Editing Light fighter (section)

==Design aims==
A key design goal of light/lightweight fighter design is to satisfy standard air-to-air fighter effectiveness requirements at minimum cost. These criteria, in order of importance, are the ability to benefit from the element of surprise, to have numerical superiority in the air, to have superior maneuverability, and to possess adequate weapon systems effectiveness.<ref name="Stevenson, pp. 33–50">Stevenson, pp. 33–50.</ref><ref name="Sprey, pp. 48–87">Sprey, pp. 48–87.</ref><ref name="Hammond, p. 36">Hammond, p. 36.</ref><ref name="Spick, 1995, pp. 45–46">Spick, 1995, pp. 45–46.</ref><ref name="Spick 1983, pp. 186–193">Gunston and Spick, 1983, pp. 186–193.</ref> Light fighters typically achieve a surprise advantage over larger aircraft due to smaller visual and radar signatures, which is important since in the majority of air-to-air kills, the element of surprise is dominant.<ref name="Sprey, 1982, p. 48">Sprey, 1982, p. 48.</ref><ref name="Gunston and Spick, 1983, p. 188">Gunston and Spick, 1983, p. 188.</ref><ref>Stevenson, 1993, p. 33.</ref>  Their comparative lower cost and higher reliability also allows for greater numbers per budget.<ref>Huenecke, p. 31</ref> Finally, while a single engine light fighter would typically only carry about half the weapons load of a heavy twin engine fighter, its surprise and maneuverability advantages often allow it to gain positional advantage to make better use of those weapons.
[[File:F-16 & MiG-29.JPG|thumb|Even though most light fighters prefer single-engine designs, this is not the case with other significant examples such as the [[Mikoyan MiG-29]], [[AIDC F-CK-1 Ching-kuo|AIDC F-CK-1]], and their related developments that pursue the [[Twinjet|two-engine]] configuration.]]
A requirement for low cost and therefore small fighters first arose in the period between World War I and World War II. Examples include several [[Royal Air Force|RAF]] interceptor designs from the interwar era and French "Jockey" aircraft of the immediate pre-World War II. None of these very light fighters enjoyed success into World War II, as they were too hampered in performance. Similar to the meaning of lightweight fighter today, during World War II the term “small fighter” was used to describe a single engine aircraft of competitive performance, range, and armament load, but with no unnecessary weight and cost.<ref>Lee, pp. 30–35</ref>

===Effectiveness===

The modern view of light/lightweight fighters is as a capable weapon intended to satisfy the main criteria of air-to-air combat effectiveness,<ref name="Stevenson, pp. 33–50"/><ref name="Sprey, pp. 48–87"/><ref name="Hammond, p. 36"/><ref name="Spick, 1995, pp. 45–46"/><ref name="Spick 1983, pp. 186–193"/> which in order of importance, are:
[[File:2015.2 공군 소링 이글 훈련 Soaring Eagle of ROK AirForce (16711215215).jpg|thumb|Light fighters are generally small, and their smaller RCS mechanically makes them harder to detect than larger and heavier fighters.]]
'''1. Superiority in the element of surprise''', to be aware of the enemy before they are aware of you. In past combats, surprise advantage has been mostly based upon small visual and radar signatures, and having good visibility out of the cockpit. Surprise is a significant advantage, since historically in about 80% of air-to-air kills, the victim was unaware of the attacker until too late.<ref name="Sprey, 1982, p. 48"/><ref>Gunston and Spick, 1983, p. 187.</ref>
{{Quote box|width=21%|align=right|quote=As the former editor of 'The Topgun Journal', the author asked hundreds of pilots over a six-year period what single advantage they would like to have, that is, longer-range missiles, more guns, better maneuverability, etc. To a pilot they all said 'The first sighting.' |author=James Stevenson |source=The Pentagon Paradox.<ref>James Stevenson, "The Pentagon Paradox", Naval Institute Press, 1993, p. 33.</ref>}}

Small fighters like the [[Northrop F-5|F-5]] with a planform area of about {{convert|300|sqft|m2}} or the [[General Dynamics F-16 Fighting Falcon|F-16]] at about {{convert|400|sqft|m2}}, compared to about {{convert|1050|sqft|m2}} for the [[McDonnell Douglas F-15 Eagle|F-15]],<ref>Sprey, 1982, pp. 88–89.</ref> have a much lower visual profile. The small fighter is typically invisible to opposing pilots beyond about {{convert|4|mi|km}}, whereas a larger fighter such as the F-15 is visible to about {{convert|7|mi|km}}.<ref>{{citation |first=LtCol Patrick |last=Higby |title=Promise and Reality: Beyond Visual Range (BVR) Air-To-Air Combat |publisher=Air War College, Maxwell Air Force Base |date= March 2005 |page=5 |url=http://pogoarchives.org/labyrinth/11/09.pdf}}</ref>  This is a non-linear advantage to the light fighter opposing a heavy fighter. Additionally, smaller targets take longer to visually acquire even if they are visible.<ref>Snyder, Harry, et al., “Air-To-Air Target Acquisition: Factors and Means of Improvement”, Virginia Polytechnic University, July 1979, prepared for USAF School of Aerospace Medicine, p. 15 (p. 18 as read on Adobe), http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA087848 {{Webarchive|url=https://web.archive.org/web/20161007064136/http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA087848 |date=2016-10-07 }}</ref> These two factors together give the light fighter pilot much better statistical odds of seeing the [[heavy fighter]] first and setting up a decisive first shot.<ref>Stevenson, pp. 22–36.</ref> Once the small fighter sees and turns towards the opponent its very small frontal area reduces maximum visual detection range to about {{convert|2|to|2.5|mi|km}}.<ref name="Gunston and Spick, 1983, p. 188"/><ref>Schallhorn et al., "Visual Search in Air Combat", Naval Aerospace Medical Research Laboratory and Naval Fighter Weapons School (TopGun), Oct. 1991, p. 6, http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA241347 {{Webarchive|url=https://web.archive.org/web/20161007061842/http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA241347 |date=2016-10-07 }}</ref>

Given similar technology, smaller fighters typically have about two thirds the radar range against the same target as heavy fighters.{{efn|The technical reasons for the modest increase in range of heavy fighter radar as compared to lightweight fighter radar in similar technology are covered in Stimson, 1983, pp. 163 to 190. In general, the radar ranges of modern airborne radars are significantly greater than the ability to identify targets as hostile in order to satisfy the rules of engagement and fire a BVR missile.}} However, this cannot be counted upon to give the large fighter a winning advantage, as larger fighters with typical radar cross sectional area of about {{convert|10|m2|sqft}} are detectable by a given radar at about 50% further range than the {{convert|2|to|3|m2|sqft}}  cross section of the light fighter.<ref>Sprey, 1982, p. 60.</ref> This approximately balances these trade-offs, and can sometimes favor the lightweight fighter. For example, from the front the F-15 actually presents about {{convert|20|m2|sqft}} radar cross sectional area,<ref>Sprey, p. 93.</ref> and has been typically defeated by opposing F-16 forces not only in close dogfighting combat, but also in extensive Beyond Visual Range (BVR) trials.<ref name="freelibrary" /><ref>Sprey p. 149.</ref> Also, airborne fighter radars are limited: their coverage is only to the front, and are far from perfect in detecting enemy aircraft. Although radar was extensively used by the United States in the [[Vietnam War]], only 18% of North Vietnamese fighters were first detected by radar, and only 3% by radar on fighter aircraft.<ref>Stevenson, p. 130.</ref>  The other 82% were visually acquired.<ref>Stevenson, 1993, p. 35.</ref>

The modern trend to stealth aircraft is an attempt to maximize surprise in an era when Beyond Visual Range (BVR) missiles are becoming more effective than the quite low effectiveness BVR has had in the past.<ref>{{citation |first=LtCol Patrick |last=Higby |title=Promise and Reality: Beyond Visual Range (BVR) Air-To-Air Combat |publisher=Air War College, Maxwell Air Force Base |date= 30 March 2005 |page=11 |url=http://pogoarchives.org/labyrinth/11/09.pdf}}</ref>
[[File:F-16 Kunsan AB Elephant Walk.jpg|thumb|Light fighters tend to be significantly cheaper to procure and operate than their heavier counterparts, allowing a numerically-bigger fleet with a same practical budget.]]
'''2. Numerical superiority in the air''', which implies the need for lower procurement cost, lower maintenance cost, and higher reliability. Not even taking into account the sometimes superior combat capability of lighter aircraft based on surprise and maneuverability, the pure numbers issue of lower cost and higher reliability (higher sortie rates) also tends to favor light fighters. It is a basic outcome of [[Lanchester's laws]], or the [[salvo combat model]], that a larger number of less-sophisticated units will tend to be successful over a smaller number of more advanced ones; the damage dealt is based on the square of the number of units firing, while the quality of those units has only a linear effect on the outcome. This non-linear relationship favors the light and lightweight fighter.<ref>Huenecke, p. 31.</ref>

Additionally, as pilot capability is actually the top consideration in maximizing total effectiveness of the pilot-aircraft system,{{efn|"In every war, it's the few superb pilots that win the air battle. A tiny handful of such pilots have dominated every air-to-air battleground since World War I: roughly 10 percent of all pilots (the “hawks”) score 60 percent to 80 percent of the dogfight kills; the other 90 percent of pilots (“doves”) are the fodder for the hawks of the opposing side. Technical performance differences between opposing fighter planes pale in comparison." Pierre Sprey, "Evaluating Weapons: Sorting the Good from the Bad", The Pentagon Labyrinth: 10 Short Essays to Help You Through It, 2011, Center for Defense, http://pogoarchives.org/labyrinth/09-sprey-w-covers.pdf}} the lower purchase and operational cost of light fighters permits more training, thus delivering more effective pilots.<ref>Sprey, p. 17.</ref>  For example, as of 2013, total heavy F-15C operating cost is reported at US$41,900 per hour, and light F-16C cost at US$22,500 per hour.<ref name="nation.time.com">See https://nation.time.com/2013/04/02/costly-flight-hours/ for hourly operating cost of USAF aircraft as reported by the USAF.</ref>

'''3. Superior maneuverability''', which in maneuvering combat allows getting into superior position to fire and score the kill.<ref>Stevenson, pp. 43–47.</ref><ref>Sprey, p. 49,52, pp. 67–75.</ref><ref name="Hammond, p. 36"/><ref name="Spick, 1995, p. 46">Spick, 1995, p. 46.</ref><ref>Gunston and Spick, 1983, pp. 190–191.</ref>  This is a function of achieving lower wing loading, higher thrust to weight ratio, and superior aerodynamics.<ref>Stevenson, p. 28.</ref><ref>Burton, Kindle locations 333–370.</ref><ref>Spick, 1995, p. 47–48.</ref>  This is sometimes described colloquially as “wrapping the smallest possible airframe around the most powerful available engine.”<ref name="Spick, 1995, p. 46"/> Professional analysis through 4th generation fighters shows that among heavier fighters only the F-15 has been generally competitive with lighter fighters, and its maneuvering performance is exceeded by several lighter fighters such as the F-16.<ref>Burton, Kindle locations 468–481.</ref><ref>Sprey, pp. 98–107, p. 109, 131, pp. 147–149.</ref>  Light fighters have no inherent aerodynamic advantage for speed and range, but when designed to be as simple as possible they do tend to have lower wing loading and higher thrust to weight ratio.<ref>Sprey, pp. 150–151.</ref>  Additionally, smaller fighters are lower in inertia, allowing a faster transient response in maneuvering combat.<ref>Sprey, p. 156.</ref>

'''4. Weapon systems effectiveness'''.<ref>Sprey, 1982, pp. 48–54.</ref><ref>Hammond, p. 36</ref><ref>Stevenson, pp. 33–49.</ref> This area is one where the light fighter can be at a disadvantage, since the combat load of a single engine light fighter is typically about half of a twin engine heavy fighter. However, modern single engine light fighters such as the [[General Dynamics F-16 Fighting Falcon]] and the [[Saab JAS 39 Gripen]] generally carry similar cannon and air-to-air missile [[Fighter aircraft#Weapons|fighter weapons]] as heavier fighters. Actual aerial combat in the modern era is of short duration, typically about two minutes,<ref name="Huenecke, p. 26">Huenecke, p. 26.</ref> and as only a small fraction of this is spent actually firing, modest weapons load outs are generally effective. The ideal weapons load for a modern fighter is considered to be an internal gun and two to four guided missiles,<ref name="Huenecke, p. 26"/> a load that modern light fighters are fully capable of while maintaining high agility. For example, the [[JAS 39 Gripen]], despite being the lightest major fighter in current production, carries a combat load of a 27mm cannon and up to six air-to-air missiles of the same types as carried by heavy fighters. Additionally, combat experience shows that weapons systems "effectiveness" has not been dominated by the amount of weaponry or "load out", but by the ability to achieve split second kills when in position to do so.<ref name="Hammond, p. 36"/><ref>Stevenson, p. 47.</ref><ref>Sprey, p. 52.</ref>

===Concept summary===
[[File:F-5andF-15.JPEG|thumb|A light F-5 in front of a heavy F-15.]]
Superior technology has often been quoted as a strong factor favoring the heavy fighter. The specific argument usually presented is that heavy fighters have superior radar range and longer range BVR missiles that take advantage of that range. This radar range advantage is one of the major reasons for the existence of the modern heavy fighter, but it has not turned out to be a significant advantage in air combat history to date for several reasons. A major reason has been because long range BVR missile shots have often been unusable, and often unreliable when they could be taken. The weight of the larger missiles also reduces performance and range needed to get in position to fire. Due to these factors, between 1958 and 1982 in five wars there were 2,014 missile firings by fighter pilots engaged in air-to-air combat, but there were only four beyond-visual-range kills.<ref>Burton, Chapter 1, Kindle Location 471.</ref>

The more general and often misunderstood argument for more technology that has been historically assumed to favor heavy fighters is not just better radar but better systems support for the fighter pilot in other ways as well. Examples include all weather capability, precise electronic navigation, electronic counter-measures, data-linking for improved information awareness, and automation to lighten pilot workload and keep the pilot focused on tasks essential to combat.<ref>Stevenson, 1993, pp. 120–121, 126–128.</ref>  This was a compelling argument, as the greatest factor in the effectiveness of a fighter plane has always been the pilot. Quoting a prominent reference, "Throughout the history of air combat, a few outstanding fighter pilots, typically less than five percent of the whole, have run up large scores at the expense of their less gifted brethren. The numerical imbalance was such that a large number of high scorers was needed. The quest was on to turn each fighter pilot into an ace, and technology seemed the easiest, and the only way to achieve it. This was the idea underlying the first two American superfighters; the F-14 Tomcat and the F-15 Eagle.”<ref>Spick, Mike, “Designed for the Kill”, 1995, p. 32.</ref>

While the technology advantage for heavy fighters that better supported the pilot may well have been a valid point in the 1970s (when the F-14 and F-15 first entered service), this advantage has not been maintained over time. Engine performance improvements have improved load carry capability,{{efn|The engine thrust to engine weight of jet engines has much improved over time. The [[General Electric J47]] of 1950s weighed 2,554 lbs and had thrust to weight of 2.34. The [[General Electric J79]] turbojet of the 1960s weighed 3,850 lbs and had thrust to weight ratio of 4.63. The modern [[General Electric F414]]-400 turbofan weighs 2,445 lbs but delivers thrust to weight of 9.0. These huge improvements allow for considerably heavier avionics and weapons loads on more recent light fighters.}} and with more compact electronics, the lightweight fighter has, from the 1980s onwards, had similar pilot enhancing technical features.<ref>Ahlgren, Linner, and Wigert, 2002, pp. 22–40, pp. 94–105.</ref><ref name="Hillaker">{{citation |last=Hillaker |first=Harry |title= Technology and the F-16 Fighting Falcon Jet Fighter|work=The Bridge|date=Spring 2004 |publisher=The National Academy of Engineering |url= https://www.nae.edu/Publications/Bridge/CentennialofAviation/TechnologyandtheF-16FightingFalconJetFighter.aspx}}</ref><ref>Spick, 2000, pp. 30–41.</ref>  The lightweight fighter carries equally effective weapons including BVR missiles, and has similar combat range and persistence. The modern lightweight fighter achieves these competitive features while still maintaining the classic advantages of better surprise, numbers, and maneuverability. Thus, the lightweight fighter natural advantages have remained in force despite the addition of more technology to air combat.<ref name="Hillaker"/>

Due to their lower costs, modern light fighters equip the air forces of many smaller nations. However, as budgets have limits for all nations, the optimum selection of fighter aircraft weight, complexity, and cost is an important strategic issue even for wealthy nations. The budgetary and strategic significance of light fighters is illustrated by the defense investment at stake. As an example where well referenced data is available, though numerous trial and combat references consider the lightweight F-16 to be as good or better on a per plane as the excellent but expensive F-15,<ref>Sprey, 1982, p. 149.</ref><ref>Lockheed Forth Worth Company (press release) http://www.thefreelibrary.com/F-16+TEAMS+DOMINATE+USAF+AIR-TO-AIR+COMPETITION-a015848749, accessed June 27, 2016.</ref> fielding and maintaining a light fighter force based on the F-16 is approximately half the cost of the same number of F-15's. The US Air Force reports the total loaded cost per hour (as of 2013) of operating the F-16C to be ~US$22,500 per hour, while that of the heavy F-15C is $41,900 per hour.<ref name="nation.time.com"/> Numerous authoritative sources report that it takes about 200 to 400 flight hours per year to maintain fighter pilot proficiency.{{efn| The US Air National Guard reports via http://www.globalsecurity.org/military/systems/aircraft/f-16-life.htm that it needs 247 hours per year for minimum necessary proficiency of its F-16C pilots, with an average sortie duration of 1.2 hours. Sprey p. 64 reports 30 sorties per month or nearly 400 hours per year for high combat proficiency. Manes reports 231 to 321 flight hours per year of logged flight time for various USAF and Air National Guard units.}}<ref>Brian Manes, Major, USAF, MS Thesis “Extending USAF F-16 Force Structure”, Air Command and Staff College, 2001, p. 17, downloadable from http://www.globalsecurity.org/military/library/report/2001/01-079.pdf</ref>

[[Lanchester's laws]] on military superiority suggest that any technical superiority of the heavy fighter on a unit basis will not always translate to winning wars. For example, late in WWII the greatly superior German [[Messerschmitt Me 262]] jet fighter, flown by the finest pilots Germany had left, many of them very high scoring aces with kill counts far in excess of Allied pilots, in its relatively small numbers suffered heavy losses and was unable to fundamentally alter the air war over Germany.<ref>Sprey, 1982, p. 23–25.</ref> Such issues are relevant to future military planning and deployments.<ref>The Rand Corporation, "Air Combat, Past, Present, and Future", 2009, available at https://www.defenseindustrydaily.com/files/2008_RAND_Pacific_View_Air_Combat_Briefing.pdf</ref>