Aircraft Structures and Design PDF

PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PU...

PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY SESSION: STRUCTURES AND DESIGN Mission Profile REVIEW LECTURER: ENGR. JUSTIN AUSTRIA Payload and type Range and/or loiter requirements Cruise speed and altitude What is Aircraft Design? Field length for take-off and landing Airplane design is the intellectual engineering Fuel reserves process of creating on paper (or on a computer Climb requirements screen) a flying machine to Maneuvering requirements (1) meet certain specifications and requirements Certification base (experimental, FAR 23, FAR established by potential users (or as perceived by the 25, military) manufacturer) and/or (2) pioneer innovative, new ideas and technology. BV 141 What is the starting point in aircraft design? Design Requirements 1. Range. 2. Take-off distance. 3. Stalling velocity. 4. Endurance [usually important for reconnaissance airplanes; an overall dominating factor for the new group of very high-altitude uninhabited air vehicles (UAVs) that are of great interest at present]. 5. Maximum velocity. CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 1 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY 6. Rate of climb. 7. For dogfighting combat aircraft, maximum tum rate and sometimes minimum tum radius. 8. Maximum load factor. 9. Service ceiling. 10. Cost. 11. Reliability and maintainability. 12. Maximum size (so that the airplane will fit inside standard hangars and/or be able to fit in a standard gate at airline terminals). Suggested Approach CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 2 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Structural System Shell elements Any deformable solid body which is capable of are curved plate elements which occupy a space. carrying loads and transmitting these loads to other Fuselages, building domes, pressure vessels, etc., are parts of the body typical examples of shells. Bar elements Are one-dimensional structural members which are capable of carrying and transmitting bending, shearing, torsional, and axial loads or a combination of all four. Bars which are capable of carrying only axial loads are referred to as axial rods or two-force members. Structural systems constructed entirely out of axial rods are called trusses and frequently are used in many atmospheric, sea, and land based structures, since simple tension or compression members are usually the lightest for transmitting forces. Plate elements Are two dimensional extensions of bar elements. Plates made to carry only in-plane axial loads are Load Classification called membranes. Those which are capable of carrying only in-plane shearing loads are referred to Surface load- those loads which are produced by as shear panels; frequently these are found in missile surface contact. Examples are dynamic and/ or static fins, aircraft wing, and tail surfaces. pressures. If the area of contact is very small, then the load is said to be concentrated; otherwise, it is called a distributed load. Body loads- Loads which depend on body volume are called body loads. Examples are inertial, magnetic, and gravitational forces. Generally, these loads are assumed to be distributed over the entire volume of the body. Dynamic loads- are time dependent, whereas static loads are independent. CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 3 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Thermal loads- are created on a restrained structure by a uniform and/or nonuniform temperature change. Regardless of the classifications of the externally imposed loads, a structural member, in general, resists these loads internally in the form of bending, axial, shear, and torsional actions or a combination of the four. Flight Vehicle Imposed Loads The first aerodynamic data required for the Bending moment- may be defined as a force whose structural system analysis are the lift, drag, and vector representation lies in and parallel to the plane pitching-moment force distributions for the complete of the cut. aircraft with the horizontal tail removed, through the range of angles of attack from the negative stalling Torque- is a force whose vector representation is angles to the positive stalling angle. normal to that cut. General Considerations Limit loads/ Applied loads- the limit loads used by Shear load- is a force which lies in and is parallel to civil agencies or applied loads used by military the plane of the cut. agencies are the maximum anticipated loads in the Axial loads- is a force which acts normal to the plane entire service life-span of the vehicle. The ultimate of the cut loads, commonly referred to as design loads, are the limit loads multiplied by a factor of safety (FS): Statically Determinate and Indeterminate Structures FS = ultimate load / limit load A structure is said to be determinate if all its external Limit load factor- is a factor by which basic loads on reactions and the internal loads on its members can a vehicle are multiplied to obtain the limit loads. be obtained by utilizing only the static equations of equilibrium. Otherwise the structure is said to be Ultimate load factor - is a factor by which basic statically indeterminate (redundant structure) vehicle loads are multiplied to obtain the ultimate loads; in other words, it is the product of the limit load factor and the factor of safety. CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 4 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Basic Flight Loading Conditions The gust load factors on an aircraft are greater when it is flying at the minimum flying weight than they are Positive High Angle of Attack (PHAA) condition- is at the gross-weight condition. obtained in a pullout at the highest possible angle of attack on the wing. The lift and drag forces are perpendicular and parallel respectively, to the Classes of Aircraft Structure relative wind, which is shown as horizontal. Primary Structure Positive Low Angle of Attack (PLAA) condition - A critical load-bearing structure on an aircraft the wing has the smallest possible angle of attack at If this structure is severely damaged, the aircraft which the lift corresponding to the limit-load factor cannot fly may be developed. For a given lift on the wing, the angle of attack decreases as the indicated airspeed increases, and consequently the PLAA condition corresponds to the maximum indicated airspeed at which the airplane will dive. This condition represents an upward acceleration at its design gliding speed Vg Negative High Angle of Attack (NHAA) condition- occurs in intentional flight maneuvers in which the air loads on the wing are down or when the airplane strikes sudden downdrafts while in level flight. In this condition usually the wing is assumed to be at the Secondary Structure negative stalling angle of attack for steady flow Structural elements mainly provide enhanced conditions. aerodynamics Fairing, for instance, are found where the wing meets Negative Low Angle of Attack (NLAA) condition - the body or a various locations of the leading edge or occurs at the diving-speed limit of the airplane. This trailing edge of the wing condition may occur in an intentional maneuver producing a negative load factor or in a negative gust condition. This condition allows for the effect of a sudden decrease in angle of attack while flying at the speed of Vg CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 5 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Monocoque The skin carries all the load Unstiffened Shell. Must be relatively thick to resist bending, compressive, and torsional loads Consist of skin and frames/formers/ bulkhead Types of Aircraft Structures Truss Type a rigid framework made up of members such as beams, struts, and bars to resist deformation by applied loads. CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 6 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Semi-Monocoque Construction with stiffening members that may also be required to diffuse concentrated loads into the Skin cover Reacts the applied torsion and shear forces transmits More efficient type of construction that permits much aerodynamic forces to the longitudinal and transverse thinner covering shell supporting members Acts with longitudinal members in resisting the applied bending and axial loads Acts with the transverse members in reacting the hoop, or circumferential, load when the structure is pressurized CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 7 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Longeron - Main longitudinal member of a fuselage or nacelle. Tie Rod (Tension Rod) – Member taking a tensile load. Strut – Member taking a compression load. Stressed skin – Structure where loads are shared between skin and framework. Bulkhead - A partition within the structure. Usually lateral but can be longitudinal. If it forms the boundary of pressurized structure it is called a pressure Spar bulkhead. Resist bending and axial loads Crack stopper - A reinforcing member normally Form the wing box for stable torsion resistance placed at right angles to the path of an anticipated crack which will reduce the rate of further propagation. Gussets - A flat sheet triangular in shape used to reinforce the corners of structure. Keelson/Keel beam - structural element frequently used to carry the fuselage bending loads through the portion of the lower fuselage which is cut up by the Stiffener and Stringers wheel wells. Resist bending and axial loads along with the skin Aircraft Drag Divide the skin into small panels and thereby increase its buckling and failing stresses Total Drag = Profile Drag + Induced Drag Act with the skin in resisting axial loads caused by 𝑪𝑫 = 𝑪𝑫𝒐 + 𝑪𝑫𝒊 pressurization Other Structural Terms CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 8 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Induced Drag – Drag induced while producing lift Exceedance Drag – Drag produced due to surface roughness. This type of drag decreases as speed increases Could be reduce by installing flush fasteners or using flush repair or application of filleting sealants 𝐶𝐿 2 𝐵2 𝐶𝐷𝑖 = 𝑤ℎ𝑒𝑟𝑒 𝐴𝑅 = 𝜋𝐴𝑅 𝑆 Profile / Form Drag – Drag produced by shape and form of the aircraft This type of drag increases as speed increases Part of this drag is interference drag and exceedance drag Interference Drag - Interference Drag is generated by the mixing of airflow streams between airframe components, such as the wing and the fuselage, or the landing gear strut and the fuselage. CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 9 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Shape Fuselage Circular Cross Section - Efficient Structural Design - Offers theoretically greater strength for shell structure - Inefficient in availability of useful shape Rectangular Cross Section - Permits the most economical use of the space - Not Suitable for shell structures Oval/Elliptical Cross Section - Best Compromise between circular and rectangular cross section CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 10 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Frames Just as for the ribs in the wing structure, the primary function of the transverse fuselage frames are: 1. Maintain the shape of the fuselage 2. To sustain concentrated loads imposed 3. Serve as attachments for equipment, flooring, and the like 4. Transmit the loads to adjacent structural members The frames may be roughly classified as the following: 1. Simple Frames 2. Intermediate Frames 3. Main Frames Simple Frames 1. Serve mainly to maintain the shape of the fuselage 2. These are not subjected to stress unless distortion of the entire adjacent structure has taken place Intermediate Frames 1. Serve to act as anchorage for medium weight equipment, control system and the like. 2. Similar simple frames but must be reinforced locally to carry the load and reduce deflection to a minimum CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 11 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY 3. Additional brackets may have to be introduced and tied in with the longitudinal stingers as well as the frames 4. These are not subjected to stress unless distortion of the entire adjacent structure has taken place Main Frames 1. To which large external loads are supplied through the landing gear, powerplant, or wing structure. 2. These are usually two in number, spaced a small distance apart and designed so as to take fittings to serve as carry through members 3. Act as the main transverse load carrying member Stringers Since the fuselage is essentially a beam, the longitudinal stringers serve an important function in that they, along with CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 12 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY the effective width of sheet covering, are the main bending Since the openings have to be reinforced along the edges, it is elements of the structure. desirable to have the top and bottom of all frames for such opening rest on longitudinal stringers. In general, since the stringers are the main bending elements, they should be continuous and therefore pass through the It is customary to spot in the stringers first, in order to avoid transverse frame unnecessarily close spacing, should the desired stringer. spacing and the required stringer spacing not coincide Where local stresses are likely to be high, bracket tying the frames and stringers together are added for greater rigidity and load carrying capability The stringer spacing is determined by the number required for the loads imposed. Longitudinal members are spaced from 6 to 12 inches apart around the largest cross section. Since the cross section gradually decreases in size, the spacing is closer towards the tail post so that alternated members may be stopped at a forward frame. It is desirable not to end all the longitudinal members at the same frame. Wings The wing is essentially a beam that is subjected to shear, bending, and torsion imposed upon it by aerodynamics and inertia loads. CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 13 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Mean Aerodynamic Chord The center of gravity of the complete airplane is placed, usually at the maximum forward position of the center of pressure on the mean aerodynamic chord in order to get the desired stability The mean aerodynamic chord is difficult to determine unless the pressure distribution is know. Moreover, the pressure Taper Ratio distribution varies with angle of attack. It is customary A wing with taper is a trade-off between elliptical (least induced therefore to use the mean geometric chord of the wing drag, difficult to manufacture) and a rectangular wing (more instead. induced drag, easy to manufacture). ▪ More taper (smaller taper ratio) means less weight The mean aerodynamic chord, or mean geometric chord, is ▪ More taper (small tip chord), more conducive to tip determined for only 1/2 of the wing, either to the side of the stall fuselage, or up to the plane of symmetry for a parasol wing ▪ Less taper means more fuel volume ▪ Tapered wings cost more than untapered wings CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 14 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Sweepback For Aircraft operating at high subsonic speeds, the use of the sweepback in the planform of the wing is favored in order to increase the critical Mach number of the wing Advantage: ▪ Delays drag divergence effects ▪ Used for balance ▪ Used for stability (dihedral effect) ▪ Better ride through turbulence characteristics Disadvantage: ▪ Contributes to pitch up characteristics ▪ Performs less during take-off and landing ▪ Reduces subsonic lift ▪ Significant weight penalty ▪ Liable to tip stall CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 15 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Dihedral Increase lateral stability. Angle varies around 3 to 8 degrees Anhedral Decrease lateral stability/ Angle varies around 3 to 6 degrees Also known as negative dihedral or drooped wing Wing Loading Wing loading is weight of aircraft over wing area (W/S) ▪ Affects [a] take-off and landing field length, [b] cruise performance (L/D), [c] ride through turbulence, and [d] weight ▪ For a short field length, a large wing / low wing loading is required Dihedral and Anhedral ▪ Wing can be kept small by using flaps ▪ For cruise at (L/D)max, a high wing loading is required Affects lateral stability but may also relate to relation of lateral ▪ For flight at high altitudes and at low speeds, a large to directional Stability wing is required. ▪ Of course a large wing means more weight A low wing loading translates to a high load factor and thus poor ride qualities CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 16 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Aspect Ratio How does aspect ratio affect induced drag? ▪ High aspect ratio means reduced induced drag; Wingtip has less area, there is less vortex induced downwash, increased (L/D)max which means a lot less induced drag. ▪ Also means high lift curve slope; good approach attitude; bad ride through turbulence ▪ The higher the AR, the higher the span, the heavier b2 AR = S Thickness Ratio ▪ Most important geometric consideration when selecting and airfoil ▪ Higher thickness ratio, higher profile drag / wave drag CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 17 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY ▪ Higher thickness ratio, lower weight ▪ Higher thickness ratio (up to 12-14%), higher Clmax ▪ Higher thickness ratio, greater fuel volume max thickn ess t/c = chord Geometric Twist – one type of airfoil used, incidence is changing relative to root chord. Linear Twist – incidence is proportional to distance from root airfoil. Aerodynamic Twist – difference in the zero-lift angles of the root and tip airfoil. Same as geometric twist if one type of airfoil is used Note: It is possible for a wing without geometric twist to have an aerodynamic twist. This can happen, for example, when the root and the tip are using different airfoil. Wing Twist Wash-out – tip airfoil has negative incidence relative to root airfoil. Wash-in – opposite of wash-out ▪ Washout delays tip stall ▪ May increase induced drag ▪ Less-loaded tip; less strength requirements; less weight Wing twist will only be optimal relative to lift distribution for one value of coefficient of lift CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 18 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Angle of Incidence The angle of incidence (sometimes referred to as the mounting Wing Vertical Position angle) is the angle between the chord line of the wing where the wing is mounted to the fuselage, and a reference axis along the fuselage ▪ Used to minimize drag at some operating condition, usually cruise. ▪ set the wing at an angel to the longitudinal axis of the fuselage corresponding to the angle at which minimum drag occurs. High Wing ▪ Used to improve attitude ▪ Places fuselage closer to the ground; easier ▪ Usually at 1-3 degrees loading/unloading; adapted by cargo aircraft ▪ Sufficient ground clearance for engine nacelle or propeller; less landing gear height needed ▪ Wing tips less likely to strike the ground ▪ Usually less in weight (Semi-Cantiliver) ▪ A strutted wing usually presents less weight but struts adds to drag. ▪ Struts for a high wing, that is struts below the wing, offer less drag compared to struts above the wing CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 19 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY ▪ Weight savings for placing wing box at the top; no fuselage stiffening necessary; however, increased frontal area adds to drag ▪ For a STOL aircraft, a high wing provides ground clearance for the large flap necessary for high CL ▪ Prevents floating (ground effect is reduced) which makes it hard to land on desired spot ▪ STOL aircraft are usually designed to operate in unimproved fields; High wing places engines and propellers away from rocks and debris ▪ Landing gear is installed to the fuselage rather than the wing to reduce strut length ▪ Fuselage needs stiffening; means more weight Low Wing ▪ External blisters (landing gear housing) might be ▪ Landing gear can be attached to (and retracted into) necessary; means added weight and drag the wing which is already strong with no stiffening ▪ Fairing where wing connects to the circular fuselage (and no external blisters) necessary is necessary ▪ Allows for a shorter landing gear strut which means ▪ Flattened bottom will provide desired floor height but less weight; however there still must be enough means more weight ground clearance ▪ Given enough ground clearance, aft-fuselage ▪ upsweep can be reduced, reducing drag ▪ Commonly adapted by large commercial transports which normally operate in well-equipped airfields; loading and unloading is not a problem ▪ Ground clearance problems may be alleviated by a dihedral; but too much dihedral can cause Dutch roll tendencies. ▪ Placing the propellers higher above the wing Mid Wing increases interference effects and cruise fuel ▪ Needs fuselage stiffening; means more weight consumption. ▪ Carry-through structure will limit space for a passenger or cargo aircraft; difficult to incorporate in a fighter aircraft in which most of the fuselage is occupied by the jet engines and inlet ducts CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 20 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Stagger – the longitudinal offset of the two wings relative to each other (positive, when upper wing is closer to the nose; negative, otherwise) Decalage – relative incidence between the two wings (positive, when upper wing has a larger incidence; negative, otherwise) Sesquiplane – Biplane that has smaller lower wing than the upper wing Wing Spar In general, a spar is though of as a member having a relatively large material in the flanges, chords, or caps located at the top and bottom member, with a relatively thin shear web Multi-Wing connecting the two. The spar is designed to be subjected to shear, bending and torsion. Form the wing box for stable torsion resistance It may be classified as tension-field beam or shear resistant beam Location Front Spar = 12 to 17 % chord Terms: Rear Spar = 65% to 75%. Usually 70% to accommodate 25% Gap– the vertical distance between the two wings chord aileron Span Ratio – the ratio between the shorter to the longer wing CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 21 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Spar Cap (flange): These consist of the upper and lower flanges attached to the Tension-field beam spar webs. The spar caps carry the bending moment - allows the shear web to wrinkle, and this the transverse shear generated by the wing in flight. The upper spar cap will be is resisted by tension in more or less the same way as wire- loaded in compression and the lower in tension for a positive braced truss. load factor (wing bending upward). The spar caps also form a - relatively light boundary onto which wing skin is attached and support the - will not wrinkle would not occur until load limit was imposed, wing skin against buckling. Concentrated load points such as so that a loads less than the load limit, the spar can be engine mounts or landing gear are attached to the main spar. considered a shear resistant beam Spar web: The spar web consists of the material between the spar caps and maintains a fixed spacing between the them. This allows the spar caps to act in pure tension and compression (bending) during flight. The spar web is responsible for carrying the vertical shear loads (lift) which arises from the aerodynamic loading of the wing. The spar webs and caps are collectively referred to as the wing spar Shear resistant Beam - designed so that the shear web will not wrinkle under limit loads - In order to increase the shear load that the web can withstand, stiffeners are attached at specified intervals CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 22 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Ribs The primary function of the ribs in the wing are 1. to maintain the chordwise shape of the airfoil 2. Act as supports of the wing skin panel or envelope 3. Transmit the pressures on the wing to the spanwise members In some cases, they also serve to act as the support members to which the landing gear members or engine mount members are attached or as support for fuel tanks, control systems and Stringers localized loads. The primary purpose of stringers in wings is to add bending strength to the wings In turn, such ribs transmit the loads to the spanwise spars. The stringer spacing is determined by the number required for the loads imposed. Longitudinal members are spaced from 6 to 12 inches apart around the largest cross section. Since the cross section gradually decreases in size, the spacing is closer towards the tail post so that alternated members may be stopped at a forward frame. It is desirable not to end all the longitudinal members at the same frame. The spacing of ribs may be determined by the need to prevent oil canning of the skin or by the optimum panel proportions. For preliminary considerations, rib spacing from 6 to 18 inches may be assumed CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 23 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Wing Attachments Externally braced - Semi-Cantilever - reduction of the bending moment imposed produces Lighter structure - Any gain in wing structure may be offset by the additional supporting structure - Causes more drag Internally braced/bolted - Cantilever - No external brace - May be heavier due wing junction will carry the bending Wing Tips moment Wingtip devices are intended to improve the efficiency of fixed- - Less drag wing aircraft by reducing drag. There are several types of wing tip devices which function in different manners, their intended CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 24 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY effect is always to reduce an aircraft's drag by partial recovery of the tip vortex energy. Such devices increase the effective aspect ratio of a wing without greatly increasing the wingspan The positive factors and offsetting factors that contribute to the ▪ A sharp tip is more effective than a rounded tip in performance improvement can be listed as follows: alleviating tip vortex effects Positive factors: ▪ The Hoerner tip is the most widely used low-drag Induced drag is reduced at takeoff and cruise. wingtip Shock drag is sometimes reduced a little at cruise ▪ Tip curved upwards/downwards increase effective due to the change in spanload produced by the span without increasing actual span device. ▪ A swept wing tip addresses the condition that vortices Offsetting factors: tend to be located at the trailing edge of the wing tip; Profile drag is increased due to: increases torsional load – Increased wetted area. ▪ Cut-off forward swept is used for supersonic aircraft; – Junction flows, high sectional loadings, etc. part with little lift is cut-off; reduced torsional load Weight is increased due to: ▪ The endplate is an intuitive solution to the leakage of – The weight of the device itself. – The weight of the high pressure flow below the wing to the low attachment fittings. pressure flow above it. – Increases in the weight of the existing wing ▪ Adds to wetted area, and therefore drag structure due to increases in static loads and to meet ▪ Might be better to just add to the span instead flutter and fatigue requirements ▪ Solution to a short span requirement Wing Fuel Tanks Integral fuel tank areas inside the aircraft structure that have been sealed to allow fuel storage Inspection panels must be provided to allow internal inspection, repair, and overall servicing CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 25 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY Area Dependent on the distance from C.G. Range from 10 to 15 percent of wing area Rudder is around 30 to 50 percent of stabilizer area Tail Length Located at the distance from C.G to the estimated CP of the horizontal or vertical stabilizer is form 2.5 to 3.5 times the wing mean geometric chord Vertical Stabilizers The Vertical Tail surface consist of the fixed surface and the movable surface (rudder) Its function is to provide directional stability and control in flight It is very important that these tail surfaces be located that they are not blanketed by the fuselage Aspect Ratio The aspect ratio of the vertical tail surface may Dorsal Fin somewhat restricted by the possible torsional moment imposed on the fuselage May be added to increase the fin area Typical aspect ratio is around range 2 to 4 (1) increase directional stability of the original surface CONFIDENTIALITY NOTICE: The contents of this review guide are intended solely for 1Aero participants and may contain confidential and privileged information. If you are not the intended end-user, you are hereby notified that any use, dissemination, copying, or storage of this review guide is strictly prohibited. We got your back, fam. Page 26 +63 915 363 5759/ +63 949 588 3874 [email protected] Attitude ∙ Skills ∙ Knowledge web.facebook.com/everythingaviation.1Aero/ PRC AERONAUTICAL ENGINEER COMPREHENSIVE REVIEW STRUCTURES AND DESIGN Aircraft Design Fundamentals, Structural Loading Conditions, Structural Analysis and Design of Airframe Components, Landing Gears, Engine Mounts and other Structural Parts, and Non -Structural Component Design FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY FOR 1AERO REVIEW PURPOSES ONLY (2) transmit the loads on the fin to greater number of the ▪ May enhance engine out control in multiengine fuselage frames aircraft with the rudders positioned in the propwash (3) reduce torsional moment about the longitudinal axis ▪ Endplate effect on the horizontal tail; reduced size (4) reduce height of the vertical tail possible (5) possible weight saving ▪ Heavier than conventional Ventral Fin Located below the fuselage More effective since area is not blanketed by the fuselage Horizontal Stabilizer Horizontal Tail consist of the horizontal stabilizer and the elevator This should be located that any blanketing by the Single Vertical Tail wing or the fuselage is avoided. ▪ Lighter construction Partial blanketing usually exist, however certain ▪ Fuselage blankets the vertical Stabilizer features may be incorporate to limit the effect.