Newbie Corner & Military Miscellaneous

[Raman]

Prop-strike on Saras is a non-issue. Looking at the profile of Saras, you'll note that the prop is well within the silhouette. The dorsal fins not only provide lateral and directional stability (especially at high AoA), but also shield the props from ground strike, which is very clever design IMHO.

[negi]

btw - why do motor boats and ships have pusher props?

Jmt

In case of boats the aft section is most stable when it comes to the water level and the pitching at various speeds and sea conditions (with increase in speed the fore section rises) , hence it is obvious choice for installation of rudder and the prop.

And even assuming water body to be placid and the ship/boat being huge enough to offer a stable platform ; the shape of the hull demands that the props be installed in the aft for effective propulsion ; i.e. if you visualize the frontal cross section of a ship/boat it resembles a wedge and from top this wedge tapers both at the front as well as at the back installing props at the front would mean the propwash will hit the ship's hull (unless the shaft be lowered further ) , hence the aft section imo is a suitable place for the prop installation.

[chetak]

[quote="Raman"]Prop-strike on Saras is a non-issue. Looking at the profile of Saras, you'll note that the prop is well within the silhouette. The dorsal fins not only provide lateral and directional stability (especially at high AoA), but also shield the props from ground strike, which is very clever design IMHO.


Afterbody strakes were also been fitted on the Dornier 228 when it had stability issues after fitment of the radome.

The strakes on the Saras have been fitted only for stability issues and are a very common solution. They may have the additional function of prevention of a prop strike.

[shiv]

post deleted

[Drevin]

deleted.

[Drevin]

deleted.

[shiv]

deleted by self

[Drevin]

deleted.

[Gaur]

Drevin
First you make profoundly stupid comments. Then, instead of apologizing, you badmouth people who get peeved by your comments. I hope you are a 12 year old retarded child. Otherwise there is no excuse for your pigheadedness.

[Drevin]

deleted.

[shiv]

Drop it drevin. You have already apologised about the professionalism" comment. Please don't commit forum suicide. Just leave it be - I don't get drawn into flamewars unless I feel very strongly for this forum which I have helped to nurture since 1997.

I see Indians as sometimes being needlessly negative and critical in the absence of insight. The Air Force was like that about its accident rate and about the LCA. The Army has been that way about Arjun. Public pressure successfully forced the Air Force to look into its own accident rate.

[Drevin]

deleted.

[Gaur]

Parijat dont get into this .... let him vent out fully ...... Than he'll understand .

Understand what exactly? That you are a blockhead? I think that we have all got that. Please take your frustration elsewhere. This is a forum for intelligent discussion and is therefore clearly above your mental level. If someone ( included someone as experienced as shiv ) makes a mistake here, he's not afraid to apologize. But that's clearly not the case with you. The problem here is not that you made a mistake. The problem is that instead of admitting your mistake like a mature person, you are resorting to name calling like a stubborn and stupid kid.

[Drevin]

Parijat there is no place for you in this war of words. Desist. Go and post in the other forums. Plz.

[shiv]

Drevin - you were so gracious earlier in this thread I was touched - but I think you were egged on by other forum comments to go ballistic, and now go off in a huff. Do what you think is right - but remember that if you were provoked into being foolish after being extremely gracious - you will be a greater loss than the now silent people who egged you on to your comments posted after a genuinely nice message that should put me to shame more than any nasty comments.

I am not referring to you - but there is a forum lesson here for trolls. Trolls often get away because there is nobody who is a big enough idiot to out-troll them I have specialised in out-trolling trolls and tend to be vicious. Sorry to have hurt you.

If you want - stay on and let us edit out this exchange of words - all of it. That is my promise to you.

[Drevin]

Fine, I will remove all personal references and all places where the word 'professional' has been used.

[Gaur]

Parijat there is no place for you in this war of words. Desist. Go and post in the other forums. Plz.

I apologize. Not because I think you are right but because I should not have indulged in name calling myself. But perhaps you are right that this is b/n Shiv Saar and you. I will not interfere from now.

[shiv]

Shiv sir, please calm down .. I want to clarify.

I didnt mean to show negative light on saras's design of clean main wing. I think you went off-track there. You also went offtrack with some of the other stuff but thats ok since you have a good sense of humor.

However rakallji got it right, I have not been a fan of the choice of engineIts just that in such a modern age of flight the pusher prop seems a bit outdated.

As pointed out, I understand that proper technical reasons went into the final choice such as flight regime, short haul etc ... I guess I have this image of a dassault falcon jet and its reliability in mind. In that context it looks more professional. Thats all. Note: Falcon has a clean wing too.

My final assessment:
My post has been taken out of context and dissected also out of context which is not fair. Besides I'm not a newbie to BR so plz stop the brain washing with me ... After 2.5 years in BR i wouldn't suddenly start flaming right .... Hope you guys can cut me some slack.

jmt

That is an extremely gracious post and drevin and I have agred to edit out comments that caused each other distress.

Please let the matter drop here.

[Drevin]

Ok. Thanks. I have removed all the posts that I could delete. Howver the original post containing the word professional in the LCA News forum can't be deleted .... I'll try again but not getting the edit option.

[munda]

I believe that the Indian Government should fund a study to ascertain the effect on Inidia's nominal and real GDP if It did not had to fight all the wars in last 60 years with rouge pakis. This type of study was conducted by Israel and results are duly noted in wikipedia in the topic "Arab Israeli Conflict". I believe India should also do such mathematics if it has not already done so. If they have already done this, then can somebody post that information.

[disha]

The twin pusher configuration is unusual and complicated. Clean wings are not the be all and end all of aircraft design, there are many tradeoffs. No particular benefit accrues in operating Indian conditions, where presumably the bulk of the Saras market exists, for a pusher design. Such a choice is debatable, but a bit late in the day

Check out Embraer Executive Jet series - phenom/legacy series. All executive Jets. It is a pusher configuration, tail mounted twin engines, clean wings. Why? [Answers Below] Also check out MD 80 http://upload.wikimedia.org/wikipedia/c ... hn.arp.jpg. Another example of a pusher configuration : http://upload.wikimedia.org/wikipedia/c ... an_717.jpg. Also check out Bombardier Global series. Another pusher configuration.

The rear mounting of the engines in the Saras necessitated the wings to be mounted more aft than usual due to cg issues. The absence of some sort of canard horizontal surface on the Saras like those on the other pushers is noteworthy. This is a non judgmental statement.

Tail mounting of engines on M80 and other Embraer jet jets necessitates the wings to be mounted more aft than usual due to cg issues. The absence of some sort of canard horizontal surface on M80 and other Embraer jets which are Saras like pushers is noteworthy. Again this is a non-judgemental statement.

Also Avanti P180 http://en.wikipedia.org/wiki/File:Aeron ... Avanti.jpg cannot be compared to Saras. Other than aft-mounted turboprops, there is no other similiarity.

One of the main reason to aft mount the engines is to reduce the cabin noise. When the primary purpose of the aircraft is to ferry the hoity-toity bureaucrats, it makes sense for their chai-biskoot to be had in peace. Hoi polloi can sit near an emergency door admiring the inner working of the engines on non-pusher configurations like Airbus 300 or B-737.

Also, pusher configurations are not "uncommon". It is just that either the companies that make them speciliazes in executive jets [Eg. Embraer] or they are out of business for non-technical results [Eg. MacDonald Douglas]

MD 80 Series [MD-90/95/Boeing 717] was one of the successful commercial aircraft with over 2400 hundered produced!!

What happened with Saras was sad. But debating about "lack of commercial success for pusher configurations" or designs for "Indian Conditions" IMHO is not being honest. Newbies, please take note.

[shiv]

I think there is also a reason for choosing prop over jet - because jets are most efficient at altitude and are good for medium to long haul. But when you need short hops the plane does not have time even to climb to cruising altitude before descent. Anyone who has flown Coimbatore-Bangalore or shorter flights on a large jet would have observed the ludicrous scenario of cabin crew having to push their trolleys up slope for the first half of the flight and then hold the same trolleys back from rolling during the second half because there is almost no cruise. Its ascent and descent.

In such short haul flights a turboprop is more fuel efficient. With high aviation fuel prices and an economic downturn, the main complaints against turpoprop (noise/vibration/slower speed) are once again becoming secondary to cost.

The Saras is likely to be superb in short haul flights like Bangalore-Mysore or Mumbai-Pune. Imagine a day when you can get on a flight from a small or medium size Indian town and fly to another such town 300 km away in an aircraft that is economical to operate out of sleepy towns carrying 20 passengers. This would be fantastic in the North East where roads and railways are difficult to build. Anyone who has flown over the North East will recall that the whole area is a series of parallel hills/mountains. A 6 hour drive leaves passengers tired merely because they are thrown one way and then another as the car winds around an endless series of turns going up and down the sides of hills.

In concept the Saras is an extremely good one for India.

[disha]

The Saras is likely to be superb in short haul flights like Bangalore-Mysore or Mumbai-Pune. Imagine a day when you can get on a flight from a small or medium size Indian town and fly to another such town 300 km away in an aircraft that is economical to operate out of sleepy towns carrying 20 passengers. This would be fantastic in the North East where roads and railways are difficult to build. Anyone who has flown over the North East will recall that the whole area is a series of parallel hills/mountains. A 6 hour drive leaves passengers tired merely because they are thrown one way and then another as the car winds around an endless series of turns going up and down the sides of hills.

In concept the Saras is an extremely good one for India.

Or fly from Mumbai-Surat. Lots of diamond merchants will love that.

I would like to add that even in implementation it is a very good one for India and the rest of the developing world. Within India, there is a huge segment of market which is under served. This segment is just enough rich to afford a regional plane [that is buy and maintain] but not rich enough to afford a regional jet. That is ability to buy Honda City but not able to afford BMW. Or ability to afford BMW but not able to afford Lamborghini. It looks sleek enough and affordable to maintain even by state governments. Imagine 2 saras per Indian State at least and you have mobile CMs. That is one segment of customers. Heck, even BCCI might buy one or two to ferry its cricketers and their gear around. The potential is unlimited.

The other segment is already pointed out by you. Of course turbo props are necessary to keep the costs and maintenance lower.

[chetak]

Check out Embraer Executive Jet series - phenom/legacy series. All executive Jets. It is a pusher configuration, tail mounted twin engines, clean wings. Why? [Answers Below] Also check out MD 80 http://upload.wikimedia.org/wikipedia/c ... hn.arp.jpg. Another example of a pusher configuration : http://upload.wikimedia.org/wikipedia/c ... an_717.jpg. Also check out Bombardier Global series. Another pusher configuration.


What happened with Saras was sad. But debating about "lack of commercial success for pusher configurations" or designs for "Indian Conditions" IMHO is not being honest. Newbies, please take note.

disha ji

Lots of difference between " pusher " and rear engined design.
The examples you have quoted are of rear engine designs. Those are birds of a different feather.

Rear engined designs are still "tractors" and not "pushers"

Props are fuel efficient as compared to jets.

Yes, undoubtedly we have advanced the aerospace design capabilities in the country and acquired manufacturing expertise with designers interfacing directly with HAL for jigs and fixtures. This is not a situation that is obtained with license manufactured aircraft that HAL may have built .


If there is not a preponderance of commercially successful pushers, its an observation and a situation that may have some technical reasons. Such reasons may have been taken cognizance of by a majority of aircraft manufacturers who do not seem to have ventured into the pusher space.

IMVHO, for a first commercial design it would have been far easier to design and build a conventionally configured aircraft.
That being said, and again without judgment, a pusher for a first passenger aircraft design may have been a tad ambitious.
Granted that NAL had some experience with earlier Rutan based designs, having studied them extensively and gained considerable expertise on composites.

We all hope that the Saras succeeds and performs as expected.



http://www.livemint.com/2008/02/1223421 ... enger.html

NAL has for the first time put a price tag to the Saras, Rs39.4 crore.

“Equivalent twin-engine turboprop aircraft on the commercial market costs anywhere from approximately $3.0 million (Rs11.89 crore) up to about $6.5 million (Rs25.77 crore),” said Raymond Jaworowski, a senior analyst at Forecast International, a US aerospace research firm.
Some of the closest competitors to the Saras would be the King Air 350 built by Hawker Beechcraft Corp. of US, the HAI Y-12 made by the Harbin Aviation Industry in China, Poland’s PZL Mielec-built M-28 Skytruck and the Czech-made LET L 410, he added. The Bangalore-based NAL expects the price of the Saras to drop subsequently to Rs32 crore on higher volumes and better manufacturing practices.


Quoting wiki

The advantages of a pusher.

Efficiency can be gained by mounting a propeller behind the fuselage, because it re-energizes the boundary layer developed on the body, and reduces the form drag by keeping the flow attached. However, this effect is not nearly as pronounced on a small airplane as it is on a submarine or ship, where it is quite important due to the much higher Reynolds number at which they operate.

Wing efficiency increases due to the absence of prop-wash over any section of the wing.

Rear thrust is somewhat less stable in flight than with a tractor configuration. This has the potential to make an aircraft more maneuverable.

The engine is mounted behind the crew and passenger compartments, so fuel does not have to flow past personnel, any leak will vent behind the aircraft, and any engine fire will be directed behind the aircraft (however, this arrangement puts the empennage at greater risk, if there is one -- but this is less of an issue if the fire occurs on, or as a consequence of, landing). Similarly, propeller failure is unlikely to directly endanger the crew.



The disadvantages of a pusher

The pusher configuration can endanger the aircraft's occupants in a crash or crash-landing. If the engine is placed behind the cabin, it may drive forward under its own momentum during a crash, entering the cabin and injuring the occupants; however there is no case where this has been reported to have occurred (in the US and UK accident records). Conversely, if the engine is placed in front of the cabin, it might act as a battering ram and plow through obstacles in the airplane's path, providing an additional measure of safety.

Crew members may strike the propeller while attempting to bail out of a single-engined airplane with a pusher prop.[citation needed] This potentially gruesome scenario helps to explain why pusher props have rarely been used on post-WWI fighters despite the theoretical increase in maneuverability.

A less dire but more practical concern is foreign object damage. The pusher configuration generally places the propeller(s) aft of the main landing gear, but often placed above the wing. Rocks, dirt or other objects on the ground kicked up by the wheels can find their way into the prop, causing damage or accelerated wear to the blades. As a result, pusher aircraft such as the canard homebuilts are not usually operated from unimproved runways[citation needed]. Also, a few centreline pusher designs (such as the Rutan Long-EZ pictured above) place the propeller arc very close to the ground while flying nose-high during takeoff or landing, making the prop more likely to strike vegetation when the airplane operates from a turf airstrip

When an airplane flies in icing conditions, a layer of ice can accumulate on the wings. If an airplane with wing-mounted pusher engines experiences wing icing and subsequently flies into warmer air, the pusher props may ingest pieces of ice as they shed, posing a hazard to the propeller blades and other parts of the airframe that can be struck by chunks of ice flung by the props.

The propeller increases airflow around an air-cooled engine in the tractor configuration, but does not provide this same benefit to an engine mounted in the pusher configuration.[citation needed] Some aviation engines experience cooling problems when used as pushers. Likewise, the pusher configuration can exacerbate carburettor icing. Some air-cooled aviation engines depend on air heated by the cylinders to warm the carburettor(s) and discourage icing; the pusher configuration can reduce the flow of warm air, facilitating the formation of ice.

Propeller noise often increases because the engine exhaust flows through the props. This effect is particularly pronounced when using turboprop engines due to the large volume of exhaust they produce. Aviation enthusiasts can often hear a Piaggio P180 Avanti approach due to the loud high-pitched wail produced by the engine exhaust blowing through the props.

Vibration can be induced by the propeller passing through the wing downwash, causing it to move asymmetrically through air of differing energies and directions.[citation needed]

Problems may emerge when using wing flaps on a pusher airplane. First, the absence of prop-wash over the wings can slow the airflow across the flaps, making them less effective. Second, wing-mounted pusher engines block the installation of flaps along portions of the trailing edges of the wings, reducing the total available flap area

Placement of the propeller in front of the tail can have a negative side effect: strong pitch and yaw changes may occur as the engine's power setting changes and the airflow over the tail correspondingly speeds up or slows down. Aggressive pilot corrections may be required to maintain the desired flight path after changing the power setting.

[shiv]

Placement of the propeller in front of the tail can have a negative side effect: strong pitch and yaw changes may occur as the engine's power setting changes and the airflow over the tail correspondingly speeds up or slows down. Aggressive pilot corrections may be required to maintain the desired flight path after changing the power setting.

Any specific reason why you highlighted this part of the post?

The Saras's prop is nowhere near the front of the tail

[shiv]

Germany's High Performance Aircraft corporation has produced, marketed and sold a 5-6 seater plane like the Saras - except that it has "pull" props and not push props - the TT62 Alekto

http://cdn-www.airliners.net/photo/High ... 0576413/L/
http://www.flightglobal.com/pdfarchive/ ... 04/2004-09 - 0639.html

But speaking of oddball designs that include pus/pull propellers, Germany again features with Dornier's Seastar.

http://1000aircraftphotos.com/Contribut ... 043L-3.jpg

[neerajb]

If there is not a preponderance of commercially successful pushers, its an observation and a situation that may have some technical reasons. Such reasons may have been taken cognizance of by a majority of aircraft manufacturers who do not seem to have ventured into the pusher space.

Boeing-717/MD-95/DC-9 gives more insight into "following the trend mentality".

http://en.wikipedia.org/wiki/Boeing_717

Within a few months, however, the abilities of the 717 became clear. It is roomier and faster than the BAe 146, cheaper to operate, and achieved a higher dispatch reliability than competing aircraft at over 99%.[6] Maintenance costs are very low: a C check inspection, for example, takes three days and is required once in 6,000 flying hours. (For comparison, its predecessor, the DC-9 needed 21 days for a C check.) The new Rolls-Royce BR715 engine design is highly modular: none of the line-replaceable units takes more than an hour to exchange, and about a third of them can be changed in under 15 minutes.

In January 2005, Boeing announced that it planned to end production of the 717 after it had met all its outstanding orders. Boeing officials cited slow sales for the aircraft's demise.[10]

A major difficulty with the 717 model was its lack of commonality with other Boeing aircraft. The trend with aircraft manufacturers, particularly Airbus, was to make a "family" of aircraft with similar cockpits and systems, which would require only one "type-rating" for a crew. That way, whatever size of aircraft that was required on a particular route -- even changing down to the day if necessary -- could be used with any of the crew type-rated for the family.

Moreover every configuration has it's pros and cons and the application decides which configuration to go for. These cons are not that significant as you mentioned and can easily be overcome by application specific design.

Cheers....

[chetak]

Placement of the propeller in front of the tail can have a negative side effect: strong pitch and yaw changes may occur as the engine's power setting changes and the airflow over the tail correspondingly speeds up or slows down. Aggressive pilot corrections may be required to maintain the desired flight path after changing the power setting.

Any specific reason why you highlighted this part of the post?

The Saras's prop is nowhere near the front of the tail

Shiv garu,
please check your "cyber" email.

[chetak]

But speaking of oddball designs that include pus/pull propellers, Germany again features with Dornier's Seastar.

I was very fortunate and honored to have been part of a small group at the Dornier plant at OP that had a very long chat with Conrado Dornier about the Seastar and his insight into the history of seaplane development and about his ancestors who contributed very considerably in this.


The Seastar has a long and interesting pedigree.
Quote
The aircraft incorporates experiential features that would be difficult to replicate without the experience gained in thousands of flying hours and flight missions that Dornier flying boats have completed worldwide since the mid-1910s.

Its origins can be traced back to the Pre WWII designs of the Dornier Do 15 Wal which was a German reconnaissance flying boat of the Second World War in service from 1933 to the early 1940s.
Followed by the Do 18, Do 26 etc

If you want oddball, please look here

http://www.aviation-central.com/famous/ ... x8d-dx.jpg

Quote
Dornier Do-X Seaplane
Claude Dornier was a man before his time. He born in German in 1884 and completed his education in 1907 at Munich's technical college. Three years later he began working at the Zeppelin airship factory. In 1911 he designed the first all-metal air plane, and Zeppelin permitted him to establish a separate division of the company, the Dornier aircraft works. It built both wooden and metal fighters for Germany in World War I.
After the war, he took over control of his aircraft factory. During this time, aircraft had such limited range, that manufacturers believed that seaplanes must be used for trans-oceanic routes. Dornier outdid everyone else. In 1929 he introduced the Do-X. It was the world's largest aircraft and its specifications were impressive - 157 wingspan and 52,000 kg take off weight. It was powered by 12 engines. The hull had three floors. The main floor provided passenger accommodations, the bottom one provided space for fuel tanks and baggage and the top floor contained cockpit, crew cabins, radio operator and flight engineer control panel. With 12 engines, a lot of flight engineering was required.
On October 21, 1929, the giant Do-X flew for one hour with 169 passengers on board. An incredible feat, but bad timing. The great Wall Street Crash occurred the next week and the world was thrown into depression. Toward generating interest in his giant plane that would hopefully result in sale, Dornier announced that he would fly the giant plane around the world. It turned out to be one of the great fiascos in aviation history. The trip was plagued with mechanical malfunctions, logistic problems, and accidents, but Dornier pressed on and completed the flight. But it took ten months.
The Italian air company SANA ordered two aircraft but they never entered service.

[RayC]

Could anyone (preferably and aeronautical engineer) give the pros and cons of the various designs?

[Lalmohan]

Could anyone (preferably and aeronautical engineer) give the pros and cons of the various designs?

its well covered in chetak's posts above and quotes from wiki

in all aircraft designs, there is no single right answer - its always a case of trade-off x for y. the arguements against pushers have normally been one of practicality in operations. the saras design in many ways does not have those issues, it resembles a normal tailed jet configuration, except that it has pusher props. there is nothing inherently flawed about this layout

[Arya Sumantra]

The reason why we end up having many inadvertent threads is probably because the icon that should read "New Thread" reads "New Post". A newbie not wanting to reply specifically to anyone's post on the thread avoids clicking "Post Reply" icon and clicks "New Post" icon instead increasing the workload for the mods.

[Hari]

I dont know this is the right place, but I want you all people to remember Capt Harshan (Ashok Chakra) , from my home town, who made supreme sacrifice of on this day(march 20) 2 years back fighting terrorist.

[sum]

RIP to the brave warrior who gave his yesterday for our today....

Btw, had a doubt (X-psoting a pic from AI thread):

Why is it that all G-suits do not cover the crotch and knees?

[Pingale]

I dont know this is the right place, but I want you all people to remember Capt Harshan (Ashok Chakra) , from my home town, who made supreme sacrifice of on this day(march 20) 2 years back fighting terrorist.

more info on how this brave soldier was martyred! RIP

Capt Harshan was to return home, they got his body

Rajeev PI Posted: Mar 23, 2007 at 0031 hrs IST

THIRUVANANTHAPURAM, MARCH 22: Today was when 25-year-old Captain R Harshan of the 2 Parachute Regiment had promised his parents he would be home to spend his long pending vacation with them and his two siblings in Thiruvananthapuram, far from the killing fields of Jammu and Kashmir at the country’s other end.

Harshan had rung up and talked to his parents on Monday night. He tried calling his younger brother Manu, an engineer in Chennai on his mobile, the same night. Manu will now forever rue that he could not pick up or return that call.

Today noon, Harshan was brought home in a casket, killed in a firefight with Lashkar-e-Toiba militants in Kupwara early on Tuesday morning , a bullet through his neck. When the ceremonial guns fired and the saluting officers retreated, his father K Radhakrishnan, a local lawyer, was holding numbly to a relative watching the flames rearing up.

“I had known him all the four years that he had been in 2 Para. I had not met another officer like him in any Special Forces formation. So quiet and so soft spoken that we often have to really prod him to speak up, yet so good at his job that he was handling the entire training of his formation by himself,” says Lt Colonel S Srivastava, second in command of Harshan’s battalion who brought the body to Thiruvanantapuram.

“He was completely committed, almost obsessed with his missions. He had led so many anti-terrorist strikes before. He was a lot more than a colleague to me, how could God do this to someone like him, “ Col Srivastava choked.

Among the thousands who came to pay him homage today were some of his old schoolmates, recalling the quiet, almost shy, youngster who outdid them in almost everything. Harshan had passed out of the Sainik School in Thiruvananthapuram’s Kazhakootam in 1997 as the school captain and the Best All Round Cadet, moving on to the National Defence Academy.

A bachelor, Harshan was very attached to his family, and even had a special reason for planning to come home today. His elder brother Vyasan, an Indian Revenue Service probationer in Nagpur, had cleared the mains of the Civil Services examination and Harshan wanted to celebrate that. He had made sure that Vyasan and Manu would take a few days off and be with him at their parental home, when he arrived. They were, today.

The Kerala Government today announced a compensation of Rs 5 lakh to Harshan’s family, and a Government job to his next of kin. It offered the same to the kin of Naik Ratheesh Kumar, another soldier who was killed in anti-terrorist action in J&K.

http://www.indianexpress.com/news/capt- ... dy/26376/0

[shiv]

I dont know this is the right place, but I want you all people to remember Capt Harshan (Ashok Chakra) , from my home town, who made supreme sacrifice of on this day(march 20) 2 years back fighting terrorist.

more info on how this brave soldier was martyred! RIP

I have cross posted it in the right thread
http://forums.bharat-rakshak.com/viewto ... 15#p639015

[k prasad]

Why is it that all G-suits do not cover the crotch and knees?

To put it gently Sum, G-suits work by pumping air (or in some cases, liquid) into the suit till it crushes and pressurizes the muscles to holy hell and back... it prevents the blood from draining out. Its like a python around the body. Now, imagine the same thing applied to ..erm.. the sensitive areas... and think about how many more children you'd like to have...

[shiv]

Why is it that all G-suits do not cover the crotch and knees?

To put it gently Sum, G-suits work by pumping air (or in some cases, liquid) into the suit till it crushes and pressurizes the muscles to holy hell and back... it prevents the blood from draining out. Its like a python around the body. Now, imagine the same thing applied to ..erm.. the sensitive areas... and think about how many more children you'd like to have...

The fundamental effect that a G-suit seeks to implement is to compress blood vessels in the body that can be compressed from the outside to stop wild movement of blood from one part of the body to the other due to G-forces. That compression is by inflating bags with a fluid/air.

For example - one can theoretically say that in a "black out" blood rushes out of the head and this can be stopped by putting an inflatable bag around the neck to compress the neck. The theory is good - but that bag will compress the windpipe as well and choke the pilot. So that option is out.

Putting compression around the knee is pointless because it is all bone and it is next to impossible to compress and restrict blood vessels at the bent knee (in the sitting posture without crushing the bone as well.

Crushing the chest is not possible without stopping breathing. So the best a G-suit can do is to put pressure around the abdomen (belly) to compress the large vein that returns blood to the heart (Inferior vena Cava) and to compress both thighs to compress all the veins there to stop a mass flow of blood to and from the thighs and legs.

Crushing the crotch is useless except as a way of dealing with Paki pilots. It is next to impossible to put pressure on the main veins at the crotch when the hips are flexed in the sitting position.

[wig]

shiv sir,
think of ayesha the goat! it ain't fair to them goats

[Gaur]

Are all the NSG SAG personnel volunteers? Another question. Are majority of SAG from para or not?