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Gun Propellants For The 27 mm Cal. Gun Eurofighter Jet

Dr. Dietmar Mueller

Fraunhofer Institut Chemische Technologie ( ICT ), D-76327 Pfinztal, Germanymue@ict.fhg.de

Walter Langlotz

Diehl BGT Defence GmbH & Co. KG

D - 90552 Roethenbach a. d. Pegnitz, Germany

44th Annual Gun & Missile Systems Conference & Exhibition

April 6 - 9, 2009

Kansas City, Mo, U.S.A.

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ContentIntroductionDNDA - Propellants● Thermodynamic Characteristics ● Temperature Behaviour of LTC Propellant in Closed Vessel● Performance, Safety Test Results● Sensitivity Data DNDA - Propellants ● Shaped Charge Tests● Erosivity

Gun Firing● 75 mm cal. Propellant Charges ( 2 LTC Propellants )● 27 mm cal. Eurofighter ( EF ) Propellant Charges

EF Propellant 27 mm cal. for PELE Ammunition

PELE Ammunition Concept

Results & Conclusion

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Since approx. 100 years are known the Nitrocellulose Propellants

Self - Ignition Temperature ~ 175 °C

Also the Multi Base Propellants like SCDB and EI, ECL Propellants are

giving the Self - Ignition at ~ 175 °C

Nitrocellulose Propellants based on DNDA and RDX the

LTC Propellants are showing

First Generation

Self - Ignition Temperature 200 - 210 °C

Second Generation

Self - Ignition Temperature > 220 °C ( Eurofighter Propellant etc. )

Introduction

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DNDA Gun Propellants

RDX

Binder, Nitrocellulose

DNDA Plasticizer

energy density adaptable

flame temperature approx. 500 K lower compared to NC Propellants

Plasticizer mixed into the Propellant - Dough

NO SURFACE COATING

Formulation Impetus (J/g) Flame Temp (K) Mw (g/mole) A 1080 2540 19.4 B 1180 2910 20.8 C 1300 3390 21.6

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0.0 0.2 0.4 0.6 0.8 1.00.00

0.25

0.50

0.75

1.00

1.25

1.50

1.75

Los 190705 - Temperaturbeschuß bei Δ=0.2g/ml in Vb=310 ml

343 K 336 K 323 K 294 K 233 K

Lebh

aftig

keit

[1/(M

Pa*s

)]

relativer Abbrand z

Closed Vessel Behaviour of LTC PropellantsVivacity of Gun Propellant based on DNDARange -40 °C till +70 °C

LOS 190705 - Firing at different temperatures ∆=0.2g/ml in Vb=310ml

p / pm

Viv

acity

[1/

MP

a*s

]

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0

0,02

0,04

0,06

0,08

0,1

0,12

0,14

0,16

0,18

0,2

0,22

0,24

. -40°C 0°C 10°C 21°C 30°C 50°C

propellant temperature (°C)

linea

r bur

ning

rate

(m/s

)

3000 bar

2500 bar

2000 bar

1500 bar

Linear burning rate of LTC Propellants at different pressures

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Formulation Impetus ( J/g ) Tf ( K ) Mw ( g/mole )

1 1080 2540 19.42 1180 2910 20.8

3 1300 3990 21.6

Performance data

Loss of weight after 18 days < 1.10 %Loss of weight after 30 days < 1.65 %

Sensitivity to friction 160 NSensitivity to impact 4 J

Self - Ignition temperature > 220 °CFast cook - off test burning

Shaped charge impact test Class A

Perfomance, Safety Test Results

Safety data

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Sensitivity Data of different DNDA - Propellants

RDX - Prop.ICT 1

i-RDX - Prop.ICT 20

RDX - Prop. mod. DNDAICT 3

Reaktion Class Shaped Charge Testcal. 35 mm

A A B

Friction Sensitivity[ N ]

288 240 240

Impact Sensitivity [ Nm ]

6,0 6,0 5,0

Ignition Temperature [ °C ] > 220 > 216 > 219

1“ Detonation - Tube no Detonation

MG cal.50 / 12.7 mm IM Reaktion Type 5 ( MIL - STD 2105 B )WIWEB Results

Propellant not burning, still in cartridge

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Shaped Charge Tests,

DNDA - Propellant ICT 1 ( RDX ), ICT 20 ( i-RDX )

Class A Class A

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ICT 3

Class B

Shaped Charge Test,

DNDA - Propellant ICT 3, Class B Test Result

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0

5

10

15

20

25

30

900 950 1000 1050 1100 1150 1200

Force (J/g)

mas

s lo

ss (%

)

double base

double base

triple base

triple base

single base

single base

single base

LTC 1

LTC 2LTC 3

LTC 4

LTC 5

Erosivity of LTC Propellants and Conventional Propellants

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75 mm Scale model gun derived from 120 mm cal. tank gun ( Diehl BGT )♦ based on interior ballistic similary laws♦ less cost ( combustible paper case, less propellant mass )

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V o vs T

1500

1550

1600

1650

1700

1750

Temp. [ °C ]V

o [

m /

s ] JA 2

LTC Prop

- 40 + 21 + 50

P m vs T

3000350040004500500055006000

Temp. [ °C ]

P m

[ ba

r ]

- 40 + 21 + 50

JA 2

LTC Prop

Test Firing in 75 mm cal. Model Gun ( Diehl BGT )Optimized propellant for firing at 21°C

muzzle velocity vs temp.gas pressure vs temp.

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1500

1550

1600

1650

1700

1750

V o

in [

m /

s ]

- 40 + 21 + 50Temp. [°C]

LTC-Prop. 2

Test Firing in 75 mm cal. Model Gun ( Diehl BGT )Performance optimized propellant

muzzle velocity vs temp.gas pressure vs temp.

JA2

3000350040004500500055006000

Pm [

bar ]

JA2

- 40 + 21 + 50Temp. [°C]

LTC-Prop. 2

P m vs T V o vs T

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2000

2500

3000

3500

4000

4500

5000

5500

6000

-60 -40 -20 0 20 40 60 80

propellant temperature (°C)

max

. pre

ssur

e (b

ar)

pressure limit

EF Propellant

Gun Firing 27 mm cal. Eurofighter

pressure vs temperature

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800

850

900

950

1000

1050

1100

1150

1200

-60 -40 -20 0 20 40 60 80

propellant temperature (°C)

muz

zle

velo

city

(m/s

)

EF Propellant

Gun Firing 27 mm cal. Eurofighter

muzzle velocity vs temperature

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800

850

900

950

1000

1050

1100

1150

1200

-60 -40 -20 0 20 40 60 80

propellant temperature (°C)

muz

zle

velo

city

(m/s

)

non-aged

aged: 8d @ 70°C

EF Propellant

Aged propellant compared with non aged propellant

muzzle velocity vs temperature

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EF Propellant 27 mm cal. Eurofighter PELE Cartridge

Combustion Temperature 2900 K Gun Erosion like Single Base Propellant

Force 1140 J/g

Ignition Temperature > 220 °C

Cook - off Cartridge 27 mm cal.

27 mm Gun Tube Mauser, MATE ( Mauser )

Q 5560 ( Ref. Prop. ) 125 °C 3,5 h Ignition

EF Propellant 125 °C 8,5 h. No Ignition

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Cook - Off Test in Gun Tube 27 mm cal. ( MATE )Gun Test Tube

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PELE® projectile DM 83 and DM 93 (with tracer)

EF DNDA gun propellant

PELE Cartridge 27 mm cal.PELE = Penetrator with Enhanced Lateral Efficiency

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Eurofighter BK 2727 mm cal.

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Diehl PELE Ammunition Concept

• PELE Projectiles → Highly effective against all targets

• New type of LTC propellantwith low flame temperature (reduced erosion), high cook - off temperature

- high internal ballistic safety

No vo - correction necessary- high shot precision within the temperature range

high density material for tube I.e. tungsten, steel

low density material for inner coreI.e. plastic or aluminum

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Part II: Fragments by PELE effect( Adjustable between 30% and 100% )

Part I: Erosion by penetration

Part III: Penetration and/or PELE effect in next plates Adjustable between 0% and 70% )

high density material for tube I.e. tungsten, steel

low density material for inner coreI.e. plastic or aluminum

kbar

4,8

1,6

-4,8

-1,6

t = 17µs t = 27µs

Pressure distribution on penetrator

PELE Function

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♦ LTC Propellants based on DNDA 5,7 and RDX for a wide Caliber - Range

♦ Excellent Shaped Charge Testresults ( Reaktion Class A )

♦ High Self - Ignition Temperature > 220 °C

♦ Insensitive, Reaction Type 5 ( MIL - STD 2105 B ) IM CharacteristicMG 12.7 mm cal. firing on Steeltube with propellant

♦ Excellent Long - Term Stability

♦ Low Combustion Temperature at High Force and Low Gun Tube Erosion

♦ Less Sensitive in Hot Gun Tube ( MATE )

♦ Propellant Charge for Eurofighter Gun, 27 mm cal. PELE Cartridge

Results & Conclusion