[audioholic]

Originally Posted by RM Motorsports

Indian air carriers as of today.

Source - Linkedin

Is there really a difference between GO First and the rest of the LCC brigade? What makes it an ULCC? I havent flown GO in a long time so cant really compare the service or experience. But I can say that Air Asia deserves to be a ULCC and I would rate Indigo's service and overall experience better.

[V.Narayan]

The legendary Boeing 747 flew for the first time on this day in 1969

9th February 1969: At 11:34 a.m., Boeing Chief Test Pilot Jack Wadell, with Engineering Test Pilots Brien Singleton Wygle, co-pilot, and Jesse Arthur Wallick, flight engineer, took off from Paine Field, Everett, Washington, aboard RA001, the prototype Boeing 747-121, and made a 1 hour, 15 minute test flight. The ship was named City of Everett after the home of the factory where it was built. It was originally registered N7470. Co-incidentally today is also the day of the first flight of the Boeing 727 tri-jet.


The test flight crew. Brien Wygle (Pilot), Jack Waddel (Captain), Jess Wallick (Flight Engineer).


The first take-off. Since then the Boeing 747 fleet across the world has accumulated, according to Boeing, a staggering 121.5 billion kms or 137,000 trips to the moon and back.


With the F-86 Sabrejet chase plane the first Boeing 747 carried 60,000 lbs (~27,200 kgs) of instrumentation for its prototype test flights.


Joe Sutter's creation ushered in a new era that brought mass air transport to the masses and changed the way airports were built and the ease, on the pocket, with which we travel. Note the landing gear has not been retracted even though the aircraft is at altitude. This is a practice especially on the first and maybe second flights of a prototype to avoid the risk of a malfunction in the landing gears when you try to drop them.


Joe Sutter...the father of the 747


Into the sky, over the horizon. 447 of the Boeing 747 are still flying. As a cargo carrier the type will soldier on till the late 2030s. With todays trend, driven by technology and costs, for twin engine planes which all seemingly look alike, the 747 will forever remain the iconic shape of the skies.

[V.Narayan]

First ever scheduled fare paying flight by a jet airliner

On 2nd May 1952, about 70 years ago at this time BOAC flew the very first fare paying scheduled passenger flight by a jet airliner. With that was born the age of fast, affordable, mass jet air travel for the common man. The aircraft was a de Havilland Comet 1 tailfin number G-ALYP pictured below. The flight was from London to Johannesburg. The aircraft had a wingspan of 115 feet, a length of 93 feet and an all up weight of 48 tonnes. It could cruise at 400 knots (~740 kmph) a mind blowing speed for that time and had an operating range with reserves of ~2400 kms. It was powered by four Rolls Royce Ghost 50 turbojets collectively producing 20,000 lbf of thrust. The aircraft carried 36 passengers in what would today be considered business class seats.

To give you a context at 93 feet it was shorter than the shortest Boeing 737 you've ever encountered and just a little longer than the ATR 72's many of us fly in India on secondary routes. But for 1952 this was streamlined, super fast and state of the art. Sadly the Comet suffered metal fatigue problems that caused three aircraft to break up in mid-flight. The research by the British made jet airliners safer for everyone forever since but they lost their lead to Boeing & McDonnell Douglas and never recovered. While the first jet airliner was the pioneering de Havilland Comet 1, the second to enter service was the Tupolev-104 of which 201 were built and carried over 90 million passengers over 25 years. One could say the Tu-104 was the world's first successful jet airliner.

Sadly G-ALYP was one of those three aircraft that broke up in mid-air in 1954 over the Mediterranean Sea. The Comet is assured of its place in the annals of aviation.


BOAC's Comet 1 G-ALYP that flew the first passenger scheduled flight. As a safety measure it was a largely overland route of London-Jo'burg and not over ocean as in London- New York.


Three Comet 1's in flight for a photo shoot sortie. G-ALYP, the hero of our story today is in the foreground. Note the streamlining, the handsome nose, the clean uncluttered wing. Note the square windows, in the top photo, at the corners of which the fatal metal fatigue cracks developed.


Passengers dis-embarking. Note how in those days air travel was (a) for the rich and (b) for whites! On a side note in 1956 my late father flew as a passenger for the first time, on a Air India Super Constellation, London to Bombay. The Indian Navy specifically told him and his accompanying colleagues to wear a suit while on board. They did not want Naval officers to look shabby.


The Tupolev Tu-104. Note the round windows that avoided the metal fatigue that doomed the Comet. The Soviets never got credit for the success of the Tu-104.


From my collection, a late model Comet 4. Note the very large swept wing and the engines in the wing root. In the early days of jet aviation engineers experimented with where to fit the engines. The nature of a jet engines meant it had to be fitted differently than a piston-prop one. de Havilland went for the engines in the wing root design. The reason was that this way the jet thrust of all four engines was as close to the centreline as practical and would create the least asymmetry in case of an engine-out situation which was a real risk with early jets. It was however a nightmare to maintain and repair but it worked. Tupolev did the same. This configuration is no longer used.

[ads11]

Did the Tupolev become operational after the findings of the square window metal fatigue on the Comet or did the Soviets independently come to the conclusion that round windows were better to avoid those same stress cracks? If the latter, you're right, that's a very crucial finding that doesn't get enough credit then.

I've never thought about how small the Comet was till you just brought up the 737 comparison. That's remarkable!

It's interesting how a lot of jets from that era have the wing root mounted engines. Can only think of the PLAAF Xian H-6s as the only currently flying fixed wing jets with that engine configuration, unless Air Koryo has any geriatric old jet that fits the bill.

Was it the 707 that was the first to really pioneer having engines mounted in podded nacelles under the wing?

[V.Narayan]

Originally Posted by ads11

Did the Tupolev become operational after the findings of the square window metal fatigue on the Comet or did the Soviets independently come to the conclusion that round windows were better to avoid those same stress cracks? If the latter, you're right, that's a very crucial finding that doesn't get enough credit then.

Was it the 707 that was the first to really pioneer having engines mounted in podded nacelles under the wing?

I believe Tupolev selected small round windows by conscious choice as the earlier Soviet airliners like the IL-14 had square windows. The IL-14 was a larger development of the DC-3. They may or may not have foreseen the effect of sharp square windows but it is generally known that round/globe shapes spread pressure evenly and square/cubes do not. The Tupolev T-104A first flew in June 1955 and was designed over roughly 1952 to 1955 time period. The de Havilland's research findings of the cause of the 3 Comet crashes became public only around December 1954. So it is speculative. But on the other hand Russians were and still are masters of metallurgy. Guess we'll never know.

What we do know is that the Tu-104 was almost twice as powerful, 50% heavier and cruised at a higher speed. Table below gives a comparison of these two pioneering aircraft. The passenger capacity is misleading as these machines were configured for what we call business class today, they had a bar, a lounge and 1950s facilities like that. An all economy sardine configuration of today would probably be at 1.75X.



The Boeing B-47 Stratojet was the first to carry its jet engines in pods. From there came the KC-135 series from which almost simultaneously evolved the Boeing 707. Photo below.



Where to fit the jet engine with the need for a clear space to discharge the eflux was a matter of much experimentation. Over half a dozen configurations were tried that I can think of before today's tried and tested solutions came about.

[V.Narayan]

Pawan Hans to be sold. Decision closed. Rs 211 crores

https://indianexpress.com/article/in...rtium-7894277/


After three unsuccessful attempts at disinvesting its stake in the helicopter services provider, the Government on Friday 29th April approved the sale of Pawan Hans Ltd along with management control to Star9 Mobility Pvt Ltd — a three-way consortium between Big Charter Private Limited, Maharaja Aviation Private Limited and Almas Global Opportunity Fund SPC. The first two are very small charter operators without depth of senior management. It seems, therefore to me, that the third a faceless fund from Dubai is the real muscle here. It is to be seen who is the real controller behind this fund. It is a sad reflection of Pawan Hans that it went for a paltry Rs 211 crores. It is to the credit of the Govt that they are learning from their mistakes and not losing the opportunity to sell by putting too high a reserve price which is the error they made the first three times listening to investment bankers.

Star9 Mobility Private Ltd, the highest bidder quoted Rs 211.14 crore, which was above the Reserve Price. The other two bids were for Rs 181.05 crore and Rs 153.15 crore. In the past on Pawan Hans and at one time on Air India the Ministry of Civil Aviation refused to listen to well intentioned advice from industry people on price and insisted on listening only to investment bankers who earned a fee with little skin in the game.

I do not know the material condition of the 42 helicopters of Pawan Hans. But if they are all in flying condition {which they may not be} then the sale value of each put together might be more than the Rs 211 crores. But I do not know the liabilities of the company. All in all a good sign of the Govt getting out of areas it does not need to be in. Ashoka Hotels anyone?

[fhdowntheline]

The TU104 caused quite the stir when it was first revealed to the West, and briefly it was the only flying commercial jet (post Comet grounding) . A re-engined and strengthened Comet-4 did come into service and actually flew the first transatlantic (with fuel stop at Newfoundland) passenger service with BOAC in 1958, before Boeing 707 did it with Panam, but by that time De Havilland had already lost the jet race in terms of capacity and range.

[skanchan95]

Originally Posted by V.Narayan

Pawan Hans to be sold. Decision closed. Rs 211 crores

Didn't Pawan Hans sign up for new HAL Dhruvs recently? I wonder what happens to them now.

[Jeroen]

The problem with the Comet window was a combination of stress and fatigue. Whereas stress and it’s effect on circular / straight corners was somewhat understood, fatigue was still a relative new and unknown area.

The research they did on the Comet to investigate the cause of the crashes, let to some of the basic understanding of the effect of fatigue due to cycle stress. I.e. the number of times a part can withstand a force being applied repeatedly. The answer, very oversimplified, once you pass a million cycles, statistically you are good to go.

The Comets problem we’re caused due to the repeated stress from the cabin pressure. This was the first plane with a full size pressurised cabin. So the cabin gets inflated and deflated each flight. The repeated pressurisation cycle caused the problem on the square corners of the windows. They found out by ducking a comet in a water bath and pushing the wings up on down for several days. Lo and behold after a few days the thing broke! This little video shows the test set up they used.

Listen to the end of the video. During design the comet cabin was tested extensively for a high number of cycles, way above its technical live span. Test were positives. However, they did the cycle tests on the same hull as the pressure tests. Prior to the cycle testing they had done numerous pressure test to actually quite high cabin pressures. Several times over the normal pressurisation. This caused changes in the metal, in fact made it more fatigue resistant. If they had two different hulls, one for the pressure test and one for the cycle testing they would have found the fatigue problem straight away.

https://youtu.be/2rvx-r2itrE

Jeroen

[TKMCE]

The next to be sold off should be Alliance Air (the former Air India Regional).

This one is a gem and if the government does not allow investment bankers to run riot with their illiteracy , it should fetch a good price.

18 ATR-72 aircraft, with an average age of 6 years , as new a fleet you can hope to have a for a government airline, an excellent operational reliability record and a good safety record as well. Unlike Air India Express which has had two hull losses (at Mangalore and Kozhikode) in the last 12 years, Alliance Air has not had any major accidents in the last 15 years or so. They also have developed a healthy network in some Tier III cities like Mysore

The airline also have the rights to some very high yield UDAAN routes like Delhi Shimla which if properly route revenue managed can be cash cows But the airline needs to be sold off fast since Air India under Tatas no longer supports them effective April 15 and they need to get connecting feeder traffic.

This should be an ideal buy for Indigo, particularly with fleet commonality in mind and a rapidly growing international route work which Alliance Air can feed.

[V.Narayan]

Originally Posted by TKMCE

The next to be sold off should be Alliance Air (the former Air India Regional).

This one is a gem and if the government does not allow investment bankers to run riot with their illiteracy , it should fetch a good price.

This should be an ideal buy for Indigo, particularly with fleet commonality in mind and a rapidly growing international route work which Alliance Air can feed.

Spoken like someone who really knows this industry.

[Cliff9091]

Was a real treat to read @V.Narayan

Post the series of crashes the Comet's Certificate of Airworthiness was revoked, the design of the aircraft was revised with the windows being changed and the fuselage being thickened to solve the cabin pressurization issue, and the new aircraft was dubbed as the Comet 4 and had a reliable run upto 1997 with the BOAC and even the RAF if I'm not wrong a few European airline companies as well.

If the Comet had succeeded, the face of British aviation would have been different as we know it today.

[sparky@home]

I remember reading a novel by Nevil Shute, long back about aircraft metal fatigue, No Highway , something like what BOAC, encountered with their Comet's. What I cannot recollect is whether it was published before BOAC incidents. BTW Nevil Shute's books have always been a good read.

[fhdowntheline]

Originally Posted by Cliff9091

Was a real treat to read @V.Narayan

Post the series of crashes the Comet's Certificate of Airworthiness was revoked, the design of the aircraft was revised with the windows being changed and the fuselage being thickened to solve the cabin pressurization issue, and the new aircraft was dubbed as the Comet 4 and had a reliable run upto 1997 with the BOAC and even the RAF if I'm not wrong a few European airline companies as well.

If the Comet had succeeded, the face of British aviation would have been different as we know it today.

The Comet 4 did not have any major success unfortunately, BOAC got rid of them as soon as they discovered that the B707 was more capable. There were a handful of airlines in the Middle East and Africa, but that was about it. The one notable operator was Dan-Air Services in the UK which operated the Comets up until 1980 or so.
PS: BOAC itself merged with BEA and became British Airways in 1972 .

[lapis_lazuli]

It seems that the sale of Pawan Hans has been put on hold by the government following NCLT orders. It seems the winning bidder, the Cayman based consortium, has irregularities.

https://www.indiatoday.in/india/stor...061-2022-05-16

Luckily, this is just 211 crores!