Forum: F-35 milestones

About 'the paint' (third entry similar but with added detail).

Production techniques gear F-35 for stealth

http://www.navy.mi.th/nrdo/jane/dev_w/p ... July48.pdf

"...In addition to machining advances that allow LM to achieve high manufacturing tolerances, advances have also been made in the composition of the radar-absorbent structure (RAS) of the aircraft. This Linhart said, is "completely different" from earlier RAS materials in the way it is resistant to chipping, even in the face of bird-strikes...."
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Lockheed Gives a Peek at New JSF Stealth Material Concept by Amy Butler May/17/2010

http://www.aviationweek.com/aw/blogs/de ... 80e3609ae1

"It is called "fiber mat," and Tom Burbage, executive vice president of F-35 program integration for Lockheed Martin says it is "the single, biggest technological breakthrough we've had on this program." He says that a new process to blend stealth qualities into composite material avoided the need for stealthy appliqués and coatings. Using a new process, Lockheed officials are curing the stealthy, fiber mat substance into the composite skin of the aircraft, according to Burbage. It “makes this airplane extremely rugged. You literally have to damage the airplane to reduce the signature,” he said in an interview with Aviation Week in Fort Worth. This top-fiber mat surface takes the place of metallic paint that was used on earlier stealthy aircraft designs. The composite skin of the F-35 actually contains this layer of fiber mat, and it can help carry structural loads in the aircraft, Burbage adds. Lockheed Martin declined to provide further details on fiber mat because they are classified. But the disclosure of this new substance comes at a time when Lockheed Martin officials are arguing that maintenance costs for the F-35 will be lower than anticipated by operators...."
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New Stealth Concept Could Affect JSF Cost By Amy Butler - May 17, 2010

http://www.aviationweek.com/aw/generic/ ... el=defense

"FORT WORTH — As the debate rages about Joint Strike Fighter life-cycle cost, Lockheed Martin officials are raising a previously unheard point to bolster their low-price claims — a new low-observability (LO) substance called fiber mat. Lockheed officials avoided the need to use stealthy appliqués and coatings by curing the substance into the composite skin of the aircraft, according to Tom Burbage, executive vice president of F-35 program integration for the company. It “makes this airplane extremely rugged. You literally have to damage the airplane to reduce the signature,” he said in an interview with AVIATION WEEK. This top-fiber mat surface takes the place of metallic paint that was used on earlier stealthy aircraft designs.

The composite skin of the F-35 actually contains this layer of fiber mat, and it can help carry structural loads in the aircraft, Burbage adds. The F-35 is about 42% composite by weight, Burbage says, compared to the F-22 at 22% and the F-16 at 2%. Lockheed Martin declined to provide further details on fiber mat because they are classified...."

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Thanks Spaz...as usual you have your finger on the pulse while I still have my hand on my.... Embarassed

Salute!

The new stuff seems a lot lighter and more durable than the old "iron ball" used on the Dragon Lady and Habu.

@ Orange: I was 39 when I landed the thing with the flap folded up. Pushing 70 now.

@ Spaz: Keep the stuff coming. It's on my "news, weather, sports" ritual every morning when trying to wake up, heh heh.

Gums sends...

Last edited by spazsinbad on Apr 18, 2012 - 02:10 AM; edited 1 time in total

Onya Gums! ['Onya' is Oz slang for "Good on you" Ozzie Expression of 'BZ' Naval Slang for "Well Done" etc.] And I thought I was old?! Very Happy

SkyDrive has an F-35 PDF with some of that older F-35 stuff in it. With only a 100Mb file size limit it is a pain to make a new one because I'm still working on the 4.4GB PDF. Anyhoo...

'Documents' Folder:
https://skydrive.live.com/?cid=cbcd63d6 ... 07E6%21116
FOR: 'F-35_471Pages_05jul2011+extraVideos.pdf' (100Mb)

OT: Salute to Gums and his cockpit days... and yes, I'm sure Spaz is the kind of man-crush most old-timers on here would wish to wake up with! Or at least have a BBQ and beer with! Now that's some respect...

'geogen' I'm not sure I'm following what you are saying above. Have you spent too many days on an isolated oil rig at sea or somesuch? Very Happy

LoL, spazs playing hard to get as the site's man-crush! (just joking joking here sir, not sure if the transliteration is understood in Aussie speak, but it's all good) Very Happy

Cheers...

[quote="geogen"]most old-timers on here would wish to wake up with!

Shocked

All kiddin aside, does anyone know if the F-35 has an all-composite skin? If it has a vast percentage of composite skin then this tech would trump any naysayers from saying the F-35 is more maintenance intensive than 4th gen stuff, minus the B. With the maintenance and logistic tools, it would actually be less than say a Typhoon IMO, although it does have a greater number of integrated systems. I would be curious to know the maintenance time per flight hour (MT/FH) for the F-22 minus the low observable treatment time. Would the F-22 stack up comparable to 4th gen? I would think the F-35 would be similar...ie more tools, single engine, newer tech, but more systems.

If the F-35 skin is not totally composite, I guess they have to result to more traditional methods for non- composite areas. Kinda limits the retrofit transfer of this tech to the F-22 as well.

Here is some info I could dig up on JSF composites:

The JSF is ~42% by weight composites.

http://www.compositesworld.com/news/loc ... 35-prepreg

More info

http://www.compositesworld.com/articles ... 35-fighter

http://www.aviationweek.com/aw/generic/ ... el=defense

Some more info (great graphic SWP - thanks):

F-35C STEALTH ON THE CARRIER DECK MEANS HIGH PERFORMANCE, LOW MAINTENANCE

http://www.jsf.mil/news/documents/20080 ... ARRIER.rtf

"...The F-35 achieves its Very Low Observable stealth performance through its fundamental design, its external shape and its manufacturing processes, which control tolerances to less than half the diameter of a human hair. Special coatings are added to further reduce radar signature.

The package is designed to remain stealthy in severe combat conditions, and tests have validated that capability. After obtaining baseline radar cross section (RCS) measurements from a highly detailed, full-scale Signature Measurement Aircraft (SigMA), a team of Lockheed Martin and Northrop Grumman engineers intentionally inflicted extensive damage – more than three dozen significant defects – on the model. The damage represented the cumulative effect of more than 600 flight hours of military aircraft operations. RCS measurements taken after the damage showed that the stealthy signature remained intact.

“Even operating in harsh carrier-deck conditions, the F-35C will require no special care or feeding. In fact, its stealth adds very little to the day-today maintenance equation,” O’Bryan said. “We’ve come a long way from the early stealth airplanes, which needed hours or even days of attention and repair after every flight. The F-35 not only avoids that intensive level of upkeep, it will require significantly less maintenance than the nonstealth fighters it is designed to replace.”
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THE F-35 LOW OBSERVABILITY’S LIFELONG SUSTAINABILITY: A REVOLUTIONARY ASSET FOR 21ST CENTURY COMBAT AVIATION

http://www.sldinfo.com/?p=6065

"...Performance-wise, it is a very aggressive capability. From a design standpoint, it is a radical change from legacy systems. In legacy stealth, the stealth in effect is a parasitic application of a multiple stack-up of material systems done in final finish after the actual airframe is built and completed. In the case of the F-35, we’ve incorporated much of the LO system directly into the air frame itself. The materials have been manufactured right into the structure, so they have the durability and lifetime qualities. It makes them much more impervious to damage. It is a much simpler system with fewer materials to contend with....

...From day one, the supportable LO has been a key entity on the program and has had a profound influence on the very design of the airplane. In fact, the element that is manufactured into the skin was an initiative brought about by our LO maintenance discipline...."
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Composites Machining for the F-35 Aug? 8/3/2010 Article From: Modern Machine Shop, Peter Zelinski, Senior Editor

http://www.compositesworld.com/articles ... r-the-f-35

“...Lockheed Martin’s precision machining of composite skin sections for the F-35 provides part of the reason why this plane saves money for U.S. taxpayers. That machining makes the plane compelling in ways that have led other countries to take up some of the cost. Here is a look at a high-value, highly engineered machining process for the Joint Strike Fighter aircraft....

...The F-35 features “supportable” VLO. That is, the VLO on this plane comes with very low maintenance cost. Stealth aircraft of the past couldn’t make that claim. Because radar detects sharp edges, even small mismatches between exterior parts on past VLO planes were smoothed out using epoxy. The epoxy would dry, harden and separate in the field—meaning it had to be frequently inspected and replaced.

By contrast, adjacent parts of the F-35 match so fluidly and precisely that no epoxy is needed. The trouble with previous stealth aircraft has disappeared....”
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Graphic from: http://www.box.com/shared/3uo7o5qt25e2x6ylc294

sufaviper wrote:

Can they not make the RAM paint in more than grey scale? How about some colors (or colours, depending on what side of the pond you are on).

Sufa Viper

The trouble is getting colors that are non-reflective on IR

First Flight of the First U.K. F-35 VIDEO

http://www.youtube.com/watch?v=mNYD-F8SXfc

"Published on Apr 18, 2012 by LockheedMartinVideos
The first flight of the first F-35 for the United Kingdom on April 13, 2012. Lockheed Martin test pilot Bill Gigliotti flew the F-35B aircraft, known as BK-1, which is also the first international F-35 to fly. The jet will complete a series of company and government checkout flights prior to its acceptance by the U.K. Ministry of Defence."

spazsinbad wrote:

The F-35 is about 42% composite by weight, Burbage says, compared to the F-22 at 22% and the F-16 at 2%. Lockheed Martin declined to provide further details on fiber mat because they are classified...."

42% of which F-35 weight condition, empty, fueled, or fueled and armed?

I'm pretty sure Burbage meant to say the F-35 STRUCTURE is about 42% composite by weight. Normally a fighter structural weight will be roughly 50% of weight empty, as engines, landing gear, flight controls, ECS, avionics, etc. are about the same total weight as the structure.

If the weight empty is 29,000 lb, that means the structure is about 14,500 lb and the composites are 42% of the 14,500 lb, or about 6000 lb. That is a lot of composite, but nowhere near "the F-35 is about 42% composite by weight".

delvo wrote:

And it's why F-22s have irregular splotches of color, so that the boundary lines you'd see between color areas aren't in the shape of a plane.

I've been wondering for a long time why the F-35 didn't get a paint scheme similar to the F-22. Instead we get a Duct Tape On The Fuselage scheme. Odd. methinks.

Some more info. A long article with only one part excerpted below:

Skinning the F-35 fighter Author: Jeff Sloan , Editor-in-Chief 19 Oct 2009

"Fastening the all-composites skin on the Lightning II requires machining and drilling technology that is optimized for cost-efficiency."

http://www.compositesworld.com/articles ... 35-fighter

"...Big job on a tight budget
One of the challenges of manufacturing a fighter that is marketed, in part, as budget-friendly, is that special care must be taken to cost-optimize every component of the plane. This is perhaps most true for the F-35’s carbon fiber composites, which comprise approximately 35 percent of the structural weight and most of the visible surface on the fighter. And with fuselage sections, wings, and tails coming from different suppliers, the biggest challenge Lockheed faces is managing the aircraft’s composite skin thickness.

Don Kinard, technical deputy, JSF Production Operations, at Lockheed Martin Aeronautics, says the company spent considerable time evaluating a variety of material types — composites, aluminum, titanium and steel — for the aircraft frame and skin to establish a cost/benefit ratio that was the most cost-effective.

“Can we make an all-composite fighter jet?” asks Kinard. “Sure, but we don’t do something just because we can. Everything is a cost-benefit analysis. Where are the best places to most efficiently use composites?” He notes that composite substructures were evaluated for the F-16, F-22 and F-35, but didn’t provide the weight savings needed to justify cost. “We needed to save a lot more weight for composite substructures to make sense,” he says. Also, he notes, in composites substructures, “z-directional properties are the problem. The strength of resin will have to be significantly improved. There’s a lot to overcome.”

As a result, composites on the F-35 are used almost exclusively in skin applications. Kinard notes that Lockheed, wherever in-flight service temperatures allow, uses carbon fiber/epoxy from Cytec Engineered Materials (Tempe, Ariz.), but much of the plane’s skin requires higher heat resistance, where Cytec’s CYCOM 5250-4 bismaleimide (BMI) is used. Although Lockheed is evaluating the new crop of out-of-autoclave (OOA) resins for special applications, Kinard foresees no near-term changes in the matrix.

During the F-35’s SDD phase, production of skin sections has differed, depending on the supplier, the part’s complexity and cost effectiveness. ATK, for instance, uses automated fiber placement (AFP) technology to produce many of the wing composite parts. Lockheed internally chose to produce the forward fuselage skins using hand layup. As the F-35 enters production, more domestic and international aerospace suppliers will be involved with composite part production, including Alenia Aeronautica (Rome, Italy), Kongsberg Defence Systems (Kongsberg, Norway) Terma A/S (Grenaa, Denmark), TAI (Istanbul, Turkey) and others. “We’re leveraging the capacity of the entire world in terms of composites fabrication,” contends Kinard.

Kinard says much of his and Lockheed’s F-35 composites energy is focused on managing the thickness of the composite skins. This is accomplished via addition and subtraction of composite plies based on careful metrology in some cases and by machining of parts in other cases.

Kinard says consistency of composite skin thickness is critical for the weight-, performance- and cost-conscious F-35. Lockheed and its partners use two methods to make sure skins meet thickness targets: Machining or post-mold ply additions. At Lockheed Martin in Fort Worth, forward fuselage skins are hand-layed on Invar 35 tooling and cured in one of three large autoclaves built by Taricco Corp. (Long Beach, Calif.). Sacrificial plies cured into the laminates are subsequently machined to control thickness of the skins. At ATK, fiber-placed skins for the wing are cured and, following cure, skin thickness is precisely measured using a process developed by Lockheed Martin’s Manufacturing Technology & Production Engineering personnel. If needed, additional plies are layed up and the entire structure is cured a second time in a process called cured laminate compensation (CLC). “The Holy Grail here is to control thickness,” he says, but points out that cost dictates the strategy for doing so...."

Forum: F-35 milestones

UK's first F-35 flies [the IRONIC 'B' Model] :-)