Engine ComparisonHAL Tejas JF 17 Thunder

General Electric F404 Klimov RD-93

Turbofan

• Some of the incoming air passes through the fan and continues on into the core compressor and then the burner

• The hot exhaust passes through the core and fan turbines and then out the nozzle, as in a basic turbojet. The rest of the incoming air passes through the fan and bypasses,

Design

• turbofan engine is the most modern variation of the basic gas turbine engine.

• the core engine is surrounded by a fan in the front and an additional turbine at the rear  and are connected to an additional shaft.

• The fan shaft passes through the core shaft

• This type of arrangement is called a two spool engine (one "spool" for the fan, one "spool" for the core.)

Working

Core Compressors and Turbine

Core Compressors and Turbine with

fan and fan turbine

Afterburner

•Most modern fighter aircraft employ an afterburner on either a low bypass turbofan or a turbojet.•The afterburner is used to put back some energy by injecting fuel directly into the hot exhaust.• When the afterburner is turned on, additional fuel is injected through the hoops and into the hot exhaust stream of the turbojet.

Engine ComparisonItems JF 17 Thunder HAL Tejas

Top Speed Mach 1.6 Mach 1.6

Total Dry Thrust 11510 lbf 12100 lbf

Total thrust with After Burner

19000 lbf 20200 lbf

Maximum Loaded Weight

12500 Kg 13200 Kg

Thrust to Weight Ratio 1.09 1.07

Wing Design ComparisonHAL Tejas JF 17 Thunder

Delta Wings Swept Wings

Delta wings:- Eg Hal Tejas, MiG-21, Avro Vulcan etc

• The delta wing is a wing shaped in the form of a triangle. It is named for its similarity in shape to the Greek uppercase letter delta(Δ)

• This wing was pioneered by Alexander Lippisch in Germany after WW1• It is great for low-speed handling and high-speed manoeuvrability and

allow a greater centre of gravity range.• SAAB of Sweden developed a Close-coupled canard delta configuration

which has become common in supersonic fighter aircraft . It modifies the airflow over the wing, most notably when flying at high angles of attack.

Delta Wings Advantage:•Can fly at high angles of attack- which that's why fighter jets use a delta wing to fly at very high angles of attack.

•Provides good amount of drag for landing - On landing you need drag and that's the purpose of flaps is to increase drag and lift and you can make the flaps a little bit smaller.

•A delta wing is naturally stable in pitch, therefore it does not require a separate tail surface

How swept angle is measured?

The characteristic "sweep angle" is normally measured by drawing a line from root to tip, 25% of the way back from the leading edge, and comparing that to the perpendicular to the longitudinal axis of the aircraft

Swept wings:MiG-15, F-86 Sabre, A-10 etc • A swept wing is a wing which angles either backward or occasionally

forward from its root rather than in a straight sideways direction.• Earliest swept wing designs was used by Jose Weiss to construct a swept-

wing tail-less glider in 1908 in England.• Swept back wings is used in airplane to solve the problem of turbulence

and drag at high speed.• Swept forward wing is used to make the flight of slow moving aircraft more

stable• Straight wings are also adopted for small planes with short takeoff and

landing (STOL), low speed, and for less fuel consumption• The fighter jet F-111 has variable sweep wings. They can move forward and

backward at 16 degree and 70 degree respectively. Here the combination was achieved to allow the fighter to fly more stably from low speed to supersonic speed.

Swept forward wingThere have only been a few aircraft built with forward-swept wings. Most notably was the X-29

Advantages:•The wing spar carry-through can be placed aft of the cabin, so cabin height can be increased. This is important for business-jet sized aircraft.

•The boundary layer at the tips is not affected by the inner wing. Controllability can be maintained up to stall.

•Aeroelastic effects will increase control commands. This makes for a very responsive airframe

Disadvantage

• Stall will happen inboard first, which will result in a pitch-up. If the tail cannot compensate, the stall is unrecoverable.

• The aeroelastic effects will encourage flutter. If flutter speed is found to be too low, the wing needs to be made stiffer, resulting in a weight increase.

Swept back wing

Advantage: •Wing sweep also helps in longitudinal stability by stretching out the wing lengthwise. This is important for flying wings which lack a separate tail surface

•  A swept back wing is more suited for aircraft operating at higher speeds, while the conventional wing that extends closer to a right angle from the fuselage is more suited for providing better lift at lower speeds.

Disadvantage: They stall tip-first, which means you can lose use of your ailerons at low speed

It is common and is found on every airplanes and fighter planes

Tejas -Indian Light Combat Aircraft (LCA), is the smallest and lightest Multi-Role Supersonic Fighter Aircraft of its class. This single engine, Compound-Delta-Wing, Tailless Aircraft is designed and developed by ADA with HAL as the principal partner along with DRDO, CSIR, BEL, DGAQA and IAF to meet diverse needs of theIndian Air Force (IAF).

HAL TEJAS

JF-17 THUNDER • JF-17 Thunder is a light weight aircraft developed jointly

by Chengdu industries (China) and Pakistan Aeronautical Complex.

• Concept was developed in 2003 in China.As Pakistan was looking for an affordable multirole aircraft, China offered Pakistan to invest in this project.

• Its designation “JF-17” is “Joint Fighter-17” in Pakistan and “FC-1” as “Fighter China-1 Fierce Dragon” in China.

• It is light weight multirole, single- engine combat aircraft .It is a 4th generation fighter aircraft.

Design & Features• The software of JF-17 thunder is hinge on Civilian c++ which controls

the avionics of aircraft.• Motorolla 88000 microprocessor powers the avionics of aircraft.• JF-17 is powered by a turbofan engine imported directly from

Russia.• Aircraft glass cockpit has a Electronic Flight Instrument system (EFIS)

and a wide holographic display which has the field view of 25 degrees.

JF-17 Thunder Engine Type• JF-17 thunder is powered by turbofan engine.• Engine produces the thrust of 19000lbs which takes the aircraft to

the speed of 1,218miles per hour.• Pakistan import turbofan engine straightly from Russia for JF-17

Thunder.• Turbofan engine are quitter due to their greater mass flow and

lower total exhaust speed. They are more efficient for range of subsonic speed and for cooler exhaust system.

WEAPONS

The final comparison

• Role: Deep penetration strike aircraft.

• 4th generation aircraft.• Maximum Range: 3000 KM• Nuclear Capability: Yes, can carry

nuclear warheads.• Can fly in all weather conditions.

•Role: Air defense interceptor.3rd generation aircraft•Maximum Range: 3482 KM•Nuclear Capability: No, not able to carry nuclear warheads.•Not tested in all weather conditions.

Tejas JF-17

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