Post by Abante on Aug 8, 2006 20:36:59 GMT -5
additional info if you want high ROF with your AEG
Advanced Gearbox Tech I
Increasing Rate of Fire with Capacitors
Introduction:
The inherent design of the AEG gearbox presents an uneven load to the AEG motor per firing cycle. During half of the firing cycle, the motor encounters gradually increasing torque loads as the main spring is compressed. After full compression is achieved, the motor encounters minimal load for the 2nd half of sector rotation as the gears reset to the firing positon virtually unencumbered. This uneven load demand on the motor results inevitably in an uneven current demand from the battery, and a naturally fluctuating voltage output. Since motor performance is tied closely to battery output, the ability to minimize voltage fluctuations, especially sudden voltage drops, can enhance motor performance and result in an increased rate of fire.
Capacitors:
Capacitors are structually simple electrical devices composing of little more than 2 conducting elements separated by a dielectric medium. Their simplicity belies their myriad uses, arising from the ability to act as temporary storage vessels for electrical energy. Capacitors store energy by maintaining a physical separation of electrical charges, creating an electrical potential. The magnitude of the potential which the capacitor is able to maintain is given by the voltage rating of the capacitor, while the total amount of energy the capacitor can store is expressed by its capacitance rating, usually in units of micro-Farads or mFD. A capacitor can not be charged with a potential higher than its rated voltage, or risk catastrophic failure. In the charged state, the capacitor acts like a mini-battery, ready to provide current when the need arises. When a charged capacitor is connected to a load, energy is released from the capacitor to drive the load until its capacity has been exhausted. When several capacitors are wired together in parallel, the resulting capacity of the system is the sum of the individual capacities of each capacitor. This property allows for easy increases in net capacitance by simply adding more capacitors to the system in parallel. The ability of capacitors to temporarily act as mini-batteries gives them the ability to act as buffers to sudden changes in voltage in an electrical circuit. As the AEG mechbox cycles, the increased load it presents to the battery causes a voltage drop as the battery tries to meet the demand. With the addition of capacitors to the circuit, the magnitude and rate of the voltage drop should in theory be reduced, resulting in improved performance.
Test Setup:
Capacitors are available in various capacities and voltage ratings. It is necessary to select a voltage rating higher than the expected full charge voltage of your battery but still balance the selection with the associated cost of higher voltage capacitors. Similarly, the higher the capacitance of the capacitor the better its ability to buffer changes, but the associated cost may soon become prohibitive. Since capacitance is added when wired in parallel, often the most economical solution is to purchase several capacitors of slightly lower capacitance ratings, and wire them together to achieve a high net capacitance.
Test platform configuration:
AEG Tokyo Marui G3 SG1
Main Spring Systema M120
Spring Guide Systema spring guide with bearing
Piston Systema aluminum
Piston Head Systema polycarbonate with bearing
Bushings Systema metal bushings
Mechbox Stock Tokyo Marui V2
Cylinder Head Stock Tokyo Marui
Cylinder Stock Tokyo Marui type 0
Gearset Prometheus High Speed
Motor Tokyo Marui EG1000
Battery Sanyo Cadnica KR-1800SCE 7 cell 8.4v
As discussed earlier, the capacity rating of capacitors add directly when wired. This allows several capacitors of lower ratings to be wired together to achieve a much higher net capacitance.Since a higher net capacitance is beneficial towards the ability to buffer sudden
Voltage changes
The completed capacitor bank results in a net capacitance rating. The entire bank is then wired to the mechbox circuitry.
*The capacitors used in this experiment were of the electrolytic variety, which requires that the polarity is taken into consideration when wiring. Incorrectly wiring the capacitors or exceeding the rated voltage of the capacitors may result in catastrophic failure through a small explosion.
Testing Procedure:
To determine the effect of capacitors on AEG rate of fire, 3 tests were conducted using 2 different capacitance levels and a control using no added capacitance. The rate of fire of each configuration is measured using the audio-analysis method with a sample size of 15 cycles per configuration. The first 3 cycles are discarded to isolate startup lag. 2 additional voltage drop tests are conducted using the zero added capacitance configuration and the maximum capacitance configuration. During these tests, the voltage drop across the mechbox load is measured in realtime with a logging digital volt meter and recorded at 1 second intervals. The mechbox is cycled for approximately 7 seconds during this test. High speed gears were used along with the M120 spring to present the largest initial torque load possible to the AEG motor, which in turn should translate to the largest initial voltage drop.
The Results:
Experiment 1: Rate of Fire
Measured Initial Voltage Added Capacitance Average Cycle Duration Rate of Fire (RPM) Percent Change
9.74 V 0 0.0577 1040 -
9.75 V 8800 mFD 0.0561 1070 2.9
9.73 V 12800 mFD 0.0557 1077 3.6
The test results clearly show an appreciable gain in rate of fire with added capacitance. Further increases in capacitance also showed continued increase at a diminished ratio.
Experiment 2: Voltage Drop
From the Voltage Drop vs Time plot, it is clear to see that not only is the magnitude of voltage drop reduced, the rate of voltage decay appears to be reduced as well, providing support for the rate of fire increases observed in experiment 1. The addition of capacitors has clearly buffered the initial precipitous voltage drop, reducing its magnitude, and continues to work in subsequent cycles to slow the rate of voltage drop.
Conclusion:
The results of the experiments show a clear advantage to adding capacitors to an AEG mechbox. The associated gain in rate of fire is advantageous from a tactical standpoint, and comes at minimal expense. Causual browsing of the capacitors available for purchase at DigiKey.com reveals that many are reasonably affordable and exhibit statistics suitable for use with an AEG. If you are handy with a soldering iron and don't mind some electrical wiring, adding capacitors to your AEG is a worthwhile endeavor
Advanced Gearbox Tech I
Increasing Rate of Fire with Capacitors
Introduction:
The inherent design of the AEG gearbox presents an uneven load to the AEG motor per firing cycle. During half of the firing cycle, the motor encounters gradually increasing torque loads as the main spring is compressed. After full compression is achieved, the motor encounters minimal load for the 2nd half of sector rotation as the gears reset to the firing positon virtually unencumbered. This uneven load demand on the motor results inevitably in an uneven current demand from the battery, and a naturally fluctuating voltage output. Since motor performance is tied closely to battery output, the ability to minimize voltage fluctuations, especially sudden voltage drops, can enhance motor performance and result in an increased rate of fire.
Capacitors:
Capacitors are structually simple electrical devices composing of little more than 2 conducting elements separated by a dielectric medium. Their simplicity belies their myriad uses, arising from the ability to act as temporary storage vessels for electrical energy. Capacitors store energy by maintaining a physical separation of electrical charges, creating an electrical potential. The magnitude of the potential which the capacitor is able to maintain is given by the voltage rating of the capacitor, while the total amount of energy the capacitor can store is expressed by its capacitance rating, usually in units of micro-Farads or mFD. A capacitor can not be charged with a potential higher than its rated voltage, or risk catastrophic failure. In the charged state, the capacitor acts like a mini-battery, ready to provide current when the need arises. When a charged capacitor is connected to a load, energy is released from the capacitor to drive the load until its capacity has been exhausted. When several capacitors are wired together in parallel, the resulting capacity of the system is the sum of the individual capacities of each capacitor. This property allows for easy increases in net capacitance by simply adding more capacitors to the system in parallel. The ability of capacitors to temporarily act as mini-batteries gives them the ability to act as buffers to sudden changes in voltage in an electrical circuit. As the AEG mechbox cycles, the increased load it presents to the battery causes a voltage drop as the battery tries to meet the demand. With the addition of capacitors to the circuit, the magnitude and rate of the voltage drop should in theory be reduced, resulting in improved performance.
Test Setup:
Capacitors are available in various capacities and voltage ratings. It is necessary to select a voltage rating higher than the expected full charge voltage of your battery but still balance the selection with the associated cost of higher voltage capacitors. Similarly, the higher the capacitance of the capacitor the better its ability to buffer changes, but the associated cost may soon become prohibitive. Since capacitance is added when wired in parallel, often the most economical solution is to purchase several capacitors of slightly lower capacitance ratings, and wire them together to achieve a high net capacitance.
Test platform configuration:
AEG Tokyo Marui G3 SG1
Main Spring Systema M120
Spring Guide Systema spring guide with bearing
Piston Systema aluminum
Piston Head Systema polycarbonate with bearing
Bushings Systema metal bushings
Mechbox Stock Tokyo Marui V2
Cylinder Head Stock Tokyo Marui
Cylinder Stock Tokyo Marui type 0
Gearset Prometheus High Speed
Motor Tokyo Marui EG1000
Battery Sanyo Cadnica KR-1800SCE 7 cell 8.4v
As discussed earlier, the capacity rating of capacitors add directly when wired. This allows several capacitors of lower ratings to be wired together to achieve a much higher net capacitance.Since a higher net capacitance is beneficial towards the ability to buffer sudden
Voltage changes
The completed capacitor bank results in a net capacitance rating. The entire bank is then wired to the mechbox circuitry.
*The capacitors used in this experiment were of the electrolytic variety, which requires that the polarity is taken into consideration when wiring. Incorrectly wiring the capacitors or exceeding the rated voltage of the capacitors may result in catastrophic failure through a small explosion.
Testing Procedure:
To determine the effect of capacitors on AEG rate of fire, 3 tests were conducted using 2 different capacitance levels and a control using no added capacitance. The rate of fire of each configuration is measured using the audio-analysis method with a sample size of 15 cycles per configuration. The first 3 cycles are discarded to isolate startup lag. 2 additional voltage drop tests are conducted using the zero added capacitance configuration and the maximum capacitance configuration. During these tests, the voltage drop across the mechbox load is measured in realtime with a logging digital volt meter and recorded at 1 second intervals. The mechbox is cycled for approximately 7 seconds during this test. High speed gears were used along with the M120 spring to present the largest initial torque load possible to the AEG motor, which in turn should translate to the largest initial voltage drop.
The Results:
Experiment 1: Rate of Fire
Measured Initial Voltage Added Capacitance Average Cycle Duration Rate of Fire (RPM) Percent Change
9.74 V 0 0.0577 1040 -
9.75 V 8800 mFD 0.0561 1070 2.9
9.73 V 12800 mFD 0.0557 1077 3.6
The test results clearly show an appreciable gain in rate of fire with added capacitance. Further increases in capacitance also showed continued increase at a diminished ratio.
Experiment 2: Voltage Drop
From the Voltage Drop vs Time plot, it is clear to see that not only is the magnitude of voltage drop reduced, the rate of voltage decay appears to be reduced as well, providing support for the rate of fire increases observed in experiment 1. The addition of capacitors has clearly buffered the initial precipitous voltage drop, reducing its magnitude, and continues to work in subsequent cycles to slow the rate of voltage drop.
Conclusion:
The results of the experiments show a clear advantage to adding capacitors to an AEG mechbox. The associated gain in rate of fire is advantageous from a tactical standpoint, and comes at minimal expense. Causual browsing of the capacitors available for purchase at DigiKey.com reveals that many are reasonably affordable and exhibit statistics suitable for use with an AEG. If you are handy with a soldering iron and don't mind some electrical wiring, adding capacitors to your AEG is a worthwhile endeavor
