Anatomy Of F-35 Development Challenges And Solutions

Variants for different customers or mission profiles
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ricnunes

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Unread post08 Sep 2018, 12:41

element1loop wrote:It's not just a USMC jet though, even Taiwan thinks the B is preferable (for their needs) to the A or C.


Exactly. The UK and Italy are also F-35B users. Spain is also reported to be interested in the F-35B.
The UK in particular is a very important user. I believe one can easily say that the US main JSF partner is the UK - which is the only Tier 1 partner - and this is exclusively due to the STOVL variant of the JSF, the F-35B.
I doubt that if there wasn't STOVL variant of the JSF (F-35B) that the UK would be a JSF partner.
A 4th/4.5th gen fighter aircraft stands about as much chance against a F-35 as a guns-only Sabre has against a Viper.
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Unread post09 Sep 2018, 21:28

The F-35B allows for smaller cheaper cat/trap-free multi-purpose carriers allowing for the maximum global use of F-35. Considering how useful the stealthy F-35 could be not only in a conventional fighter-bomber role but as a missile tracker for SAM's on surface ships there just could not be a better aircraft entering service now in all its variants that enhances combined western global naval air power so much. Don't forget Japan has its eyes on the F-35B too for its helicopter carriers. The F-35C is great but there will be more F-35B on ships around the world. This is also not taking into consideration how useful the F-35B is on land not really needing a dedicated long airfield. The opposition all around the world are screwed from this much derided aircraft !
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Unread post14 Sep 2018, 16:55

Anatomy Of F-35 Development Challenges And Solutions
07 Sep 2018 Graham Warwick

"...Throughout the program, one variant—the short-takeoff-and-landing (STOVL) F-35B with its unique shaft-driven lift fan—drove the defining challenges. The F-35B exists today because of its commonality with the conventional (CTOL) F-35A and carrier-based (CV) F-35C, but all three variants are better aircraft because of the challenges that had to be overcome for it to survive...." [then graphics with numbered list of fixes - lightweight stuff indeed]

Source: http://aviationweek.com/defense/anatomy ... -solutions
RAN FAA A4G Skyhawk 1970s: https://www.faaaa.asn.au/spazsinbad-a4g/ AND https://www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/
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zerion

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Unread post25 Mar 2019, 18:28

I didn’t want to start a new thread so I’m posting this here.
I believe I read somewhere that the A was designed first then adapted for the STOVL B, also that the large engine dictated the wide body and not necessarily the lift fan.
So far my search skills have failed me. Does anyone know what I’m talking about, or am I making things up. :mrgreen:
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Unread post25 Mar 2019, 19:38

You are essentially correct. The "chubbiness" of the F-35 would have been there even if the B never existed.
"The early bird gets the worm but the second mouse gets the cheese."
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Unread post25 Mar 2019, 22:01

zerion wrote:I didn’t want to start a new thread so I’m posting this here.
I believe I read somewhere that the A was designed first then adapted for the STOVL B, also that the large engine dictated the wide body and not necessarily the lift fan.
So far my search skills have failed me. Does anyone know what I’m talking about, or am I making things up. :mrgreen:


Lockheed did state they envisioned a slightly longer narrower fuselage in original designs. Final wingspan and length was largely dictated for the “B” by elevators, the “C” had no such limitations considering spot factor, there were no length/wingspan concerns. As far as the “A”, commonality logically wins, having a longer fuselage, or narrower, etc. would the added cost and complexity offeset any advantage in minor performance gains?

https://apps.dtic.mil/dtic/tr/fulltext/u2/a399988.pdf
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Unread post25 Mar 2019, 23:13

zerion wrote:I didn’t want to start a new thread so I’m posting this here.
I believe I read somewhere that the A was designed first then adapted for the STOVL B, also that the large engine dictated the wide body and not necessarily the lift fan.
So far my search skills have failed me. Does anyone know what I’m talking about, or am I making things up. :mrgreen:


JSF was birthed from what was then JAST ooa 7 August 1995. Amongst many other things, it merged the notional operational needs of that would have been met by the MRF, A/F-X and the CALF (Common Affordable Lightweight Fighter) efforts. Early (pre-PWSC) risk reduction efforts specifically addressed resolution of competing requirements into a 'family' of aircraft, which was not only a technical matter but a political one as well.

We've discussed this here in previous years and I'm sure you can root around here and find it. Spaz can help. There are many who, for differing reasons, want to point to one set of requirements as the defining limitations in the design. Those that design aircraft will tell you that all designs are an amalgam of compromise(s). JSF is no different.
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Unread post26 Mar 2019, 00:52

IF this is helpful then STEVIE THE WONDER I believe has canvassed these ideas extensively here with many external and internal links to information/opinions and suchlike. Searching this forum using 'Design' only without the ' ' I found this ORPHAN post/topic from THE STEVE: viewtopic.php?f=60&t=52754&p=361458&hilit=Design#p361458 Replies anyone? Buehler?

search.php?keywords=Design&terms=all&author=&fid%5B%5D=65&sc=1&sf=titleonly&sr=posts&sk=t&sd=d&st=0&ch=300&t=0&submit=Search
RAN FAA A4G Skyhawk 1970s: https://www.faaaa.asn.au/spazsinbad-a4g/ AND https://www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/
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Unread post26 Mar 2019, 04:53

zerion wrote:I didn’t want to start a new thread so I’m posting this here.
I believe I read somewhere that the A was designed first then adapted for the STOVL B, also that the large engine dictated the wide body and not necessarily the lift fan.
So far my search skills have failed me. Does anyone know what I’m talking about, or am I making things up. :mrgreen:

When the different programs were combined. The C was the driver for the design, USN wanted high lift body sections and 2,000lb bombs and a large load. USMC wanted STOVL. USAF wanted 1,000lb and shorter range, I don't recall the load. So really the A had nothing to do with the design.
Aussie fanboy
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Unread post26 Mar 2019, 05:15

In the internet age and forum search ENABLISEATION it should be easy to find stuff. Have a look at these results &
search.php?st=0&sk=t&sd=d&sr=posts&keywords=Genesis&fid%5B%5D=65&ch=-1

Genesis of the F-35 Joint Strike Fighter by Dr. Bevilaqua: https://www.scribd.com/document/284662003/PaulB-F35

Should be in this F-35 forum somewhere so I should find it IF'n SCRIBD is a problem.

RANDOM LINK from above search: viewtopic.php?f=22&t=25537&p=274779&hilit=Genesis+Bevilaqua#p274779
&
viewtopic.php?f=58&t=12237&p=176068&hilit=Genesis+Bevilaqua#p176068
"Functional analysis has been used to design a common aircraft to replace the U.S. Air Force F-16s, Navy and Marine Corps F/A-18s, and Marine AV-8s. The technical and program challenges involved in developing a common aircraft for all three services were met by designing three highly common, but not identical, variants of the same aircraft. The key elements of this commonality are an innovative propulsion system that can be switched from a turbofan cycle for conventional flight to a turboshaft cycle for vertical takeoff and landing and a basic structural arrangement that can accommodate the substitution of stronger parts in the Naval variant to absorb the greater takeoff and landing loads of carrier operations."


Same document 7.7Mb PDF: http://citeseerx.ist.psu.edu/viewdoc/do ... 1&type=pdf [attached below]
Genesis of the F-35 Joint Strike Fighter 2009
Paul M. Bevilaqua JOURNAL OF AIRCRAFT Vol. 46, No. 6, Nov–Dec 2009, 2009 WRIGHT BROTHERS LECTURE

“...The technical challenges involved in designing a single aircraft for all three services were met by designing three highly common, but not identical, variants of the same aircraft. The STOVL variant, which was designed first, incorporates a shaft-driven lift fan in a bay between the inlet ducts and a thrust-vectoring cruise nozzle. The airframe was designed to Air Force specifications, so that the conventional takeoff and landing variant was developed by removing the lift fan and vectoring nozzles from the STOVL variant and substituting a fuel tank and a conventional cruise nozzle. The Naval variant was similarly developed from the conventional variant by increasing the wing area, designing stronger landing gear, and using stronger cousin parts to handle the larger airframe loads associated with carrier takeoffs and landings. Both the STOVL and Naval variants are about 15% heavier than the conventional variant....”
Attachments
Genesis of the F-35 Joint Strike Fighter - Dr Bevilaqua 12 pages - 10.1.1.174.1142.pdf
(7.65 MiB) Downloaded 188 times
RAN FAA A4G Skyhawk 1970s: https://www.faaaa.asn.au/spazsinbad-a4g/ AND https://www.youtube.com/channel/UCwqC_s6gcCVvG7NOge3qfAQ/
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zerion

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Unread post26 Mar 2019, 23:24

Spaz found what I was looking for. Thanks everybody.
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Unread post27 Mar 2019, 14:07

That was a long read, but I'm glad I did. Sounds like the design challenges of the B made all 3 variants better aircraft.

I'm sold on STOVL now (wasn't before). Consider for example if the Iraqi air force had had STOVL configured jets during DS. Their airfields got cratered, yes. But an operational STOVL aircraft may have allowed them to fight on. Consider also if these were F-35B's. They would have probably allowed Iraq to have some reasonable view of the battlespace, even after having the rest of their eyes and ears taken out.

And they would have been lethal to our 4th generation F-14's, 15's and 16's, nevermind tankers and AWACS. To me, F-35B's greatly complicate Chinese/Russian planning in the event of a conflict. If you take out all of our big runways, you take out virtually all CTOL aircraft. But you'll never know how many B's are out there, still capable of putting up a fight.

Bravo, LM. It'll never be a Raptor in kinematics, but in almost every other respect its a superior fighter. We should be buying more, but that's another topic/thread for another time.
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Unread post27 Mar 2019, 17:01

mixelflick wrote:I'm sold on STOVL now (wasn't before). Consider for example if the Iraqi air force had had STOVL configured jets during DS. Their airfields got cratered, yes. But an operational STOVL aircraft may have allowed them to fight on. Consider also if these were F-35B's. They would have probably allowed Iraq to have some reasonable view of the battlespace, even after having the rest of their eyes and ears taken out.


I would say that the viability, usefulness and above all the effectiveness of STOVL aircraft in actual combat zones was more than proven during the Falklands War (with the Harrier and Sea Harrier).

Now imagine a "supersonic Harrier" with unprecedent Sensor Fusion, Stealth, very big/heavy loadouts, performance such as agility and range that matches "conventional" (non-STOVL) aircraft and above all easy for pilots to operate such as landing vertically (which is something that the Harrier isn't) or resuming an extremely improved Harrier with all its faults solved, what do you get? That's right, a F-35B :wink:
A 4th/4.5th gen fighter aircraft stands about as much chance against a F-35 as a guns-only Sabre has against a Viper.
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Unread post28 Mar 2019, 13:20

Falklands was one example, but I don't think the best.

The best IMO was Desert Storm. We struck every airfield every day of the week and twice on Sundays. I actually believe that had a lot more to do with the fact they didn't come up after the first week vs. they were "scared". The value of STOVL to them would have been massive.

The value of STOVL is more difficult to see if you're the US. When was the last time our bases (or even 1 base) was incapacitated by the enemy? Was a LONG time ago. Looked at from that perspective, STOVL capability and its cost doesn't make much sense. But that was the past. The future is quite clear to see: Chinese IRBM's and possibly hypersonics are going to put our bases in the SCS at risk.

Looked at that way, I'd actually advocate for buying more B's. And not just for the USMC. I think the Air Force should certainly consider it. Because I have a sneaking suspicion the person that gives that the green light is going to look like an absolute genius, if and when trouble with China kicks off.

Does anyone know if the USAF ever gave it any though?
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Unread post28 Mar 2019, 15:53

'mixelflick' asked:
"...Looked at that way, I'd actually advocate for buying more B's. And not just for the USMC. I think the Air Force should certainly consider it. Because I have a sneaking suspicion the person that gives that the green light is going to look like an absolute genius, if and when trouble with China kicks off. Does anyone know if the USAF ever gave it any thought?"

Yes indeedy the USAF did - long ago. Past discussions would have this article amongst it - you need to read it all THOUGH.
USAF: F-35B cannot generate enough sorties to replace A-10
16 May 2012 Dave Majumdar

"The US Air Force has concluded that the short take-off vertical landing (STOVL) Lockheed Martin F-35B- model aircraft cannot generate enough sorties to meet its needs; [BRAINFART] therefore the service will not consider replacing the Fairchild Republic A-10 Warthog close air support jet with that variant....

...USAF chief of staff Gen Norton Schwartz, speaking at an event hosted by the Brookings Institution in Washington, D.C. "But the reality is, is that scenario is not a high sortie generation scenario." The USAF and the US Navy need greater sortie generation rates than the F-35B can provide, Schwartz says. "What we think is needed is high sortie generation in order to provide persistence over the target and to engage the variety of targets that may exist," he says. "Not in a confined battlespace, but more on a theatre basis."...

...Retired Lt Gen George Trautman, a former US Marine Corps (USMC) deputy commandant for aviation, disputes Schwartz's assertion that the F-35B cannot generate as many sorties as the A or C model aircraft. "The F35B has highest sortie generation rate among the three JSF [Joint Strike Fighter] variants," Trautman says. "There may be other reasons the air force doesn't want the B, but sortie rate isn't a factor."

In fact, the USMC's concept of operations depends on the STOVL variant generating more sorties more rapidly than other JSF models, says retired USMC Lt Gen Emerson Gardner, a former naval aviator. The key performance parameters (KPP) for the F-35 require higher sortie rates for the B-model at four sorties per day. The A and C models are only required to generate three sorties per day. "So far in SDD [System Development and Demonstration], all three variants are on track to exceed their KPPs at the completion of SDD," Gardner says. "The B looks to come in at about six sorties per day, the A at about 3.5 and the C at close to four."…"

Source: https://www.flightglobal.com/news/artic ... ac-371985/
Last edited by spazsinbad on 28 Mar 2019, 16:39, edited 1 time in total.
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