NATF: planned Navy versions of the F-22 and F-23

[Maki]

I was wondering if anybody knows anything more about the NATF & pre-NATF Tomcat replacement proposals.The only one i know about is the Lockheed swing-wing NATF proposal that is based on the F-22.I've read that they chose swing-wings because it was the easiest way to offer F-22 performance and to be able to land on a carrier.The Navy concluded that such a design would have very little commonality with the land based version,so it would be expensive as developing a clean sheet design and there was concern that the projected weight would be beyond suitable for operating off carriers that are currently in use.
I can find no info on Northrop-McDD's NATF proposal,but I can only speculate that it was a highly modified YF-23.
The NATF program was started in 1988,and that was sometime after Lockheed and Northrop were selected as finalists for prototype production,so I believe that there were no other NATF concepts from other manufactures that were part of the ATF competition,but I'm very interested if there were any pre-NATF concepts during the early 80's.

 

[flateric]

Use search at the forum with a keyword NATF. Sure that you will not find much more on the subject nearest 5 years or so, especially regarding Northrop/MDC NATF

 

[flateric]

Lockheed-Boeing-P&W NATF ad from ca.1991 AWST (where's GD?)

 

[Mark Nankivil]

This seems to be the appropriate thread for this image I found in the Vought Archives last week. Any ideas?

Enjoy the Day! Mark

 

[Apollo Leader]

That looks like Lockheed's canard, double-delta ATF concept which was used in various literature and advertisements throughout the mid to late 80's. First time I've ever seen this depiction.

 

[Orionblamblam]

That looks like Lockheed's canard, double-delta ATF concept which was used in various literature and advertisements throughout the mid to late 80's.

Naw. See, this version is the special Heavy Lift Biplane Configuration.

 

[Sundog]

That design looks similar to the configuration seen from Lockheed Martin that showed up in those Syd Mead Posters (I still have mine ), but that Lockheed design had the intakes on the underside of the wing roots and in the image above the inlets are obviously not located below the designs waterline.

 

[Mark Nankivil]

I suppose it'll skip better on the water

Enjoy the Day! Mark

 

[flateric]

It's also resembles one of Grumman ATF artist's concepts, but that lacks canards, and have vertical tails placed on short tailbooms.
http://www.secretprojects.co.uk/forum/index.php/topic,106.msg21041.html#msg21041

 

[Spring]

Weird, variable geometry was still considered as an important idea for the NATF?, i mean, with the aerodynamic/FBW advances, VG is not a step back?

An F-22 with more span was never concidered?, what about the NAVY's F-23 version?

 

[Apollo Leader]

That looks like Lockheed's canard, double-delta ATF concept which was used in various literature and advertisements throughout the mid to late 80's.

Naw. See, this version is the special Heavy Lift Biplane Configuration.

The Syd Mead concept paintings for Lockheed is what I'm refering to. I guess none of them are actually double deltas (like the F-16XL).

http://www.secretprojects.co.uk/forum/index.php/topic,1165.0/highlight,lockheed+atf.html

 

[F-14D]

Weird, variable geometry was still considered as an important idea for the NATF?, i mean, with the aerodynamic/FBW advances, VG is not a step back?

An F-22 with more span was never concidered?, what about the NAVY's F-23 version?

FBW and vg are not exclusive concepts. What vg buys you is the ability to operate over wide speed ranges, allows you to have an efficient supersonic profile, while also having the ability to operate a low speeds with good control and not have to have a larger angle of attack (especially important in carrier operations) and the ability to loiter more efficiently. Its disadvantages are increased complexity (because there are more things to move) and greater weight than with a fixed wing structure. It also introduces another variable into weapons calculations. For example, on the F-14, when air-to-ground mode was selected the wing would automatically sweep to 55 degrees and lock, so as to take that variable out of the fire control system's bombing equations. If you do not have those requirements (ala USAF F-22), then the weight of the vg structure outweighs its advantages. If you do have those requirements, the VG can actually weigh less than the fixed wing. FBW doesn't change these basic considerations. For example, in the case of the more advanced, but stillborne A/FX, all of the proposals used FBW of some sort, and I believe all of them were vg.

An F-22 with a bigger wing wouldn't really help with the Navy's needs, plus you run into the stowage issue. All we know about Northrop/MDD's NATF is that it was allegedly a canard of "unique" configuration, and not much else. People have been trying to get an illustration of it for years.

 

[OM]

Naw. See, this version is the special Heavy Lift Biplane Configuration.

...Are you kidding? This was an example of the new manufacturing technology they developed for this bird. They simply had two of them mate and produce a third.

You should have seen the size of the eggs they laid...

 

[Maki]

I always wondered how stealthy VG wings can be. They seamed to have seriously considered them for NAFT and A/F-X ,which is not surprising since they perfectly fit the mission profile for these aircraft (very long loiter time, slower approach speeds for carrier landings..etc),but I can't help wonder if the stealth requirement was the downfall of NATF. It seams very difficult to make a stealth VG aircraft. The wing roots themselves seem like a nightmare for stealth designers, let alone the changing angles of the leading edges of the wings. I guess that was one of the reasons the Navy considered the NATF such a big technological risk :-\

 

[F-14D]

I always wondered how stealthy VG wings can be. They seamed to have seriously considered them for NAFT and A/F-X ,which is not surprising since they perfectly fit the mission profile for these aircraft (very long loiter time, slower approach speeds for carrier landings..etc),but I can't help wonder if the stealth requirement was the downfall of NATF. It seams very difficult to make a stealth VG aircraft. The wing roots themselves seem like a nightmare for stealth designers, let alone the changing angles of the leading edges of the wings. I guess that was one of the reasons the Navy considered the NATF such a big technological risk :-\

VG might be harder to do stealthily, but it probably wasn't a big reason in the Navy's pullout. They wanted their fighter to be stealthy, but they didn't need the extremes AF wanted. After all, on some of their missions, like Fleet Air Defense, Combat Air Patrol, BARCAP and the like, their radars were going to be radiating like mad anyway, so the opponents were going to know they were around somewhere. In fact, in some cases that's an asset because it will make the opponents layoff the aircraft being escorted on the incoming's main target if they know they have to "deal with" defenders. If you don't mind, 'm going to liberally steal from myself for this next part of my theory from a post from another topic a year ago...

Some of Navy's reluctance can be laid to a statement made by AF around the time of the rollouts. Basically they said that the Navy would not be allowed to buy a version of the aircraft that was not selected for ATF. While this may seem to be a cost decision, keep in mind that the Navy and AF version were going to be built on separate production lines, anyway and what would primarily be common would be subsystems (including engines and fire control, although the Navy version would probably have been more capable). Possibly AF was wanting to avoid a repeat of the LWF situation, wherein the F/A-18A/B was noticeably more capable than the F-16 A/B (with the arrival of improved avionics in the Falcon C/D this gap was dramatically narrowed). Who knows, but this gave USN a lot of pause, and they were already worried about the cost of NATF. They wanted much (but not all) of the capabilities that AF was looking for in fighters, and they definitely wanted it to be dual role with a secondary strike capability, given the fixed amount of deck space. It seemed that they might have thought the AF model would be "too much" fighter and not enough other stuff. The NATF was going to be very expensive, so if they couldn't get a version optimized for their needs, maybe they shouldn't continue through. They probably also thought that an advanced Tomcat, combined with AIM-152 could give them "enough" fighter and they could concentrate their bucks on attack. (Dick Cheney's cancellation of the F-14D was totally unexpected). An F-23 NATF with its larger weapons capacity could accommodate AIM-152, whereas an F-22 NATF might not have been able to. Also, Navy was a strong believer in IR guided missiles, while AF was not (at one point, according to press reports, AF argued that AIM-9 capability was unnecessary and recommended that it be removed from production F-22s in the interest of cost).

Given this, Navy was not too enthusiastic a proponent from that point on, and after the decision basically decided to drop out.

 

[Colonial-Marine]

I figured I would resurrect this threat rather than continuing discussion on the F-23 topic.

From the previous discussion, it seems the main reason for such major airframe changes on the NATF proposals (particularly the F-23 based design) were due to increased range and other requirements specified by the Navy.

Now lets say the Navy was for some reason looking for just a navalized ATF. No increased range, loiter, or other requirements. The only thing they need is the ability for it to successfully operate from CVNs. Would the airframes be nearly identical to the ATF, or would some extensive modification still be required?

The impression I got from Abraham Gubler regarding the F-23 was that it could theoretically be converted to naval operations easier than the F-22. The redesigned airframe (canards, wing shifted back, and conventional tail layout?) was more for the increased fuel, range, weight, and so forth.

I know that Carlo Kopp, the guy who runs AirPower Australia is seen as somewhat crazy these days, but he does discuss navalizing the F-22 here:
http://www.ausairpower.net/APA-NOTAM-230209-1.html

So is such talk pure fantasy or possible?

Also are there any official drawings, sketches, etc. of the F-23 based NATF? Can't seem to find any.

 

[overscan (PaulMM)]

No drawings have been published to date.

With stealth designs, there seems to be a general reluctance to publish alternative projects and layouts, I think because a good stealthy configuration gets stored by the company for possible reuse for a later project with different parameters. Just because it wasn't optimal for ATF doesn't mean the shape isn't good for a UCAV, for instance, or the alternate intake design on a B-2 project might be useful for a cruise missile. There is value in the geometry itself, so you don't want to publicise the shape.

Just my theory.

 

[Abraham Gubler]

From the previous discussion, it seems the main reason for such major airframe changes on the NATF proposals (particularly the F-23 based design) were due to increased range and other requirements specified by the Navy.

It’s wrong to say there is a ‘main reason’. As has been said continually on the other thread the Navy’s requirement was very different to the Air Forces. Aircraft are designed to requirements and need to balance a range of competing interests. More range means more of a fuel fraction which means more weight at takeoff which means bigger wings, which means more drag, which means more thrust, etc., etc.

Now lets say the Navy was for some reason looking for just a navalized ATF. No increased range, loiter, or other requirements. The only thing they need is the ability for it to successfully operate from CVNs. Would the airframes be nearly identical to the ATF, or would some extensive modification still be required?

To takeoff and land on a carrier you first need the interfaces (catapult arm, tail hook) and the structural strength to survive the increased forces. This means more weight compared to an air force aircraft. You then need to be able to fly slow enough (and you are heavier than before) with enough control to safely approach the carrier and land on the deck. This means more lift and more control effect. Which usually means bigger wings and more tail.

The impression I got from Abraham Gubler regarding the F-23 was that it could theoretically be converted to naval operations easier than the F-22. The redesigned airframe (canards, wing shifted back, and conventional tail layout?) was more for the increased fuel, range, weight, and so forth.

The F-23 has lower wing loading (to the F-22) so presumably can fly slower. It has less attitude control effect so would probably need a conventional tail for carrier approach control.

I know that Carlo Kopp, the guy who runs AirPower Australia is seen as somewhat crazy these days, but he does discuss navalizing the F-22 here:
http://www.ausairpower.net/APA-NOTAM-230209-1.html

Well in this online *article* they say it would be an easy thing to replace the forward undercarriage doors with lifting wings. Since no part of the forward fuselage of an F-22 is stressed to absorb the force of lift it is safe to say it’s not a serious proposal. Other statements in this paper like assessing converting the F-22’s wing to a blown wing as ‘low risk’ are equally fantastical. That they then ‘flew’ this beast in Microsoft Flight would hardly add credibility to anyone in the industry or forces.

 

[flateric]

Since no part of the forward fuselage of an F-22 is stressed to absorb the force of lift it is safe to say it’s not a serious proposal.

...note that Abe even didn't start talking of aerodynamics here, that would be another interesting chapter...

 

[Abraham Gubler]

...note that Abe even didn't start talking of aerodynamics here, that would be another interesting chapter...

We can add another chapter in relation to engine air flow interruption...

 

[AeroFranz]

The F-23 has lower wing loading (to the F-22) so presumably can fly slower. It has less attitude control effect so would probably need a conventional tail for carrier approach control.

For what it's worth, the F-23 had massive pitch authority. AFAIK, it was flying with large amounts of rear cg, and was in fact a 'lifting tail'. the fact that yaw was taken care of by wing split surfaces meant that all the tail throw could be used for pitch control. OTOH I'm not sure those wing split surfaces would have enough yaw authority at low speeds.

Well in this online *article* they say it would be an easy thing to replace the forward undercarriage doors with lifting wings. Since no part of the forward fuselage of an F-22 is stressed to absorb the force of lift it is safe to say it’s not a serious proposal. Other statements in this paper like assessing converting the F-22’s wing to a blown wing as ‘low risk’ are equally fantastical. That they then ‘flew’ this beast in Microsoft Flight would hardly add credibility to anyone in the industry or forces.

I agree. This is barely short of ridiculous, and is coming from someone who is not a designer.

 

[Colonial-Marine]

I had rather thought that F-22N concept was a bit of a stretch. The main concern with the F-22 seems to be the high landing speed however. So factoring in the weight increase to enable carrier takeoff and landings, would there be any way to significantly reduce approach speed besides for a VG setup?

As far as the F-23 goes, obviously none of us have flown the thing. Yet presuming it handled well enough at carrier approach speeds, it looks to me as if it would be possible to adapt to carrier operations, without such significant airframe modifications. Obviously the strengthened landing gear, tailhook, and etc. would add weight, but two F119s are hardly lacking in thrust, and it seems insufficient lift wouldn't be a problem. The suitability of such a concept seems to hinge just on the very low speed handling.

Clearly such a pure conversion from the ATF wouldn't fit any Navy needs (at least at the time) but it is another interesting "what-if" scenario.

 

[Sundog]

I had rather thought that F-22N concept was a bit of a stretch. The main concern with the F-22 seems to be the high landing speed however. So factoring in the weight increase to enable carrier takeoff and landings, would there be any way to significantly reduce approach speed besides for a VG setup?

As far as the F-23 goes, obviously none of us have flown the thing. Yet presuming it handled well enough at carrier approach speeds, it looks to me as if it would be possible to adapt to carrier operations, without such significant airframe modifications. Obviously the strengthened landing gear, tailhook, and etc. would add weight, but two F119s are hardly lacking in thrust, and it seems insufficient lift wouldn't be a problem. The suitability of such a concept seems to hinge just on the very low speed handling.

Clearly such a pure conversion from the ATF wouldn't fit any Navy needs (at least at the time) but it is another interesting "what-if" scenario.

The F-22 could have gained a greater aspect ratio wing, in much the same sense that the F-35C did. Of course, the F-35C has reduced G load capability, because the main spar wasn't redesigned, but I don't know that the Navy would have required the same maneuvering capability. Of course, the greater AR wing would also reduce supercruise speed.

As for the YF-23 Naval variant, it was reportedly quite different from the YF-23 and rather ugly to boot.

 

[elmayerle]

Actually, the wings for the different F-35 versions are distinct, but with common interface points that allow a lot of common plumbing & common structure where loads permit, as well as only one style of assembly fixturing. Getting commonality of installations while allowing for structural differences between versions made the design effort "sporting".

Note: I've seen a model of the NATF-23, it's definitely different froam the YF/F-23 and is, indeed, rather uglier.

 

[Abraham Gubler]

I had rather thought that F-22N concept was a bit of a stretch. The main concern with the F-22 seems to be the high landing speed however. So factoring in the weight increase to enable carrier takeoff and landings, would there be any way to significantly reduce approach speed besides for a VG setup?

I doubt changing the wing to a VG wing would help much. The F-22 has about as big a wing as you can fit into that airframe. They could have a bit more span F-35 style but that wouldn't help much.

Perhaps the most viable F-22 “N” modification would be to blow the wings like in the A3J Vigilante (and Buccaneer + TSR.2). This would require consuming a lot of internal space for piping bleed air from the engine to the wings and some fancy LO work to keep the vents stealthy. It would also mean deletion of the ailerons which could be replaced by elevons (as in the TSR.2) or drag roll (as in the A3J) and a lot more air braking (to reduce approach speed as the engines need to be kept at high power for the blowing). This is probably the most minimal change to an F-22 to make it carrier capable. It would certainly not be a simple or easy change and if the wings can't be kept stealthy would blow the RCS but it would make it slow enough to land safely on a carrier all day, every day.

 

[donnage99]

For what it's worth, the F-23 had massive pitch authority. AFAIK, it was flying with large amounts of rear cg, and was in fact a 'lifting tail'. the fact that yaw was taken care of by wing split surfaces meant that all the tail throw could be used for pitch control. OTOH I'm not sure those wing split surfaces would have enough yaw authority at low speeds.

The yf-23 has quite large tail surface (though I remember that the production model would have slightly smaller ones). However, at the same time, the tails are set diaognally instead of horizontally. How would this compare to a horizontal tails? Would it be a factor that effects pitch authority? If so, we can't just jump to a conclusion that it has more pitch control over the f-22 because of surface area, right?

 

[flateric]

it's definitely different froam the YF/F-23 and is, indeed, rather uglier.

Evan, I was told to think along these lines in planform view - can you say your 'yes' or 'no' about that?

 

[Matej]

Evan, I was told to think along these lines in planform view - can you say your 'yes' or 'now' about that?

How sophisticate you eliminated the "no" from the possible answers ;D

 

[flateric]

Oh, damn

 

[AeroFranz]

The yf-23 has quite large tail surface (though I remember that the production model would have slightly smaller ones). However, at the same time, the tails are set diaognally instead of horizontally. How would this compare to a horizontal tails? Would it be a factor that effects pitch authority? If so, we can't just jump to a conclusion that it has more pitch control over the f-22 because of surface area, right?

It definitely does affect pitch authority. As a first approximation, you can assume that the equivalent horizontal tailplane has the horizontal projected area of the ruddervators. So you can look at the top view of the YF-23 and assume those tails are flat, for our purposes. Also, compared to a fin+elevator layout, the flying tail (all-moving) generates higher moments.

But yeah, I don't know how much I'd be willing to bet on pitch control being adequate without running some numbers. I guess you could compare the tail volume coefficient of the YF-23 to other carrier borne supersonic fighters aircraft (say an F-14, a super bug, a vigilante, and a Phantom). Horizontal tail volume coefficient (there is a corresponding vertical TVC) is often used as a first order calculation to size a tail, and is

Tail moment arm * horizontal tail area / (wing mean aerodynamic chord*wing area) (Raymer, 4th ed.)

airplanes designed to similar missions/maneuvering requirements will have similar tail volume coefficients.

 

[elmayerle]

it's definitely different froam the YF/F-23 and is, indeed, rather uglier.

Evan, I was told to think along these lines in planform view - can you say your 'yes' or 'no' about that?

it's not fair, but "somewhat" is the most honest answer I can give (yes, it had canards and the wing moved aft - I don't honestly remember how the inlets were configured). There are some aspects that are similar but others are not. Mind you, you have to remember that it's been 15+ years since I saw that model.

 

[flateric]

Evan, zillion thanks! Hope, one day it will see the light of the day...

 

[Triton]

Artist's impression of Lockheed navalized F-22 NATF proposal.

 

[Lampshade111]

That is higher quality than most copies of that picture I have seen. Thanks.

 

[Orionblamblam]

More coming soon...

 

[archipeppe]

Oooohhhhh.....

 

[lantinian]

: Here we go again....

 

[Matej]

I definitely switch my 5 view effort from YF-23A to this!

 

[SOC]

Looks like they raised the engine intakes to fit them against the fuselage side. Canards are a bit "weird", but not getting how this jet was supposed to be butt ugly.

 

[flateric]

Pelican! Pelican!