9 Non-Recoil Protected Model 9 Recoil Protected - .223 Class 9 For
Recoil - ThursdayLee
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Transcript of Recoil - ThursdayLee
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Experimental Performance Analysis on Recoil Pad for Reducing
Firing Shock Force
Experimental Performance Analysis on Recoil Pad for Reducing
Firing Shock Force
May 19-22, 2008
Joon-Ho Lee*, Eui-Jung Choe, Je-Wook ChaeAgency for Defense Development, Korea
Jeong-Hoon KangS&T Daewoo, Korea
NDIA International Infantry & Joint Services Small Arms Systems Symposium
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Introduction□ Recoil (Kick)
Physical property acting on rifle by firing Momentum of rifle = Momentum of projectile + Momentum of powder gases(Newton’s third law of action-reaction)
Firing shock force (N), recoil energy (J), impulse (N·s)Proportional to powder & gases quantity, exhausting gases velocity, muzzle velocity, projectile massInversely proportional to rifle mass
Felt recoilRelated to peak pressure on the skin, which is caused by stopping the recoiling rifleItems such as recoil pads, muzzle brakes and shock absorbers are utilized to reduce the amount of felt recoil.
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Introduction□ Recoil Pad
Protect shooters from shock and vibration caused by firing. Minimize recoil transmitted to shooters, which allows them to operate longtime with comfort. Help shooters to aim at the target and fire precisely.
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Research Background□ Experimental Prototype of New Rifle
Shoulder-fired dual barrel weapon system which consists of 5.56 mm and 20 mm caliber barrels
However, firing a 20 mm ammunition produces high recoil. negative impact on the shooting performance
To reduce the total weight, recoil pad is used to reduce the high recoil of the weapon so that the soldier can fire the 20 mm ammunition precisely at the target without hesitation.
Mockup of New Rifle
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Objectives
□ Test and evaluation of the performance of recoil padsCriterion : recoil-related firing shock forceDesign variable : material property (hardness)
□ Development of experimental setup for recoil padsHow to measure firing shock force, transmitted through the buttstock and recoil pad, while the rifle being fired on the sliding gun mount
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Shape of Recoil Pad to be Tested
3D ProE Model Recoil Pad
Designed and manufactured to be fit for the contour of shoulder areaon which the rifle is rested.
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Impulse-Recoil Measurement□ TOP 3-2-826 (kinetic tests for small arms)
Measuring the impulse (I) and recoil energy (E) of small-caliber weapon by means of ballistic pendulum
4 Supports – 6 Wires System
( ) 02( )rifle cradlem m d
I N sT
π += ⋅
221 ( )
2 2 rifle riflerifle
IE m v Jm
= =
Intrinsic recoil-related values of rifle (irrespective of recoil pad)
: The performance of recoil pad can not be evaluated by ballistic pendulum.
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Experimental Setup with Recoil Pad
Front Slider Force Transducer
Connection Point between Rifle and Mount Recoil Pad Test Fixture Gun Mount
Rear Slider
The rifle moves horizontally on the sliding gun mount.
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Experimental Setup with Recoil Pad
Force Transducer
Test Fixture
Gun Mount
Buttstock
Central Axis of Buttstock and Recoil Pad
Recoil Pad
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Experimental Setup without Recoil Pad
Front Slider Force Transducer
Gun Mount
Rear Slider
Connection Point between Rifle and Mount
The rifle moves horizontally on the sliding gun mount.
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Experimental Setup without Recoil Pad
Force TransducerGun Mount
Buttstock
Central Axis of Buttstock and Recoil Pad
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Experimental Setup
Experimental Prototype on the Sliding Gun Mount
With Recoil Pad Without Recoil Pad
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Experimental Setup
Material of test fixture : AluminiumThe inner curved surface of test fixture was manufactured to be perfectly matched with the outer curved surface of recoil pad by using NC machine and 3D contour data from 3D ProE model of recoil pad.
The pressure, exerted by the recoil force, is distributed evenly on thewhole contact surface.
Test Fixture Inner curved surface
Outer curved surface
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Experimental Results without Recoil Pad
0.000 0.005 0.010 0.015 0.020 0.025-0.25
0.00
0.25
0.50
0.75
1.00
Nor
mal
ized
For
ce
Time (sec.)
#1 #2 #3 #4 #5
0.000 0.005 0.010 0.015 0.020 0.025-0.10
-0.05
0.00
0.05
0.10
0.15
Nor
mal
ized
For
ce
Time (sec.)
#1 #2 #3 #4 #5
In case of 5.56 mm ammunition(5 shots)
In case of 20 mm ammunition(5 shots)
Peak firing shock force = 0.136Fref Peak firing shock force = 0.883Fref
□ Measured Firing Shock Force
Peak shock force of firing 20 mm ammunition is around 6.5 times higher than that of firing 5.56 mm ammunition.
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Experimental Results with Recoil Pad
0.000 0.005 0.010 0.015 0.020 0.025-0.25
0.00
0.25
0.50
0.75
1.00
Nor
mal
ized
For
ce
Time (sec.)
SR 18 CR 24 CR 30 CR 50 CR 80 Without Recoil Pad
0.000 0.005 0.010 0.015 0.020 0.025-0.10
-0.05
0.00
0.05
0.10
0.15
Nor
mal
ized
For
ce
Time (sec.)
SR 18 CR 24 CR 30 CR 50 CR 80 Without Recoil Pad
Material(Hardness)
SR(Hardness 18)
CR (Hardness 24)
CR(Hardness 30)
CR(Hardness 50)
CR(Hardness 80)
Without Recoil Pad
5.56 mm 0.068 0.081 0.090 0.101 0.121 0.136
20 mm 0.588 0.645 0.689 0.715 0.778 0.883
Peak Firing Shock Force ( x Fref )In case of 5.56 mm ammunition In case of 20 mm ammunition
* SR : Silicone Rubber, CR : Polychloroprene
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Experimental Results with Recoil Pad
In case of 5.56 mm ammunition In case of 20 mm ammunition
□ Motion of Recoil Pad by High Speed Camera
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Summary
□ Effect of the Hardness of Recoil PadThe performance of reducing firing shock force was increased as the hardness of the recoil pad was lowered.In case of SR(hardness 18), the peak firing shock force was reduced by 50% in case of 5.56 mm ammunition and 33% in case of 20 mm ammunition, respectively.
□ Experimental Setup to Evaluate the Performance of Recoil Pads
It can be referred for the test and evaluation of recoil pads which will be attached to shoulder-fired weapon systems with high recoil, developed in the future.
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End of Presentation
Thank you very much!Thank you very much!
Contact Information Name : Joon-Ho Lee
Phone Number : +82-42-821-2769
Company : 5th R&D Institute-3, Agency for Defense Development, Korea
E-mail : [email protected], [email protected]