Sprey quarter century

April 2006 © Pierre M. Sprey 2006 1

Comparing a QuarterCentury of Fighters

F-100 to F-18

By Pierre M. Sprey

Sponsored bythe Strauss Military Reform Project

of theCenter for Defense Information


Outline Purpose The fighters to be compared Criteria for comparing fighters Fighter effectiveness estimates Combat and test results Some lessons learned Applying the lessons learned


Why review old fighters?

“Those who cannot rememberthe past are condemned torepeat it.” G. Santayana


Which fighters to compare?


Basis for comparing fighters

Compare combat results, whereavailable

Compare combat-derivedeffectiveness criteria

Use F-86 as the point of reference forall comparisons Combat is the ultimate (and the unkindest)

judge


Combat-derived effectivenesscriteria in priority order

1. See him first2. Outnumber him3. Outmaneuver ’em to fire4. Kill ’em quick


1 Criterion

Achieve surprisebounces withoutbeing surprised

Why? From WWI to

Vietnam, 65% to95% of all air-to-air losses wereshot downunaware


2 Criterion

Outnumber theenemy in the air

Why? 70 vastly superior

Me 262s wereground down by2,000 inferior P-47sand P-51s


3 Criterion

When surprisefails, out-maneuver theenemy to gainfiring position

Why? Always dominated

by pilot ability &training


4 Criterion

Achieve reliablekills during anysplit-secondopportunity

Why? The more aircraft

engaged, the morefleeting the firingopportunities &the moredangerous thefiring delays


Combat-derivedeffectiveness criteria: 1

Angle obscuredRearward visibility

ΔV CruiseSustained speedadvantage in combatarea

Achieve surprisebounces and without

getting bounced

• Presented area• Smoke or no smoke• Electronic emissionsor no emissions

Invisibility

MeasureNecessary

effectivenesscharacteristics

Desired Effect



Outnumber theenemy in the air Sorties per day per

procurement $

• Large force size (inaircraft and skilledpilots) withinavailable budget• High sortie rates

MeasureNecessary

effectivenesscharacteristics

Desired Effect



• Number of accelerations/decelerations available (atvarying H, V, and R)• For rough comparisons,use fuel fraction

• Adequate fuel tocomplete more combattasks (maneuvers) in equalor less time than enemy

Outlast the enemy while outmaneuvering him

• Time to roll 180º and backat max g• Time to pitch from 1g tomax g and back to 1g

• Quick Transients

• CLMAX X Area Weight

• Quick deceleration andhigh instantaneous g (orturn rate)

Outmaneuver enemy to:• Gain firing position• Deny/defeat his firing

• 1g PS (subsonic, transonic)• Quick acceleration orclimb

MeasureNecessary effectivenesscharacteristicsDesired Effect



• Weight/cost of enemy ECM• Penalty of enemy’stactical counters

• Minimum vulnerability tohardware ECM or tacticalcountermeasures

• time from opportunity tobreakaway

• Minimum time fromrecognition opportunity tobreaking away (to attacknew target or to avoidattack)

• Number of on-board kills• Adequate ammo formultiple engagementsObtain a reliable kill during

any split-second firingopportunity from 100 feetto max visual ID range

• Kills/trigger squeeze incombat

• High PK versus close-inmaneuvering targets

MeasureNecessary effectivenesscharacteristicsDesired Effect


What have the last 25 yearscontributed to effectiveness inair-to-air combat?

LethalityDogfight performanceForce sizeAchieving surprise bounces


Findings: Surprise

Since the F-86, our aircraft(except F-5 and F-16) havesignificantly decreased in abilityto achieve surprise bounces dueto increases in size, smoke, andemissions


Findings: force size

Unnecessary increases incomplexity and cost havedecreased the effective force sizeper constant $ by factors of 25 to100 since the F-86


Findings:maneuvering performance

In dogfight performance, 1g PShas not improved significantlysince the F-104A.

Large deterioration in max g issomewhat reversed by the F-15and F-16


Findings:transient performance

Standard measures (or flighttests) of transient performanceat high g do not yet exist. Onlythe F-86, F-5, and F-16 haveattained excellent transientperformance


Findings:combat lethality Combat gun lethality (and range) has

deteriorated since World War II andKorean-era calibre .50 machineguns.

IR missile lethality in combat was 1/2of gun lethality.

Radar missile lethality was 1/2 that ofIR missiles—despite continuousmissile R&D since 1948.


1952-78 fighter era

Did the 1952-78 era produce anyfighters as great as the P-51 andF-86?


Five “almost great” fighters

Obsessive emphasison Mach 2 burstspeed ruined anotherwise brilliantdesign

With 25% more wing,low tail, andtransonic inlet, couldbeat F-14, F-15, andmatch F-16.

F-104A (J79-19)

Only twin-engineever to become afirst rate fighter

With 20% lessweight, could havedominated any U.S.or foreign fighter upthrough F-14

F-5E

CommentShortcomingsType



Showed that asingle, fixed inletF100 engine designcan havesignificantly longerrange, highersupersonicacceleration andbetter transientperformance than atwin with movableinlets

Addition of 3,000pounds and $3million per unit tothe F-16 changed agreat fighter to an“almost great”

F-16




• First double delta• First highperformance delta• OutmaneuversMirage III and F-106

With J79 engine,would have beenbest fighter of the1960-1976 era

J-35 Draken

Same performanceas F-106 at one-halfthe size

With J79 engine,would have beenbest fighter of the1960-1976 era

Mirage III



How much progress in combateffectiveness since F-86?

Combat results Korea (1950-52) F-86 produced 14:1

kill-loss ratio against MiG-15 North Vietnam (1967-72)

• F-4 obtained between 1:1 and 2:1 against MiG-21



Combat results (continued) Israeli (1967 & 1973) Mirage III

achieved better than 20:1 againstMiG-21 (preferred by Israelis over F-4)

Indo-Pakistani War (1965)• F-86 Mk VI (bought for $100,000) attained better

than 6:1 against Indian MiG-21, Su-7, and Hunter.• 90 F-86s + 75 others achieved air superiority in 7

days against force of 700



Test Results 1965 Operation Featherduster air-to-air tests.

• F-86 had exchange ratio advantage over F-100, F-4, F-104, and F-105• Matched 1:1 against F-5

1977 AIMVAL/ACEVAL test.• F-14 and F-15 could not achieve significant exchange ratio advantage

over the F-5

After 30 years and 12 new fighterprograms, have we yet designed a fighterclearly superior to the F-86?


Progress:surprise bounces

Visual size



Rearward visibility



Cruising speed

All Others


Progress:effective force size

Unit program cost@750 a/c in FY $79


Progress: performanceFuel Fraction


Progress:dogfight performanceAcceleration—Ps @ 1g or maximum rate of climb


Progress:dogfight performanceInstantaneous turn CL MAX (S/W) @Mach 0.5


Progress: lethality


Some lessons

We have not been able to convertlarge U.S. advantages in engine,structural, aerodynamic, andmicroelectronic technologies intoa fighter radically superior to allits predecessors and foreigncompetitors


Some lessons

Some reasons Lack of clear understanding of the critical

components of fighter combat effectiveness Inability to enforce design discipline upon

service and industrial bureaucracies Addition of heavy air-to-ground (and/or

interceptor) compromises to every fightersince 1950—persistence of the World War IIfighter-bomber mentality


Some lessons

Some reasons Failure to improve engine thrust-to-weight

since the J85-21, due to misoptimization forexcessive bypass, pressure, and temperature(and specification inflation)

Refusal to recognize that Vietnam combatdemonstrated the ineffectiveness of airintercept radars and radar missiles (forreasons that R&D cannot eliminate)


Applying the lessons learned

A new air-to-air fighter to dominateall existing fighters would need toemphasize 20 minutes combat cruise above Mach 1.2 Subsonic maximum g and transients near

F-16 level Primary dependence on passive avionics/

anti-radiation missile


Applying the lessons learned

Radical elimination of specificationsand equipment

Size smaller than F-5 Cost below $4 million (in FY79 dollars) More lethal gun (higher V0, smaller

caliber) More reliable snap-shoot IR missile

(head on unnecessary)

Sprey quarter century

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