Rockwell USN VFMX oblique wing fighter

[overscan (PaulMM)]

Oblique wing fighter circa 1984 (seems to be Navy, however...)

 

[vstol]

Can you tell me the source of the "Rockwell Mission fighter.jpg" graphic? Here is a color image.

 

[overscan (PaulMM)]

Looks like its from a modelling newsletter, but I think the source is the Journal of Aircraft:

http://pdf.aiaa.org/jaPreview/JA/1985/PVJAPRE45221.pdf

Unfortunately, I don't have access to the whole article. An earlier revision of this article, mentioned in the preview, included a partial drawing which is clearly the same drawing, so I imagine the revised article above is the source.

 

[Abraham Gubler]

Rather optimistically I have established a thread hoping to find out more information on the proposals for the US Navy's VFMX program for a single type to replace both the F-14 and A-6.

Stevenson in “The $5 Billion Misunderstanding: The Collapse of the Navy’s A-12 Stealth Bomber Program” says the VFMX [cV Fighter Medium attack eXperimental] RFP on 17 May 1982 looking at all current aircraft for attack modification and new proposals including the fighter mission. He details how VFMX was killed off in favour of a cheaper alternative (F-14D/A-6F) thanks to entrenched Navy bureaucrats and DepSecDef Thayer.

According to the only online source of being able to find (a one page article from Flight in 1983: http://www.flightglobal.com/pdfarchive/view/1983/1983%20-%200467.html) VFMX was conceived for IOC in 1996 with a focus on signal suppression, affordability and stealth only if it doesn’t compromise performance. Flight says the Navy gave a free hand to contractors to propose solutions with Grumman, North American Rockwell, McDonnell Douglas and General Dynamics responding.

Unfortunately no new information or imagery on any of the VFMX new proposals.

According to http://www.aircraftdesign.com/acpix.html a North American proposal had an oblique wing.

http://www.aircraftdesign.com/ri-columbus%20vfmx%20obliquewing.jpg

 

[Pioneer]

Stevenson in “The $5 Billion Misunderstanding

Wow have you seen how much this book is Worth
I would love to ready it!
I have read the Pentagon Paradox - full of great info!!!!!

VFMX was conceived for IOC in 1996 with a focus on signal suppression, affordability and stealth only if it doesn't compromise performance.

Sorry to be cynical but did you put the U.S Navy and the word affordability in the same sentence? ???

Sorry but I know of the A-12 Avenger program.
But was the A-12 Avenger originally developed under VFMX [cV Fighter Medium attack eXperimental] RFP??


Regards
Pioneer

 

[overscan (PaulMM)]

Merged with older posts of the Rockwell oblique wing fighter.

The only source appears to be this article in the Journal Of Aircraft:
http://pdf.aiaa.org/jaPreview/JA/1985/PVJAPRE45221.pdf

 

[Skybolt]

I have access (with some effort) to the complete collection of JoA. Just let the Polytechnic Library re-open this week.

 

[overscan (PaulMM)]

A. Adams and S. Parkola (Pratt & Whitney) report AIAA-82-1139 Charting Propulsion 's Future - The ATES Results from 1982 says VFMX was optimised for the Combat Air Patrol mission. Engine parameters were:

VFMX Aircraft
Thrust AB : 26,300
Thrust, Int : 15,620
Bypass Ratio: 0.82
Pressure ratio: 24
Throttle ratio: 1.13
Combustor Exit Temperature: 2900
Mission: Combat Air Patrol

 

[Abraham Gubler]

Wow have you seen how much this book is Worth
I would love to ready it!
I have read the Pentagon Paradox - full of great info!!!!!

It was cheap when I brought it. As to the great info you need to be a special sort of person to be motivated to read the 450 pages of detail of the paperwork and committees of the US military procurment process. I needed the intervention of a 24 hour flight to Europe before I could do it...

Sorry but I know of the A-12 Avenger program.
But was the A-12 Avenger originally developed under VFMX [cV Fighter Medium attack eXperimental] RFP??

Thomason's "Strike From the Sea" (cheaper and with better pictures) details that VFMX was cancelled and OSD/Congress directed Navy to buy the Naval ATF and develop the strike only (self defence air to air) ATA (A-12) which would also be used by USAF as a F-111 replacement.

 

[overscan (PaulMM)]

http://www.obliqueflyingwing.com/OWhistory.pdf by forum member Mike Hirshberg has some more info on the Rockwell oblique wing VFMX.

 

[Abraham Gubler]

VFMX Aircraft
Thrust AB : 26,300
Thrust, Int : 15,620
Bypass Ratio: 0.82
Pressure ratio: 24
Throttle ratio: 1.13
Combustor Exit Temperature: 2900
Mission: Combat Air Patrol

That sounds like F110 performance.

 

[F-14D]

Wow have you seen how much this book is Worth
I would love to ready it!
I have read the Pentagon Paradox - full of great info!!!!!

It was cheap when I brought it. As to the great info you need to be a special sort of person to be motivated to read the 450 pages of detail of the paperwork and committees of the US military procurment process. I needed the intervention of a 24 hour flight to Europe before I could do it...

Sorry but I know of the A-12 Avenger program.
But was the A-12 Avenger originally developed under VFMX [cV Fighter Medium attack eXperimental] RFP??

Thomason's "Strike From the Sea" (cheaper and with better pictures) details that VFMX was cancelled and OSD/Congress directed Navy to buy the Naval ATF and develop the strike only (self defence air to air) ATA (A-12) which would also be used by USAF as a F-111 replacement.

VFMX, originally to replace the F-14A and A-6E, was originally projected to have an IOC of 1997. When its funds were zeroed, the F-14D and A-6F programs were started in in 1985 as some in OPNAV felt that two evolutionary programs would have a better chance of survival than one mongo "non-joint" program. Tomcat D and Intruder F were to bridge the gap until the arrival of NATF and ATA, respectively. The thing was, A-6F's IOC wasn't all that much sooner than what was originally believed would be the entry into service of the ATA,. Once SECNAV Warner was no longer around, A-6F did not enjoy enough support to survive and so it went away. Ironically, it seems that the wrong decision was made for the right reasons.

Years later John Warner wrote that he felt he ended up making the wrong call with the A-6F and if had to do it over again, he would have not started the A-6F but accelerated the F-14D development while building in all-weather strike from the start, essentially the F-14D Quickstrike.

 

[Lampshade111]

I am amazed an oblique wing has actually been considered for a combat aircraft, let alone an aircraft not designed for experimental purposes.

 

[rousseau]

The VFM-X project includes three proposals at least, despite A-6F was well known, there was a F/A-18AW has never been published. With 8% wing area enlarged the A-18AW would be different from traditional version of Hornet in veiw.

 

[fightingirish]

Does "AW" stand for "All-Weather", just like in the USMC with their All Weather Fighter Attack Squadrons (VMFA(AW)-###) and their F/A-18D Hornets?

 

[flateric]

The only source appears to be this article in the Journal Of Aircraft:
http://pdf.aiaa.org/jaPreview/JA/1985/PVJAPRE45221.pdf

Design Comparisons
With these inherent advantages of an oblique wing design
established, a direct comparison of the two designs on a common
mission can be made. The mission chosen will emphasize
the efficient loiter capabilities of the oblique wing design combined
with a supersonic dash to a combat condition. We chose
a hypothetical fleet air defense mission (Fig. 7), in which the
aircraft takes off from a carrier, cruises at the most efficient
condition to a station 300 n. mi. out, and loiters until a dash is
required to a combat location 100 n. mi. away. Following this,
the aircraft returns at best cruise altitude and velocity to the
carrier. Loiter time is 3 h for the baseline mission. The ground
rules chosen for this study, in addition to the common
mission, were that design criteria would be the same and common
technologies would be utilized for both aircraft. The only
difference in technology between the two designs (Table 2) is
the oblique wing itself. Both aircraft utilized advanced propulsion
systems optimized using a parametric deck to satisfy the
design requirements. Both aircraft carried the same weapons
and avionics suites, including 10 air-to-air missiles, and utilized
advanced materials wherever required, including composite
wings. The fuselage design (Fig. 8) was common to both
aircraft because of the avionics systems and the large number
of missiles required. As shown in Fig. 8, the missiles occupy
most of the available space on the underbody of the twinengine
design.
The two wing planforms are compared in Fig. 9. Maximum
leading-edge sweep was set at 65 deg, and an aspect ratio of
10.2 was chosen to maximize the loiter efficiency. These were
chosen as a starting point because NASA obtained a large
body of wind tunnel data on this planform in the early
1970s.5'6 Further studies confirmed that the aspect ratio could
be higher for mission efficiency but is limited by maximum
span considerations for carrier operations. The difference in
effective aspect ratio in the swept condition between the symmetric
and oblique wing designs is shown in Fig. 9. The symmetric
design has a minimum aspect ratio for supersonic flight
of 2.74; the oblique wing, 1.82. Volume distributions are compared
in Fig. 10 for the final-sized aircraft. The oblique wing
design exhibits much less volume at the center of the aircraft.
There is an overall increase in total volume on the symmetric
design due to the larger wing resulting from the sizing, the
overwing fairing required to close out the pivots, the glove required
for aerodynamic trim, and the larger engines required
because of the less efficient design. The result of this volume
distribution is illustrated in Fig. 11. The area of the wing on
the sized symmetric aft-sweep design is 649 ft2 compared to
583 ft2 on the oblique wing. Wave drag is approximately 26%
lower at the supersonic dash Mach number of 1.5. Taking all
the drag factors into consideration at Mach 1.6, there is a
substantial decrease at both 35,000 and 50,000 ft for the oblique
wing (Fig. 12). This is approximately an 11-21% decrease
in drag and results from all three components: friction drag
(because the aircraft itself is smaller and more efficient), wave
drag, and trimmed drag due to lift (because of the minimized
effects of aerodynamic center shift).
In carrier applications, takeoff gross weight can be severely
limited. Therefore, a valuable comparison is the useful load at
a constant takeoff gross weight representative of maximum
good design practice. Illustrated in Fig. 13 is a buildup by
component of the two designs at a constant gross weight. Once
again, it is apparent that the oblique wing design weights are
superior and that the total for the structure group is 14%
lower than that for the symmetric design. Because of the
greater efficiency due to lower drags, the propulsion group is
approximately 10% lighter than the symmetric design; and the
total weight empty for the oblique wing design is 11 % lower
than that of the conventional design, accounting for subsystems
and other miscellaneous weights that are approximately
the same for both designs. This decrease of 11% in
weight empty results in an increased useful load of 16% for
the oblique wing design, where useful load includes fuel and
weapons as well as the crew. The result of these weight and
performance advantages is shown nondimensionally in Fig.
14. The 100% design mission is the 400-mile radius mission
shown in Fig. 7. In scaling the radius, the cruise legs and the
supersonic dash are scaled by the same percentage. The aircraft
takeoff gross weight ratio compares to the design weight
used in Fig. 13. The advantage of oblique wings can be used in
either of two ways: 1) for a constant mission there can be a
17% gross weight reduction for the oblique wing design, or 2)
if maximum design takeoff gross weight is limited because of
carrier compatibility considerations, a 29% greater mission
radius can be achieved with the oblique wing design.
For a more severe (longer) mission, the variable-sweep
design becomes heavier more rapidly than the oblique wing
design, so that these differences are accentuated. Because of
such constraints in the naval application as landing speeds and
launch weight limits, the point is rapidly approached where a
more stringent requirement cannot be satisfied with a variable
aft-sweep design. A greater operating radius would require the
introduction of major new technologies into the aft-sweep
design before those same technologies would be needed for an
oblique wing.

 

[aim9xray]

Years later John Warner wrote that he felt he ended up making the wrong call with the A-6F and if had to do it over again, he would have not started the A-6F but accelerated the F-14D development while building in all-weather strike from the start, essentially the F-14D Quickstrike.

Warner?? I think that's the wrong John, think Lehman.

 

[F-14D]

Years later John Warner wrote that he felt he ended up making the wrong call with the A-6F and if had to do it over again, he would have not started the A-6F but accelerated the F-14D development while building in all-weather strike from the start, essentially the F-14D Quickstrike.

Warner?? I think that's the wrong John, think Lehman.

touche

 

[F-14D]

But Warner was also SecNav at one point, so an understandable error to make.

Thanks for the face-saver, but I still goofed. I knew which one it was.

 

[Vahe Demirjian]

There's an artist's conception of a Rockwell design for an oblique wing carrier defense fighter jet at the following link:

https://pdfs.semanticscholar.org/82fd/2588c5a9638dbae0e7ed8d031466801de4f7.pdf