Sunday, August 09, 2015

“Fighter Aircraft” Design: Driven by Operational Requirements

Part 1: Introduction

In the wake of the disinformation cascade set off by the mischaracterization of an F-35 Developmental Test report leaked to the poster-boy for Punk Journalism (and his equally hapless compadres) it became apparent that somebody, someplace should highlight just how infantile all the F-35 H8er and click-bait copycats have been on the subject.

Since ‘Axe is Boring’ ‘broke’ the story (if you can call being hand-fed the raw data by some other cretin and then making sh*t up about things he doesn’t understand ‘breaking’), I think we’ve seen every perversion of reality about the test itself, the relevance of the test, the F-35’s capabilities, the history of air combat, ‘dogfighting’, and airpower-in-general trotted out and gleefully regurgitated as if it were gospel by the innumerate and the illiterate.
As creative as the fiction published about the aircraft (it was an early production 'A' model: AF-2) performance during  the Developmental Test has been, it seems most if not all of the F-35 criticisms related to the ‘leaked’ test report fall into two broad categories. In the first category we can place all the claims/accusations that the F-35 is not somehow ‘fighter’ enough to successfully engage in air combat. In the second category we can place all the assertions that the scenarios flown in this one test were representative of how the F-35 would perform Air Combat Maneuvering aka ‘Dogfighting’ in actual combat.

We will deal with both these strains of criticisms in what will be Part 2 and Part 3 respectively within this short series. In Part 2, we will recall a rather cogent, insightful and in many ways prophetic AIAA paper from 1970s: “The Characteristics of a Fighter Aircraft”. This paper is the text transcript for the Wright Brothers Lectureship in Aeronautics speech given by Prof. Gero Madelung (speak German?) to attendees of the annual AIAA Aircraft Systems and Technology Meeting in 1977.  I’ll then introduce the thoughts on fighter development from a very influential and widely-cited engineer (among aircraft design types anyway) who among other things can be considered the originator of the concept ‘supermaneuverability’.  Thus, Part 2 (which may have to be broken into sub-parts if it gets too unwieldy) will bring us up to speed on top-level ‘fighter’ aircraft design drivers right up to the present-day state-of-the-art, and maybe a peek or two at the future.

Whereas Part 2 will provide proper background and perspective, Part 3 will be where the perspective will be applied and so will be more ‘analytical’. We will break down a 1 vs. 1 air combat scenario into a high-level conceptual model of constituent phases and associated combatant states. Then we will apprise the F-35’s potential advantages and disadvantages at different points of reference during engagement scenarios as it moves into and out of those phases and states and under what conditions it can navigate its way through those phases and states. We will also weigh the relevance of those advantages/disadvantages to possible combat outcomes.

Part 3 will take some time to complete after Part 2, so I will ask the readers to bear with me on any delays, or perhaps I will invite comment on aspects of the approach to Part 3 as I build the conceptual model. We should not have to account for probability of outcomes and only illuminate the ‘possibilities’ for discussion-- which will simplify the problem significantly but not to the point that careful construction will not still be necessary just to avoid oversimplification on the one hand or sophistry on the other. This is the hard part of Part 3: to make complete enough to be valid and convey meaning, not so complete that too many eyes glaze over. The topic would be a lot easier for me to treat if there were more authorized references to the F-35’s Developmental Test that I could tie into, but we’ll muddle through without them somehow.

This is also probably going to seem awfully obvious and trivial in many places to some, but I want to have a single reference to point non-technical minds to in the future. -- Because this is one of those topics where you could get worn out just beating down the same stupidity and misperceptions every time they pop up.
Finally, in each part I will include a reminder:
Nowhere in this series of posts, or in any other posts the reader will find here, is the assertion made that ‘maneuverability’ (however one defines it) is "unimportant"-- in the past, modern day or immediate future . This must be stated unambiguously up front because I've seen the tiresome broad-brush accusation of same made too-often when anyone dares challenge some closely held belief as to maneuverability’s relative importance to fighter design or dares challenge the vague reasons why many of the uninitiated think “maneuverability” is important. 
This note won’t stop tired criticisms from arising, but it will make intelligent people stop and think before they paper any comment thread with false conclusions. And this series of posts isn’t for the people too stupid to know better anyway.

Part 2 is here


Jason Udan said...

can't wait to read it

bring_it_on said...

@ Tim, in the absence of data you conclude that the Aim-120D is an 'unknown' vs the threat of DRFM jamming, a threat that has existed for many years What about the Aim-120C7 being tested against high end 'threat represented' Jamming equipped QF4. That news is a few years old. The D only builds on the capability over the C7 btw. If you look hard enough, you'll find information on the fact that the AMRAAM has been fired against a maneuvering target that utilizes representative jamming. They aren't going to throw out statistics and numbers just to please certain folks in the media that may have such an opinion (those that constantly bring arguments like " Stealth is dead" based on Russian and Chinese Radar OEM claims, AMRAAM won't work in a jam environment etc etc). What if there is a passive capability to home on to a jam? What then?? Again, material is available just need to look a little harder.

"""The new variant's anti-jamming performance was demonstrated last year when it shot down two targets protected by jamming. The first shot, conducted over the Eglin Test Range at Eglin Air Force Base, Florida, on 19 August 2003, resulted in a 'kill' against a full-sized target defended by what Raytheon described as "realistic electronic attack techniques", while the second was against a subscale target at White Sands Missile Range, New Mexico, on 6 September in the presence of "complex electronic attack techniques". Both resulted in direct hits."""

The DRFM threat has existed and the entire Russian capability is built around DRFM protection front and back. Given we want to fight and win in complex BVR scenarios, unless one believes that the USAF is oblivious to facts that a simple google search could bring to light one has to take the little info that is made available and look at the classified budget to see where the investments are likely focused on when it comes to maintaining air-superiority something that the USAF has done for a long long time.

bring_it_on said...

So nothing as far as solid data. We know there is something that is out there known as DRFM jamming. We don't know any data other than reports that the last two major versions of AMRAAM have been tested against both maneuvering and jamming targets. But we must conclude that the absence of data must point to similar 'overestimation' of performance that was perhaps once done in history. If one assumes that we'll never learn from history, create and establish best practices based on historic wrongs than one can definitely carry on with that argument, otherwise current jet fighters should have the same reliability issues that the first generation jet fighters faced, or we should have never been able to create airframes that can survive 12,000 hours of high performance...because once upon a time we failed to properly design something because our data was not the most comprehensive.

bring_it_on said...

Let me also flip this argument on its head..How have the advanced DRFM jammers and techniques performed against modern missile seekers ??

SMSgt Mac said...

Sorry to now have you talking to ghosts Bring_it_on, but evidently Tim A not only forgot he was person non grata here, (see comments here: he seemed to believe he had sufficient standing to make requests/demands? WTFO?
I guess he also missed the part about 'high-level' or interpreted it to mean 'end-game'?
To cut any similar silliness off at the knees. I've DONE (7-8 years ago, when it was still tedious building up a lot of 'first' objects) the operational modeling including 'flyout' and 'end-game' with source data you will never see on the internet, and building vetted DoD 'mission' scenarios that can simulate single combat up through theater-wide operations: not some tarted-up commercial 'shoot-em-up' game with unknown guesses for GR&As and linkages. I'm not going to go into any detail about any results I've seen except to say I'm not in the least bit concerned about anything Tim A. seems to have a bug up his a** about. I COMPLETELY understand why those in the position to make the decisions about these kinds of things aren't unduly 'concerned' either.

Angus McThag said...

I'm a super layman with a lot of this, but I can't help but recall that F-105D's did manage to shoot down (a few) MiG-17Fs over Vietnam.

I'd think that alone would put paid to the idea that maneuverability is everything.

Joseph Kusko said...

@Angus McThag
Even though Sprey has put out a lot of junk, I do have to agree that his basic premise in here ( that surprise, and the opportunity to exploit it, is the most important factor in killing the other guy in the sky. Hence the focus on LPI radar, IRST systems, stealth and other technologies that try to give the first strike to our guys.

Even without surprise, maneuverability wasn't always needed. To take an example from WWII, Hellcats and Corsairs completely dominated the A6M Zero, despite the fact that they were much less agile. Hit-and-run tactics won the day over the skies of the Pacific. In late 1941, the Spit Mk V was being marauded by the FW-190A even though the Mk V had a much better turning circle. The 190 was simply faster and could utilize hit-and-run tactics so the Brits could never get close. (If it hadn't been for cooling problems on the BMW 801, the 190 would have been unmatched until mid 1942 when the Spitfire Mk IX was introduced.)

S O said...

The A6M wasn't really more agile than Hellcats - it was more manoeuvrable only at low speeds. The Hellcat pilots chose to fight at higher speeds.

Other times such a choice of conditions led to stalemates, sucha s when Sea Harriers and Mirage III met in 1982 and often did nto engage decisively becuase neither was ready to fight teh way the other pilot preferred (Mirage pilots wanted to fight high, Harrier pilots preferred low - several encounters were ended only when fuel ran low).

About surprise; passive or LPI sensors and stealth are oriented at surprising the red pilot. The F-35's DAS is meant to prevent the blue pilot from getting surprised. I suppose this will become a must-have upgrade for all combat aircraft in the 2020's, and thus many efforts to achieve surprise will mostly be wasted.

SMSgt Mac said...

Sorry I didn't see your comment in the queue earlier SO.\
I agree and you point out what is the most important factor in determining who wins and who loses is who controls the time and conditions under which combat is entered. Surprise attack is the number one way this control has been applied, but if the enemy knows your there but can't 'touch' you. In WW2 P-38s at altitude could engage the Zekes at will and dive away with near impunity, that too was a form of control. I keep a copy of Martin Caiden's book 'Zero', coauthored by the Zero's designer and several Japanese fighter pilots, that made it very clear that until the Hellcats and the Corsairs started showing up in numbers, their biggest frustration was their helplessness against Lightings under normal conditions, and biggest prize was getting a Lightning pilot to screw up and engage in dogfighting at lower speeds and altitudes.