Diploma project - Design of passenger aircraft of regional local air lines

Contents

1. Preliminary surveys

2. Selection of aircraft diagram and engine type

3. Calculation of take-off weight and selection of aircraft main parameters

4. Determination of main flight performance characteristics of the aircraft

5. Aircraft layout

6. Determination of characteristics of maneuverability, longitudinal stability and controllability

7. Development of the unit structure

8. Scientific Research Section (R&D)

9.Technological section

10. Organizational and Economic Section

11. Protection of labor and environment

12.Analysis of design results

List of used literature

List of drawings

Structural and power arrangement

5.3.1. Fuselage.

The fuselage design is a half-monocoque, consists of three main sections: nose, middle and tail.

The crew cabin and passenger cabin are located in the sealed part of the fuselage.

In the front part of the fuselage there are: on the LH side - an emergency exit measuring 510x910 mm and on the starboard side a cargo hatch measuring 960x1300 mm. Under the wing on the starboard side of the fuselage there are emergency exits measuring 510x910mm, also on the starboard side in the tail part there is an emergency exit measuring 720x1380. The front door is located in the tail of the fuselage on the left side, measuring 760x1700.

The nose of the fuselage to frame No. 7 includes:

- radio transparent deflectable fairing of radar antenna;

- front sealed partition;

- NLG compartment;

- crew cockpit canopy;

- crew cabin floor;

- partition along fr. No. 7 with a door to the crew cabin.

In the middle part of the fuselage from the partition along fr. No. 7 to the sealed partition along fr. No. 31, the passenger cabin is located.

In the zone of propellers, the fuselage structure is reinforced in order to achieve permissible levels of vibration and noise. Fairings are installed on both sides of the lower part of the fuselage, which cover the attachment units of the MLG, strut and wheel struts in the retracted position. APU is installed in RH fairing.

The tail part of the fuselage with the unit is a single subassembly, in which the keel spars are combined with the power frames of the keel attachment.

The fuselage will be made mainly of aluminum alloys, floor panels and wing bays with a fuselage - from composite materials.

The design of the fuselage will be developed taking into account panel assembly and the wide use of press riveting. The skin will be made of aluminum alloys with additional reinforcement by understudies and frames in the area of ​ ​ the door, hatch and window openings. The skin, doublers and frames form a layered structure and are interconnected using gluing.

Transverse set consists of power and typical intermediate frames. The stringers will be made of sheet material. The joints of the wing with the fuselage are closed with slides.

5.3.2. Wing.

Wing consists of center-wing and two cantilevers. Joint of center plan with cantilevers is detachable.

The wing (center wing) is attached to the power frames of fuselage No. 17 and No. 19 using connecting units installed on the center wing spars and on the fuselage frames.

The joints of the wing with the fuselage are closed with slides.

On the wing (center wing), in the area of ​ ​ ribs No. 7, 8 and 9, engine nacelles are installed.

The wing structure is a two-legged circuit, a conventional riveted structure made of aluminum alloys.

Upper and lower panels of power set of wing are made of sheets of skin with pressed stringers riveted to them. The thickness of the skin is from 1 to 4 mm. Separate skin panels will be made of thicker sheets 610 mm thick by chemical etching and machining to obtain local strengths at transverse joints, attachment of engine nacelles, flap supports, fuel system fittings, etc.

Maximum dimensions of skin sheets: width 1.2 m, length 9.3 m. Stringers up to 10 m long. On the wing consoles there are technological joints of skin sheets and stringers in scope.

Spars and wing ribs are a common beam structure. Nerves - beam and truss types.

For attachment of engine nacelles, wing mechanization, control surfaces, etc., brackets, assemblies and fittings will be used in the wing structure,

In the design of the nose and tail parts of the wing, honeycomb structures with skin made of composite materials will be used.

The wing power caisson from the axis of symmetry (rib No. 0) to rib No. 18 will be sealed under the fuel tank-compartment.

Removable panels are provided on the upper surface of the wing for access to the inside of the wing caisson and process assembly.

Main elements of the wing:

TE flaps are double-slotted with fixed deflector.

On each half-wing there is one permanent flap, which occupies the half-wing section from the fuselage side by span up to 71.3% of the half-span.

In the chord, the flap consists of the main link, a deflector fixed to it and occupies 35.4% of the wing chord.

TE flaps maximum deflection angle is 40 °.

TE flaps are hung on the wing by means of wing and TE flaps brackets located below the wing contour and closed by fairings.

Flaps - prefabricated structures, will be made of composite materials, honeycomb fillers, power elements and hinge brackets - from aluminum alloys.

Ailerons occupy end parts of wing consoles from 71.3% to 100% of wing half-span.

Deflection angles of ailerons: up 25 °, down 17 °.

Ailerons have axial compensation with an area of ​ ​ 28% of the aileron area and horn - mass compensation.

Ailerons design is similar to TE flaps design.

The airbrakes consist of four sections of two sections per

each half of the wing.

The design of the airbrakes will be made of composite materials, the suspension units - of aluminum alloys.

Deflection angle of airbrakes is 35 °.

5.3.3. Plumage.

The tail unit of the T-shaped scheme consists of an arrow-shaped vertical unit and a straight horizontal unit installed in its upper part.

The horizontal plumage is trapezoidal in plan, has a sweep of about 9 ° along the 1/4 chord line, is made of modified profiles of the NACA009 type (with its toe bent upwards) and relative thickness along the entire span with = 10.4%.

Horizontal plumage consists of stabilizer, balancing surface and height rudder with horn compensation.

Balancing surface is used for balancing (trimming) of aircraft by pitch at setting of altitude rudder to position close to neutral at steady flight modes.

Altitude rudder is used for manoeuvre. Horn compensation on the steering wheel performs the function of weight balancing of the steering wheel.

Stabilizer - two-spar circuit; consists of the nasal, intergeron (caisson) and tail parts and tips. The span is made of two permanent cantilevers (process joint along the aircraft axis).

The stabilizer is attached to the upper part of the keel by means of connecting units.

According to the test results, the stabilizer can be installed relative to the aircraft axis in the range of wedge angles + 1 °.

The vertical plumage is trapezoidal in plan, has an sweep of 35 ° along the 1/4 chord line; is made of symmetrical profiles of NACA009 type with relative thickness over the entire span with = 11.8%.

Vertical plumage consists of a keel with a tip and a ridge, as well as a rudder with horn compensation and a servo compensator. Horn compensation on the rudder performs the function of weight balancing of the rudder.

The keel design is similar to the stabilizer design.

The joint of the keel with the fuselage is carried out directly through the belts and walls of the spars, which are attached to the power frames.

The plumage is a riveted structure made of aluminum alloys. Panels of power set are made of sheathing sheets with pressed stringers riveted to them. The thickness of the skin is from 0.6 to 2 mm. Spars and ribs - beam structure.

Honeycomb structures with composite sheathing will be used in the nose and tail parts of the unit. Separate sections of socks of vertical and horizontal plumage are made of radio-transparent composite materials.

Removable hatches are provided on the side surface of the keel and lower surface of the stabilizer for access to connection points and rudder control elements.

5.3.4. Chassis.

The aircraft landing gear is 3 rack with a nose wheel, retractable. The nose strut is telescopic with paired wheels, retracts forward into the fuselage. The main supports are retracted into fairings under the fuselage.

Development of the unit design

The aircraft keel was chosen as the unit for design development. The keel is part of the T-shaped plumage of the aircraft.

7.1. Selection of structural-power scheme.

KSS of keel form longitudinal and transverse elements and skin.

Longitudinal set: three spars and stringers.

Transverse set: normal and power ribs.

Material of sheet elements of structure D16 and D16T, spar belts, power ribs and stringers - pressed profiles of material D16 and D16T.

Structurally, the keel consists of:

- toe of keel;

- caisson part;

- tail part.

The sock is located between a front edge and a front longeron (the front longeron is located for 15% of a chord of a keel). It consists of 2 sections. Made of fiberglass.

Caisson part is located between front and rear spars. Parallel to the rear spar passes the middle. Stabilizer is fixed on front and middle spars in 4 points. The stringers are located parallel to the rear spar with a pitch of 120 mm.

To reduce the weight of the keel, all elements of the longitudinal set and skin of the caisson part of the keel have a variable section.

Skin is made of sheet mm, has variable thickness from side rib (mm) to end rib (mm). To attach stringers, ribs and spars on the skin, tracks with a thickness of 2 mm are left. Thickness treatment is carried out by chemical etching.

Beam structure spars. They consist of belts, walls and posts. The walls of the spars at the root have a thickness of mm, at the end of mm. They have relief holes. Belts are made of pressed profiles of angular section. Initial section 50 (6) h40 (3) - at a front longeron and 30 (6) h40 (3) - for average and back longerons. Belts are machined in width.

Stringers are made of two profiles, have a joint along the length.

Normal ribs made of sheet mm, with compensator, with relief holes at the junction and riffs. Power ribs, composite: sheet wall mm without relief holes, belts - pressed profiles, posts - pressed profiles. Power ribs are placed on the rudder supports, on board and at the end of the keel. The pitch of the nerves is 400mm.

The caisson forms a closed loop working for torsion and general bending.

The tail part of the keel is located between the rear spar and the axis of rotation of the rudder. It includes P.N. suspension units (made of D16 plate) and slit sealing. The latter consists of a skin and sheet membranes supporting it.

Research section

SUBSTANTIATION OF AIRCRAFT DIAGRAM.

8.1. Substantiation of the aerodynamic scheme of the aircraft.

A modern aircraft is a complex technical system, the elements of which, individually and all in total, should have maximum reliability. The aircraft as a whole must meet the specified requirements and have high efficiency at the appropriate technical level.

When developing new-generation aircraft projects that will enter service in the early 2000s, great importance is attached to achieving high technical and economic efficiency. These aircraft should not only have good performance at the time of commissioning, but also have the potential for modification to systematically increase efficiency throughout the entire period of mass production. This is necessary in order to ensure that new requirements and advances in technology are met at minimal cost.

When considering the scheme of a passenger aircraft of local airlines, it is advisable to study all previously created aircraft in this class.

The development of passenger aviation actively began after World War II. Since then, the scheme of aircraft of this class, gradually undergoing changes, has come to the most optimal today. In most cases, this aircraft, made according to a normal aerodynamic scheme, is a monoplane. Engines are usually located under the wing (HPT), under the wing on pylons or on the wing (TRD). The tail unit is made rather according to the T-shaped scheme, sometimes according to normal. Fuselage section consists of circular arcs. The chassis is made according to the scheme with a nose wheel, the main struts are often multi-wheeled and multi-support, retractable either into elongated engine nacelles of turboprop engines (for aircraft weighing up to about 20 tons), or into strays on the fuselage.

A typical fuselage layout is a cockpit in the bow, a long passenger cockpit.

Deviation from this established layout scheme can only be caused by some special requirements for the aircraft. In other cases, when developing a passenger aircraft, designers try to adhere to this particular scheme, since it is almost optimal. The rationale for this scheme is given below.

The use of a normal aerodynamic scheme for transport aircraft is primarily due to its advantages:

- Good longitudinal and track stability. Thanks to this property, the normal circuit greatly benefits the duck and tailless circuits.

- On the other hand, this scheme has sufficient controllability for a non-maneuverable aircraft. Due to the presence of these properties in the normal aerodynamic scheme, the aircraft is easy to control, which makes it possible to operate its pilots of any qualification. However, the following disadvantages are inherent in the normal scheme:

- Large losses on balancing, which, all other things being equal, greatly reduces the quality of the aircraft.

- The useful mass yield of the normal scheme is lower, since the mass of the structure is usually greater (if only because the "tailless" has no horizontal plumage at all, and the "duck" has a positive lift, working as a wing and therefore unloading the wing, which makes it possible to reduce the area of ​ ​ the latter).

- The influence of the flow bevel behind the wing on the horizontal plumage, although not as critical as the influence of the PGO in the "duck," but, nevertheless, you have to reckon with this, the wing and horizontal plumage in height differed. It should also be taken into account the fact that aircraft made according to the "duck" and "tailless" schemes during take-off and landing require large angles of attack, which makes it structurally almost impossible to use swept wings of large and medium elongation, since the use of such wings and large angles of attack is associated with a very high landing gear. Because of this, the duck and tailless schemes use only small extension wings of triangular, Gothic, ogival or sickle shape in plan. Due to the small elongation, such wings have low aerodynamic quality in subsonic flight modes. These considerations determine the feasibility of using duck and tailless schemes on aircraft, in which the main flight mode is supersonic flight.

Comparing all the advantages and disadvantages of three aerodynamic schemes, we come to the conclusion that it is advisable to use a classic aerodynamic scheme on a subsonic passenger aircraft.

8.3. Plumage diagram.

For passenger aircraft, two plumage schemes are competing: normal and T-shaped.

The powerful satellite jet from the propeller adversely affects the usual low horizontal tail unit and can degrade the stability of the aircraft in some flight modes. The high horizontal plumage significantly increases the stability of the aircraft, as it extends beyond the zone of influence of the satellite jet. At the same time, the efficiency of the keel is also increased. A regular keel of equivalent geometry must have an area 10% larger. Since the high horizontal plumage has a larger horizontal arm due to the rearward bevel of the keel, a force on the handle is required to create the necessary longitudinal moment, twice as much as with a conventional horizontal plumage. In addition, the T-tail provides a higher level of comfort for passengers, as it reduces the vibration of the structure from the impact of a satellite jet from the propeller. The weight of the usual and T-shaped plumage is approximately the same.

The use of the T-tail increases the cost of the aircraft by less than 5% due to an increase in the cost of development and production equipment. However, the advantages of this plumage justify its use.

Among other advantages of the T-shaped plumage are:

- Horizontal plumage is an "endplate" for vertical plumage, which increases the effective extension of the keel. This reduces the vertical plumage area and thereby facilitates construction.

- Horizontal plumage is removed from the zone of influence on its design of sound waves, which can create a danger of fatigue failure. The service life of the horizontal plumage increases.

Process

9.2. Aircraft structure division.

The need to divide the aircraft structure into parts, units, panels, compartments and units is dictated by the requirements of production and the need to have structural, operational connectors and joints.

The presence of structural connectors is due to the functional purpose of the allocated substructures .

For example, the structural connectors in the wing are caused by the need to attach mechanization and controls to it.

Technological joints are created taking into account the possibilities of production at this stage of its development and are determined, in particular, by the overall dimensions of the equipment.

Operational connectors and joints are created in order to replace, inspect or regulate various mechanisms and systems during the operation of the aircraft. In some cases, operational connectors are caused by restrictions on the overall size of individual units according to the conditions of their transportation and storage in warehouses.

Structural and operational connectors and joints are indicated during the design of the aircraft.

Rational division of the structure into compartments, panels, assemblies and parts allows you to significantly reduce mass, increase the life and reliability of the structure as a whole, which is achieved by a sharp reduction in the volume of connections while increasing the overall dimensions of semi-finished products and parts.

In all possible cases, the functions of structural, technological and operational connectors, joints and cuts (hatches) must be combined, thereby reducing the number of structural connections.

9.8. Description of the structure of the stabilizer assembly slipway.

The vertical slipway is used to assemble the keel. Keel position - sock up. The slipway consists of:

1) Structural elements (frames): bases, columns, transverse beams, upper and lower beams, inclined beam;

2) Installation elements: upper and lower cups for chopper retainers;

3) Fixing and clamping elements: clamps, mounting plate, choppers.

Choppers and a mounting plate are equipped with hydraulic detectors. Spar position retainers are located on the choppers.

Accuracy of unit surface shape is achieved by means of impression from carbinol-cement mass taken from article surface layout.

Retainers of choppers and retainers of units are fixed in cups with special cement mass.

Lifting and fixing of choppers and mounting plate is carried out by hydraulic detectors. The slipway is equipped with lighting and a compressed air main.

9.10. Process of keel sock manufacturing.

1. Prepare mold surfaces by applying two layers of anti-adhesion material solution in mutually perpendicular directions. Dry each layer for 15 min. Perform heat treatment of lubricant at t = 220 ± 5 ° С for 2 hours.

2. Inspect the autoclave, its instruments and pneumatic system.

3. Prepare honeycomb, prepreg and binder, glue and adhesive film.

4. Lay the prepreg layers as shown.

5. Apply VK51 liquid glue sublayer. Glue flow rate 150200 g/m. Hold for 15 min at temperature 1530 ° С.

6. Lay honeycomb block made as per drawing.

7. Apply VK51 glue on side faces of honeycomb aggregate. Hold for 30 min at temperature 1530 ° С. Glue flow rate is 200 -300 g/m.

8. Remove protective layer of polyethylene film from BK51 adhesive film; apply the film to the honeycomb aggregate; remove the second protective layer.

9. Lay the prepreg layers as shown.

10. Lay the dividing fabric.

11. Lay elastic shell and sealing bundle; assemble vacuum bag with simultaneous installation of vacuum valves and thermocouples.

12. Check the vacuum bag for tightness and place in the autoclave.

13. Create a pressure of 0.075-0.085 MPa in the vacuum system. For 20-30 minutes bring the temperature to 80 ° C and the pressure (0.31 ± 0.05) MPa.

14. Turn off the vacuum pump, connect the bag system to the atmosphere.

15. Continue heating to 110 ° C for 10-15 minutes and provide a molding pressure of 0.6 MPa when the temperature reaches 110 ± 7 ° C.

16. Continue to increase the temperature to 165 ° C for 20-30 minutes, maintain the molded material at a pressure of 0.6 MPa and a temperature of 165 ± 5 ° C for 6 hours. During the entire process, the temperature spread should not go beyond ± 0.5 ° C, and the pressure spread should not exceed 0.025 MPa.

17. Cool the molded material to a temperature of 50 ° C at a rate of 0.5-1 ° C per minute under a pressure of at least 0.25 MPa.

18. Remove the vacuum bag, remove the article from the mold.

19. Perform inspection of the article: visual detection of shells, detachments, foreign inclusions; measurement by templates, gauges, thickness meters of geometric dimensions of the product; check of part material continuity by non-destructive methods; check of density, porosity, content of components, strength indices for compliance with the drawing and material certificate; weighing to an accuracy of 1%.

20. Transfer of the product to subsequent process operations.

9.11. Quality control of production of parts from composite materials.

There are many methods of quality control for the production of parts, assemblies and assemblies from KM. It should be noted that none of the control methods taken separately gives a complete and objective picture of the quality of the CM product. The most complete information on the nature, size, location and other parameters of the defect of the CM article can only be obtained using several complementary control methods. There are methods of destructive testing and non-destructive testing.

With a destructive control method, samples for mechanical testing of the CM according to their layer-by-layer structure (if they are not cut directly from the part) must fully correspond to the structure of the part, and the test method - the type of loading of the part.

Currently, various types of nondestructive CM quality control are used for CM quality control.

Conclusion

From the table above, it can be seen that the designed aircraft has better take-off and landing characteristics than prototype aircraft .

Due to better wing mechanization, the landing speed is lower and the runway length is shorter. This can be explained by the fact that the wing mechanization of the designed aircraft occupies a greater wing span.

The designed aircraft satisfies the conditions set for it. The flight range, landing speed, of the designed aircraft is higher than the requirements set in the task.