From 38eec03bd15652f41ac4b6e6b80cd55084e18904 Mon Sep 17 00:00:00 2001
From: timeeapacala <“t.pacala@tu-berlin.de”>
Date: Fri, 14 Feb 2025 17:11:37 +0100
Subject: [PATCH 1/4] - update to the documentation: MLM, MRM, loading diagram,
modes description
---
.../weight_and_balance_analysis/basic-concepts.md | 15 ++++-----------
.../analysis/weight_and_balance_analysis/usage.md | 14 +++++++-------
2 files changed, 11 insertions(+), 18 deletions(-)
diff --git a/docs/documentation/analysis/weight_and_balance_analysis/basic-concepts.md b/docs/documentation/analysis/weight_and_balance_analysis/basic-concepts.md
index 59b5c00..76ab9ae 100644
--- a/docs/documentation/analysis/weight_and_balance_analysis/basic-concepts.md
+++ b/docs/documentation/analysis/weight_and_balance_analysis/basic-concepts.md
@@ -50,20 +50,16 @@ Let us start defining the different masses calculated by the tool and how they a
With the knowledge about the OEM, the design payload mass and the design fuel masses at different points during flight, the total design masses of the aircraft at specific times can be calculated:
- - ***design mass mission*** (the mass of the aircraft in the parking position before the start):
+ - **Maximum Ramp Mass (MRM)** is the mass of the aircraft in the parking position before the start:
- $$ design\_mass\_mission = OEM + design\_fuel\_mass\_mission + design\_payload\_mass. $$
+ $$ maximum\_ramp\_mass = OEM + design\_fuel\_mass\_mission + design\_payload\_mass. $$
- ***design mass at take-off*** (equal with the MTOM and to the ***design mass*** written in the acxml)
- ***design mass at midflight***
- ***design mass at landing***
The **Maximum Landing Mass (MLM)** is the maximum mass at which the pilot of the aircraft is allowed to attempt to land due to structural or other limits.
-Two calculation modes are available:
-
- - based on the mission information and the consumed fuel during flight (`default method`):
-
- $$ MLM = OEM + design\_fuel\_mass\_landing + design\_payload\_mass $$
+The following calculation mode is available:
- via the `RWTH regression method`: This calculation uses different formulas depending on whether the maximum takeoff mass exceeds a threshold value of 15,000 kg.
@@ -134,10 +130,7 @@ Below is a detailed breakdown of idealized key loading processes and their effec
- High-Wing Aircraft:
- Fuel is consumed in the reverse order: central or fuselage tanks → inner tank → outer tank.
-!!! note
- For the moment only the loading case 3 - 1 - 2 - 4 is implemented. The different selection of the loading scenarios can be made in the _weight\_and\_balance\_analysis\_conf.xml_ file.
-
-Finally, the **most forward and most aft _x_-CG positions** and the corresponding masses are depicted from the resulting diagramm.
+The sequence between the different loading scenarios can be made in the _weight\_and\_balance\_analysis\_conf.xml_ file. The shift in CG due to the different loading scenarios is considered only for the longitudinal axis, as it is assumed that the aircraft is loaded symmetrically. Finally, the **most forward and most aft _x_-CG positions** and the corresponding masses are depicted from the resulting diagramm.
---
## Mass Moments of Inertia {#inertia}
diff --git a/docs/documentation/analysis/weight_and_balance_analysis/usage.md b/docs/documentation/analysis/weight_and_balance_analysis/usage.md
index efda403..172a885 100644
--- a/docs/documentation/analysis/weight_and_balance_analysis/usage.md
+++ b/docs/documentation/analysis/weight_and_balance_analysis/usage.md
@@ -87,11 +87,6 @@ By changing the program settings im the configXML we can manipulate how the w&b
<aircraft_type description="Aircraft configuration for determination of the nondimensional radii of gyration by Raymer. Selector: blended_wing / jet_fuselage_eng / jet_two_wing_eng / jet_four_wing_eng">
<value>jet_two_wing_eng</value>
</aircraft_type>
- <maximum_landing_mass description="Selector for the calculation method of the maximum landing mass. Selector: mode_0 (OME + Payload + Reserve_fuel) / mode_1 (by_regression_RWTH)">
- <method description="selected method">
- <value>mode_0</value>
- </method>
- </maximum_landing_mass>
<refueling_mode description="Selector to specify if refueling should be done for the design or ferry range mission. Selector: mode_0 (design mission) / mode_1 (ferry range)">
<method description="selected method">
<value>mode_0</value>
@@ -107,6 +102,11 @@ By changing the program settings im the configXML we can manipulate how the w&b
<value>mode_0</value>
</method>
</passengers_boarding_mode>
+ <loading_mode description="Selector to specify the loading scenario: Selector: mode_0: ref_pass_cargo_def / mode_1: ref_cargo_pass_def / mode_2: cargo_ref_pass_def / mode_3: pass_ref_cargo_def / mode_4: pass_cargo_ref_def">
+ <method description="selected method">
+ <value>mode_0</value>
+ </method>
+ </loading_mode>
</calculation_methods>
</basic>
</standard>
@@ -117,10 +117,10 @@ By changing the program settings im the configXML we can manipulate how the w&b
In this part of the configXML we can select the calculation methods and aircraft configuration for the inertia, the maximum landing mass and the modes for the loading scenarios. Each mode has a description and the selection is made by changing the respective `value`. Most of the default modes coming with the package are set to `mode_0`. This means that:
- the mass moments of inertia are calculated using the LTH Tables
-- the maximum landing mass is calculated based on the mission information and the consumed fuel during flight
- the selected scenario for refueling is to fill up the tanks with the fuel for the design mission
- the passengers should board each row at a time from the front to back and back to front
-- the cg shift due to defueling (fuel consumption during flight) should also be considered in the loading diagramm
+- the cg shift due to defueling (fuel consumption during flight) should also be considered in the loading diagramm
+- the loading sequence is first refueling (ref), then boarding the passengeres, after that adding the cargo and finally defueling (def).
## Tool Execution {#tool}
Once the desired methods are selected and the requirements are in place, the tool can run. In order to start the w&b analysis tool, we can execute it directly from the console if all paths are set (see [How to run a tool](howToRunATool.md)) or run the _main.py_ inside the tool folder.
--
GitLab
From 9c6d63bfa1892cb09e43ac6b2b96197f9f29de50 Mon Sep 17 00:00:00 2001
From: timeeapacala <“t.pacala@tu-berlin.de”>
Date: Fri, 14 Feb 2025 17:13:38 +0100
Subject: [PATCH 2/4] same
---
.../analysis/weight_and_balance_analysis/basic-concepts.md | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/docs/documentation/analysis/weight_and_balance_analysis/basic-concepts.md b/docs/documentation/analysis/weight_and_balance_analysis/basic-concepts.md
index 76ab9ae..b015448 100644
--- a/docs/documentation/analysis/weight_and_balance_analysis/basic-concepts.md
+++ b/docs/documentation/analysis/weight_and_balance_analysis/basic-concepts.md
@@ -52,7 +52,7 @@ With the knowledge about the OEM, the design payload mass and the design fuel ma
- **Maximum Ramp Mass (MRM)** is the mass of the aircraft in the parking position before the start:
- $$ maximum\_ramp\_mass = OEM + design\_fuel\_mass\_mission + design\_payload\_mass. $$
+ $$ MRM = OEM + design\_fuel\_mass\_mission + design\_payload\_mass. $$
- ***design mass at take-off*** (equal with the MTOM and to the ***design mass*** written in the acxml)
- ***design mass at midflight***
--
GitLab
From 9e2c5ee52a0087f1f6120f1e50becdba363a42a2 Mon Sep 17 00:00:00 2001
From: timeeapacala <“t.pacala@tu-berlin.de”>
Date: Wed, 19 Feb 2025 12:00:28 +0100
Subject: [PATCH 3/4] reference added
---
.../analysis/weight_and_balance_analysis/index.md | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/docs/documentation/analysis/weight_and_balance_analysis/index.md b/docs/documentation/analysis/weight_and_balance_analysis/index.md
index b2424fb..064927a 100644
--- a/docs/documentation/analysis/weight_and_balance_analysis/index.md
+++ b/docs/documentation/analysis/weight_and_balance_analysis/index.md
@@ -1,5 +1,5 @@
# Introduction {#mainpage}
-The aircraft’s mass plays a crucial role in determining the flight performance and evaluating the design, with the ultimate goal being to minimize the operating empty mass. 🏋️♀️ Knowing individual masses is essential for calculating the center of gravity (CG) and determining the placement of critical components like the landing gear and wings. ✈️ The CG significantly affects the aircraft's stability and controllability. An improperly located CG can compromise flight safety, requiring careful planning to ensure it remains within allowable limits throughout the flight, including during fuel consumption and payload variations. This analysis is typically conducted through a weight and balance evaluation using a loading diagram :chart_with_upwards_trend:, which defines the permissible range for combinations of aircraft mass and CG positions. Mass considerations are also fundamental to cost estimation. As an aircraft’s mass increases, it requires more lift, which leads to higher drag, increased thrust demands, elevated fuel consumption, and ultimately greater fuel and operating costs. 💸
+The aircraft’s mass plays a crucial role in determining the flight performance and evaluating the design, with the ultimate goal being to minimize the operating empty mass. 🏋️♀️ Knowing individual masses is essential for calculating the center of gravity (CG) and determining the placement of critical components like the landing gear and wings. ✈️ The CG significantly affects the aircraft's stability and controllability. An improperly located CG can compromise flight safety, requiring careful planning to ensure it remains within allowable limits throughout the flight, including during fuel consumption and payload variations. This analysis is typically conducted through a weight and balance evaluation using a loading diagram :chart_with_upwards_trend:, which defines the permissible range for combinations of aircraft mass and CG positions. Mass considerations are also fundamental to cost estimation. As an aircraft’s mass increases, it requires more lift, which leads to higher drag, increased thrust demands, elevated fuel consumption, and ultimately greater fuel and operating costs. <sup>[1]</sup> 💸
In UNICADO, the _weight\_and\_balance_analysis_ tool is used to compute the aircraft's masses, determine the CG positions, calculate mass moments of inertia, and generate the loading diagram. The terms "mass" and "weight" are often used interchangeably in aircraft design, though they are scientifically distinct. In this context, both terms are used to refer to the aircraft's mass.
@@ -27,3 +27,5 @@ The following pages will help you understand the code structure:
We appreciate it!
+---
+<sup>[1]</sup> SCHOLZ, Dieter, 2015. Aircraft Design. Lecture Notes. Hamburg University of Applied Sciences. URL: http://LectureNotes.AircraftDesign.org.
\ No newline at end of file
--
GitLab
From fc7c9c7813dcaab25fbf787a2fc7b02eb6eb411f Mon Sep 17 00:00:00 2001
From: timeeapacala <“t.pacala@tu-berlin.de”>
Date: Wed, 19 Feb 2025 15:48:41 +0100
Subject: [PATCH 4/4] update of the inertia calculation description
---
.../basic-concepts.md | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/docs/documentation/analysis/weight_and_balance_analysis/basic-concepts.md b/docs/documentation/analysis/weight_and_balance_analysis/basic-concepts.md
index b015448..fb10b53 100644
--- a/docs/documentation/analysis/weight_and_balance_analysis/basic-concepts.md
+++ b/docs/documentation/analysis/weight_and_balance_analysis/basic-concepts.md
@@ -163,13 +163,19 @@ Where:
- $f_{xx}$ and $f_{yy}$: Technology factors set to $1.25$ respectively $1.15$
- $ R_x, R_y, R_z $: Nondimensional radii of gyration. The following values are implemented:
-| **Aircraft Configuration** | $ R_x $ | $ R_y $ | $ R_z $ |
-|-----------------------------------------|-----------|-----------|-----------|
-| Fuselage-mounted engines | 0.24 | 0.34 | 0.42 |
-| 2 wing-mounted engines | 0.23 | 0.33 | 0.45 |
-| 4 wing-mounted engines | 0.24 | 0.36 | 0.44 |
-| Blended wing body | 0.28 | 0.40 | 0.46 |
+| **Aircraft Configuration** | $ R_x $ | $ R_y $ | $ R_z $ |
+|---------------------------------------------|-----------|-----------|-----------|
+| Single prop engine | 0.25 | 0.38 | 0.39 |
+| Twin prop engine | 0.30 | 0.40 | 0.44 |
+| 2 fuselage-mounted jet engines | 0.24 | 0.34 | 0.42 |
+| 2 wing-mounted jet engines | 0.23 | 0.33 | 0.45 |
+| 4 wing-mounted jet engines | 0.24 | 0.36 | 0.44 |
+| Blended wing body | 0.28 | 0.40 | 0.46 |
+The aircraft configuration is determined based on the data from the TLARs. For this, the information about the possible propulsion types, mounting positions and number of engines are used.
+
+!!! note
+ If no matching radii of gyration are found, a critical message is shown and the values for the radii are set to the ones for a jet with two wing mounted engines to keep the workflow running. It is the user's responsability to check the validity of the chosen calculation methods and the results.
#### 2. Using the LTH Tables (*Luftfahrttechnisches Handbuch*)
The LTH provides tabulated values and empirical methods specific to various aircraft configurations. These tables account for typical mass distributions and structural layouts. They are more accurate than Raymer’s approach but require knowledge of the specific aircraft class and design. The `calculate_inertia_by_lth_method` function is tailored specifically for conventional tube-and-wing configurations. This method uses aircraft mass properties like the OEM, the payload mass ($m_{payload}$) and the fuel mass ($m_{fuel}$) and geometric dimensions such as wing span $b$ and fuselage length $l$. All cross-product terms ($I_{xy}$, $I_{xz}$, etc.) are set to $0$, assuming symmetry.
--
GitLab