-35B will have the most complex single engine f

Unread postPosted: 30 Dec 2011, 09:40
by FlightDreamz
Really should have had some "yes" answers in this poll (even if the "yes" came with some caveat's)! :roll: I agree with Shaken and alloycowboy all new technology will have it's "teething" phase, but I believe the F-35A & C will prove to have a good single engine track record. And the F-35B will be light years beyond the AV-8 Harriers once they get all the kinks worked out of the lift fan doors, auxiliary air inlets, etc. see http://www.aviationweek.com/media/image ... taway.html

RE: Re: RE: F-35B will have the most complex single engine f

Unread postPosted: 30 Dec 2011, 09:47
by spazsinbad
http://www.aviationweek.com/media/image ... taway.html)
"You have reached this page in error. Please log in"

Lose the ')' and: http://www.aviationweek.com/media/image ... taway.html WORKS! :D

Great interactive Cutaway.

RE: Re: RE: F-35B will have the most complex single engine f

Unread postPosted: 30 Dec 2011, 14:09
by JetTest
Another thing hcobb seems to miss is that the specially prepared hardened landing pads are designed for very long-term use supporting probably thousands of take-offs and landings at a fixed operating base. Landings at any austere base will total orders of magnitude less for any given spot.

RE: Re: RE: F-35B will have the most complex single engine f

Unread postPosted: 31 Dec 2011, 00:03
by That_Engine_Guy
Harriers would damage surfaces if not kept moving or landing in different areas, unless that is they are landed on 'specially prepared hardened landing pads'

Ever notice at airshows, when a Harrier would perform, they would typically NOT perform a vertical take off or landing. They were almost always STOL? And when performing a hover, the Harrier would be high enough to not damage said airport's landing or taxi surfaces (or sling chunks of sod from the infields).

Yes the F135-PW-600 will be the most complicated single engine EVER! Much the engines used in military aircraft before it were often called 'the most complicated'.

We don't have the best fighters in the world because we're using outdated engines with lack-luster technology or performance, otherwise the tried-and-true J75-P-17 from 1955 (which still holds the air breathing single engine speed record in the F-106) would be the 'standard' engine for new US fighter programs!

Likewise, IF the F136-GE-600 had seen production it would have run neck-in-neck with the PW motor as they would have shared the -600 gear common to both types. Both motors would have been complicated enough in the -100/400 types, but the added components of the -600 would have doubled their complexities.

Yes there will be engineering challenges, PW has already had to address drive shaft, lift post and clutch issues not foreseen when the 'requirements' were provided and/or contracted initially. In-flight testing has proven that modeling and simulation will still not provide a 100% solution to flight testing.

Yes there will be concerns, with ANY new propulsion system there will be tension.

Yes there will be incidents (God willing nobody will be hurt) but we learn from these to make even MORE reliable engines. Nobody is perfect, these propulsion systems are the results of decades off data, years of engineering and planning, dozens if not hundreds of contractors, all working for a common goal. Keep our pilots safe, and give them the best propulsion system to fit their needs.

NO this does not mean you get everything you want in an engine, aviation is a huge compromise. Get this, take that. More power, more fuel, bigger tanks, more weight, bigger wings, more drag, more power, bigger engine, more fuel, bigger tanks.....

Complex is complex whatever company builds it, if that is what you were getting at...

You obviously have NO IDEA what modern military augmented gas turbine engine looks like inside, how they're manufactured, built, operated, maintained, modified, matured, studied, cataloged, tracked, funded, forecast, or designed. Computers (FADECs), sensors, resolvers, solenoids, electronics, lines of code, MIL specs, software and interfaces; built in redundancy and fail safes; 4 or more levels of fault accommodation built into the system to provide 'reliable' power even when things do go wrong.

All of this equipment not only has to work correctly, but it has to last! The engines today far out-live the the previous generation of military jet engines.

Early F100s (also the most complex motors of the late 60's) had 800 hour overhauls on hot section components; today the latest F100-PW-229 EEP (with a helping of F119/F135 tech built in) will last 6000 engine cycles (8-10-12 years! depending on use)

The Jumo 004 of the ME262 had a 50 hour TBO in the 1940s (Though they rarely lasted that long without failing)

If I was a MOD I'd be changing the 'vote' options or deleting the 'vote' portion of the tread all together.

Seems like this was a personal talking point, not even a good joke or valid debate.

Where is my bourbon? :wtf:
TEG

RE: Re: RE: F-35B will have the most complex single engine f

Unread postPosted: 31 Dec 2011, 01:45
by alloycowboy
The Engine Guy..... your wrong about the F-135 engine, it's relatively simple compared other aviation engines. Just take a look at Rolls Royce Merlin or Pratt and Whittney Dual Wasp Engine.

Image

Re: RE: Re: RE: F-35B will have the most complex single engi

Unread postPosted: 31 Dec 2011, 01:57
by popcorn
That_Engine_Guy wrote:
If I was a MOD I'd be changing the 'vote' options or deleting the 'vote' portion of the tread all together.

Seems like this was a personal talking point, not even a good joke or valid debate.

Where is my bourbon? :wtf:
TEG

Yup, a loaded question.

Re: RE: Re: RE: F-35B will have the most complex single engi

Unread postPosted: 31 Dec 2011, 02:35
by That_Engine_Guy
alloycowboy wrote:The Engine Guy..... your wrong about the F-135 engine, it's relatively simple compared other aviation engines. Just take a look at Rolls Royce Merlin or Pratt and Whittney Dual Wasp Engine.

If you only consider "Mechanical Complexity" you may have a point. Turbine engines are mechanically simpler in terms of basic operation.

The Brayton Cycle is very simple when compared to Otto Cycle.

Jet engines have almost no 'timing' to speak of, and few moving part compared to a piston engine, either V or Radial.

Visual beauty.... is a stretch; Personally I find almost ANY aviation engine visually striking. :inlove:

But when it comes to overall complexity, the F135 should have everything to date beat!

Electronically speaking the F135 will be the most intelligent (complicated) engine ever produced. This thing will rival the engines of the space shuttle from some of the things I've read.

The F135 team has also issued a contract of its own to Diagnostic software maker Qualtech Systems Inc. of Wethersfield, CT to provide real-time on-board diagnostics for its jet engines. The contract calls for Qualtech Systems to provide fault isolation development software tools and an an on-engine "diagnostic reasoner" as part of Pratt & Whitney's Joint Strike Fighter Engine Prognostics & Health Management (PHM) Program.

PHM will make use of electrostatic and other sensors to monitor such parameters as debris generation, vibration, blade health and lubricating-oil quality. The suite of sensors will constantly monitor approximately 500 data streams, which will be integrated with the F-35's own systems. The complete PHM system has been developed in partnership with NASA Ames, which created vital data-fusion algorithms, NASA Dryden and NASA Glenn, with flight development to be carried out with a C-17. As noted previously, the aim is to predict the need for inspection or parts-replacement, so that, via a satellite link, the airbase or aircraft carrier knows the engine health before the aircraft returns from its mission.


http://www.f-16.net/index.php?name=PNph ... c&p=116344

I hate to say but the intelligence of this engine, coupled with the advanced manufacturing processes, advanced materials, and '-600 portion' of the propulsion system for STOVL; easily outstrips the mechanical complication of the Merlin, Wasp or even the mighty Wasp Major.

The later never had 500 data-streams performing life engine diagnostics to aid maintenance for not only it's self, but it's co-motors longevity/safety over the cycle-life of the engine's use. (If not future military engine programs)

IMO :cheers: TEG

RE: Re: RE: Re: RE: F-35B will have the most complex single

Unread postPosted: 31 Dec 2011, 06:51
by hcobb
The Merlin never had to worry about tapping a small part of the prop thrust and vectoring that off the wing tip.

Re: RE: Re: RE: Re: RE: F-35B will have the most complex sin

Unread postPosted: 31 Dec 2011, 07:55
by That_Engine_Guy
hcobb wrote:The Merlin never had to worry about tapping a small part of the prop thrust and vectoring that off the wing tip.

The Merlin wasn't designed for 3 different airframes, for 3 different operating parameters. Conventional, Naval/Ship-Born, STOVL

The F135 was tailor made specifically for this and given the extra stage of low-pressure turbine and engine control logic specifically for the extra power to drive the -600's LiftSystem.

The F135's low-pressure turbine was designed for minimum pressure loss, and given an extra stage to extract HP with the least amount of engine performance impact. In addition, engine's control system is programmed for the resulting loss of operating pressure ratio when the roll-posts bleed air from the N2 compressor. It also contends with the added load to the low pressure turbine and the restriction of the 3BSM/nozzle bent from the 0* position. Added engine inlets open to allow larger amounts of airflow to help compensate for the low airspeed and increased demand.

This is WHY the F135-PW-600 is THE most complex single engine propulsion system ever devised for a fighter aircraft. The F135-PW-600's LiftFan, drive shaft, clutch, Roll-Posts, and 3BSM make it even more complex that it's -100/400 sisters.

My answer to this question: "YES; the Pratt & Whitney F135-PW-600 (to include RR-USA's LiftSystem) that powers the F-35B is THE most complex single engine fighter engine to date*"

Even though this option was not given in the poll.

Keep 'em flyin' :thumb:
TEG

*that we know about, or are authorized to know about!

RE: Re: RE: Re: RE: Re: RE: F-35B will have the most complex

Unread postPosted: 31 Dec 2011, 13:52
by madrat
What's the difference between the F135-PW-100 and F135-PW-400?

RE: Re: RE: Re: RE: Re: RE: F-35B will have the most complex

Unread postPosted: 31 Dec 2011, 15:31
by spazsinbad
WickedPedia seems to give a good summary but I'm certain the TEG can add more details:

http://en.wikipedia.org/wiki/Pratt_%26_Whitney_F135

http://en.wikipedia.org/wiki/Pratt_%26_Whitney_F135

"The conventional and carrier aviation engines, the F135-PW-100 and F135-PW-400, have a maximum (wet) thrust of approximately 43,000 lbf (191 kN) and a dry thrust of approximately 28,000 lbf (125 kN). The major difference between the -100 and -400 models is the use of salt-corrosion resistant materials.[11]

The STOVL variant, F135-PW-600, delivers the same 43,000 lbf (191 kN) of wet thrust as the other types in its conventional configuration. In STOVL configuration, the engine produces 18,000 lbf (80.1 kN) of lift thrust. Combined with thrust from the LiftFan (20,000 lbf/89.0 kN) and two roll posts (1,950 lbf/8.67 kN each), the Rolls-Royce LiftSystem produces a total of 41,900 lbf (186 kN) of thrust, almost the same vertical lifting force for slow speed flight as the same engine produces at maximum afterburner, without the extreme fuel use or exhaust heat as wet thrust.[12]

The STOVL variant engages a clutch to extract around 35,000 shp (26,000 kW)[citation needed] from the LP turbine to turn the forward lift fans, while switching power cycle from mixed (turbofan) to unmixed (turboshaft). Power is transferred forward through shaft to a bevel gearbox, to drive two vertically mounted contra-rotating fans. The uppermost fan is fitted with variable inlet guide vanes and the fan discharges efflux (low-velocity unheated air) through a nozzle on the underside of the aircraft. This cool air from the lift fan has the added benefit of preventing hot exhaust gases from the core section from being reingested into the engine while hovering. Finally, bypass duct air is sent to a pair of roll post nozzles and the core stream discharges downwards via a thrust vectoring nozzle at the rear of the engine.[3] Measured by lift thrust in full vertical lift mode, the engine operates as 43% turbojet, 48% turboshaft, and 9% turbofan."

RE: Re: RE: Re: RE: Re: RE: F-35B will have the most complex

Unread postPosted: 31 Dec 2011, 15:40
by spazsinbad
The Shaft Driven Lift Fan Propulsion System for the Joint Strike Fighter
Paul M. Bevilaqua ASTOVL Program Manager
Lockheed Martin Skunk Works Palmdale, California

http://www.dtic.mil/dticasd/sbir/sbir032/n184.doc (5.5Mb)

"Abstract
Analysis and testing are used to show the feasibility of an innovative shaft driven lift fan propulsion system for supersonic STOVL aircraft. Dual cycle operation of the cruise engine makes it possible to convert some of the jet thrust to shaft horsepower for driving the lift fan. Operation of the propulsion system is described and it is analytically shown that the designs of the engine, drive shaft, and clutch are within the state of the art. A demonstrator engine and lift fan were assembled from available components and operated for almost 200 hours in a full size airframe model. Testing proved the feasibility of changing the engine cycle to drive the lift fan, and of rapidly transferring thrust back and forth between the engine and lift fan to provide pitch control. The durability of the mechanical drive system and flight weight gearbox were also demonstrated."

The .DOC file has a lot of text explanations and illustrations about how the STOVL engine works.

RE: Re: RE: F-35B will have the most complex single engine f

Unread postPosted: 31 Dec 2011, 16:59
by Lieven
:: Message from the moderators: Weremoved the 'tongue-in-cheek' poll but we'll leave the thread open for now. We've sent a message to hcobb to refrain from trolling.

If anyone feels like posters are trolling too much, just click the 'Report this post to a moderator' link and we'll look into it. ::

Re: RE: Re: RE: F-35B will have the most complex single engi

Unread postPosted: 31 Dec 2011, 17:00
by discofishing
hcobb wrote:
hcobb...is there a reason you won't let anybody vote "yes"?
The absence is tongue in cheek, really.

I personally have grave doubts about how well the F-35B will work, once the Marines get it down in the mud and the gravel.

Surely the same service can not be proudly stating both of these things:

The Marines are planning to use the F-35B from "unimproved surfaces at austere bases" and are preparing landing spots with "special, high-temperature concrete designed to handle the heat from the JSF".


I have my doubts as well, but I'm hoping LM and the Marines can prove me wrong. I don't see why F-35Cs can't be used at austere bases and on unimproved surfaces.

Unread postPosted: 31 Dec 2011, 17:15
by southernphantom
Hardly surprising, but one can hope that complex doesn't mean unreliable. @alloycowboy old reciprocating engines may *look* complex, but you're ignoring the electronics and software that make modern turbines tick.

Re: RE: Re: RE: Re: RE: Re: RE: F-35B will have the most com

Unread postPosted: 31 Dec 2011, 20:15
by That_Engine_Guy
madrat wrote:What's the difference between the F135-PW-100 and F135-PW-400?

spazsinbad wrote:WickedPedia seems to give a good summary but I'm certain the TEG can add more details



Spaz got it; the -400 is "Navalized" per USN regulation to use specified materials or add special coatings where required for use at sea. (Just as one example, there may be other requirements)

Magnesium has one of the highest galvanic corrosion rates, but is used on jet engines due to it's light weight. The -400 may use another type of material in this case, or require some sort of 'MIL-SPEC' coating to protect it from long term corrosion at sea.

In other words, if a particular air force (land based) decided to purchase F-35C aircraft for a particular tactical reason, the user could opt for the cheaper/lighter F135-PW-100 to be installed. I would see no reason why a foreign military would want to pay for USN requirements for their engines if they didn't need too... esp considering life-cycle costs for the 'special' materials, coatings, and processes; it could be significantly cheaper to maintain over 20 years. (You're already paying for wing-folds, heavy gear, massive hook, etc...)

Keep 'em flyin' :thumb:
TEG

Re: RE: Re: RE: Re: RE: Re: RE: F-35B will have the most com

Unread postPosted: 31 Dec 2011, 20:28
by neptune
That_Engine_Guy wrote:
madrat wrote: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 :)

Re: RE: Re: RE: Re: RE: Re: RE: F-35B will have the most com

Unread postPosted: 31 Dec 2011, 20:41
by That_Engine_Guy
neptune wrote: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.

:cheers: TEG

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

Unread postPosted: 17 Jun 2014, 16:38
by spazsinbad
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)

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

Unread postPosted: 21 Nov 2014, 02:24
by spazsinbad
X-35B VLs & LiftFan Development


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

Unread postPosted: 12 Oct 2015, 17:36
by tritonprime
Rolls-Royce video for the Rolls-Royce LiftSystem


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

Unread postPosted: 14 Aug 2018, 02:02
by spazsinbad
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.

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

Unread postPosted: 14 Aug 2018, 10:44
by spazsinbad
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.

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

Unread postPosted: 19 Apr 2020, 15:42
by flaggy

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

Unread postPosted: 21 Apr 2020, 13:11
by mixelflick
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..

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

Unread postPosted: 21 Apr 2020, 13:35
by spazsinbad
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

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

Unread postPosted: 21 Apr 2020, 14:17
by hythelday
spazsinbad wrote: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 :shock:

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

Unread postPosted: 21 Apr 2020, 15:11
by spazsinbad
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

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

Unread postPosted: 21 Apr 2020, 17:43
by hythelday
spazsinbad wrote: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.

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

Unread postPosted: 21 Apr 2020, 20:18
by spazsinbad
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?

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

Unread postPosted: 22 Apr 2020, 05:43
by hythelday
spazsinbad wrote: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.

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

Unread postPosted: 22 Apr 2020, 07:53
by spazsinbad
hythelday wrote:
spazsinbad wrote: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.

Just because you borrow facts not in dispute does not mean you can guess the rest. In any event I do not care. Find proof.

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

Unread postPosted: 22 Apr 2020, 08:39
by hythelday
spazsinbad wrote:Just because you borrow facts not in dispute does not mean you can guess the rest. In any event I do not care. Find proof.


The guess is a guess, and one can always make it. That's why I guess and suspect, not claim. Do you know exactly what limited design and performance data LM purchased?

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

Unread postPosted: 22 Apr 2020, 08:58
by spazsinbad
hythelday wrote:
spazsinbad wrote:Just because you borrow facts not in dispute does not mean you can guess the rest. In any event I do not care. Find proof.

The guess is a guess, and one can always make it. That's why I guess and suspect, not claim. Do you know exactly what limited design and performance data LM purchased?

A guess is a guess is a guess. I prefer to find evidence and not guess. As mentioned - I don't care and that is not a guess.