F35B 1

[rb1957]

does anyone else think that the F35B is a horrible design ? lugging around that lift engine and all it's extra structure must compromise performance.

brings to mind the Russian "Harrier", Yak-38, .... which of course was no Harrier.

maybe we managed to convince the Russians to spend money on the Yak-141 ?

another day in paradise, or is paradise one day closer ?

 

[moon161]

I think Lockheed actually purchased or licensed aspects of the Yak 38/141 design in the 90s.

I think the arranged marriage/shotgun wedding aspects of the program are a lot more far reaching than whether the b variant is ugly or not.

I remember in the 90's when the aim was 'Like an F-16, but stealthy' and the joke was that JASF stood for 'Joint Affordable Strike Fighter'

It may be worth noting that the more and most succussful multirole fighters, F4, F15, F16, F18 were all air superiority programs at the beginning.

 

[moon161]

References Lockheed funding Yakovlev after the soviet collapse

https://taskandpurpose.com/military-tech/f-35-yak-141-freestyle-vtol-jet/

It's funny how propagandistic this article is considering the large number of failed american and european VSTOL fighter concepts there were before the Hawker Kestrel leading to the harrier leading to the AV8B, and that the Yak 141 was the first supersonic VSTOL to make it past prototype.

 

[MintJulep]

I guess that it has valid use cases in some potential theaters.

Less clear if those use cases are "essential".

 

[moon161]

^ That's the 'do marines need planes' question.

 

[moon161]

Cause that drove it, not the 20 or so that the english navy will buy.

 

[moon161]

And also (the sales pitch is), stealth, sensor fusion & networking and so on is that will be effective where the plane is not kinematically dominant.

 

[3DDave]

AFAIK there's no separate lift engine in the F35B. The main design feature is a large lift fan which is a fairly good way to go - it allows a better coupling of engine power into moving air; much better than hot high velocity of jet exhaust as in the AV-8B design.

https://en.wikipedia.org/wiki/Rolls-Royce_LiftSystem

 

[LiftDivergence]

I always thought Air Power Australia sight had great technical coverage with regard to air power - there are many articles related to the F-35 if you look through. Some of it is from an Australian perspective and the articles are a bit old at this point, but still very thorough.

Here are some good places to start with the F-35:

"Lockheed-Martin F-35 Lightning II Joint Strike Fighter -Assessing the Joint Strike Fighter"

http://www.ausairpower.net/APA-JSF-Analysis.html

"Joint Strike Fighter"

http://www.ausairpower.net/jsf.html

(This one links to a bunch of other articles on the F-35).



Keep em' Flying
//Fight Corrosion!

 

[rb1957]

"AFAIK there's no separate lift engine in the F35B. The main design feature is a large lift fan" ... sure, that is what they have in the F35B (that and a steerable exhaust nozzle). But it is still a tonne of weight and volume.

another day in paradise, or is paradise one day closer ?

 

[Comcokid]

F-35B suffers from the same basic project issue of the F-111. Planes that are also a Swiss Knife of features.
F-111 - design a plane to be a nuclear bomber, tactical attack, and supersonic fighter, and it ends up not doing anything well. The pivot for the swing-wing needed to make it do everything was too heavy
F-35B - a multi-role combat aircraft that's stealth, supersonic, and STOVL. Ends up not doing anything well. The components for the lift fan needed for the multi-role and STOVL add too much weight.

If you read the book "Boyd: The Fighter Pilot Who Changed the Art of War" by Robert Coram you begin to understand how these projects come about.

 

[RoarkS]

I've been able to see it up close. I think its structure design a hot mess. Cad/fea nerds armed with a CNC's and a procurement department still trying to make up for f22 losses. I'm pretty sure the design process went like this:

F16 guy: well we could make this out of aluminum sheetmetal...
HR: but then we would have to have trained techs who can rivet and install nutplates. We outsourced that job code.
Purchasing: Eh... just machine the whole thing out of titanium.
Intern: What about the threaded fastener... oh what's a nut plate... make that out of titanium too and use jo-bolts cause the sales engineer took us to lunch last week. By the way... pretty sure we need to invent some custom d-subs cause a 38999 wont fit here... I need this sweet web here to make it look nifty.
Management: Our engineering team has spent too much time on this project... calls engineering...
Engineer A: Wait who is this kid... We're finishing up the back 9 we'll be in about 1:30 after lunch.
Engineer B: Oh it's the airforce liaison officers ex wifes nephew... Is he still working on the flight line reel mount?

Boom... F35.

 

[aerovib]

Eh, I'm not sure that's very fair. I'm pretty sure CFRP composites can have a smaller RADAR return than an aluminum part of same geometry. And carbon and aluminum have galvanic corrosion issues, while carbon and titanium get along well (see page 2) . So I'd think you'd have to have very good electrical isolation of aluminum parts (including rivets), which the designers probably felt they couldn't guarantee for the life of the aircraft. Therefore, titanium parts.

I should mention that I have heard of aluminum rivets being used on composite structure, just the fibers were glass not carbon. So apparently de-lamination during bucking of the rivets isn't necessarily a problem.

edit: I should add this link:

https://www.compositesworld.com/articles/skinning-the-f-35-fighter

about a third of the way through the article it starts talking about the F-35 skin.

 

[thebard3]

RoarkS-
You must have worked at the same companies as me.

Brad Waybright

The more you know, the more you know you don't know.

 

[WKTaylor]

To expand on comments by C'kid...

It seems that USN-developed carrier-based jets have evolved to meet the needs of land-based air forces fairly elegantly... A-4, A-7, F-4, F-18... but jet-aircraft developed primarily for the US Air Force, have NEVER been adapted/suited-for navy/marine forces.

AND the jet-VTOL flight profile seem unsuited for land-bases and fleet-carrier operations... best fit is with the helo/assault carriers [no catapult or wires]. Which makes it a totally different dog.

YEAH... the F-35 concept reminds me of the fabled USAF/USN program from the 1960s for an all-purpose fighter-Bomber... which led to the 'swing-wing' F-111... which was an under-performing fighter-interceptor-recce, a so-so intermediate range medium bomber [FB-111] and was way too heavy/large [no-go] for USN carrier operations. What an ab*rtion finally put-to-bed in the 1990s.

Uniquely, to a moderate degree, the Army/USAF/USN/USMC do 'share' adapted-helicopter types... but that's another story...

BTW... there are numerous organizations dedicated to aircraft types... out of admiration/respect/love... A-4, A-7, A-37, F-4, F-16, F-106, O-2, OV-10, etc-etc-etc... the '-111 Aardvark' has no such following/organization. I had some interesting technical design info/notes on the -111 [structural] and finally gave it to the F-106.org guys hoping it find a home in a museum. PS: the -111 was loaded with 'weight-saving' alloys like 7079-T6 and 7178-T6... which proved to be SCC/EXCO nightmares... not to mention the UHS steel wing carry-thru [fast-fracture critical].

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[rb1957]

this wasn't meant to comment on AF planes being adapter to USN ... just the whole concept feels "totally" flawed.

but that does raise an interesting question ... the USN doesn't have an F35 equivalent. Have they gone beyond the F18 (in it's various guises) ?

another day in paradise, or is paradise one day closer ?

 

[WKTaylor]

RB...

The F-35C is the USN carrier variant. Navy seems reluctant [dragging-its-wet-feet] to 'field' a single-engine jet of that size/complexity/cost for carriers, when it [appears] satisfied with the super-sized twin-engine F-18E/F Super Hornet(s)... which happens to be fairly close in size/capacity/capability to an F-15... both Boeing-St Louis products.

BTW... the only USAF-developed jet to ever make a direct-transition to the USN was the Northrop YF-17 Cobra [F-16 won the USAF fighter competition]. The YF-17 was evolved to the heavier/carrier-capable F-18A/B by MDC-St Louis.

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

 

[Comcokid]

Actually to justify the F-111 the Pentagon tried to get the Navy use it. The version modified for the Navy was designated the F-111B. Seven were built and flown. It had a lot of problems and was heavy. Navy refused even to take money and upgrade it. When was the last time you heard of a military branch refusing money? That lead to the Navy developing the F-14 Tomcat.

 

[verymadmac]

There is an interesting point noted in jan roskam's autobiography (I think) that GD F111 concept won over Concept that the company Roskham worked for produced because they claimed higher commonality with the Navy model and they failed to ID the weight increase due the navy's engine access requirements (with resulted in a Tee shaped primary structure for the rear fuse).

Wasn't the big difference between the F111 & F14 was that welded titanium had matured sufficiently to provide a suitable alternative to high strength steel.

I think the F111's greatest achievement was main streaming fracture mechanics.

 

[RoarkS]

F-35C the USN carrier version... The tail hook was a disaster.
Essentially a clean sheet design of an aircraft that looks like the other F-35s.