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Modified F-35A with F-35C wing?
Would there be any benefit to an F-35A with the F-35C planform, and without the folding mechanism? Chiefly, would it allow for a greater payload/range and other benefits? How about negatives? Even with the folding mechanism, it looks like the F-35C can haul about 6% more fuel.
Re: Modified F-35A with F-35C wing?
N328KF wrote:Would there be any benefit to an F-35A with the F-35C planform, and without the folding mechanism? Chiefly, would it allow for a greater payload/range and other benefits? How about negatives? Even with the folding mechanism, it looks like the F-35C can haul about 6% more fuel.
No realistic benefit. The F-35A already has an impressive range and the C wing would add drag as well as additional fuel and if you compare the ranges from the last SAR the A model has essentially the same range as the C even with the smaller wing (potentially different reserve fuel weight but the A model profile is more aggressive than the C). You can also see in the acceleration numbers that the C struggles compared to the A with the wing profile being the major distinction.
The A model is a 9G airframe while the C is a 7.5G airframe (both aircraft are rated for 50 degree AoA). Potentially the A model could stay at the same 9G with a larger wing, which would likely require reinforcement increasing weight (almost certainly not as much as the wing mechanism but additional weight nonetheless).
Finally the way the two aircraft handle is a little different. The A is a real blend between the F-16 and F-18 while the C moves more like a SH. That translates to the A model being a very good sustainer as well as instantaneous turner and regains speed exceptionally well. The C model is a better instantaneous turner compared to sustainer (makes sense with more drag from the wing) and likely regains energy marginally slower than the A model.
Re: Modified F-35A with F-35C wing?
If it was beneficial, I'm sure they would have done it. It would save on production costs.
Re: Modified F-35A with F-35C wing?
Wouldnt a larger wing allow better low speed performance. Seeing how the F-35A is replacing the A-10... a lower airspeed version would be useful in the CAS role.
Re: Modified F-35A with F-35C wing?
Oroka wrote:Wouldnt a larger wing allow better low speed performance. Seeing how the F-35A is replacing the A-10... a lower airspeed version would be useful in the CAS role.
The F-35C has 30 percent more wing area than the other two variants, larger tails and control surfaces, and wingtip ailerons specifically for the low speed handling of a carrier approach. Those changes reportedly drop the landing speed from approximately 155 knots for the F-35A to around 135 knots for the F-35C.
I’m not sure it would be worth the cost and effort of development for the very small subset of CAS missions that might benefit from those changes. The CAS mission is so much more than low and slow and with the aircraft almost certainly flying at higher speeds than carrier approach for most CAS missions how influential would the larger wing actually be? It might marginally increase loiter time but the payload of the A and C is the same and as indicated the G load of the C airframe is less than the A.
Re: Modified F-35A with F-35C wing?
I've always thought there was potential for a long range derivative of the F-35 with reduce agility. It would fill the role traditionally filled by the F-15E.
The F-35C wing without the fold mechanism would pretty much be a new wing. New skins and new internals. So they could make it as thick/thin as they wanted to suit the fuel volume and agility requirement.
The F-35C if land based could probably have maximum takeoff weight increase. The wing would probably increase fuel load to well over 10,000kg putting the combat radius very close to 1000nm.
But I strongly believe it would be better to make a clean sheet F-111 sized aircraft using off the shelf components to reduce risk. With twin F-135 engines and F-35 avionics to create a 1500nm range aircraft still capable of going supersonic and carrying A2A missiles for self defense.
The F-35C wing without the fold mechanism would pretty much be a new wing. New skins and new internals. So they could make it as thick/thin as they wanted to suit the fuel volume and agility requirement.
The F-35C if land based could probably have maximum takeoff weight increase. The wing would probably increase fuel load to well over 10,000kg putting the combat radius very close to 1000nm.
But I strongly believe it would be better to make a clean sheet F-111 sized aircraft using off the shelf components to reduce risk. With twin F-135 engines and F-35 avionics to create a 1500nm range aircraft still capable of going supersonic and carrying A2A missiles for self defense.
Re: Modified F-35A with F-35C wing?
RJMAZ wrote:I've always thought there was potential for a long range derivative of the F-35 with reduce agility. It would fill the role traditionally filled by the F-15E.
The F-35C wing without the fold mechanism would pretty much be a new wing. New skins and new internals. So they could make it as thick/thin as they wanted to suit the fuel volume and agility requirement.
The F-35C if land based could probably have maximum takeoff weight increase. The wing would probably increase fuel load to well over 10,000kg putting the combat radius very close to 1000nm.
But I strongly believe it would be better to make a clean sheet F-111 sized aircraft using off the shelf components to reduce risk. With twin F-135 engines and F-35 avionics to create a 1500nm range aircraft still capable of going supersonic and carrying A2A missiles for self defense.
The thing is the USAF won’t build anything right now that would possibly impinge on the B-21 numbers and mission. Its already going to be smaller and have less range than the B-2.
In my view what the US needs to make sure it does is build strike capability into the next two engine fighter program.
I would propose an aircraft a base MTOW of 67,000 pounds, wing area of 850 feet and internal payload of 6,800 pounds (externally capable of 15,600). That lets me carry two JASSM plus 6 AIM-120 if I wanted to. It’s basically an enlarged F-35 weapons bay. Internal fuel is about 23,000 pounds so a bit more than an F-22 fraction wise and less than the F-35.
I figure with next generation engines you could get around 31.2k pounds dry thrust per engine and bank the rest into a fuel consumption decrease. Wet thrust around 47.5k per. Your TW at fuel full MTOW and wet thrust is 1.37 which is better than a raptor. Most of the weight to performance metrics are.
The key to me is to design in conformal tanks from the start. The F-15 picks up about 11,000 pounds of gas this way. That is why I didn’t push the initial metrics. We need margin in the gear and body to carry the extra gas. With the conformal tanks added you are looking at a plane that performs between the raptor and the F-35 but has a MTOW pushing 80,000 pounds but should comfortable outrange almost everything as it would have 34,000 pounds of gas and a reasonable internal payload.
That lets you get your hot fighter with high level performance if you don’t have the conformals and a long range striker that still approaches the raptor with them. Additionally without the conformals you can just make you way down to a carrier safe weight for recovery and launch. You might even get away with common gear since the base model needs heavy gear to support the conformal tank configuration. Maybe not but it should be close weight wise.
Re: Modified F-35A with F-35C wing?
RJMAZ wrote:I've always thought there was potential for a long range derivative of the F-35 with reduce agility. It would fill the role traditionally filled by the F-15E.
…
But I strongly believe it would be better to make a clean sheet F-111 sized aircraft using off the shelf components to reduce risk. With twin F-135 engines and F-35 avionics to create a 1500nm range aircraft still capable of going supersonic and carrying A2A missiles for self defense.
So something along the lines of the FB-22 concept, a larger delta wing airframe with long range and decreased G capability.
https://en.wikipedia.org/wiki/Lockheed_Martin_FB-22
bigjku wrote:In my view what the US needs to make sure it does is build strike capability into the next two engine fighter program.
I would propose an aircraft a base MTOW of 67,000 pounds, wing area of 850 feet and internal payload of 6,800 pounds (externally capable of 15,600). That lets me carry two JASSM plus 6 AIM-120 if I wanted to. It’s basically an enlarged F-35 weapons bay. Internal fuel is about 23,000 pounds so a bit more than an F-22 fraction wise and less than the F-35.
Holes inside planes add weight so I expect a larger weapons bay would bring some additional structural penalties to the airframe. With the move to hypersonics the bays would likely need to be longer and thinner, which would likely suit increased AAM carriage anyway.
bigjku wrote:I figure with next generation engines you could get around 31.2k pounds dry thrust per engine and bank the rest into a fuel consumption decrease. Wet thrust around 47.5k per. Your TW at fuel full MTOW and wet thrust is 1.37 which is better than a raptor. Most of the weight to performance metrics are.
Would you really need that much thrust? The new AETP engines don’t appear to be going for much in the way of thrust increases but bringing better fuel efficiency and acceleration. The focus is likely on increased electrical generation to improve the capability of future DEW.
bigjku wrote:The key to me is to design in conformal tanks from the start. The F-15 picks up about 11,000 pounds of gas this way. That is why I didn’t push the initial metrics. We need margin in the gear and body to carry the extra gas. With the conformal tanks added you are looking at a plane that performs between the raptor and the F-35 but has a MTOW pushing 80,000 pounds but should comfortable outrange almost everything as it would have 34,000 pounds of gas and a reasonable internal payload.
That lets you get your hot fighter with high level performance if you don’t have the conformals and a long range striker that still approaches the raptor with them. Additionally without the conformals you can just make you way down to a carrier safe weight for recovery and launch. You might even get away with common gear since the base model needs heavy gear to support the conformal tank configuration. Maybe not but it should be close weight wise.
The conformal fuel tanks don’t add that much empty weight though. The F-16 CFTs weight 900 pounds for the pair and I believe (don't know for sure) the F-15s are probably in the 1500-2000 pound range. The plumbing for CFTs doesn’t add a lot of weight either, for example every RAF T3 Eurofighter already has the plumbing fitted even though the Eurofighter CFTs have never made it out of basic concept testing.
Re: Modified F-35A with F-35C wing?
Ozair wrote:So something along the lines of the FB-22 concept, a larger delta wing airframe with long range and decreased G capability.
https://en.wikipedia.org/wiki/Lockheed_Martin_FB-22
Very similar to that. It bridges the gap between the F-35 and B-21. Budget probably won't allow it in the near term but it would be a quick development and could quickly come after B-21 is in full production.
There would no doubt be missions where you need supersonic, decent agility, penetration and persistance deep over enemy territory. It would link into the mission requirement they have listed as penetrating counter air. This is commonly linked to the requirement for the 6th fighter program. My idea is that it would be lower performance, lower risk and quicker to develop option than the true ideal 6th gen solution.
It could potentially be a stop gap solution to allow a decade or two to develop a true hypersonic aircraft.
I personally think aircraft carriers will be sunk easily in a future conflict and that our lack of long range fighter aircraft will be our achilies heal. 1000nm combat radius allows the aircraft to take off from Japan and hit any target in north korea with room to spare.
bigjku wrote:The key to me is to design in conformal tanks from the start.
I strongly agree. The upper skin of the main body of the fuselage could be removable for example. Running from just behind the cockpit to the very back. A conformal tank can then add massive amounts of fuel while keeping the design stealth.
Re: Modified F-35A with F-35C wing?
RJMAZ wrote:Very similar to that. It bridges the gap between the F-35 and B-21. Budget probably won't allow it in the near term but it would be a quick development and could quickly come after B-21 is in full production.
I like the concept but I don’t like its chances. I think the USAF would prefer an additional 20 or 40 B-21s and forego the dev and time required to fund this. Given there will be approx 100 B-21s and the USAF is keen for 150+ they clearly want to concentrate their forces into a fewer number of platforms. The B-21 will likely already be using the F135 and a host of other F-35 systems so it accomplishes most of your requirements.
RJMAZ wrote:There would no doubt be missions where you need supersonic, decent agility, penetration and persistance deep over enemy territory. It would link into the mission requirement they have listed as penetrating counter air. This is commonly linked to the requirement for the 6th fighter program.
While the USAF seems very sure on its 6th gen I wonder how much of an impact weapons development will have on this program. If you consider your qualities above, much of that may be achieved with a hypersonic weapon, or a drone completing that delivery forward of the manned asset controlled by a B-21.
RJMAZ wrote:My idea is that it would be lower performance, lower risk and quicker to develop option than the true ideal 6th gen solution. It could potentially be a stop gap solution to allow a decade or two to develop a true hypersonic aircraft.
Not sure anything that goes supersonic today could ever be developed quickly. Given how long and extensive the F-35 test program has been, and likely the B-21 will be, quick programs are far from the norm. Even the MQ-25 will be a five year + dev program for four airframes and that is using software code already developed for the X-47B.
RJMAZ wrote:I personally think aircraft carriers will be sunk easily in a future conflict
I am of the opposite view as I think the carriers have a bright future ahead. We are probably at a mid point now where some offensive missiles may have a chance of penetrating the defensive screen but the advent of DEW will make a significant change to ship defences. Subs are also far more likely to be a threat to carriers but even then I’d expect a carrier in 2035 to be surrounded by a ring of UUVs.
RJMAZ wrote:our lack of long range fighter aircraft will be our achilies heal. 1000nm combat radius allows the aircraft to take off from Japan and hit any target in north korea with room to spare.
AETP for the F-35 will see its combat radius likely push out past 1000nm bringing that 5th gen penetration capability well within reach. At the very least it will be able to cue systems, sensors and weapons from standoff range.
Re: Modified F-35A with F-35C wing?
Ozair wrote:I like the concept but I don’t like its chances. I think the USAF would prefer an additional 20 or 40 B-21s and forego the dev and time required to fund this.
I saw this discussion over at F-16.net and it reminded me of this thread. It seems PCA might not be the 6th gen fighter but a much larger 5th gen fighter with double the range.
What would be more valuable is a force of evolved F-35 and PCA if you really want to tear into a large conventional force fast. More F-22A just doesn't bring what's going to get it done sooner. PCA and F-35 can kick down all doors and cover the bombers to IPs. And if enough PCA do their assigned role quickly you won't even need F-22A around, as PCA Counter-Air attacks will wrap BVR fighters up via other means. And even if F-22As were there they still won't actually solve the A2A problem, via slammer. It will always be the PCA that puts the F-22 out of the BVR business in a battle, not the F-22A that does that itself, as PCA will close down IADS and airfields plus kill fighters.
So someone will say the F-22A can drop bombs too. then what's the point of having dedicated F-22A A2A fighters on Day-1 then? No, F-22A are too small in numbers to diversify out of A2A, they will only carry A2A weapons within a major air battle. But it's all moot anyway, as F-22A are not going to cut it on range as a penetrator or cover for PCA.
At least the F-35 has real modification and development potential to build in a regionally meaningful range and speed extension for operations across the Indo-Pac geography--and give it reach, sans over exposing the tankers. Exposing tankers is out--can't do that.
So PCA is the only thing that can get in the early deep-penetration attacks to kill the air threat. An evolved speed and range-extended F-35 will perfectly complement PCA capabilities closer to the margin of deep-strike reach. PCA and F-35 will really alter the outcome and the F-22A won't.
F-22A would be good for killing vLO leakers attempting to attack allied forces and forward protection of key support aircraft.
Bottom line is, this is no longer the traditional 4th-gen Hi-Lo mix situation. That is more 4th-gen thinking. The F-35 doesn't need an F-22A to cover it while it attacks. F-35 is not going to be oblivious or caught unawares by approaching fighters, plus it is VLO in X-band and thermal.
F-35 can provide for its own high-cover, especially with expanded speed, altitude and range envelope.
Better bang for the buck is right.
PCA will be a much better bang for the buck too.
Now I just watched a video of the J-20. That design scaled up 10% with a pair of F-135's is exactly what the PCA should look like. Delta canard provides speed and range advantages but consumes more energy while turning. It would provide double the range of the F-22, similar speed but with a reduction in outright agility.
Taking the J-20 specs off wikipedia and scaling it up 10% we have:
Length: 20.4 m -> 22.4m
Wingspan: 13.5 m -> 14.9m
Wing area: 78 m2 -> 95 m2
Empty weight: 19,391 kg -> 25,500kg
Max takeoff weight: 36,287 kg -> 48,000kg
Fuel capacity: 11,363kg -> 15,000kg
Thrust: 290kn -> 380kn
Re: Modified F-35A with F-35C wing?
RJMAZ wrote:I saw this discussion over at F-16.net and it reminded me of this thread. It seems PCA might not be the 6th gen fighter but a much larger 5th gen fighter with double the range.
There is some reasonable info on what the USAF wants from PCA, as per this article, http://www.airforcemag.com/MagazineArch ... ority.aspx
I still question how this will get funded and developed in the timeframe the USAF are seeking. In the next ten years F-35 procurement ramps up, B-21 procurement starts, T-X starts, KC-46 continues, talk of AWACS/JSTARS replacement, perhaps B-52 upgrade, a suite of 5th gen weapons including hypersonics, initial work on a new transport may commence…the list goes on.
In that context how much funding will actually go to development and testing of a PCA, essentially an all new design as per the article, in the manned fighter space. From the article,
The PCA, then, will have to have “broadband, broad-spectrum stealth” as a primary design consideration, Carlisle said. The current state of stealth “is optimized for the X-band. So, we need to get broadband stealth” that can get past a variety of radar frequencies. Once that is obtained, “range, payload, and endurance” are the three major attributes needed, along with “broad-spectrum avionics,” advanced electronic warfare, and “counter-countermeasures.”
Such an aircraft doesn’t sound like a traditional fighter such as the F-22 or F-35, and Carlisle said that will all be part of the trade-off studies.
“It may be bigger than we think,” he said. “Maneuverability is one of those discussions—as in, if it’s penetrating, what level of maneuverability does it need? We don’t know the answer to that yet.”
Carlisle has previously said the need for a deep magazine of weapons, long range, and extreme stealth suggests the PCA aircraft might turn out to be more like the B-21 bomber than the F-22, but the AOA has not yet had time to explore such an idea.
Based on Gen Carlisle’s comments IMO a modified B-21 seems more appropriate than an all new design, especially if stealth, range, payload and endurance are the key design requirements. You have long range, platform growth, deep weapons bays and a broadband stealth design already.
RJMAZ wrote:Now I just watched a video of the J-20. That design scaled up 10% with a pair of F-135's is exactly what the PCA should look like. Delta canard provides speed and range advantages but consumes more energy while turning. It would provide double the range of the F-22, similar speed but with a reduction in outright agility.
I doubt an aircraft that size would meet the requirement. It probably wouldn’t have sufficient range or payload for what the USAF is seeking from PCA, especially in the context of forward basing from Guam or Japan and from the article how far Gen Carlisle insinuates the aircraft would have to travel based on the target set.
Re: Modified F-35A with F-35C wing?
Ozair wrote:I still question how this will get funded and developed in the timeframe the USAF are seeking. In the next ten years F-35 procurement ramps up, B-21 procurement starts, T-X starts, KC-46 continues, talk of AWACS/JSTARS replacement, perhaps B-52 upgrade, a suite of 5th gen weapons including hypersonics, initial work on a new transport may commence…the list goes on.
A significant portion of the procurement funding could come from purchasing less KC-46 tankers.
Penetrating Counter Air (PCA) and B-21 would signifcantly reduce the need for tankers. This knock on effect allows the tankers to be located closer to friendly airports. This reduces tanker transit time which allows for increased fuel offload and time on station with any given tanker fleet.
The F-22's short range and ability to burn fuel quickly causes a significant drain on tankers and puts the tankers at risk close to the front line. The F-22's main role would get replaced by the PCA, it would become increasing difficult to justify the small and expensive to maintain fleet of F-22's for its supreme dogfighting agility.
Development cost would be low as every major component would be off the shelf. Maybe the AESA module count might increase iver the APG-81 but with the same backend.
Ozair wrote:I doubt an aircraft that size would meet the requirement. It probably wouldn’t have sufficient range or payload for what the USAF is seeking from PCA, especially in the context of forward basing from Guam or Japan and from the article how far Gen Carlisle insinuates the aircraft would have to travel based on the target set.
The J-20 should already have a combat radius 50% greater than the F-22 and 30% greater than the current F-35 based on its fuel fraction and what the Su-30 can do. Enlarged 10% and with modern western engines it would be well over 1200nm combat radius.
Re: Modified F-35A with F-35C wing?
RJMAZ wrote:A significant portion of the procurement funding could come from purchasing less KC-46 tankers.
Penetrating Counter Air (PCA) and B-21 would signifcantly reduce the need for tankers. This knock on effect allows the tankers to be located closer to friendly airports. This reduces tanker transit time which allows for increased fuel offload and time on station with any given tanker fleet.
There is no way the USAF is dropping KC-46 numbers. PCA would be a small percentage of the fleet, perhaps 200 aircraft if the USAF were very lucky, while the legacy fleet, F-15E, F-16 etc are currently slated to remain around until 2040.
RJMAZ wrote:The F-22's short range and ability to burn fuel quickly causes a significant drain on tankers and puts the tankers at risk close to the front line. The F-22's main role would get replaced by the PCA, it would become increasing difficult to justify the small and expensive to maintain fleet of F-22's for its supreme dogfighting agility.
The expensive gold plated solution is PCA to replace F-22 due to range issues (which aren’t as significant as you are stating, the F-22 in an A2G loadout can still reach out 600nm which is the same or longer than F-15E (with F-15E having route diversion). F-15E is currently slated to remain in service until 2042 anyway.
RJMAZ wrote:Development cost would be low as every major component would be off the shelf. Maybe the AESA module count might increase iver the APG-81 but with the same backend.
Idealistic. You still have a significant cost to integrate all those components together, a significant time frame to test the airframe and clear weapons, build production capacity. B-21 is also supposed to be as off the shelf as possible but the 2010 dollar acquisition cost is still above US$550 million and the dev and engineering contract reportedly around US$21.4 billion. Not small change especially in the context of the main acquisition priorities for the USAF are F-35, B-21 and KC-46.
RJMAZ wrote:The J-20 should already have a combat radius 50% greater than the F-22 and 30% greater than the current F-35 based on its fuel fraction and what the Su-30 can do. Enlarged 10% and with modern western engines it would be well over 1200nm combat radius.
Be wary of any figures for J-20. As for F-35 and Su-30, we know in a comparable A2A config that the aircraft are very closely matched on range.
Discussing maximum mission radius, Mazanowski presented an air-to-air mission profile in which all the aircraft took off with a weapon load, remained at high altitude and returned after about a minute of combat. All but the F-35 and Su-30MKI were carrying three external fuel tanks.
Under this scenario, the Rafale had a maximum mission radius of 896 n miles, the F/A-18 816 n miles, the F-35 751 n miles, the Eurofighter 747 n miles, the Su-30MKI 728 n miles and the Gripen 502 n miles.
https://www.scribd.com/doc/261728653/lo ... pabilities
The above was with some significant engine penalty fort he F135 and given the quote is from 2009, today likely sees the F-35 push out another 50-75nm based on current range numbers. With AETD that is likely pushed again out, in an A2A high altitude config, close to that 1200nm figure. USAF aircrew who have come from the F-15 have stated the F-35 has a longer range than their previous aircraft so some additional context for the figures.
It is certainly possible that a larger J-20 could reach out that far but do you think that is far enough? If PCA is really focused on those long range targets then 1200nm is probably not far enough, certainly within the context of the USAF stated desire for range, payload and endurance.
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