HYDROSTATIC LOCK

Hydrolock (a shorthand notation for hydrostatic lock) is an abnormal condition of any device which is designed to compress a gas by mechanically restraining it; most commonly the reciprocating internal combustion engine, the case this article refers to unless otherwise noted. Hydrolock occurs when a volume of liquid greater than the volume of the cylinder at its minimum (end of the piston's stroke) enters the cylinder. Since most common liquids are incompressible the piston cannot complete its travel; either the engine must stop rotating or a mechanical failure must occur.

 

Bend Connecting Rod due to Hydrolock

 

Symptoms and damage :-

If an engine hydrolocks while at speed, a mechanical failure is likely. Common damage modes include bent or broken connecting rods, a fractured head, a fractured block, crankcase damage, damaged bearings, or any combination of these. Forces absorbed by other interconnected components may cause additional damage. Physical damage to metal parts can manifest as a "crashing" or "screeching" sound and usually requires replacement of the engine or a substantial rebuild of its major components.

If an internal combustion engine hydrolocks while idling or under low power conditions, the engine may stop suddenly with no immediate damage. In this case the engine can often be purged by unscrewing the spark plugs or injectors and spinning the engine to expel the liquid from the combustion chambers and then restarted. Depending on how the liquid was introduced to the engine, it possibly can be restarted and dried out with normal combustion heat, or it may require more work, such as flushing out corrupted operating fluids and replacing damaged gaskets.

If a cylinder fills with liquid while the engine is turned off, the engine will refuse to turn when a starting cycle is attempted. Since the starter mechanism's torque is normally much lower than the engine's operating torque and momentum this will usually not damage the engine but may burn out the starter. The engine can be drained as above and restarted. If a corrosive substance such as water has been in the engine long enough to cause rusting, more extensive repairs will be required.

Amounts of water significant enough to cause hydrolock tend to upset the air/fuel mixture in gasoline engines. If water is introduced slowly enough, this effect can cut power and speed in an engine to a point that when hydrolock actually occurs it does not cause catastrophic engine damage.

 

Automotive

Hydrolock most commonly occurs in automobiles when driving through floods, either where the water is above the level of the air intake or the vehicle's speed is excessive, creating a tall bow wave. A vehicle fitted with a cold air intake mounted low on the vehicle will be especially vulnerable to hydrolocking when being driven through standing water or heavy precipitation. Engine coolant entering the cylinders through various means (such as a blown head gasket) is another common cause. Excessive fuel entering (flooding) one or more cylinders in liquid form due to or other abnormal operating conditions can also cause hydrolock.

 

DRDO - NISHANT

 The DRDO Nishant is an Unmanned Aerial Vehicle (UAV) developed by India's ADE (Aeronautical Development Establishment) a branch of DRDO for the Indian Armed Forces. The Nishant UAV is primarily tasked with intelligence gathering over enemy territory and also for reconnaissance, training, surveillance, target designation, artillery fire correction, damage assessment, ELINT and SIGINT. The UAV has an endurance of 4 h 30 min. Nishant has completed development phase and user trials. 

DRDO - NISHANT

 

 

The 380 kg (840 lb) Nishant UAV requires rail-launching from a hydro-pneumatic launcher and recovered by a Parachute System. Launches at a velocity of 45 m/s are carried out in 0.6 second with 100 kW power and subsequent launches can be carried out in intervals of 20 minutes. The Mobile Hydro-Pneumatic Launcher (MHPL) system mounted on a Tatra truck weighs 14,000 kg (31,000 lb) and boasts of a life cycle of 1000 launches before requiring overhaul. Nishant is one of the few UAVs in the world in its weight-class capable of being catapult-launched and recovered by using parachute, thus eliminating the need for a runway as in case of conventional take-off and landing with wheels.

On 3rd Feb 2011 Nishant UAV has successfully completed confirmatory trials conducted by the Indian Army at Pokhran ,Rajasthan.

 

Features

• Day/night capability training vehicle

• Battlefield reconnaissance & surveillance,

• Target tracking and localization

• Artillery fire correction

• All terrain mobility

• Target designation (using integral laser target designator)

• Endurance: 4 h 30 min

Ground support systems

• Mobile hydropneumatic launcher (MHPL)

• Ground control station (GCS)

• Antenna vehicle/Ground Data Terminal(GDT)

• Avionics preparation vehicle(APV)

• Mechanical maintenance vehicle

• UAV transportation vehicle

• Power supply vehicle

General characteristics

• Crew: None

• Payload: 45 kg

• Length: 4.63 m (15.2 ft)

• Wingspan: 6.57 m (21.6 ft)

• Empty weight: 380 kg (840 lb)

• Powerplant: 1 × RE-2-21-P or RE-4-37-P

Performance:

• Maximum speed: 185 km/h

• Cruise speed: 125 km/h to 150 km/h

• Range: 160 km (100 mi)

• Service ceiling: 3,600 m (up to 11,800 ft)

Launch & recovery

• Launch: Mobile hydropneumatic launcher (MHPL) system

• Recovery: Parachute + landing bags

DRDO DRONES- AURA(Autonomous Unmanned Research Aircraft)

AURA

The AURA will be a stealth UCAV, capable of releasing missiles, bombs and precision-guided munitions. The programme is in its project definition stage. The design is in line with what former DRDO chief controller for Aeronautics said in 2007, that India's combat drone would be a stealthy flying-wing concept aircraft with internal weapons and a turbofan engine.The UCAV's design is similar to Northrop Grumman's B-2 Spirit.The ADA describes the AURA as a "self-defending high-speed reconnaissance UAV with weapon firing capability". The first images released as part of a presentation shows the UAV as having a stealth design.The AURA will cruise at medium altitude and will be capable of carrying two or more guided strike weapons with on-board sensors for targeting and weapon guidance. The flight control system and data link packages of Aura (unmanned combat aerial vehicle) will be designed and developed jointly by ADA and Defense Electronic Application Laboratory. DRDO's Chief Controller, R&D (aeronautics), Dr Prahlada said, "Capable of flying at altitudes of 30,000 feet and weighing less than 15 tonnes, the UCAVs will have rail-launching for the missiles, bombs and PGMs (precision-guided munitions) they will carry.". The DRDO is going to use a Kaveri engine to power this unmanned vehicle. The AURA will be approximtely 15 tonnes aircraft with a range of 300+ km.

AURA (Autonomous Unmanned Research Aircraft)
Role	Unmanned Stealth Bomber
Manufacturer	DRDO
Designer	DRDO
First flight	2015
Introduction	2019-2020
Status	Under Development
Primary user	Indian Air Force Indian Navy

STIRLING ENGINE

A Stirling engine is a heat engine operating by cyclic compression and expansion of air or other gas, the working fluid, at different temperature levels such that there is a net conversion of heat energy to mechanical work.Or more specifically, a closed-cycle regenerative heat engine with a permanently gaseous working fluid, where closed-cycle is defined as a thermodynamic system in which the working fluid is permanently contained within the system, and regenerative describes the use of a specific type of internal heat exchanger and thermal store, known as the regenerator. It is the inclusion of a regenerator that differentiates the Stirling engine from other closed cycle hot air engines. Originally conceived in 1816 as an industrial prime mover to rival the steam engine, its practical use was largely confined to low-power domestic applications for over a century. The Stirling engine is noted for its high efficiency compared to steam engines,quiet operation, and the ease with which it can use almost any heat source. This compatibility with alternative and renewable energy sources has become increasingly significant as the price of conventional fuels rises, and also in light of concerns such as peak oil and climate change. This engine is currently exciting interest as the core component of micro combined heat and power (CHP) units, in which it is more efficient and safer than a comparable steam engine.

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TEJAS PRODUCTION BY HAL

Hindustan Aeronautics Ltd aims to deliver 16 Tejas a year from its new production line>>

If the indigenous Tejas Light Combat Aircraft (LCA) has taken decades for completion, it is now in a record-breaking sprint to the finish line. The Tejas has flown an unprecedented 450 test flights this year towards a splashy ceremony in Bangalore scheduled for December 20, where Defence Minister A K Antony will preside over its induction into the Indian Air Force (IAF).
That landmark event will be the award of the Tejas’ Initial Operational Certificate (IOC), which will allow the country’s first indigenous modern fighter to be flown by regular pilots of the Indian Air Force (IAF). The first Tejas squadron (18-20 fighters) will be based at Sulur, near Coimbatore.
So far, only highly qualified test pilots of the National Flight Testing Centre (NFTC) in Bangalore have flown the Tejas. In the 2,400 test flights since it took to the air in 2001, the NFTC has incrementally flown the Tejas higher, faster and carried out increasingly difficult manoeuvres and weapon firings to test it meets the IAF’s requirements.
On Saturday, Group Captain Suneet Verma, a veteran NFTC test pilot, fired an air-to-air missile from the Tejas at an airborne target off the Goa coast, striking the target and taking the Tejas a step closer towards IOC.
While awarding the IOC, Antony will ceremonially hand over to the IAF boss, Air Chief Marshal N A K Browne, the fighter’s “Release to Service Document (RSD)”, which specifies the capabilities the Tejas has already demonstrated during flight testing.
This includes aerodynamic capabilities like speed, acceleration, climb rate and angle of attack; and also the basic weapons operations already tested on the Tejas, and the fighter’s proven radar and sensor capabilities. The Tejas flight-testing programme has been a prolonged and painstaking exercise, since this is India’s first modern fighter. The Aeronautical Development Agency (ADA) – a special purpose vehicle of the Defence R&D Organisation (DRDO), set up to manage the Tejas programme – worried that a crash during flight-testing might be a fatal blow to the project itself, and so has handled flight testing cautiously, taking twice the time that experienced countries do.
Once the IOC is awarded, Hindustan Aeronautics Ltd (HAL) will build the IAF’s first 20 Tejas fighters on a brand new production line in Bangalore. HAL has told Business Standard that it aims to roll out the first two fighters by March 2014, deliver eight fighters by end-2014, and then enhance the production line’s capability to 16 fighters a year.
So far, the IAF has committed to just 40 Tejas fighters. Of these, 20 will be built to IOC standards, and the next 20 ordered when Final Operation Clearance (FOC) is obtained. The defence minister has ordered the DRDO to ensure the FOC is not delayed beyond end-2014.
Avinash Chander, the DRDO chief, tells Business Standard the FOC will involve firing a range of different weapons, including missiles and bombs, and testing the fighter for mid-air refuelling.
“With the IAF now enthused about the Tejas, and participating actively in the project, we will surely obtain FOC next year. We could not have completed over 450 test flights this year without close cooperation between the IAF, ADA and HAL,” says Chander.
After obtaining FOC for the Tejas, ADA will start work on the Tejas Mark II. The key change is replacing the General Electric F-404 engine that powers the Mark I with the larger, more powerful GE F-414 engine. This will involve re-engineering the Mark I to fit in the bulkier F-414, a technological challenge for ADA.
ADA has also briefed Business Standard that the Tejas Mark II would have more fuel capacity for added range; a retractable mid-air refuelling system; a DRDO-built Airborne Electronically Scanned Array radar; world beating air-to-air missiles; an on-board oxygen-generating system, and a state-of-the-art Electronic Warfare suite to confuse enemy radars and sensors. “Eventually, the IAF is very likely to have at least 200 Tejas fighters in its fleet,” says Chander.

America's Next Bomber

America’s next bomber could cost $810 million apiece>>

The U.S. Air Force’s new long-range bomber may cost as much as $81 billion for the 100 planes planned, 47 percent more than the $55 billion sticker price the service has listed.
The Air Force based its estimate of $550 million per plane on the value of the dollar in 2010, and it represents only the production costs for an aircraft that won’t be deployed for at least 10 years. Including research and development, the bomber would cost as much as $810 million apiece in this year’s dollars, according to calculations by three defense analysts.
The cost of the new bomber will draw close scrutiny in an era of declining defense budgets, as the Pentagon faces $500 billion in reductions over nine years under the budget process called sequestration. The Air Force’s track record also is being questioned after soaring costs for the aging B-2 stealth bomber the new plane would replace and the F-35 fighter jet, the most expensive U.S. weapons system, that’s now being built.
“The Air Force has zero credibility on start-of-program cost estimates unless and until it ponies up real details about the bomber and its acquisition plan,” Winslow Wheeler, a former Government Accountability Office defense analyst now with the Project on Government Oversight in Washington, said in an e-mail. “It is a fool’s errand, or worse, to pretend the cost stated now is anything but a bait-and-switch buy-in gambit.”
B-2, F-35
The B-2 was planned as 132 planes for about $571 million each in 1991 dollars before the first Bush administration cut the fleet to 20 planes in the early 1990s. That resulted in a price of about $2.2 billion per bomber, a fourfold increase, in a program that remained highly classified during its development.
The F-35 program has a current price tag of $391.2 billion for 2,443 aircraft, a 68 percent increase from the projection in 2001, as measured in current dollars, for 409 fewer planes than originally planned.
Whatever its ultimate cost, the new bomber would mean billions for the defense contractor chosen to build it. Lockheed Martin Corp. (LMT:US) of Bethesda, Maryland, and Chicago-based Boeing Co. (BA:US), the No. 1 and No. 2 U.S. defense contractors, said in October that they’ll bid for the project as a team. They may end up competing against Northrop Grumman Corp. (NOC:US) of Falls Church, Virginia, the prime contractor for the B-2, which hasn’t yet announced an intention to bid.
The Air Force has requested $379 million in funding for development this year, increasing to more than $1 billion in fiscal 2015 and $2.8 billion in fiscal 2018, according to data released by the service.
Through 2023
The Air Force hasn’t provided its rationale for the increased spending. The Congressional Budget Office said the Air Force plans to request $32.1 billion through 2023.
The $550 million per plane projection for the new bomber is “the only cost estimate approved for public release at this time,” Air Force spokesman Ed Gulick said in a statement.
Gulick said the estimate is a “target that helps balance capabilities and cost” and is being used in “rigidly containing the design” of the bomber.
The more complete “program acquisition unit cost” will be derived later by adding research and development, as well as estimating “inflation up to the year you purchase aircraft,” Gulick said.
The Air Force’s cost estimate “seems rather ambitious,” said Todd Harrison, a defense budget analyst with the Center for Strategic and Budgetary Assessments, a Washington-based policy group. He calculated a price of $810 million a plane in fiscal 2014 dollars, or $81 billion for 100, based on $20 billion in projected research and development costs.
Historical Increases
“Aircraft programs, and stealth aircraft in particular, have gone far over their initial cost estimates,” Harrison said. “If you factor in historical cost growth, the total program cost could easily top $100 billion.”
Russell Rumbaugh, a defense analyst with the Stimson Center, also a policy group in Washington, said his comparable estimate is $682 million per plane. Kevin Brancato, a defense analyst with Bloomberg Government, projected $784 million per plane in this year’s dollars.
“The incentives in the budget system almost force the services to low-ball their cost estimates,” said Gordon Adams, a professor at American University in Washington who oversaw the national security budget for the White House under President Bill Clinton. “Otherwise they do not get the program in the budget. It grows later.”
The Air Force now operates a fleet of 159 long-range bombers, including 63 swing-wing B-1Bs developed in the 1980s by Rockwell International, which is now part of Boeing, and the 20 B-2s from the 1990s.
Aging B-2s
The new bomber is needed because the “B-2 is an older airplane that’s getting expensive” to maintain and “it’s not as stealthy as we’re now capable of making aircraft,” Deputy Defense Secretary Ashton Carter said in an interview before he left office Dec. 4.
As the Air Force anticipates its needs 10 or 20 years from now, “expecting those aircraft to perform reliably at such advanced ages may prove to be overly optimistic,” said Mark Gunzinger, an airpower analyst with the Center for Strategic and Budgetary Assessments.
The Air Force is still flying 76 B-52 bombers from the H series that entered service in May 1961. They remain capable of launching conventional and nuclear bombs and cruise missiles.
Top Projects
The Air Force has identified the new long-range bomber as one of its top three weapons projects, along with the F-35 from Lockheed and the KC-46 aerial refueling tanker made by Boeing.
Defense Secretary Chuck Hagel has said the bomber will support the U.S. strategy of rebalancing toward Asia. Pentagon officials have said they’ll do as much as they can to shelter such priority weapons systems from the automatic budget cuts.
An Air Force summary of the bomber describes a stealth aircraft able to deliver both nuclear and conventional weapons. While the “baseline aircraft” would be piloted, the bomber would be designed to “enable future unmanned capability,” according to the service.
Beyond that, the Air Force, which has said the bomber would incorporate “proven technologies,” has said little about its classified plans for the new plane.
“It would be a mistake to view this aircraft as simply another bomber,” said Retired Lieutenant General David Deptula, the Air Force’s former chief of intelligence, surveillance and reconnaissance.
‘Cloaked in Secrecy’
It may take off on a bombing run, using intelligence and surveillance sensors provided from other platforms and on-board jammers to degrade ground radar, he said in an e-mail. The bomber crew also could use its radar and sensors to direct land-and sea-based strikes, as well as collect intelligence on the return flight, according to Deptula, who helped plan the air campaign in the 1991 Gulf War.
“The operational characteristics are going to be cloaked in secrecy for a while, and I think that makes perfect sense,” Air Force Chief of Staff General Mark Welsh told reporters in November.
Welsh said capabilities would be carefully weighed against the $550 million-a-plane target.
“What we don’t want to do is try to reach into some level of technology that’s impractical.” That’s when “prices start to get out of control and your requirements start to drift,” Welsh said. “We are not going to go there.”
Adams cited the B-2’s cost escalation, as well as plans for a medium-range bomber that Defense Secretary Robert Gates canceled as too costly in 2009. Gates supports the new bomber.
“How many times are we going to go down this overpriced bomber road?” said Adams said. “It’s like Lucy with the football. We never get to kick an affordable aircraft through the goalpost.”