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- convair880mfan
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Why didn't airline makers follow the lead of the Lockheed L-1011 and use stabilators instead of THS?
Many people have said that the Lockheed L-1011 was ahead of its time in many of its features. One of its features was the use of an all-flying tail in place of the traditional trimmable horizontal stabilizer. If this was a good idea, why wasn't it used in later jetliner designs? Anyone know?
Re: Why didn't airline makers follow the lead of the Lockheed L-1011 and use stabilators instead of THS?
I would think extra cost and complexity is the reason.
You are about ten years too late for these L-1011 questions. Members 474218 (a Lockheed L-1011 technical support engineer) and 411A ( long time L-1011 pilot) were most knowledgeable about the L-1011 but unfortunately passed years ago. It is well worth searching their posts (on this site and google) as they answered many technical questions about the L-1011.
https://www.airliners.net/forum/viewtopic.php?f=11&p=18138119&t=1219285
https://www.airliners.net/forum/viewtopic.php?t=1213793
You are about ten years too late for these L-1011 questions. Members 474218 (a Lockheed L-1011 technical support engineer) and 411A ( long time L-1011 pilot) were most knowledgeable about the L-1011 but unfortunately passed years ago. It is well worth searching their posts (on this site and google) as they answered many technical questions about the L-1011.
https://www.airliners.net/forum/viewtopic.php?f=11&p=18138119&t=1219285
https://www.airliners.net/forum/viewtopic.php?t=1213793
Re: Why didn't airline makers follow the lead of the Lockheed L-1011 and use stabilators instead of THS?
convair880mfan wrote:Many people have said that the Lockheed L-1011 was ahead of its time in many of its features. One of its features was the use of an all-flying tail in place of the traditional trimmable horizontal stabilizer. If this was a good idea, why wasn't it used in later jetliner designs? Anyone know?
DLC was one of the more notable 'ahead' features on the TriStar compared to other jetliners, in addition to some of its manufacturing methods. The all-flying stabilizer (stabilator) doesn't really rank as highly, as it has appeared on many types of aircraft and is featured heavily on fighters.
Re: Why didn't airline makers follow the lead of the Lockheed L-1011 and use stabilators instead of THS?
Aaron747 wrote:convair880mfan wrote:Many people have said that the Lockheed L-1011 was ahead of its time in many of its features. One of its features was the use of an all-flying tail in place of the traditional trimmable horizontal stabilizer. If this was a good idea, why wasn't it used in later jetliner designs? Anyone know?
DLC was one of the more notable 'ahead' features on the TriStar compared to other jetliners, in addition to some of its manufacturing methods. The all-flying stabilizer (stabilator) doesn't really rank as highly, as it has appeared on many types of aircraft and is featured heavily on fighters.
The combination of DLC and the all flying tail was significant however, it gave the L1011 significant benefits in stability and enormous pitch authority
Re: Why didn't airline makers follow the lead of the Lockheed L-1011 and use stabilators instead of THS?
Aaron747 wrote:The all-flying stabilizer (stabilator) doesn't really rank as highly, as it has appeared on many types of aircraft and is featured heavily on fighters.
All-moving stabilizers are mostly beneficial for supersonic flight and were introduced on the first supersonic fighters very quickly. The benefits for subsonic flight are less obvious and the tradeoff generally favors the traditional horizontal stabiilzer.
Re: Why didn't airline makers follow the lead of the Lockheed L-1011 and use stabilators instead of THS?
There is always a trade off between sophistication and cost. Period..
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- Starlionblue
- Posts: 21730
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Re: Why didn't airline makers follow the lead of the Lockheed L-1011 and use stabilators instead of THS?
Lpbri wrote:There is always a trade off between sophistication and cost. Period..
That's a bit of a broad statement, and I don't entirely agree.
The A350 vastly simplified cruise trim compared to the A330, with partial flap extension instead of the complex trim tank system. More sophisticated, and much cheaper.
Another example is the structurally simplified but aerodynamically more sophisticated flaps on the 787 compared to previous Boeing models.
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- celestar345
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Re: Why didn't airline makers follow the lead of the Lockheed L-1011 and use stabilators instead of THS?
Aaron747 wrote:DLC was one of the more notable 'ahead' features on the TriStar compared to other jetliners, in addition to some of its manufacturing methods. The all-flying stabilizer (stabilator) doesn't really rank as highly, as it has appeared on many types of aircraft and is featured heavily on fighters.
I personally would say the DLC is there as a result of the stabilator, as the authority will be too large for fine handling at landing phase.
Lpbri wrote:There is always a trade off between sophistication and cost. Period..
It's probably better described as 'trade off between desire result and cost'... it's either you put in a lot of effort to make it very sophisticated to achieve what you need, or to make it much simpler for what you want. Especially with the introduction of computerized fly-by-wire, you can do magic by just changing the software parameters, not adding to the hardware cost.
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