DRDO-VRDE - Engine Developments for UAVs

Vehicles Research and Development Establishment, Ahmednagar

ENGINE DEVELOPMENMT FOR

UAV APPLICATIONS.

EXPERIENCES AND CHALLENGES.

Dr C.P.RAMANARAYANAN


UNMANNED AERIAL VEHICLE

UAV is an aerial vehicle capable of sustained flight without need

for a human operator onboard.

Although UAV’s are mostly used in military applications nowadays,

the UAV’s can also perform such scientific, public safety and commercial

tasks as image acquisition of disaster areas, map building, communication

relays, search and rescue, traffic surveillance and so on..

EUROUVS has drawn up a classification of UAV systems:

1. Micro and Mini UAV’s

2. Tactical UAV’s – Close/Short/Medium/Long Range/MALE

3. Strategic UAV’s – HALE

4. Special Task UAV’s – Lethal/Decoys/Stratospheric/Exo-

Stratospheric


UAV ENGINE TECHNOLOGY

• Engines for unmanned aerial vehicle applications that

require 120 hp or less are typically based on spark ignition,

reciprocating internal combustion engines using gasoline or

similar fuels.

• The engine construction includes 2-stroke, 4-stroke

(naturally aspirated and boosted) as well as rotary style

engines.

• New requirements are also dictating the need for the

use of new light weight materials and multi fuel capabilities.

UAV ENGINES - SPECIAL REQUIREMENTS


• High Power to weight ratio.

- Ratio of the order of 2 or more.

• Long Endurance

– Mission duration of 20-50 hours or more.

• Duty Cycle

– Demanding duty cycle with high Altitude take off.

Compactness

– Low Volume

• Simple Maintainability

– Robustness, lower skills ground crews.

• Signature

– Low heat signature/EMC


POWER PACK FOR VARIOUS CLASS OF UAV’s

ENGINES FOR UAV’s

UAV TYPE ENGINE TYPE POWER RANGE (HP)

Micro Electrical 1

Mini Piston (2 X 2) 1 – 20

TAC, CR/LE Rotary (WANKEL) 20 – 90

MALE Piston (4 X 4) 90 – 250

MALE Turbo – Prop 250 – 500

HALE / TCUAV Turbo – Jet / Fan Above 500


VRDE – ASSOCIATION IN UAV ENGINES

VRDE has been tasked for development of mini UAV’s

of less than 150kg class.

It is also involved in the development of small, low

weight, high-specific power output engines.

VRDE has successfully developed a few two stroke

engines and have been tested.

Development of Wankel Rotary Engine was taken up in

collaboration with NAL and ADE and has been realised

successfully with completely indigenous technologies.

Currently development of engines of higher class is in

progress.


VRDE IN UAV ENGINE DEVELOPMENT

The salient features of the engines developed include:

• High power to weight ratio

•Hard chrome plated aluminum cylinders

•Diaphragm type carburetors for all position operation

•Multi-piece crankshaft.


SPECTRUM OF 2-STROKE UAV ENGINES

Four-cylinder 37 hp engine Two-cylinder 21 hp engine

Single-cylinder 11 hp engine TBI system for 2-cylinder engine


VRDE – ASSOCIATION IN UAV & AERIAL ENGINES

0.0

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rust (k

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Thrust Vs RPM: Single, Twin and Four-cyl engine

Four-cylinder

Two-cylinder

Single cylinder

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Fuel Consumption Vs Speed Four Cylinder

Two Cylinder

SingleCylinder


FLIGHT ROTARY ENGINE FOR NISHANT UAV

• The engine is jointly designed and developed by NAL, VRDE and ADE.

• The engine weighs less than 30 Kgs, and has high power to weight ratio in

single rotor category.

• The engine has a power of 55 hp and can also be used for powering smaller

air vehicles.



Power output 55HP@ 8000rpm

Swept Volume 324 CC

Compression Ratio 9.2

Min SFC 250 gm/bhp-hr

Idle Speed 2700-2900 rpm

Ignition System Electronic 28v CD Ignition

Cooling Water cooled Housing &

air cooled rotor

Carburetor Diaphragm Type

Lubrication Total loss type lubrication

Weight (Dry) 26 kg

55 HP ROTARY ENGINE



TESTING OF ROTARY ENGINE

Various testings carried out:

- Thrust cradle testing

- Dynamometer testing

- Running-in testing

- Endurance testing (Based On JAR Cycle/ Cemilac Reco. Cycle) - Mission cycle testing

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rustin

kg

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Thrust Cradle &

Dynamometer testing



INTEGRATION & FLIGHT TRIAL

Integration of Engine on

UAV ‘Nishant’

Flight testing on ‘Nishant’


4-STROKE ENGINE FOR MALE UAV

• VRDE is currently working on horizontally opposed 4-cylinder

4-stroke turbocharged SI engine.

• The engine will develop thrust for the take off weight of about

2000kg.


BROAD SPECIFICATION PORPOSED ENGINE.

TARGET 4-STROKE ENGINE

Type of the engine

4cylinder, 4 stroke horizontally

opposed, spark ignited

reciprocating piston engine with

turbocharger

Take off power 120 ± 3 BHP with turbocharger at sea

level

Maximum continuous power 105 ± 3 BHP with turbocharger at

sea level

Maximum operating altitude 36000 ft

Specific fuel consumption 275 ± 5 g/kWh at max. continuous

throttle

Dry engine weight 75 ± 2 Kg

Max engine speed 6000 RPM

Endurance 36+ hours

Operating temperature -40°C to +55° C

Maximum propeller speeds 2300 to 2500 rpm


WORLD/INDIAN SCENARIO IN MALE UAV ENGINES

• Most of the MALE UAVs are fitted with four-stroke four-cylinder engines

• For 125 HP engine for MALE UAV, a 1500 – 2000cc engine will be

adequate for meeting the requirements

• Four-cylinder Horizontally opposed four-stroke engine configuration

with Turbocharger will serve the purpose of propulsion system for

INDIA’s version of MALE UAV ‘RUSTOM’

ROTAX ENGINES LYCOMING ENGINES LIMBACH

(AUSTRIA) (USA) (GERMANY)


4-STROKE ENGINE FOR MALE UAV - RUSTUM

Critical factors/technologies involved:

• Turbo-charging technology for SI Engine

• Multi Point Fuel Injection (MPFI) for multi-cylinder four-stroke

engine.

• Composite coating technology on aluminium alloy.

• Application of High specific strength material like Maraging

steels and Al alloys.


FUTURE UAV ENGINES

DIESEL UAV ENGINES

Highly Fuel-efficient than present gasoline engines

Strategically suitable for single fuel concept

HYDROGEN OPERATED ENGINES

Suitable for very high altitude operation

Highly complex challenging technology

Very long endurance is possible


DIESEL ENGINES FOR UAV’s

REQUIREMENT OF DIESEL ENGINE FOR UAVs

The vast majority of UAVs are using currently utilizing gasoline fuels

(e.g. Hunter, Shadow, Predator etc.)However, these engines can be

improved to Diesel version due to following:

1. Causes a specific gasoline logistics train since most military vehicle use

diesel fuel.

2. Gasoline vapor is explosive, hence is a hazard to the aircraft and ships

that transport it.

3. Gasoline engines are less efficient than heavy fuel engines thus

providing shorter flight/loiter times.


ADVANTAGES OF DIESEL ENGINES

Reliability

Maintenance

Turbocharge

and supercharge

Fuel economy

Durability

Efficiency


CHALLENGES IN HEAVY FUEL ENGINES

High peak pressure

Produce black soot

Expensive

DIESEL UAV ENGINES DEVELOPERS

GAP DIESEL ENGINE NASA DEVELOPMENT USA

DYNA CAM ENGINE

ECO–MOTORS DIESEL ENGINE GERMANY

AUSTRO ENGINE AE 300 AUSTRAIN

DELTA HAWK DIESEL ENGINE USA

CENTURIONS GERMANY

DIESEL AIR LIMITED UK


THANK YOU

Documents

DRDO-VRDE - Engine Developments for UAVs