Ok, first, the delta wing is a well proven configuration, very solid, and for high mach speed it doesnt need very poweful engines.

We cant really know about aerodynamics, I must admit, but your small plane seems to have a shape too complicated for such small size, why must have the Fanker/Fulcrum layout for such small plane?, you will save weight stuffing both engines in the same structure, instead putting them on pods, the reason why the flanker has such design is because is more practical for such size, because structural issues for its huge lifting body…but your aircraft is lighter (or it must be).

Boeing recently tried delta wing; http://www.youtube.com/watch?v=zbPx6rQO3qg

I have an idea for really lite structure.

Light loaded it has 212 kg/m2 loading and top loading around 385 kg/m2.

I estimate mach 3 even with J-85s ( proven for hypersonic speeds ) at 24 km altitude.

This thread turned one year old yesterday !

I think we have a healthy baby now !

😉

These were munchkins..USAF fighters from 1970ies ! I like’em alot. F-16 was created from this stuff..

There was one error in the ruddervator area….corrected here !

Finally the side view also !

Lotsa lotsa fuel can be fitted inside ( 2500-3000 liters ).

This is kinda like cross breed in between SU-35 and YF-23 but all arranged into F-5 size ( or Gripen ).

Able little MUNCHKIN or what ?

If F-20 isn’t tail heavy…then my A4SF-1G is nose heavy !

You should read a lot more about how shape of aircraft affect performance.

When the F5D Skylancer was developed from the F4D Skyray, it was a larger aircraft with the same engine but was two hundred miles an hour faster as stated by the engineers who built it, simply because they eliminated the flat windshield and replaced with a V shaped one.

The windshield on your aircraft alone will restrict its speed greatly.
The lack of space will restrict its ability to reach any speed due to fuel use to attain anything near a high-speed.
It would have less range than a F-5 because two engines use more fuel than one without exception.
A English Electric Lighting could shoot it out of the sky because it would have superior performance but then with the extremely limited range of your gnat it would never be a threat to anything period.

A more recent small fighter, F-20, died for reasons this analyst said:

We wanted hot, light airplanes that were just as stripped-down as possible… They took an austere, stripped-down F-5 and ruined it by loading crap on it. Adding Sparrow missiles required huge complexity on the airplane. Adding air-to-ground capability ruined the F-20A.
The Tigershark gained it performance by eliminating two small J-85s for one larger engine.

Your Neverland idea will never leave Neverland.
Pierre Sprey, DoD senior analyst.

Your dream has even more problems that the Tigershark had.

Skylancer had 5 degs steeper windshield than Skyray…but F-20 had actually 7 degrees steeper than F-5…wonder why ? F-20 had 14 degrees steeper wind screen steepness than a F4D Skyray !

Biggest problem in my dream is a company that could manufacture them and funding most likely.

Below the mistake is clear 500 kg heavier engine reaches also 11 inches more aft than previous pair of J-85s…for compensation nose has been lenghtened by 6 inches…pilot has not moved forward..gear, machine gun and radar has.

Also the trade mark Coke Bottle fuselage no longer exists ( area ruled lay out ).

Most dramatical difference in the wing leading edge 5 degs steeper form which brought the leading edge 8 inches forward at the root..changing the aerodynamical CENTER few ( 5-6 in ) inches forward !!!??