Ground Report)

8/3/2019 Ground Report)

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Minor Project-I

On

STUDY AND FABRICATION

OF GROUND SPOILERS

Under the guidance of

Mr.Tonny. k sir

By

D.Prudhvi (R340308013)

K.Murali krishnam raju (R340308018)

M.Pavan kumar (R340308023)

M.Pankaj kumar (R340308028)



CONTENTS: page no:

1) Abstract

2) Introduction

3) Working of ground spoilers

4) Further work

5) Conclusion



Page no: 01

ABSTRACT:

Ground spoilers are lift reducing devices made of solid metals of composite alloys like CFRP

(carbon fibre reinforced fibre).there are onboard and inboard spoilers. Spoilers increase drag and

reduce lift on the wing. If raised on only one wing, they aid roll control, causing that wing to drop. If

the spoilers raise symmetrically in flight, the aircraft can either be slowed in level flight or can

descend rapidly without an increase in airspeed. When the spoilers rise on the ground at high speeds,

they destroy the wing's lift, which puts more of the aircraft's weight on the wheels.

The flight spoilers are available both in flight and on the ground. However, the ground spoilers can

only be raised when the weight of the aircraft is on the landing gear, usually activated by a sensor.

When the spoilers deploy on the ground, they decrease lift and make the brakes more effective. In

flight, a ground-sensing switch on the landing gear prevents deployment of the ground spoilers.

Spoilers are plates on the top surface of a wing, which can be extended upward into the airflow and

spoil it. Spoilers are used by gliders to control their rate of descent and thus achieve a controlled

landing at a desired spot. These are the ground spoilers as shown in the figure…



Page no: 02

GROUND SPOILERS:

A spoiler (sometimes called a lift dumper) is a device intended to reduce lift in an aircraft. Spoilers

are plates on the top surface of a wing which can be extended upward into the airflow and spoil it.

The spoiler creates a carefully controlled stall over the portion of the wing behind it, greatly reducing

the lift of that wing section. Spoilers differ from airbrakes in that airbrakes are designed to increase

drag while making little change to lift, while spoilers greatly reduce lift while making only a

moderate increase in drag. When the spoilers rise on the ground at high speeds, they destroy the

wing's lift, which puts more of the aircraft's weight on the wheels. , the ground spoilers can only be

raised when the weight of the aircraft is on the landing gear. When the spoilers deploy on the ground,

they decrease lift and make the brakes more effective. In flight, a ground-sensing switch on the

landing gear prevents deployment of the ground spoilers. Conventionally an array of such spoilers is

provided for failsafe purposes. Spoilers are made from solid material such as metal or composite

alloys. The edge of spoilers includes solid rubber seals which prevent leakage of airflow between

them in either deployed or retracted positions.

WORKING OF GROUND SPOILERS:

http://www.worldlingo.com/ma/enwiki/en/Stall_%28flight%29

http://www.worldlingo.com/ma/enwiki/en/Air_brake_%28aircraft%29

http://www.worldlingo.com/ma/enwiki/en/Air_brake_%28aircraft%29

http://www.worldlingo.com/ma/enwiki/en/Stall_%28flight%29



In some of the aircrafts, there are seven spoiler panels on each wing. The two inboard panels

are ground spoilers and can be extended only on the ground through the action of the speed

brake lever. They are

Page no: 03

operated by hydraulic system. With the left main gear strut compressed, this linkage opens a

hydraulic valve allowing pressure to go to the ground spoiler actuators when the speed brake

lever is moved aft. Since these panels are used only on the ground to spoil lift after landing,

they go to the full up position when actuated. There are no intermediate positions for the

ground spoilers.

The remaining five panels on each wing are flight spoilers. The three inboard flight spoilers are

powered by another hydraulic system. The two outboard flight spoilers are powered by

hydraulic system which was used for ground spoiler. Individual actuators operate the spoiler

panels.

The flight spoilers, which operate in conjunction with the ailerons, provide the major portion of

roll control by spoiling lift on the low wing. After a small movement of the control wheel,

spoiler action is programmed in proportion to the further movement of the control wheel. A

full roll control input would cause the flight spoilers of the low wing to rise to a maximum of

approximately 25 degrees. The spoiler panels of the high wing would remain down.

In some jet there are Four spoilers on each wing. As shown in Figure 2 they are numbered from

inboard to outboard. The one closest to the fuselage is named spoiler #1, the following spoiler in

spanwise direction is spoiler #2 and so on. Because the spoilers #2, #3 and #4 are located on the

outer wing, they are named



Page no: 04



Page:05

Outboard spoilers. This group of spoilers is also named as multi function spoiler, because they

support several tasks. Spoiler #1 on the other hand, located on the Spoiler arrangement along the

wing inboard wing is the inboard spoiler. Its a origin ground spoiler. The three outboard spoilers are

designed in a similar way. The surface area is shaped like a trapezoid and the actuator system is

linked centred in spanwise direction. Once again spoiler #1 differs. Its surface area is rectangular andthe actuator is linked to a bearing hinge position, but not at the centre.



Figure 3 shows spoiler #2 and its hinge fittings. The letter H means hinge. The first number in the

index describes the spoiler the hinge belongs to, the second one the position of the hinge at the

spoiler. The numbers are counted span wise, for both numbers. E.g. H22

means: Hinge fitting of

spoiler #2, the second hinge from inboard to outboard (cf. Figure 3) the spoilers do exactly what their

name implies. They spoil the aerodynamic lift of an airplane. The outboard spoilers of the 728 fulfil

different functions during a flight. There is the support of a roll manoeuvre, the reduction of thespeed on cruise and the lift dumping immediately after touchdown, to increase the deceleration

during the role out. Spoiler #1 is defined as ground spoiler. It is only used after touchdown. Then all

spoilers deflect to 45° (full deflection) to spoil the aerodynamic lift (lift dumping). Thus lift dumping

is done by all four spoilers together. A roll maneuver will be supported by deflection of the outboard

spoilers (#2 - #4) to a maximum of 30°. An important function in flight is the so called speed brake.

Spoiler #2 and #3 fulfill this task by deflections between 0° and 30°. The operating conditions of

spoilers are different. They have to withstand corrosion caused by great differences in temperatures,

sun radiation and humidity. In each flight segment the way they are loaded is varying. The weight of

fuel and the pay load deter-mines the different loading conditions. Therefore appropriate loads and

flight conditions are important for a fatigue investigation. The spoilers are made of CFRP.

Page no:06



A section view shows the setup of the spoilers (cf. Figure 4). The skin is made of laminated CFRP.

The thickness differs as shown Figure 4 corresponding to the local strains. The spoiler is filled with

honeycombs. The hinges are machined of aluminium which are riveted to the front spar of the

spoiler.

Page no: 07



Further

work:

Conclusion:





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