Hello everyone,

I am here to annoy you once again! Muwahahaha!

While surfing airliners.net for pictures of the L-1011, I noticed a small difference in some Delta Air Lines L-1011's. There appears to be an "extension" of sorts of the cone of the engine. Here's an example:

Delta L-1011 modified

and in this picture, taken earlier this year, there is no modification:

Unmodified L-1011 engine

I do know that Delta had some range-enhancements done on the L-1011 which entailed fitting the -500 series' engines, but still, the -500 does not have this "extended tailcone."

L1011-500

Any insight would be greatly appreciated! Thanks.

The engines on the very early model Tristars had an even longer "hot section" fitted. It was shown through tests though, that they offered no performance gains, so a redesigned shorter "hot section" covering was installed, and early models were retrofitted with the samller and lighter units.

Thanks a lot Empress, I knew it would be something incrediby simple. I knew that something was not right, but I knew that it would be a simple explanation from someone else.

Similar things happened with the 747, through different variants.

In the beginning, the L-1011, beside the normal cascade vanes reverse for the by-pass stream, had also clamshells for the reverse of the hot stream. That's why the hotstream cone was longer.

It's quite difficult to see the clamshalls in this picture, but they are there and opened.
http://img46.imageshack.us/img46/9496/reverseil5.jpg

Also see these pictures:
http://www.airliners.net/open.file/0374849/L/
http://www.airliners.net/open.file/0640580/L/