Construction Methods of: a) Stressed-skin Fuselage, b) Formers, Stringers, Longerons, Bulkheads, Frames, Doublers, Struts, Ties, Beams, Floor Structures, Reinforcements, c) Methods of Skinning, d) Wing and Empennage Attachements, Tipe Konstruksi Pesawat Udara Dua Tipe/Jenis Utama dari Konstruksi Struktur : 1. Rangka Batang (Truss) atau Kerangka (Framework) – umumnya digunakan untuk pesawat terbang ringan, bermesin-tunggal (single–engine models), fuselage tidak bertekanan (unpressurized fuselage). 2. Stressed-skin Structure – (struktur kulit yang menahan tegangan /cangkang bertekanan): a. Monocoque (Bhs Perancis: hanya cangkang / single shell only) b. Semi-monocoque (cangkang yang diperkuat /- kaku atau stiffened shell) c. Reinforced Shell Structure. 2 Types of Aircraft Construction Two Main Types of Construction in use: 1. Truss or Framework Structure -Type of Construction, generally used for light, single – engine models, unpressurized fuselage, aircraft. 2. Stressed-skin Structure – Type of Construction: a. Monocoque (single shell only) b. Semi-monocoque (stiffened shell) c. Reinforced Shell Structure. 3 Aircraft Structures Construction • TRUSS-TYPE STRUCTURES • Had struts and wire-braced wings • Occupants sat in open cockpits • Cockpits fabric-covered • STRESSED-SKIN STRUCTURES (skin memikul beban) • All of the structural loads are carried by the skin. • Thin wood skin • Or aluminum-alloy sheets (skins) 4 Konstruksi Rangka Batang (Truss or Framework Construction) Konstruksi Rangka Batang (Truss or Framework Construction) Occupants sat in open cockpits Konstruksi Rangka Batang (Truss or Framework Construction) Struktur konstruksi tipe TRUSS / FRAME - terdiri dari: • 4 (empat) buah Longeron – yang ditempatkan di keempat sudut struktur – gunanya untuk memikul sebagian besar beban-beban Tekan (compressive) dan Tarik (tensile). • Cross members/bracings – batang yang menyilang secara diagonal – memisahkan longeron, ideal-nya batang diagonal terutama memikul beban Tarik (Tension), kenyataannya ia juga mengalami beban Tekan/Kompresi (Compression). Konstruksi Rangka Batang (Truss or Framework Construction) Komponen truss /rangka-batang ..... (- samb) : • Frame – batang vertikal & horizontal mempertahan bentuk struktur. • Fuselage truss mempunyai cross-bracing tipe N, X, atau W (warren). • Truss /framework (primary structure) dibungkus dengan pembungkus (cover) dari bahan (fabric) dari katun atau linen gunanya untuk memberi bentuk aerodinamis. Bungkus ini – merupakan struktur sekunder . Konstruksi Rangka Batang (Truss or Framework Construction) Konstruksi Rangka Batang (Truss or Framework Construction) Kekurangan utama (Disadvantages) – adalah: • Bentuknya tidak aerodinamis (non-streamlined shape). • Bobot nya – berat. Keuntungannya (Advantage) – lebih kaku / kokoh. Definisi : Stressed Skin Structure : A type of aircraft structure in which all or most of the stresses are carried in the outside skin. • A stressed skin structure has a minimum of internal structure. Struktur Kulit di Tegangkan/Ketatkan : adalah - Tipe/jenis struktur pesawat terbang dimana seluruhnya atau sebagian besar tegangan dipikul oleh kulit luar. Definisi : Definisi berikut ini akan diterangkan kemudian : Monocoque Structure ; Semi-monocoque Structure ; Reinforced Shell Structure; Structure of early machines: •Wings of bent wooden ribs covered with fabric •Body of open Frameworks of wood strips lashed together with wire •Landing gear were skids 1/15/2012 13 World War - I: •Biplane •open cockpits • radial engines 1/15/2012 14 World War - I: •metal tube Truss construction •Welded thin-walled metal tube • covered with fabric • lighter weight and stronger 1/15/2012 15 Structure of early machines: •1st airplane – made with truss structure of wood or bamboo, and •The lifting and control surfaces were covered with cotton or linen fabric. •This structure was lightweight, but difficult to streamline. •When aircraft speeds increased that the streamlining became important. •1920s and 30s: •Stressed-Skin Construction Lockheed airplane – used the molded plywood monocoque structure 1/15/2012 17 Stressed – Skin Construction Fig.1-3 : • Pesawat terbang yang pertama kali menggunakan struktur kulit yang memikul beban (stressed- skin) – lapisan luar (skin) terbuat dari kayu tipis yang dibentuk dengan cetakan beton (concrete molds). 18 1/15/2012 19 • 1920s and 30s : . Sheet - Metal Aircraft Construction • Pure Aluminum alloy is weak. •During WW-I, Germans discovered that to increase Al- strength without increasing its weight, was by alloying it with Copper, Manganese, and Magnesium. •This new alloy was called – Duralumin, and it was the forerunner or the high-strength and lightweight alloys that are used in the aircraft construction today. Duralumin : is the name for the original alloy of Aluminum (Al), Magnesium (Mg), Manganese (Mn), and Copper (Cu). Duralumin – is the same as the modern 2017 aluminum alloy. •1920s and 30s : •Aluminum skin 1/15/2012 21 I. Evolution of Aircraft Structures II. Types of Aircraft Structures: •1920s and 30s : A. That Produce Lift B. That Produce Control C. That Modify Lift •Aluminum D. That Aid Control E. That Hold People structure F. That Support the Aircraft (Ground) •MONOCOQUE G. That Hold the Powerplant H. Rotorcraft construction 1/15/2012 22 MONOCOQUE – Type of Fuselage Construction (Bhs Perancis) Monocoque : artinya Hanya cangkang (shell only) . Rancangan / design monocoque hanya memakai kulit yang diketatkan atau cangkang tertekan (stressed skin) untuk menahan hampir semua beban-beban primer (twisting dan bending). Struktur ini dapat sangat kuat tetapi tidak dapat menahan penyok atau deformasi pada permukaannya. Ciri khas ini dapat dengan mudah diperagakan oleh kaleng aluminium tipis dari kemasan minuman ringan: . y.i. Dengan memberikan gaya yang cukup besar pada ujung-ujungya tanpa menimbulkan kerusakan. 23 MONOCOQUE Type of Fuselage Construction: . Tetapi, jika sisi dari kaleng penyok atau retak sedikit saja, kaleng tsb akan rusak (collapse) dengan mudah. Cangkang Telor Pure - Monocoque Structure 24 MONOCOQUE • In this method, the exterior surface of the fuselage is also the primary structure. •A typical early form of this was built using molded plywood. •A later form of this structure - uses fiberglass cloth impregnated with polyester or epoxy resin, instead of plywood, as the skin. 25 Monocoque Fuselage Construction Konstruksi Monocoque murni – terutama terdiri dari : Skin, Formers assy, dan Bulkheads. Formers dan Bulkheads memberikan bentuk bagi fuselage, tapi SKIN – pemikul beban / tegangan (stresses) utama. 26 •Since 1930s : •SEMI-MONOCOQUE construction 1/15/2012 27 Stressed-Skin Construction . Stressed-Skin Construction – is widely used because: – It has a high strength per weight ratio – It provides a large unobstructed internal volume – It (the tube) provides the largest volume per surface area ratio possible – It can be easily formed into streamlined shapes. Stressed-Skin Construction MONOCOQUE structures (hanya cangkang): • Pada konstruksi tipe monocoque – skin memikul seluruh beban /stress, dan tidak ada penopang didalamnya (internal supports), seperti tabung (tube). • Skin cukup tebal - terbuat dari konstruksi “sandwich”. Contoh: • De Havilland Mosquito (PD-II pesawat fighter bomber milik Inggris) – konstruksi sandwich kayu balsa - dan - plywood (kayu lapis); • Modern high performance Sail planes; • Helicopter Rear Fuselage, Sail planes dan pesawat modern lainnya – fiber glass & carbon fiber composites. Stressed-Skin Construction • Kebanyakan pesawat udara modern – terdiri dari konstruksi struktur berdinding tipis (thinned walled structures or shells). • Struktur tipe Konstruksi Monocoque atau Semi-monocoque. Definitions . MONOCOQUE structures: .Unstiffened shells. .Must be relatively thick to resist bending, compressive, and torsional loads. Virtually no internal framework 31 Definitions . SEMI – MONOCOQUE structures: • Constructions with stiffening members that may also be required to diffuse concentrated loads into the cover. • More efficient type of construction that permits much thinner covering shell. BEDA - Struktur Konstruksi MONO - & SEMI-MONOCOQUE • Monocoque • Virtually no internal framework • (Nyaris tidak ada kerangka didalamnya) • Semi-monocoque • Internal arrangement of formers and stringers is used to provide additional rigidity and strength to the skin. • (Susunan dalam dari formers dan stringers digunakan untuk memberikan tambahan kekakuan dan kekuatan kepada skin) 33 BEDA - Struktur Konstruksi MONO - & SEMI-MONOCOQUE Monocoque Construction Semi-monocoque Construction 34 Definitions . REINFORCED SHELL structure : • This is the most commonly used structure in modern all-metal aircraft. •The shape is provided by Bulkheads, Formers, and Stringers, but •The structure is reinforced with Longerons that help carry the Loads. •A sheet-metal skin riveted over the structure – carries a major portion of the flight loads. Stressed-Skin Construction SEMI – MONOCOQUE structures: • Pada konstruksi tipe ini – skin memikul sebagian beban /stress, dan diberi penguat/pengaku didalamnya yang ikut memikul beban. SKIN dari semi-monocoque di-perkuat / perkaku (stregnthened / stiffened) oleh: (a) LONGERONS (4 buah) – arah memanjang (longitudinal), memberi kekuatan bending dan ketahanan (resistensi) terhadap beban kompresi (tekan). (b) STRINGERS (kecil-kecil & banyak) – penguat arah memanjang, (c) FRAMES (untuk Fuselages) , RIBS (wing, tail-units) – arah melintang /transverse. (d) BULKHEADS – arah melintang/transverse.