http://news.yahoo.com/blogs/technolo...224458312.html
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I wonder why they didn't simply turn it off immediately!
i caught a glimpse of the video yesterday........crazy!!! I would figure there would be some sort of dampers to prevent something like this occuring. Glad all were safe.
It was about 12 seconds from the time the first oscillations began until the fuselage split open, there probably was not enough time to diagnosis the problem and try to correct.Quote:
Originally Posted by gonzalu
i'm not sure where the throttle and fuel handles are on an A-star but there's no reason the pilot shouldn't be able to feel the thing start vibrating out of sync and not immediately kill the engine.
Actually, not knowing a whole lot about flying helicopters, I resorted to one of the pilots my parents routinely use to ferry helicopters from place to place when they ship helicopters for clients and I was told that the most effective way to break the ground res occuring is to add power and lift off as it harmonizes the blades. Ground res is at least in part created by low RPM mixed with out of balance blades and a whole skew of things I care not to learn about because I am a fixed wing kind of guy. It scientificly made sense though in explination.
Found a rather funny instance of ground res and recovery on You Tube in my curiosity http://www.youtube.com/watch?v=6vICf8l-KV0
SHAKE AND BAKE!!!
AMAZING that the guy did not get his head clipped by those rotors!
odd number bladed helicopters are more susceptible to this, which is why you typically see two or four rotor birds.
like hiss said, the best thing to do it pull power and collective (pitch) and go flying. like a vintage tailwheel aircraft and ground looping - take it back in the air - can't ground loop airborne or have ground resonance.
there are great videos on this, including a Chinook that was deliberately put into this situation in testing.
http://www.youtube.com/watch?v=vTRuWgoEFxo
the blades are free to move forward and rearward on the rotor head. normally the blades are all perpendicular to the head, but may advance or retard at times. in flight, they will do this but all the same amount. on the ground, some blades may advance and some may retard compared to normal position. when this happens, the rotor goes out of balance, and in short order, the helicopter shakes itself to death.
That is nothing....In theis video, the the tail rotor is causing an Air Resonance that is Dampend by the final revision of the Turbo Entabulator causing the airflow to circulate around the Fugodil Parrallell across the Barometric Pam. This was done on the Russian bird as the Grammeters were easily distributive across the entire airframe. The idea was sound but ineffective as it uses too much fuel and is at full power with no payload. Now if they could just get it more efficient that would be awesome.
http://www.youtube.com/watch?NR=1&feature=endscreen&v=M5POy9iKtPA
Fred, do you mean gyroscopic precession and retreating blade stall? :D
Not Excactly... the base-plate of prefabulated amulite, surmounted by a malleable logarithmic casing in such a way that the two spurving bearings were in a direct line with the pentametric fan. The main winding was of the normal lotus-o-delta type placed in panendermic semi-boloid slots in the stator, every seventh conductor being connected by a nonreversible trem'e pipe to the differential girdlespring on the 'up' end of the grammeters. This is what caused the flux leading up to the the gyroscopic Precession caused the retreating blade.Quote:
Originally Posted by Nick
For those of you who are in the dark, please review the original theory. This is SERIOUS STUFF FOLKS!
http://www.youtube.com/watch?v=rLDgQg6bq7o
Just to confirm, that Russian chopper vid has the rotor in alignment (accidentally I'm sure) with the camera's frames per second,so it only looks like it's not moving, right?
Yessir.Quote:
Originally Posted by Phil D.
NICK???? That could have been some serious fun.
;)