EVBEC - Revision history

Benstern: spelling

2007-06-05T17:36:32Z

spelling

Boilingleadbath: formatting

2007-04-16T13:13:31Z

formatting

← Older revision		Revision as of 08:13, 16 April 2007
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	To calculate the velocities, EVBEC uses a 2 step procces:		To calculate the velocities, EVBEC uses a 2 step procces:
	0) Take the muzzle velocity of the round found in the latke C:B test at the same ratio		0) Take the muzzle velocity of the round found in the latke C:B test at the same ratio<br>
	1) We find the energy of the test projectile, add the energy required to displace the air in the barrel, multiply this by the compression ratio, subtract the displacement energy, and convert it back into a velocity.		1) We find the energy of the test projectile, add the energy required to displace the air in the barrel, multiply this by the compression ratio, subtract the displacement energy, and convert it back into a velocity.<br>
	2) We find the ratio of the modeled launcher's chamber size to the test launcher's, multiply this by the ratio of the test launcher's projectile mass (including effective propellent masses) to the test launcher's projectile mass (including their effective propellent masses).		2) We find the ratio of the modeled launcher's chamber size to the test launcher's, multiply this by the ratio of the test launcher's projectile mass (including effective propellent masses) to the test launcher's projectile mass (including their effective propellent masses).

Boilingleadbath: updated it to account for V1.5

2007-04-16T13:12:28Z

updated it to account for V1.5

← Older revision		Revision as of 08:12, 16 April 2007
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	EVBEC stands for "Energy & Volume Based Estimator for Combustions", and is intended to calculate the muzzle velocity of [[combustion launcher]]s.		EVBEC stands for "Energy & Volume Based Estimator for Combustions", and is intended to calculate the muzzle velocity of [[combustion launcher]]s.
	The latest version (V 1.3) can be downloaded from [[spudfiles]] ~~right~~ [http://www.spudfiles.com/forums/viewtopic.php?t=1212& here]		The latest version of the spreadsheet (V 1.5) can be downloaded from [[spudfiles]] [http://www.spudfiles.com/forums/viewtopic.php?t=1212& here]
			A web-based version written in javascript, which is significantly more user freindly, is hosted [http://www.spudfiles.com/EVBEC/JSE.html here].

	==Physics model==		==Physics model==
	EVBEC assumes ~~that~~:		EVBEC assumes the following is true:
	*Energy produced from combustion is directly proportional to chamber volume.		*Energy produced from combustion is directly proportional to chamber volume TIMES the chamber pressure in absolute terms.
	*The portion of this energy utilized in a launcher is directly ~~derivable from~~ the [[Chamber to barrel ratio]].		*The portion of this energy utilized in a launcher is directly related to the [[Chamber to barrel ratio]].
	*The [http://www.burntlatke.com/launch.html latke tests] are accurate.		*The [http://www.burntlatke.com/launch.html latke tests] are accurate.
			The amount of energy required to displace the air in the barrel is porportional to the atmospheric pressurevolume.
			The amount of eneryg 'stolen' by the velocity of the gasses origionaly in the barrel can be found by mass(average velocity), and that this hteft can be modeled as adding their effective mass to the projectile's mass.
			*The amount of energy 'stolen' by the velocity of the propellent gasses can be is equal to their masses times their average velocities at projectile exit, and that this theft can be modeled as adding their effective mass to the projectile's mass.

	~~From these assumptions~~, ~~one can get~~ the ~~driving equation~~ of ~~EVBEC~~:		To calculate the velocities, EVBEC uses a 2 step procces:
	~~v<sub>simulation</sub>=v<sub>~~test~~</sub>/SQRT~~(~~(S<sub>~~test~~</sub>/S<sub>simulation</sub>)/~~(~~M<sub>test</sub>/M<sub>simulation</sub>)~~)		0) Take the muzzle velocity of the round found in the latke C:B test at the same ratio
			1) We find the energy of the test projectile, add the energy required to displace the air in the barrel, multiply this by the compression ratio, subtract the displacement energy, and convert it back into a velocity.
			2) We find the ratio of the modeled launcher's chamber size to the test launcher's, multiply this by the ratio of the test launcher's projectile mass (including effective propellent masses) to the test launcher's projectile mass (including their effective propellent masses).

	~~Where:~~		===differences between spreadsheet and javascript versions===
	*v is velocity
	*S is chamber volume
	*M is mass

	~~Using this~~, the velocities are calculated for all the ratios tested by latke, and the proper ratio to use to find the velocity is indicated on a graph.		In the spreadsheet, the velocities are calculated for all the ratios and barrel diameters tested by [[latke]], and the proper ratio to use to find the velocity is indicated on a graph. This uses the actual dataset.

			In the javascript version, the velocity is calculated using a curve fit of the 3/4" data, and the velocity is output as a number in a cell.

	==limits of the physics model==		==limits of the physics model==
	The physics model does not account for the following:		The physics model does not account for the following:
	*Differing burn times		*Differing burn times
	*Variations in efficiency caused by different projectile masses. (which is why the 1.5" data is "out there")		*Differing amounts of heat loss
			*Evaporation of tater juices
			*Differing amounts of friction
			*Variations in efficiency caused by different projectile masses. (which is probably why the 1.5" data is "out there")
	*Odd effects caused by launcher design (ie; breach restrictions).		*Odd effects caused by launcher design (ie; breach restrictions).

	~~Several of these problems are likely to be alleived when the results of some recent tests being carried out by pimpmann22 of the spudfiles forums are released.~~

	==use==		==use==
	Generic directions for use are provided in the documentation of the ~~program~~, and a detailed artical on modeling combustion spudguns, mostly with EVBEC, is provided [http://www.spudfiles.com/forums/viewtopic.php?t=5966& here].		Generic directions for use are provided in the documentation of the spreadsheet, and a detailed artical on modeling combustion spudguns, mostly with EVBEC spreadsheet, is provided [http://www.spudfiles.com/forums/viewtopic.php?t=5966& here].
			The javascript version has many tooltips and is fairly self explanatory.

	[[category:Concepts]]		[[category:Concepts]]

Boilingleadbath: categorized

2007-04-15T12:07:08Z

categorized

← Older revision		Revision as of 07:07, 15 April 2007
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	==use==		==use==
	Generic directions for use are provided in the documentation of the program, and a detailed artical on modeling combustion spudguns, mostly with EVBEC, is provided [http://www.spudfiles.com/forums/viewtopic.php?t=5966& here].		Generic directions for use are provided in the documentation of the program, and a detailed artical on modeling combustion spudguns, mostly with EVBEC, is provided [http://www.spudfiles.com/forums/viewtopic.php?t=5966& here].

			[[category:Concepts]]

Boilingleadbath: + link to use directions

2007-02-11T23:42:23Z

+ link to use directions

← Older revision		Revision as of 18:42, 11 February 2007
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	==use==		==use==
	~~Directions~~ for use are provided in the documentation of the program.		Generic directions for use are provided in the documentation of the program, and a detailed artical on modeling combustion spudguns, mostly with EVBEC, is provided [http://www.spudfiles.com/forums/viewtopic.php?t=5966& here].

Boilingleadbath: v1.2 -> v1.3 update

2006-11-18T18:51:17Z

v1.2 -> v1.3 update

← Older revision		Revision as of 13:51, 18 November 2006
Line 1:		Line 1:
	EVBEC stands for "Energy & Volume Based Estimator for Combustions", and is intended to calculate the muzzle velocity of [[combustion launcher]]s.		EVBEC stands for "Energy & Volume Based Estimator for Combustions", and is intended to calculate the muzzle velocity of [[combustion launcher]]s.
	The latest version (V 1.2) can be downloaded from [[spudfiles]] right [http://www.spudfiles.com/forums/viewtopic.php?t=1212& here]		The latest version (V 1.3) can be downloaded from [[spudfiles]] right [http://www.spudfiles.com/forums/viewtopic.php?t=1212& here]

	==Physics model==		==Physics model==

70.31.208.207: spelling

2006-03-04T22:40:30Z

spelling

← Older revision		Revision as of 17:40, 4 March 2006
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	==Physics model==		==Physics model==
	EVBEC assumes that:		EVBEC assumes that:
	*Energy produced from combustion is directly ~~porportional~~ to chamber volume.		*Energy produced from combustion is directly proportional to chamber volume.
	*The portion of this energy utilized in a launcher is directly derivable from the [[Chamber to barrel ratio]].		*The portion of this energy utilized in a launcher is directly derivable from the [[Chamber to barrel ratio]].
	*The [http://www.burntlatke.com/launch.html latke tests] are accurate.		*The [http://www.burntlatke.com/launch.html latke tests] are accurate.
Line 24:		Line 24:
	*Odd effects caused by launcher design (ie; breach restrictions).		*Odd effects caused by launcher design (ie; breach restrictions).

	Several of these problems are likely to be alleived when the results of some recent tests being carried out by pimpmann22 of the spudfiles forums are ~~relesed~~.		Several of these problems are likely to be alleived when the results of some recent tests being carried out by pimpmann22 of the spudfiles forums are released.

	==use==		==use==
	Directions for use are provided in the documentation of the program.		Directions for use are provided in the documentation of the program.

Boilingleadbath: +link

2006-02-11T00:30:04Z

+link

← Older revision		Revision as of 19:30, 10 February 2006
Line 1:		Line 1:
	EVBEC stands for "Energy & Volume Based Estimator for Combustions", and is intended to calculate the muzzle velocity of [[combustion launcher]]s.		EVBEC stands for "Energy & Volume Based Estimator for Combustions", and is intended to calculate the muzzle velocity of [[combustion launcher]]s.
	The latest version (V 1.2) can be downloaded from [[spudfiles]] right [		The latest version (V 1.2) can be downloaded from [[spudfiles]] right [http://www.spudfiles.com/forums/viewtopic.php?t=1212& here]

	==Physics model==		==Physics model==

Boilingleadbath: -link error

2006-02-11T00:28:39Z

-link error

← Older revision		Revision as of 19:28, 10 February 2006
Line 5:		Line 5:
	EVBEC assumes that:		EVBEC assumes that:
	*Energy produced from combustion is directly porportional to chamber volume.		*Energy produced from combustion is directly porportional to chamber volume.
	*The portion of this energy utilized in a launcher is directly derivable from the [[~~chamber:barrel ratio\|~~Chamber to barrel ratio]].		*The portion of this energy utilized in a launcher is directly derivable from the [[Chamber to barrel ratio]].
	*The [http://www.burntlatke.com/launch.html latke tests] are accurate.		*The [http://www.burntlatke.com/launch.html latke tests] are accurate.

Boilingleadbath: -typo

2006-02-11T00:27:51Z

-typo

← Older revision		Revision as of 19:27, 10 February 2006
Line 9:		Line 9:

	From these assumptions, one can get the driving equation of EVBEC:		From these assumptions, one can get the driving equation of EVBEC:
	~~[math]~~v<sub>simulation</sub>=v<sub>test</sub>/SQRT((S<sub>test</sub>/S<sub>simulation</sub>)/(M<sub>test</sub>/M<sub>simulation</sub>))~~[/math]~~		v<sub>simulation</sub>=v<sub>test</sub>/SQRT((S<sub>test</sub>/S<sub>simulation</sub>)/(M<sub>test</sub>/M<sub>simulation</sub>))

	Where:		Where:

← Older revision		Revision as of 12:36, 5 June 2007
Line 1:		Line 1:
	EVBEC stands for "Energy & Volume Based Estimator for Combustions", and is intended to calculate the muzzle velocity of [[combustion launcher]]s.		EVBEC stands for "Energy & Volume Based Estimator for Combustions", and is intended to calculate the muzzle velocity of [[combustion launcher]]s.
	The latest version of the spreadsheet (V 1.5) can be downloaded from [[spudfiles]] [http://www.spudfiles.com/forums/viewtopic.php?t=1212& here]		The latest version of the spreadsheet (V 1.5) can be downloaded from [[spudfiles]] [http://www.spudfiles.com/forums/viewtopic.php?t=1212& here]
	A web-based version written in javascript, which is significantly more user ~~freindly~~, is hosted [http://www.spudfiles.com/EVBEC/JSE.html here].		A web-based version written in javascript, which is significantly more user friendly, is hosted [http://www.spudfiles.com/EVBEC/JSE.html here].

	==Physics model==		==Physics model==
Line 8:		Line 8:
	*The portion of this energy utilized in a launcher is directly related to the [[Chamber to barrel ratio]].		*The portion of this energy utilized in a launcher is directly related to the [[Chamber to barrel ratio]].
	*The [http://www.burntlatke.com/launch.html latke tests] are accurate.		*The [http://www.burntlatke.com/launch.html latke tests] are accurate.
	The amount of energy required to displace the air in the barrel is ~~porportional~~ to the atmospheric pressurevolume.		The amount of energy required to displace the air in the barrel is proportional to the atmospheric pressurevolume.
	The amount of ~~eneryg~~ 'stolen' by the velocity of the ~~gasses origionaly~~ in the barrel can be found by mass(average velocity), and that this ~~hteft~~ can be modeled as adding their effective mass to the projectile's mass.		The amount of energy 'stolen' by the velocity of the gases originally in the barrel can be found by mass(average velocity), and that this can be modeled as adding their effective mass to the projectile's mass.
	*The amount of energy 'stolen' by the velocity of the ~~propellent gasses~~ can be is equal to their masses times their average velocities at projectile exit, and that this theft can be modeled as adding their effective mass to the projectile's mass.		*The amount of energy 'stolen' by the velocity of the propellant gases can be is equal to their masses times their average velocities at projectile exit, and that this theft can be modeled as adding their effective mass to the projectile's mass.

	To calculate the velocities, EVBEC uses a 2 step ~~procces~~:		To calculate the velocities, EVBEC uses a 2 step process:
	0) Take the muzzle velocity of the round found in the latke C:B test at the same ratio<br>		0) Take the muzzle velocity of the round found in the latke C:B test at the same ratio<br>
	1) We find the energy of the test projectile, add the energy required to displace the air in the barrel, multiply this by the compression ratio, subtract the displacement energy, and convert it back into a velocity.<br>		1) We find the energy of the test projectile, add the energy required to displace the air in the barrel, multiply this by the compression ratio, subtract the displacement energy, and convert it back into a velocity.<br>
	2) We find the ratio of the modeled launcher's chamber size to the test launcher's, multiply this by the ratio of the test launcher's projectile mass (including effective ~~propellent~~ masses) to the test launcher's projectile mass (including their effective ~~propellent~~ masses).		2) We find the ratio of the modeled launcher's chamber size to the test launcher's, multiply this by the ratio of the test launcher's projectile mass (including effective propellant masses) to the test launcher's projectile mass (including their effective propellant masses).

	===differences between spreadsheet and javascript versions===		===differences between spreadsheet and javascript versions===
Line 33:		Line 33:

	==use==		==use==
	Generic directions for use are provided in the documentation of the spreadsheet, and a detailed ~~artical~~ on modeling combustion spudguns, mostly with EVBEC spreadsheet, is provided [http://www.spudfiles.com/forums/viewtopic.php?t=5966& here].		Generic directions for use are provided in the documentation of the spreadsheet, and a detailed article on modeling combustion spudguns, mostly with EVBEC spreadsheet, is provided [http://www.spudfiles.com/forums/viewtopic.php?t=5966& here].
	The javascript version has many tooltips and is fairly self explanatory.		The javascript version has many tooltips and is fairly self explanatory.

	[[category:Concepts]]		[[category:Concepts]]