McDonnell-Douglas fixed-wing VFX design

[KJ_Lesnick]

Wouldn't it be cool if McDonnell/McDonnell-Douglas had went with a fixed-wing VFX design that met the USN's requirements as good as Grumman's design did (Grumman's design was said to be head and shoulders over the other designs) and won, with the USN then managing to successfully get the USAF's FX program cancelled, with the VFX being used for both services?

It would have a number of benefits.  McDonnell/McDonnell-Douglas applied much of the information it learned from the VFX program on the FX program (It didn't devote much effort towards the FX program, until it lost the VFX program) so the knowledge from the VFX ended up used on the FX design.  If it featured a fixed-wing, several thousand pounds could be trimmed off the aircraft increasing its thrust/weight-ratio (To make it better, the McDonnell Douglas's VFX design was to weigh around 34,500 pounds empty, and the Grumman F-14 was 39,600 pounds empty).  

Making a fixed-wing plane that could do what the VFX could do would be tricky, but I think it might be possible if you had a pancake the size of the F-14, a somewhat larger wing than the F-15 with 5-additional degrees of sweep, a slightly lower T/C ratio, a re-designed trailing-edge, a LERX, and full-span leading and trailing edge maneuvering flaps. 

The pancake would add over 440 square feet of wing to the aircraft; the wing would be larger, which would further add lift for low-speeds, but it would be a little thinner, which would increase lift more than drag-levels; the leading and trailing-edge devices could be adjusted automatically by computer to vary the camber as a function of airspeed, mach-number, and g-load to optimize L/D-ratios across the speed range, and at low-speeds, a full span trailing-edge flap would increase lift and lower landing speeds.  The flaperon-shrouds, similar to those seen on the F/A-18 would further increase lift at low-speeds; the re-designed trailing-edge would increase roll-authority at low-speeds as most of the wing would have no trailing-edge sweep, the inboard section would in order to reduce drag at higher-speeds similar to the English Electric Lightning; full-span flaperons would provide better roll-rates over a traditional aileron (The F-15 had a better roll-rate than the F-14); the large LERX would provide vortex generation for high alpha maneuvering as well as good supersonic maneuvering performance (the higher wing-sweep would help too -- all of these variables reduce trim-drag).  I don't think it could meet the supersonic maneuvering performance the actual F-14 could, but who knows?  I'm pretty sure it could at least equal the F-15 which did very well. 

The weight reduction from eliminating the swing-wings could be substantial, and I wouldn't be surprised if you could shave off 8,000 pounds from the design.  That could yield an empty weight of only 28,500 pounds, which would only be 500 pounds greater than the F-4, and only 1,500 pounds heavier than the F-15A.  Assuming the plane would use the same 16,400 pound fuel-load, you would have a fuel-fraction of just under 36.53% which I think would have exceeded even the YF-16.  Fuel fraction is often more important a factor in determining an aircraft's range than the actual fuel-load in pounds.  Even if the L/D ratio was a little less than the F-14, the fuel-fraction could potentially offset it.

[gofy]

Could you do a profile of this plane??

[KJ_Lesnick]

Gofy,

The design I just proposed?  I'm collaborating with ElectrikBlue on such a design (He is developing the line-drawings, which as usual, are absolutely fantastic), the design is not by any means complete, but I'll ask ElectrikBlue if I can use the concepts so far to illustrate my point.

[McColm]

Would that look like the F-15N?

[KJ_Lesnick]

This is the basic design so far...


(Image courtesy of ElectrikBlue)

The design is not complete by any means (For one there's no underside or side view), though there is clearly a basic shape established.  We haven't quite established an engine bay shape yet, or the exact details of the area-ruling, the surface detail is still heavily based on Robert Beechy's Fixed-Wing Grumman 303/F-14 design.

Still you can see the basic idea.