You guys ought to check the stats between Iranian F14As and Iraqi airplanes.

I don’t think that the F14A was all that overrated in its time.

Nic

Great idea to use the conflict between unable air forces as basis for assessments. Third world conflict, third world tactics, not in any way comparable to the mission of the USN.

When I picked the MiG-23, what I meant was that although it has very good performance, esp speed and accelaration, I did not pick it for such reasons. The MiG 23, often overlooked by the MiG-21 and the later MiG-29, it was the first Soviet fighter to combine speed with a useful range and a half decent weapon load. It did for the Soviets what the F-4 did a decade earlier for the U.S, NATO and many other air forces.

I still have my issues with “useful” range. The newer models (-ML, -MLA and -MLD) had reduced fuel capacity. Drop tanks are limited to one 800l center line tank. The R-29 and R-35 are not famous for fuel economy.
The MiG-23 can achieve pretty nice range in ferry flights when it has the fuel tanks installed and is limited to M0.8, but in a combat situation the range will be pretty crappy. Actually, the need for good take-off performance (that is why it got the swing wings) eases the need for long range. Its predecessors needed at least 8000ft runway (the Suchoi 7, -9 and -11 are told to have pretty lousy field performance) and especially in the north of Russia such runways are short in supply. In Middle Europe the Russians could expect that each runway between Elbe and Oder would be bombed (at least attempted) within hours, so that secondary airports were necessary. The MiG-23 could handle that and still achieve good performance. The MiG-23 is hence a classical cold warrior, much more than counterparts as the F-4 or the Mirage, or the MiG-21.

and what provoked the development of the MiG-25 in the first place? the SR-71/A-12 and perhaps the B-70 – with only the “Habu” actually seeing service, and even then with only a few dozen actually built.

Quite a lineage if you ask me.:cool:

I always thought that the main specifications and performance criteria for the F-15’s basic design were decided by the lessons learned in the Vietnam war by the US air power establishment.
I’d almost say that it was combat against North Vietnamese MiG-17/19/21 which had a greater input into the F-15’s design than the apparent high speed of the MiG-25.

And what was the reason to develop the Blackbird or the Valkyrie? The Soviet SAM system and The Bomb. I guess we have to credit The Bomb in the first place.

-so dropping out the constants [Cdf and k are independant of M and $]-

Nice calculation. I pinned it down on paper to understand it. Makes sense and strictly logical.

Two things you should consider:
1. The sweep effect does not work strictly geometrical. Due to 3D-wing flow the practical effect of a sweep is normally sqrt(cos). So if a 45° wing sweep reduces the airfoil Mach number by cos(45) = 0.707 when taken geometry, it is in reality only 0.84.

2. The quoted line ruins your calculation, as it is wrong, at least for anything going beyond M0.8. As I said, the transonic drag rise is lower for highly swept wings, but your calculation is based on the lift-induced drag, which becomes practically zero for speeds beyond M0.9.

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For a highly swept wing, the peak becomes lower and supersonic drag is overally lower. Disadvantage is a high bleed in energy for higher lift coefficients.
Today’s fighters have found good compromises between supersonic and sub/transonic performance, all with very efficient structure. The swing wing is the dream of the aero-people, but does not pay off when looked at in the context.

The F-18 does it through having a different wing postion, the Su-27 is similar, although it uses ventral fins as well – which can be more aggressive as it doesn’t take off from carriers.

Hmm – about using FBW to get over it, stability and control people have fits if the airframe is unstable in both directions through the flight regime. But 3D TVC would solve all that.

My understanding is that F-18 and Su-27 (as well aus MiG-29) have less shielded fins. First, the fins still get some air through the gap between wing and tail. Second, the vortex extending from the LEX increases dynamic pressure on the fin. This effect was so violent on the F-18 that is has small vertical fences on the inlet channel to reduce the load on the fin. There are some downloadable videos on the NASA homepage, just look for HIRV (??) (High Incidence Research Vehicle).

Can anybody give me a robust figure for the Tomcat’s range or operational radius?

Swing Wings

Swing wings enable much more efficient loading of the wing through different flight regimes – for a variable sweep aircraft drag increases linearly with Mach number – whereas for a fixed wing aircraft it increases proportional to Mach number squared. No amount of tricks are going to overcome that.
You can use a thin aerofoil section, like the F-18 has, to try and get away with not having the wing sweep – but we all know the problems associated with thin low swept wings (rather, I’m assuming you do).

I tend to disagree. The swing wing was half heritage and half necessity on the Tomcat. In the late 60s, nearly everything had swing wings (F-14, Tornado, MiG-23, Tu-22, B-1A (which was in planning), Mirage VG).

Your story about drag has wet feet: Drag increases basically squared with speed, but only for subsonic speeds. When the airflow becomes transonic, things get funny. Right is that aircraft with high wing sweep experience less transonic drag rise between 0.9 and 1.2 (which is a reason the Hornet has a little drag problem in this region), but there are better ways:

The big drawback of variable sweep is weight, limited structural strength, complexity and limited number of pylons. That does not offset the advantages any more. Just look for the last proposal with swing wings.

I wouldn’t change the swing wing (for the reason mentioned above). To a large extent the aerodynamics would stay similar – perhaps a triplane configuration would be incorporated to improve supersonic manouvering. However, since the original Tomcat had a wing-glove, that shouldn’t be a large problem.

Funnily the Tomcat wasn’t particularly good in aerodynamics. The lateral stability must be considered poor in some flight regimes (OK for 1970, but not OK for 2005).
Your “supersonic manouvering” is limited on the Tomcat mostly by the G-limit and the available thrust, I don’t think that contro authority is an issue. Again: How many tri-plane configs have entered service? Additional surface = additional drag and weight. Not the best way to lose something of the 19 tons.

Increasing the size of the vertical stabilisers is not a large issue either (not on an aircraft with the structures for an arrestor hook close to the two fins).

And it wouldn’t help too much. Look how F-18 and Su-27 achieve superior lateral stability. The F-14’s vertical fins are shadowed for higher AoAs. However, with modern control techniques and high authority FBW you could help out, but this would again need considerable investment.

I wouldn’t bother too much with stealth features, on a VG aircraft with external stores, your never gonna get great RCS figures anyway.
[…]
Flying faster at low level is an excellent way of getting into topology cover (i.e. get a mountain between you and the missile launcher) increasing your chances of avoiding the missile. No-one ever had too much speed in a warplane.

I don’t consider the USN as extremely wise, especially is it always between needs, lobbies and congress (like basically every western military organisation). But I think they had their reasons for trading speed against stealth. Flying supersonic close to ground is luxury no fighter can afford for more than 2-3 minutes. For max speed dry at SL you will see Tomcat and Hornet within a range of maximum Mach 0.05.

Pardon?

A long ranged fighter-bomber? One which would be much more efficient than any Hornet for the Navy’s current needs…

I don’t think you considered that paragraph before posting it. 😮

Actually, I didn’t really consider it. But I don’t see why a mobile force like the US Navy should put the focus on range. For a force that is mostly limited by the number of aircraft available, the focus is on high availability, easy maintenance, similar stocks of weapons and spares, and multi-mission capability.

The Tomcat can do Mach 1.2 at sea-level – and Mach 2.34 at altitude.

It is limited to M1.88 for most times and will not sustain anything beyond that speed much long, either.

The aircraft you propose would have its advantages, but it would not save much costs, would still carry the inherent weaknesses of the Tomcat (weight!) and would look best in a photoshop fan-work. Actually, that is all that I have ever seen of the Tomcat 21.

Seeing as anything above cruise is likely to use up the fuel in minutes, I had assumed that. I am also aware of the drag rule, how to calculate drag and the effects of drag at transonic speeds.
The thing about the Lightning is that the difference between clean and normal load is very little. There are very few combat aircraft like that.

With two missiles and just few tons of fuel, the additional drag by loads is limited. Modern aircraft are – as you indicate – more versatile in external loads and may therefore show much more different behavior when not clean.

All what I read here leads me to the perception that the Lightning was the first (recoverable) “boster” stage of a man guided surface-to-air missile with terminal IR-guidance.