Its all in the wings
Joined: Jun 2001
Aviation Qualifications: ATPL
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From: OZ
Blu-y,
Tail mounted engines can cost a lot in design. Start with the simple fact that, because there are no podded engines to hold down the wings, the wing structure must be heavier to resist the moments generated by lift. Just for starters that is costly. It goes on - do some homework and you'll get the idea. Yes, I know, rudder can be smaller due asymmetrics and that is a saving but there is the fuel system etc, etc.
Tail mounted engines can cost a lot in design. Start with the simple fact that, because there are no podded engines to hold down the wings, the wing structure must be heavier to resist the moments generated by lift. Just for starters that is costly. It goes on - do some homework and you'll get the idea. Yes, I know, rudder can be smaller due asymmetrics and that is a saving but there is the fuel system etc, etc.
Joined: Mar 2005
Aviation Qualifications: Military
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From: Aus
Basil, I'd put my money on one of the Bombadiers, likely one of the Global kind, I'd further bet the 7000 and 8000 with the GE Passport engines. As usual, I'd probably lose the bet if horses are any guide.
Joined: Jul 2013
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From: Everett, WA
PDR, go ahead and be the skeptic, but consider these facts:
The MD-90 incorporated new, 1990's technology V2500 engines to replace the 1960s technology JT-8D engines on the MD-80. This should have provided a huge improvement in fuel burn - but it didn't. The MD-90 operating costs were barely better than the MD-80. As a result, nearly 1200 MD-80s were delivered over 17 years, compared to 116 MD-90's over 6 years before it was euthanized .
People that worked on the MD-90 told me the problem was the aircraft was so severely overweight, with most of that due to the heavy engines and the associated nose ballast.
The MD-90 incorporated new, 1990's technology V2500 engines to replace the 1960s technology JT-8D engines on the MD-80. This should have provided a huge improvement in fuel burn - but it didn't. The MD-90 operating costs were barely better than the MD-80. As a result, nearly 1200 MD-80s were delivered over 17 years, compared to 116 MD-90's over 6 years before it was euthanized .
People that worked on the MD-90 told me the problem was the aircraft was so severely overweight, with most of that due to the heavy engines and the associated nose ballast.
Joined: Dec 2002
Aviation Qualifications: ATP+Mil
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From: Where the Quaboag River flows, USA
A little research shows the V2500 is about 900 pounds more per engine than the -217, according to Wiki. Add in the pylon flaps, structure improvements and certainly over a ton-plus total at the wrong location.
High compression turbofans are heavy, an inescapable fact. Also, a reason reengining the CRJ series is a non-starter.
High compression turbofans are heavy, an inescapable fact. Also, a reason reengining the CRJ series is a non-starter.
Last edited by galaxy flyer; 28th November 2017 at 03:31.
Joined: Apr 2001
Aviation Qualifications: ATP+Mil
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From: surfing, watching for sharks
Tail mounted engines can cost a lot in design.
Joined: Feb 2013
Posts: 17
Likes: 1
From: 60 north
How can wingmounted engines allow for lighter wing structure.
Torsion damping can not possibly be that heavy on a modern wing.
Compared to all the crap that is associated with an engine on a lifting surface.
Heavy engine on wing = more wing and heavy wing.
Torsion damping can not possibly be that heavy on a modern wing.
Compared to all the crap that is associated with an engine on a lifting surface.
Heavy engine on wing = more wing and heavy wing.
Joined: Jul 2013
Aviation Qualifications: Non-Aircrew
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From: Everett, WA
All of this has been known about since the 707.
Joined: Jun 2001
Aviation Qualifications: ATPL
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From: OZ
The early B747-200s had ballasted nose cowls for the outboard engines for flutter damping we were told.
Another fringe benefit of the engine struts on #1 and #4 was that the inboard edge of the strut was made vertical about 3 inches high and brought aft over the leading edge as a cheap fence, making a virtue out of necessity.
Another fringe benefit of the engine struts on #1 and #4 was that the inboard edge of the strut was made vertical about 3 inches high and brought aft over the leading edge as a cheap fence, making a virtue out of necessity.
