Aircraft Drawing 6x6ew

Purpose of Drawings Drawings created by Project Engineering Design Group ( the group of people that design parts) have several purposes: To describe parts exactly To tell manufacturing how to fabricate, assemble, and install parts properly To make sure that parts can be fabricated, assembled, or installed exactly the same each time 2

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To tell the material department what materials and parts to order To help Boeing keep an accurate, permanent record of all work completed. To specify tolerances so manufacturing and inspection can make sure parts meet requirements To list specifications for testing parts (what and how to test) To supply airlines with information for customer

Production drawings are made up of:   

Picture Sheet Part List Reference Information

Picture Sheets The picture sheet show:  What the parts look like  The size and shape of parts  How parts and assemblies fit together  Where the parts and assemblies are located (installed). Picture sheets contain dimensions, symbols, notes, and tolerances.

Figure 1.1 Picture sheet

Part List The part list (PL) provides the following :  Part number  Part name (nomenclature/description)  Quantity required  Where to find the part on the picture sheet (zone code)  Where the drawings final products will be used (the next assembly).  Manufacturing data  Flagnotes and general notes  Standard drawing notes  Revision section.

Figure 1.2 Parts List

Engineering Standards Many additional materials are required to the Boeing drawing system. These materials called engineering standards are contained in engineering standards manuals. They control how parts are designed and made. Drawings show what to fabricate, assemble, or install and the engineering standards tell how it must be done. Information that is the same for many drawings is provided in these engineering standards.

Boeing engineering standards include: D·4900 Boeing Drafting Standards Standards for making the drawing. If everyone follows these standards, all drawings will be completed without variations. D-18888-1 Boeing Process Specifications To1erances and how to perform certain operations, such as installing nuts, bolts, and rivets.

D-18888-3 Boeing Material Standards Specifications and tolerances for purchased material such as sheet aluminum, paints, seat fabrics, and carpets. D-590 Boeing Parts Standards Sizes and tolerances for purchased parts such as rivets, nuts, bolts, bearings, and gaskets. D-5000 Boeing Design Standards Information on stress tolerances of materials, compatibility of materials, and other engineering requirements.

Engineering standards and other reference documents can be found in many places. Some of those places are: PSDS ( using REDARS terminals) Microfilm files Technical libraries Design Engineering groups Factory areas Quality Assurance groups  manufacturing Engineering groups

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Typically, all aircraft factories have a drawing room manual that details all lines, symbols, and conventions used by that company. However, in an effort to establish an industry standard, applications for aircraft drawings have been standardized.

TYPES OF DRAWINGS 

As an aircraft technician there are several types of drawings and graphic representations you must become familiar with. Each type of drawing is designated to transmit a certain piece of information. The most common type of drawing you will use is the working drawing.

Type of Drawings 

Three classes of working drawings are: Assembly Drawing  Installation Drawing  Detail Drawing Other types of drawings include sectional drawings, exploded view drawings, block diagrams, logic flowcharts, electrical wiring diagrams, pictorial diagrams, and schematic diagrams. Each type of drawing is designed to transmit a certain type of information. 

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Assembly drawing  

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What is Assembly Drawing ? Assembly drawings show a number of detail parts or sub-assemblies that are ed together to form a specific component or machine. Cannot tell what the inside of the part looks like from the view. Show overall arrangement clearly, but not the details and the dimensions. 4

Assembly information includes:       

List of required components. How parts fit together. Part numbering and marking instructions. Fastening methods. Protective finish requirements. Process specifications and standards. Next higher drawing number (where the assembly will be used).

Assembly Drawing

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Installation Drawing  

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What is Installation Drawing ? Drawing shows how item can / has / will be install. Where parts and assemblies will be located in the airplane, can also show assembly and detail part information. This type of drawing shows the general arrangement or position of parts with respect to an aircraft and provides the information needed to install them. 8

Installation information includes:  

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List of required components Location dimensions ( in reference to airplane structure) Part number and affectivity Fastening methods Process specifications and standards

Installation drawings are easily recognized by their titles. If the word “installation” or the abbreviation “INSTL” appears in the title, it is an installation drawing. Examples of installation drawing titles are: “BULKHEAD INSTALLATION-BODY STATION 311” “RIB INSTL-WING STATION INSPAR RIB NO.29”

The list of items for installation drawings is almost identical to the list of items for assembly drawings. The major difference between an assembly and installation drawing is the location of parts An assembly drawing describes how parts relate to each other An installation drawing describes a location Comparison of assembly installation of parts or assemblies in theand airplane.

Drawings

Installation Drawing

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Installation Drawing

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Installation Drawing

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Detail Drawing  

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What is Detail Drawing ? A detail drawing shows all information necessary to determine the final form or to purchase a part, A detail part is individual and unique. In a detail drawing of a part, the picture sheet and part list together give complete manufacturing data needed to fabricate each part. A detail drawing may contain single or multiple parts, but each part remains separate and is not ed together. 13

The detail in the Size and shapeinformation description  detail Tolerance informationincludes: drawing 

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Stock size and material requirements Heat treating requirements Machine finish requirements Part numbering and marking instructions Hole locations Protective finish Process specifications and standards

Detail Drawing

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Detail Drawing

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Pictorial View

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Methods of Illustration 

Orthographic View / Projection / Drawing.

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Auxiliary View / Drawing. Isometric View / Drawing. Oblique View / Drawing. Perspective View / Drawing.

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Orthographic view 

Several views can be combined on a single drawing using one of the two available projection systems, first angle, and third angle projection.

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Orthographic view

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Orthographic view

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Orthographic view

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Orthographic view

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Orthographic view 

Symbol

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Orthographic view

Location 1st Angle 

FRONT

TOP

SIDE

3rd Angle

TOP

FRONT

SIDE

First angle

Third angle

Auxiliary Views

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Auxiliary views are often necessary to show the true shape and length of inclined surfaces. • Used in cases where features are not parallel to the principal planes of projection.

Auxiliary Views – Cont. 

Auxiliary Projection

Auxiliary Views – Cont. 

Principle Auxiliary View Arrangement TOP AU LI XI Y AR

RIGHT SIDE FRONT

Need for Auxiliary Views

Need for Auxiliary Views –Cont.

Isometric View 

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This is one of a family of threedimensional views called pictorial drawings. In an isometric drawing, the object's vertical lines are drawn vertically, The horizontal lines in the width and depth planes are shown at 30 degrees to the horizontal. 25

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When drawn under these guidelines, the lines parallel to these three axes are at their true (scale) lengths. Lines that are not parallel to these axes will not be of their true length. The representation of the object in figure 2 is called an isometric drawing.

Isometric View

Figure 2 An Isometric Drawing

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Isometric View

Figure 2 An Isometric Drawing / view with dimensions 27

Oblique View

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Oblique drawings have a set of 45° lines and a set of horizontal lines parallel to the drawing plane. Front of the object identical to the front view of an orthographic drawing. Depth axis drawing often used about 30 degree. 28

Oblique View

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'Oblique' Drawing 

  'Cabinet Oblique‘ and  'Cavalier Oblique'

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One remaining drawing conventions is Oblique drawing . In this convention the angles used are 45 degrees and 90 degrees.  The only difference between the two styles is in the scale of the dimension doing away from the viewer.  In Cabinet oblique the scale (depth) is halved whilst in Cavalier oblique the depth scale is the same as in the X and Y directions.

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Cavalier Oblique 

It is hard to believe their lines running away from the viewer in the Cavalier Oblique view on the left are actually the same length as the vertical and horizontal lines.

Cabinet Oblique 

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The Cabinet drawing shown on the right here actually looks far more realistic despite ( actually because of ) the half scale lines running away from the viewer . We are all used to seeing perpective having aneffect on object we view everyday life and expect distances to look less in this way.

Perspective View  

Perspective Drawing Object seen for points from eyes:  

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One point perspective Two point perspective

Is used when you need to see an object similar to the way of human eye sees. Ray of an object meet at a distance point on the horizon referred to as the vanishing point. The rays that project from the drawing intersect at a vanishing point on the horizon. Not generally used in aircraft drawings.

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Perspective View 

One point perspective

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Perspective View 

Two point perspective

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V.P.

Horizon Line

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Perspective View

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SECTIONAL DRAWING 

Cross-Sectional Views A cross-sectional view portrays a cutaway portion of the object and is another way to show hidden components in a device.

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The lines are thin and are usually drawn at a 45-degree angle to the major outline of the object.

SECTIONAL DRAWING

SECTIONAL DRAWING

Section “A-A”

SECTIONAL DRAWING 

Half-Sections A half-section is a view of an object showing one-half of the view in section

Half-Sections

EXPLODED VIEWS

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Exploded views are often a good way of showing detail. The animation below shows the pens being disassembled and then reassembled. In an exploded drawing the pens would only be drawn with all the parts disassembled (taken apart). It is important to recognise that all the parts are in line with each other, drawn usually along a centre line which is drawn through the entire centre of the design.

EXPLODED VIEWS

Block Diagram 

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A block diagram is a pictorial representation of some process or model of a complex system. Geometric shapes (e.g. rectangles, circles etc.) are often used in the diagram to aid interpretation and clarify meaning of the process or model. The geometric shapes are connected by lines to indicate association and direction/order of traversal.

Block Diagram

LOGIC FLOWCHARTS 

Data Flow Diagram (DFD) modelling is a top-down decomposition technique which results in Process Descriptions

LOGIC FLOWCHARTS

LOGIC FLOWCHARTS

SCHEMATIC DRAWING 

What is Schematic Drawing ?

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schematic drawing - Drawing of an electrical or mechanical system

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schematic diagram - a drawing intended to explain how something works; a drawing showing the relation between the parts

SCHEMATIC DRAWING 

schematic diagram

SCHEMATIC DRAWING 

wiring diagram - a schematic drawing of the wiring of an electrical system

WIRING DIAGRAM

Pictorial Diagram 

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The simplest of all diagrams is the pictorial diagram. It shows a picture or sketch of the various components of a specific system and the wiring between these components. This simplified diagram provides the means to readily identify the components of a system, even if you are not familiar with their physical appearance.

Pictorial Diagram 

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This type of diagram shows the various components without regard to their physical location, how the wiring is marked, or how the wiring is routed. It does, however, show you the sequence in which the components are connected. Figure 3-6  is a pictorial diagram of an automobile starting and ignition system. If you are not already familiar with the components of this system, study the diagram. You should then be able to recognize the physical appearance of each component and its interconnections with the other components of the system. Figure 3-6.—Pictorial diagram of automotive starter and ignition systems.

Pictorial Diagram

Pictorial Diagram

Common features of Engineering Drawings : Drawings convey the following critical information Geometry – The shape of the object, represented as views, how the object will look when it is viewed from various standard directions, such as front, top, side, etc.  Dimensions – The size of the object is captured in accepted units.  Tolerances – The allowable variations for each dimensions.  Material – Represents what the item is made of. 

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Finish

– Specifies the surface quality of the item, functional

Lines Styles and Types 

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Visible

– are continuous lines used to depict edges directly visible from a particular angle. Hidden – are short-dashed lines that may be used to represent edges that are not directly visible. Center – are alternately long- and short-dashed lines that may be used to represent the axes of circular features. Cutting plane – are thin, medium-dashed lines, or thick alternately long-and double short-dashed that may be used to define sections for section views.

Section

– are thin lines in a parallel pattern used to indicate surfaces in section views resulting from "cutting“. Section lines are commonly referred to as "cross-hatching”.