Landracing Forum
Tech Information => Aerodynamics => Topic started by: wobblywalrus on February 07, 2016, 11:19:41 PM
-
This is not land speed aero. It is interesting, though. www.bbc.com/future/story/20160201-the-wwii-flying-wing-decades-ahead-of-its-time (http://www.bbc.com/future/story/20160201-the-wwii-flying-wing-decades-ahead-of-its-time)
-
Jack Northrop and the Flying Wing: The Story Behind the Stealth Bomber
-
The "blended-wing-body" (BWB) and the "flying wing" are two significantly different designs that are often confused. Neither beats a conventional tube-wing-tail when all mechanical, structural, pressurization, materials, engine, noise, balanced field length, etc. requirements are applied. There's a reason the 777X looks the way it does.
Unusual configurations abound in the conceptual design areas of Boeing and Airbus. When and if they ever beat a conventional, they will be produced immediately. Those companies are in business to make money.
-
FBW makes all sorts of weird stuff possible.
-
FBW makes all sorts of weird stuff possible.
Computer controlled fly by wire does.... :cheers:
-
FBW makes all sorts of weird stuff possible.
Computer controlled fly by wire does.... :cheers:
Actually, not so much. The "relaxed" stability margins that 4th and 5th generation fighters fly with are just that: relaxed margins. Ditto for aft CG fuel loading of airliners at initial cruise to reduce trim drag.
In an effort to work with more efficient configurations, aft CG, transonic and supersonic flight, and higher maneuverability vs. stable CG and dynamic stability, commercial and military design has progressed to the point of reducing margins below the ability of the pilot's ability to maintain control in dynamic, not static flight modes. Please refer to the Cooper-Harper scale and its influence and implications on controllability.
"Relaxed stability" or dealing with dynamic instability has been done for over 60 years. First with analog SAS (stability augmentation system), later with digital. All successful, operational FBW air vehicles are statically stable and may venture into dynamic instability in parts of the envelope. All of them will depart computer-controlled flight as the stability limits are reached.
("Envelope": defined as the dynamic pressure/Mach/alpha/pitch-yaw-roll-rate/CG vs. altitude that an aircraft is capable of achieving)
No successful program has ever flown a vehicle with a wide operating envelope that was statically unstable in level flight.
Read that 2, 4, 10 times and do the research before responding.
-
I was under the impression that the F-17 crossed into the statically unstable in level flight region, or is it just very close to unflyable by an unassisted human in level flight?
-
I was under the impression that the B2 was not flyable without the computer... and I pretty sure the one that crashed was due to a faulty input to the computer
Your Info May Vary :cheers:
-
It is my understanding that the B2 has four flight-control computers and a fly-by-wire control system to overcome the flying wing's inherent poor stability by continuously and automatically making split-second control adjustments, independent of the pilot.
Bill
-
I know a guy who was there and he says the B49 was a controllable aircraft. Opinions may differ.
-
Regarding the B-2 crash Wiki has a good summary of the cause.
https://en.wikipedia.org/wiki/2008_Andersen_Air_Force_Base_B-2_accident
Crash was due to high humidity / heavy rains affecting sensors the flight computer used to determine rotation speed, then due to the early rotation, and wrong sensor data, the computer made a wrong conclusion and executed a 1.6 G uncommanded pitch up maneuver which resulted in the crash.
-
Everything old is new again..
-
sooooo----- when do I get a new body to replace this 74 year old one with all of it aches and pains :?
-
sooooo----- when do I get a new body to replace this 74 year old one with all of it aches and pains :?
After you go though the process . . . . . . reincarnation!!! Problem is, you might come back as a ? ? ? ? ? ?
My current thinking is: probably not worth it. Pretty sure I don't want to make all those mistakes, AGAIN . . . . .
:cheers:
-
Mark, say it ain't so -- we don't get to come back for another round WITH all of the learnin' we accumulated on this pass through the vale of tears? Noo-oo-oo-ooooooo, DAMMIT!