Showing posts with label Technical. Show all posts
Showing posts with label Technical. Show all posts
Number Two engine and 'S' duct explained by Lockheed
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| Number Two engine and 'S' duct |
The Number Two engine is installed in the aft fuselage. Like the wing engines it is a 50,000 pound thrust Rolls Royce Engine. Its inlet is a curved "S" duct which provides performance equivalent to that of a straight through duct,
(There is no performance penalty)
Aside from improved looks, there are several advantages to using an "S" duct. First, this lowers the #2 engine, which gives a low center engine thrust line. This reduces pitch up tendencies, and permits both wider lateral spacing of the wing engines, and a wider flap span.
The aft fuselage does not taper as much as other wide body aircraft because of #2 engine. This allows a longer fuselage constant section and more passenger room.
The lower engine allows for a one piece rudder which gives improved handling by increasing rudder effectivity.
Surprisingly, the "S" duct design also reduces aircraft weight. The engine is mounted in the aft fuselage. This eliminates the need for heavy structural supports (800 lbs.) which would otherwise be required, Those supports, if used, would reduce the passenger cabin by 65 square feet, or 11 seats.
L-1011 customer codes by Lockheed
In a similar way to Boeing that used to identify the original customers of its aircraft by attributing a special code in the last two digits of a certain type's series, Lockheed used a prefix in the Serial Number.
It happened that certain airlines which operated both standard length and -500 TriStars, had two different codes, also marking that difference between the models.
TAP's customer code prefix was "293B-". TAP also operated two second-hand L-1011s originally intended for Air Canada that were not taken up by this airline. These two aircraft had the prefix "193H-" attributed to AC's -500 models, although their first operator was Royal Jordanian.
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| L-1011 customer codes table - click to enlarge |
For the complete serial numbers' list of the L-1011s registered in Portugal, please refer to the Aircraft page, in our website.
An article from AirlineReporter
It was published by AirlineReporter a comprehensive article about the L-1011 and what made this aircraft so unique.
This article starts with a brief description of the historical context of the time where the L-1011 developed and the goal of Lockheed of designing a product that made the difference by employing advanced technology and unique features.
Then it proceeds with the inputs of the airlines on the L-1011 and with special cabin details that made the TriStar a pleasurable aircraft for the passengers.
It even includes the proposed self-dimming windows (a concept very similar to what we find today on the Boeing 787) that unfortunately did not make it into production aircraft:
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| Self-dimming windows © AirlineReporter/Lockheed |
Another interesting curiosity revealed was that the L-1011 flight deck was proposed in three different colours to the operators: grey, blue and olive. TAP's original L-1011s were delivered with their flight decks in tones of blue.
Finally, the article tells about the remarkable TriStar's AFCS, whose systems are also described in this website's Specialties page.
- AirlineReporter: Requiem For a Trijet Masterpiece - The Lockheed L-1011
L-1011 cockpit DVD - quite an adventure
Air Utopia's Trailer
Despite being an unconditional fan of the L-1011 (hell! I started working as a Flight Attendant and one of the reasons - if not the main one - was because I wanted to fly the TriStar again and that was the only way to achieve that goal) it took some time until I decided to purchase a copy of this DVD.
The aircraft depicted in this film is the oldest L-1011 in the world still flying and the first one to be converted to a freighter standard in 1987. We are talking about MSN 193A-1012, the 12th TriStar coming out from production line.
This particular aircraft (a dash 1 TriStar) was delivered to Eastern Airlines in November of 1972 (more than 37 years ago!) with N311EA registration. Then it was converted to an L-1011-1F freighter and delivered to Tradewinds in 1991.
After 2004 it was exported to Thailand where it flew for SkyEyes and Thai Sky Airlines, the last one having ceased its operations in 2006 and leaving all its three TriStars in storage at Bangkok (DMK). In 2006 and after two years without flying, a new owner decided to pick up MSN 1012 and that's where our adventure starts.
Before jumping into the movie itself, let's see some technical information about this aircraft from Lockheed's Goldenrod Issue:
- Type: -1
- SN: 1012
- Config: F (= Freight)
- Engine: 22B
- GTOW: 430K (pounds)
- MLW: 358K (pounds)
- ZFW: 332K (pounds)
- FUEL: 160K (pounds)
- Hrs: 61.460
- Cycles: 27.086
Air Utopia's DVD begins with the final inspections and preparations for the delivery ferry flight from Bangkok (DMK) to Dhaka (DAC) in Bangladesh. This is a short hop flight of approximately 830 nautical miles:
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| Flight Route |
Inside the airframe they were also carrying a spare engine.
We can see refuelling procedure and the use of drip-sticks to ensure they have the correct fuel quantity reading in the cockpit gauges.
They pressurize the hydraulic systems still without engines running (with the help of the Air Turbine Motors) and cycle the landing gear on the ground by pulling the lever to the up position. Obviously the landing gear wouldn't retract (unless the aircraft was completely jacked up) but they done that to guarantee there were no hydraulic fluid leaks.
A rather unusual and spectacular view of the TriStar is given when they are checking #2 engine, entering the S-duct as shown in the trailer. As they check the fan blades one by one, one can clearly understand why they do that "tac-tac-tac-tac" sound when they are windmilling.
Then a complete walkaround inspection and cockpit pre-flight preparations and checklists are carried out with lots of technical details explained by the narrator. The L-1011 cockpit provides the best panoramic view of all widebody jets with large and curved windshields.
A quick peep of the FESC (the electronic bay as it is called on the TriStar) is also shown.
Finally we have a successful start-up of the engines filmed from inside and outside where we can hear the typical and amazing low-frequency sound from those RB211-22B engines. First they started up #2 engine as it's nearer from the APU and you will have less pneumatic energy losses along a shorter duct. Then they open the crossbleed valves and slightly advance the #2 power lever in order to have more pneumatic pressure to get #1 and #3 engines into life. This is a very usual procedure for starting up the TriStar engines and that I saw many times when I worked for Luzair.
Take-off is filmed with simultaneous dual perpectives: one from inside the cockpit and a RH wingview from the cabin.
After cleaning the wing, the crew tries to engage the autopilot. And then the first difficulties start to come up. The autopilot 'A' handle switch is completely stuck in the OFF postion and autopilot 'B' always trips OFF shortly after being engaged. The brave crew of this aircraft decides to proceed with the flight and handflies the L-1011 until a cruise altitude of 27.000 feet, demonstrating the recognised handling and aerodynamic qualities of the TriStar. Somewhere during their cruise the crew resets some pitch and roll C/B's and autopilot 'B' becomes operational. We can ear someone saying "Now we can relax, who wants a Martini?"!
But they were wrong... Suddenly engine #1 oil pressure reading gauge in the Flight Engineer panel shows zero and they have to cutoff the engine to avoid damage to it. With so many adversities happening and that are normal for an aircraft that was in storage for so long, it's amazing to see how this experienced crew handles the situation without any sign of stress. They decide to return back to Bangkok and fortunatelly now they have the help of the autopilot. If you couldn't see the instrument gauges in the front panel you could never say they were flying with a wing engine out. However, final approach and landing is perfectly handflown by the captain and he achieves a really smooth touchdown. With one engine reverse inop and perphaps due to the assymetric braking, the brakes of one main landing gear became hot and captain decided to taxi-in with idle reverse on engine #2.
What was intended to be a delivery flight happened to be a fantastic test-flight which Air Utopia had the luck to record with their cameras.
Everyone that's ever been involved with aircraft [L-1011] has a special place for it in their hearts and it's gonna go down in history as one of the classic widebody transport of all time.
In my case I really do miss it. Today Airbus may build the A380 and other great aicraft. They're still too small when compared with the TriStar!
With a running time of 115 minutes, I really would like to thank Air Utopia for this great production. I have some other L-1011 cockpit DVD's but this is clearly the best insight view of the TriStar I have ever seen.
If you are interested you can easily order your examplar from Air Utopia website:
- Air Utopia: Lockheed L-1011 TriStar
TriStar EFIS cockpit upgrade for Royal Air Force
Here is a clear picture of what it looks like:
The IS&S Flat Panel Display System (FPDS) is an easily installed cockpit upgrade for the Tristar L1011 aircraft. The Primary Flight / Navigation Displays are designed to replace the existing EADI and EHSI display, altimeter, airspeed, vertical speed indicators. The Engine Instrument Display System (EIDS) is designed specifically as a low-cost upgrade of the Tristar engine instrument cluster, replacing primary and secondary engine indicators.
This easily retrofitted replacement system is compatible with the existing cockpit configuration. It provides all existing primary flight, navigation, engine related parameters, hydraulic indication, and flap and trim position indicators using five (5) AMLCD (Active Matrix Liquid Crystal Displays) in lieu of over 73 LRUs. Its unique design concept permits accelerated modification of graphic display formats, and as importantly, rapid certification.
- Full article: Here
This mod is supposed to be done by Marshall Aerospace.
Lockheed first proposed an EFIS cockpit in 1981 when they installed and tested this design in their prototype msn 1001.
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| L-1011 EFIS cockpit, 1981 |
However, it never went into production.
Did you know that...
1. Pan Am was the first airline to operate the TriStar 500 with extended wingtips/active ailerons, in 1980?
2. The first TriStar 500 models delivered to British Airways in 1979 did not originally have the wingtip extensions? They were retrofitted later.
2. The first TriStar 500 models delivered to British Airways in 1979 did not originally have the wingtip extensions? They were retrofitted later.
3. The extended wingtips/ active ailerons were first installed and tested in the L-1011 prototype (N1011)?
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| N1011 - standard lenght TriStar - with active ailerons |
You can read more about active ailerons/active control system here.
Lockheed 2000 Freighter
This was an old idea from Lockheed to convert some L-1011s to freighter aircraft. However, Lockheed never sold this mod program.
Lockheed L-1011 vs McDonnell Douglas DC-10
We must be careful when comparing these two aircrafts. The main difference is: when did McDonnell Douglas have its first DC-10 long-range aircraft? It entered in service in 1972 with the DC-10-30 series.
Now the same question for Lockheed, when did it have its long-ranger? It entered in service only in 1979! Of course Lockheed could not compete in the long range market.
There were sold 199 L-1011 -1,-100,-200 and there were sold 138 DC-10-10 and DC-10-15. Now this is a fair comparison!
Why the long range version of the TriStar was so delayed? Well, not because of RB211 reliability problems or so. Just because its production and development for more powerful versions was halted almost for one year due to RR bankruptcy, which also affected initial sales. It was delayed even further due to overcapacity with the airlines and depressed market. The TriStar 500 could have been ready by 1977 and before that Lockheed studied -250 long range version with the same -500 engines, MTOW and fuel capacity. But it never came to a production standard. There are only 6 L-1011-250 which were converted from -1 series in 1986, already after the shut down of the L-1011 production line!
When TriStar 500 entered in service, it was too late. In the early 80's it was facing competition not only from the DC-10 but also from 2nd generation and more fuel efficient, two crew man, twin jets.
No doubt the L-1011 was technically superior and safer than the DC-10. However, the DC-10 when compared to the TriStar had a better payload-range having from the beginning a true long range version.
The L-1011-1 was simply fine for USA's coast to coast routes for which it was designed.
Why the DC-10 stayed longer with airlines? Easy. More aircrafts flying, more spare parts, effective technical support from McDonnell Douglas.
Finally, it seems that McDonnell Douglas also never made money with the DC-10 program. If it wasn't for the KC-10 contract with 60 units built for USAF, which kept the production line opened until 1988, it would also have suffered big losses.
Now the same question for Lockheed, when did it have its long-ranger? It entered in service only in 1979! Of course Lockheed could not compete in the long range market.
There were sold 199 L-1011 -1,-100,-200 and there were sold 138 DC-10-10 and DC-10-15. Now this is a fair comparison!
Why the long range version of the TriStar was so delayed? Well, not because of RB211 reliability problems or so. Just because its production and development for more powerful versions was halted almost for one year due to RR bankruptcy, which also affected initial sales. It was delayed even further due to overcapacity with the airlines and depressed market. The TriStar 500 could have been ready by 1977 and before that Lockheed studied -250 long range version with the same -500 engines, MTOW and fuel capacity. But it never came to a production standard. There are only 6 L-1011-250 which were converted from -1 series in 1986, already after the shut down of the L-1011 production line!
When TriStar 500 entered in service, it was too late. In the early 80's it was facing competition not only from the DC-10 but also from 2nd generation and more fuel efficient, two crew man, twin jets.
No doubt the L-1011 was technically superior and safer than the DC-10. However, the DC-10 when compared to the TriStar had a better payload-range having from the beginning a true long range version.
The L-1011-1 was simply fine for USA's coast to coast routes for which it was designed.
Why the DC-10 stayed longer with airlines? Easy. More aircrafts flying, more spare parts, effective technical support from McDonnell Douglas.
Finally, it seems that McDonnell Douglas also never made money with the DC-10 program. If it wasn't for the KC-10 contract with 60 units built for USAF, which kept the production line opened until 1988, it would also have suffered big losses.