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Post by Flying Dutchman on Mar 25, 2014 17:14:30 GMT 1
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philidor
in service - 6 years
Posts: 8,950
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Post by philidor on Mar 26, 2014 0:29:30 GMT 1
As a possible passenger, I don't particularly want to know !
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Post by Flying Dutchman on Mar 26, 2014 9:24:44 GMT 1
One of the calculations by a aviation engineer did the calculations based on a empty aircraft, easier to succeed with a light aircraft.
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Taliesin
Final Assembly Line stage 1
In Thrust we trust
Posts: 228 
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Post by Taliesin on Aug 5, 2015 12:47:44 GMT 1
Anyone doubting the feasibility of looping a modern passenger airplane has never seen one take off at an airshow.
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Post by airboche on Aug 5, 2015 13:11:39 GMT 1
AFAIK: The Airbus-FBW system will prevent any angle of attack over 30 degrees nose up (decreasing to 25 degrees at lower speeds). Any g-load over 2.5 g will be prevented as well (certification requirement). A loop is just not possible.
Plus, structurally I wouldn't want to try it with any airliner.
Several (!) german registered 707s ripped of engines and crashed while trying to repeat the famous Boeing test pilot barrel roll in the 1960s as they couldn't fly it as super-precise as he had done before and over g-ed their aircraft.
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XWB
in service - 11 years
Posts: 16,115
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Post by XWB on Aug 5, 2015 13:42:17 GMT 1
The system can be disabled. Test pilots can fly their aircraft in Direct Law.
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Post by airboche on Aug 5, 2015 13:51:38 GMT 1
They would still bend or ripp off parts without the protections doing some looping. These are installed for a reason.
The B-47 Bomber had to do some wild pull up (toss) maneuver back then to drop it's bomb load (nuke). Many crashed doing so and the rest had to be retired due to early fatigue soon after. That might be the closest real world comparison to looping a swept wing airliner.
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Post by stealthmanbob on Aug 5, 2015 13:55:52 GMT 1
They would still bend or ripp off parts without the protections doing some looping. These are installed for a reason. The B-47 Bomber had to do some wild pull up (toss) maneuver back then to drop it's bomb load (nuke). Many crashed doing so and the rest had to be retired due to early fatigue soon after. That might be the closest real world comparison to looping an airliner. Maybe a wing over would be possible with an empty aircraft ? Very powerful engines, and less stress on the airframe ? |
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Taliesin
Final Assembly Line stage 1
In Thrust we trust
Posts: 228
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Post by Taliesin on Aug 5, 2015 13:59:10 GMT 1
AFAIK: The Airbus-FBW system will prevent any angle of attack over 30 degrees nose up (decreasing to 25 degrees at lower speeds). Any g-load over 2.5 g will be prevented as well (certification requirement). A loop is just not possible. The FBW system is a good point, but I think in Direct Law it should be doable. If you go M0.82 at FL350 and descend on full power to FL300, you should reach speeds close to M0.9. If you pull on the stick for a steady 1.5(ish)g under full power, you should have no problems looping the airplane. The kinetic energy difference of 270m/s to 100m/s alone can be converted into an altitude difference of 3200m or 10500 feet. Now that is without taking into account any kind of drag, but also any kind of thrust. Plus, structurally I wouldn't want to try it with any airliner. If you do a loop, all the airplane sees structurally is downwards g-forces, exactly what it was built to handle anyway. I think structurally, we're ok. Several (!) german registered 707s ripped of engines and crashed while trying to repeat the famous Boeing test pilot barrel roll in the 1960s as they couldn't fly it as super-precise as he had done before and over g-ed their aircraft. I just did some searching and all I found was a Braniff test pilot who ripped off 3 engines with a Dutch Roll. |
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Post by airboche on Aug 5, 2015 13:59:43 GMT 1
If you fly her as perfectly as Bob Hoover it should work:
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