Rocket Vent Hole Size Calculator: Difference between revisions

From FreeCAD Documentation
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{{Docnav
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{{GuiCommand
{{GuiCommand
|Name=Vent Hole Size Calculator
|Name=Rocket Vent Hole Size Calculator
|Icon=Rocket Calculator.svg
|Icon=Rocket_Calculator.svg
|MenuLocation=Rocket → Calculators → Vent Hole Size Calculator
|MenuLocation=Rocket → Calculators → Vent Hole Size Calculator
|Workbenches=[[Rocket_Workbench|Rocket Workbench]]
|Workbenches=[[Rocket_Workbench|Rocket Workbench]]
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== Description ==
== Description == <!--T:3-->


<!--T:4-->
This calculator determines the minimum size of vent holes for barometric altimeters based on the volume of the space and the number of vent holes.
This calculator determines the minimum size of vent holes for barometric altimeters based on the volume of the space and the number of vent holes.


<!--T:5-->
Calculation comes from the rule of thumb of 1/4" vent hole for every 100 cubic inches of volume. A single vent hole of the appropriate size is susceptible to noise caused by breezes and wind gusts. These effects are minimized by using multiple vent holes distributed around the volume, with 3 holes being considered a practical minimum. The combined area of all vent holes will be equivalent to that of a single larger hole.
Calculation comes from the rule of thumb of 1/4" vent hole for every 100 cubic inches of volume. A single vent hole of the appropriate size is susceptible to noise caused by breezes and wind gusts. These effects are minimized by using multiple vent holes distributed around the volume, with 3 holes being considered a practical minimum. The combined area of all vent holes will be equivalent to that of a single larger hole.


== Usage ==
== Usage == <!--T:6-->
[[File:Calc vent hole size.png|center]]


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[[File:Calc_vent_hole_size.png]]
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<!--T:7-->
# There are several ways to invoke the command:
# There are several ways to invoke the command:
#* Press the {{Button|[[Image:Rocket Calculator.svg|16px]] [[Rocket_Vent_Hole_Size_Calculator|Vent Hole Size Calculator]]}} button.
#* Press the {{Button|[[Image:Rocket_Calculator.svg|16px]] [[Rocket_Vent_Hole_Size_Calculator|Vent Hole Size Calculator]]}} button.
#* Select the {{MenuCommand|Rocket → Calculators → [[Image:Rocket Calculator.svg|16px]] Vent Hole Size Calculator}} option from the menu.
#* Select the {{MenuCommand|Rocket → Calculators → [[Image:Rocket_Calculator.svg|16px]] Vent Hole Size Calculator}} option from the menu.
# Enter the parameters of your electronics bay.
# Enter the parameters of your electronics bay.


== Calculation ==
== Calculation == <!--T:8-->


<!--T:9-->
Vent hole size is calculated using the following formula:
Vent hole size is calculated using the following formula:


<!--T:10-->
::<math>D_{vent} = 0.004396 D \sqrt{\cfrac{L}{N}}</math>
::<math>D_{vent} = 0.004396 D \sqrt{\cfrac{L}{N}}</math>


<!--T:11-->
where
where


<!--T:12-->
::<math>D_{vent} = </math> vent hole size
::<math>D_{vent} = </math> vent hole size
::<math>D = </math> body tube diameter
::<math>D = </math> body tube diameter
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::<math>N = </math> number of vent holes
::<math>N = </math> number of vent holes


=== Units ===
=== Units === <!--T:13-->


<!--T:14-->
Calculations are done using metric units, but will display in your preferred units. Values can also be entered using any supported units by including the units with the value (''eg'' 5 oz, or 23.2 g)
Calculations are done using metric units, but will display in your preferred units. Values can also be entered using any supported units by including the units with the value (''eg'' 5 oz, or 23.2 g)


== References ==
== References == <!--T:15-->


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# http://vernk.com/AltimeterPortSizing.htm
# http://vernk.com/AltimeterPortSizing.htm



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{{Docnav
{{Docnav
|[[Rocket_Thrust_To_Weight_Calculator|Thrust To Weight]]
|[[Rocket_Thrust_To_Weight_Calculator|Thrust To Weight Calculator]]
|
|
|[[Rocket_Workbench|Rocket Workbench]]
|[[Rocket_Workbench|Rocket Workbench]]
|IconL=Rocket Calculator.svg
|IconL=Rocket_Calculator.svg
|
|
|IconC=RocketWorkbench.svg
|IconC=RocketWorkbench.svg

Latest revision as of 08:54, 18 March 2021

Other languages:

Rocket Vent Hole Size Calculator

Menu location
Rocket → Calculators → Vent Hole Size Calculator
Workbenches
Rocket Workbench
Default shortcut
None
Introduced in version
0.19
See also
None

Description

This calculator determines the minimum size of vent holes for barometric altimeters based on the volume of the space and the number of vent holes.

Calculation comes from the rule of thumb of 1/4" vent hole for every 100 cubic inches of volume. A single vent hole of the appropriate size is susceptible to noise caused by breezes and wind gusts. These effects are minimized by using multiple vent holes distributed around the volume, with 3 holes being considered a practical minimum. The combined area of all vent holes will be equivalent to that of a single larger hole.

Usage

  1. There are several ways to invoke the command:
    • Press the Vent Hole Size Calculator button.
    • Select the Rocket → Calculators → Vent Hole Size Calculator option from the menu.
  2. Enter the parameters of your electronics bay.

Calculation

Vent hole size is calculated using the following formula:

where

vent hole size
body tube diameter
body tube length
number of vent holes

Units

Calculations are done using metric units, but will display in your preferred units. Values can also be entered using any supported units by including the units with the value (eg 5 oz, or 23.2 g)

References

  1. http://vernk.com/AltimeterPortSizing.htm