Nope. That was the Douglas X-3 Stiletto. Complete failure as a supersonic airplane, and had an instability called "dynamic coupling" (also referred to as roll coupling or inertia coupling), which was essentially unknown before then. There were many close calls with that program, but in the end it was considered a success, due to the understanding gained learning about dynamic coupling.
NASA Armstrong Fact Sheet: X-3 Stiletto | NASA
NASA Armstrong Fact Sheet: X-3 Stiletto | NASA
This article has a couple of examples, one recent and the other way back in 1956.
Dutch F-16 fighter jet SHOT ITSELF with cannon during drills, probe reveals — RT World News
The bullets begin to decelerate as soon as they leave the gun barrel. The plane could slow down, remain at the same velocity, or accelerate......since it has a pilot with several thousand pounds of thrust at his disposal. Stay on the same course as the rounds you just fired, push the throttle forward, and you just might catch them.
I don't remember the details but the stories came from the guy's who flew those things at Homestead AFB. I used to go there with a friend who had access, to shop at their surplus depot.
The point is when computer assisted control came along it made sense to reinvent the Starfighter.They didn't as where would the profit be. It seems from what others say here 737 max goes too far in using deliberate intentional instability. An interesting speculation. Personally, I think it's software not realising something is badly wrong and handing back control without the pilot needing to get the manual. It could be true that it would be unsafe to do that. It wouldn't be for me say if that is wise. It is not failsafe. my
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I lived in The next village to Woodford and my father worked at AVRO as an inspector, first in weapons research and later with Vulcan and HS748.
I remember standing on the school playing field, in the mid- late fifties, and first hearing the Vulcan wind up the engines (see my earlier post) then seeing it climb almost vertically after using less than half the runway. If you were lucky, one on the Vulcans would do a loop or a barrel roll !!! ( Some experts say that it could not do this but I have seen it!! )
Andy
The bullet also start to drop immediately after leaving the barrel at a certain rate according to the the laws of gravity.
In level flight what you describe is impossible but the scenario laid out by Jan is possible but very rare.
Hmm. RT.. such a good source of fake news...
I think the one I remembered was that 1956 incident. Yeah I'm that old ...
That involved firing during climb, then leveling out/diving.
Jan
All airliners have positive dynamic and static stability.
Relaxed and/or unstable flight characteristics are the realm of fighters, where the advantages of instability outweigh the (rather significant) disadvantages.
Transport category aircraft are stable.
Obviously the bullets would drop due to gravity.
I don't claim to know anything about flying an airplane, but aircraft were much a part of my family history and often the subject of talk between my parents and their friends. Somewhere in our collection of memorabilia I have a letter of commendation from Charles Lindbergh to my grandfather for a sign he painted on the roof of his factory pointing the way to what is now ATL after a pilot had landed his plane at the wrong place.
My parents were both air traffic controllers. I can remember being scared stiff climbing the stairs to the tower in what is now MIA. My mother was the first female air traffic controller, ever. We visited the tower a couple times in my early childhood. Even after she had retired when I was born, she would grab the microphone and talk to pilots when she heard a familiar voice.
My father was a decorated bomber pilot during WWII in the Pacific theater. As a child I was taken to nearly every air show in Florida, including some private shows at Homestead AFB for military and ex military personnel. That's where I first saw and touched an F-104. It looked tiny parked next to a B-52. This had to be about 1960.
There was a military "lifer" who lived two houses down from us in the 60's. He had been a pilot in WWII and was in the Coast Guard at that time. He would often point out different planes by their sound long before they could be seen. I never could do that except for the P-51 Mustang. It was obvious.
Somewhere in my past I heard the story about an F-104 shooting itself down enough times to remember it, but I can not find any mention of it on the web. it would have happened sometime in the late 50's to mid 60's for me to have heard about it.
Google finds that one, not an F-104 though. Maybe that's what the talk was about....I was a kid then, and sometimes I can remember old stuff, but mix up the details, especially numbers. I can still remember songs and artists from that era after only hearing a little piece though.
F11F-1 Shoots Itself Down
There was an elderly priest in our diocese who used to be a commercial pilot. He was also rather fond of whiskey. When he accidentally landed his DC3 at Linden Airport instead of Newark, he decided to hang it up and applied to the seminary. (Linden is 9 miles south of EWR and has no control tower.)
Jim - had a great time a couple of days ago strolling through one of those “lists of eXperimental aircraft” , the X-36 and Boeing’s Bird of Prey are two that struck me as directly out of a video game, or early Michael Bay film.
Both designs proved to be flyable, although what I gleaned is that the X36 was only a remotely operated small scale model.
Both designs proved to be flyable, although what I gleaned is that the X36 was only a remotely operated small scale model.
Attachments
I have read that the instability of 737max is due to placement of the engines.The speculation seems to be linked with how they look. I doubt this. Firstly centre of gravity is about the simplest task an engineer has to solve. The 737max has efficiency advantages it would not have with mildly wrong placement. If the placement is a compromise it will be understood. To my best understanding this problem is software that doesn't offer a failsafe alone.
From this page - 737 MAX - MCAS
Emphasis mine;
"The LEAP engine nacelles are larger and had to be mounted slightly higher and further forward from the previous NG CFM56-7 engines to give the necessary ground clearance.
This new location and larger size of nacelle cause the vortex flow off the nacelle body to produce lift at high AoA. As the nacelle is ahead of the C of G, this lift causes a slight pitch-up effect (ie a reducing stick force) which could lead the pilot to inadvertently pull the yoke further aft than intended bringing the aircraft closer towards the stall.
This abnormal nose-up pitching is not allowable under 14CFR §25.203(a) "Stall characteristics". Several aerodynamic solutions were introduced such as revising the leading edge stall strip and modifying the leading edge vortilons but they were insufficient to pass regulation. MCAS was therefore introduced to give an automatic nose down stabilizer input during elevated AoA when flaps are up."
It's a stick force gradient issue. This is all about having the airplane feel like an airplane and react to control inputs like an airplane to its pilots. The biggest and most important point here is something called positive stick force gradient, where if the pilot on the controls wants to increase the rate of change in which an airplane moves, the controls must get heavier for said increase. An aircraft that doesn't do that won't feel "right" to a pilot and the required control inputs won't maker sense. (I also realize that this explanation likely doesn't make sense as well, as trying to describe how an airplane flies by feel to someone who has never flown is analogous to describing the sensation of sex to a virgin...)
Anyway, the problem is that the small amount of lift spilling off the nacelles at high angles of attack is quite a bit forward of the wing's center of pressure, causing a slight nose-up moment, that manifests itself as the stick getting lighter for an increase in pitch change, and that's expressly prohibited as it won't make sense to the muscle memory of the pilots... It's not how an airplane is supposed to fly.
MCAS is supposed to automatically counteract that with nose down stabilizer trim. The programming of that routine is obviously flawed, and the fix is forthcoming.
Emphasis mine;
"The LEAP engine nacelles are larger and had to be mounted slightly higher and further forward from the previous NG CFM56-7 engines to give the necessary ground clearance.
This new location and larger size of nacelle cause the vortex flow off the nacelle body to produce lift at high AoA. As the nacelle is ahead of the C of G, this lift causes a slight pitch-up effect (ie a reducing stick force) which could lead the pilot to inadvertently pull the yoke further aft than intended bringing the aircraft closer towards the stall.
This abnormal nose-up pitching is not allowable under 14CFR §25.203(a) "Stall characteristics". Several aerodynamic solutions were introduced such as revising the leading edge stall strip and modifying the leading edge vortilons but they were insufficient to pass regulation. MCAS was therefore introduced to give an automatic nose down stabilizer input during elevated AoA when flaps are up."
It's a stick force gradient issue. This is all about having the airplane feel like an airplane and react to control inputs like an airplane to its pilots. The biggest and most important point here is something called positive stick force gradient, where if the pilot on the controls wants to increase the rate of change in which an airplane moves, the controls must get heavier for said increase. An aircraft that doesn't do that won't feel "right" to a pilot and the required control inputs won't maker sense. (I also realize that this explanation likely doesn't make sense as well, as trying to describe how an airplane flies by feel to someone who has never flown is analogous to describing the sensation of sex to a virgin...)
Anyway, the problem is that the small amount of lift spilling off the nacelles at high angles of attack is quite a bit forward of the wing's center of pressure, causing a slight nose-up moment, that manifests itself as the stick getting lighter for an increase in pitch change, and that's expressly prohibited as it won't make sense to the muscle memory of the pilots... It's not how an airplane is supposed to fly.
MCAS is supposed to automatically counteract that with nose down stabilizer trim. The programming of that routine is obviously flawed, and the fix is forthcoming.
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In my case no, nothing to do with looks. I have no idea how the aircraft is built and for all I know the new turbines may be lighter so moving them a bit forward would leave c.g. intact or close to it as before.
Agreed, no biggie.
Agreed again.
My opinion and thats all it is, an opinion, is there more to it and it really is in the realm of the engineers.
From my reading the Max8 has a tendency to pitch up upon application of power, (no idea how much power) no big deal, it can be compensated for.
what I would seek clarity on is...
What I am reading though seems to be that MCAS is activated by an angle of attack sensor of which there are two. It will respond to one sensor output in lieu of two but how does it know which one is correct if both give different outputs.
I would think you need a minimum of three sensors providing outputs and MCAS would accept two similar signals and reject a third that was out of range of the two in agreement.
Is turbine % also a part of MCAS?
Of course we can have power on / off / accelerated stalls, chandelle's gone bad etc so by itself turbine % is not a sole indicator of a stall condition but if there is more data being considered would that not be a good thing.
I have just seen this.737 MAX - MCAS
Andrew
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