Ciao Ragazzi, qualcuno di voi sa la corretta procedura fatta dal solista della PAN durante la Lomçovak.
velocità d'ingresso, regolazione del trim, e via via ?!
http://video.google.it/videoplay?docid= ... %C3%A7ovak
non è un pan....
Lomçovak
Moderatore: Staff md80.it
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Blood
- 02000 ft
- Messaggi: 331
- Iscritto il: 8 giugno 2006, 17:04
Lomçovak
[font=Comic Sans MS]In un Mondo regolato dalla legge causa/effetto ogni coincidenza è quanto meno sospetta N.W.[/font]
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http://www.italianvipers.com
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Sonny
- 05000 ft
- Messaggi: 760
- Iscritto il: 20 luglio 2006, 20:59
- Località: IN OGNI DOVE
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libelle
- 05000 ft
- Messaggi: 780
- Iscritto il: 8 dicembre 2005, 18:57
- Località: Firenze
- Contatta:
Il Lomçovak non è altro che un frullino eseguito in verticale. Nei velivoli con motore a pistoni il giochetto è facilitato dal fatto che il pilota sfrutta l'effetto coppia impresso dall'elica.
In pratica la manovra del Lomçovak viene iniziata quando l'aereo ha ancora una discreta velocità. Scopo della procedura è infatti ottenere uno stallo accelerato seguito da un avvitamento imposto dal piede. Quando la velocità è quella corretta il pilota tira tutta la barra alla pancia con un movimento secco e deciso, contemporaneamente spinge tutto il piede dalla parte verso cui si vuol fare il lomçovak.
Tirando indietro tutta la barra si produce sulle ali uno stallo accelerato (difatto lo stallo dipende dall'angolo di incidenza, non dalla velocità) e contemporaneamente si spnge sul pedale, in modo da agire a fondo sul timone (che è il comando aerodinamico che ha sempre maggiore efficienza) innescando il movimento rotatorio spinto dalla coppia dell'elica e dal motore a pieni giri. Per quanto ne so io infatti la manetta deve essere sempre tutta avanti. L'aereo inizia a frullare rapidamente per poi rallentare e abbassare il muso (qualsiasi aereo correttamente centrato abbassa il muso dopo la fase di stallo). A quel punto il pilota non deve far altro che assecondare questa fase: comandi al centro e barra leggermente avanti. L'aereo ricomincerà a volare immediatamente.
Sembra che il 339 sia l'unico aereo Jet a poter eseguire questa manovra. Non ne conosco le motivazioni aerodinamiche, ma secondo me, in teoria qualsiasi aereo potrebbe effettuare una manovra del genere. Limiti strutturali permettendo,
In pratica la manovra del Lomçovak viene iniziata quando l'aereo ha ancora una discreta velocità. Scopo della procedura è infatti ottenere uno stallo accelerato seguito da un avvitamento imposto dal piede. Quando la velocità è quella corretta il pilota tira tutta la barra alla pancia con un movimento secco e deciso, contemporaneamente spinge tutto il piede dalla parte verso cui si vuol fare il lomçovak.
Tirando indietro tutta la barra si produce sulle ali uno stallo accelerato (difatto lo stallo dipende dall'angolo di incidenza, non dalla velocità) e contemporaneamente si spnge sul pedale, in modo da agire a fondo sul timone (che è il comando aerodinamico che ha sempre maggiore efficienza) innescando il movimento rotatorio spinto dalla coppia dell'elica e dal motore a pieni giri. Per quanto ne so io infatti la manetta deve essere sempre tutta avanti. L'aereo inizia a frullare rapidamente per poi rallentare e abbassare il muso (qualsiasi aereo correttamente centrato abbassa il muso dopo la fase di stallo). A quel punto il pilota non deve far altro che assecondare questa fase: comandi al centro e barra leggermente avanti. L'aereo ricomincerà a volare immediatamente.
Sembra che il 339 sia l'unico aereo Jet a poter eseguire questa manovra. Non ne conosco le motivazioni aerodinamiche, ma secondo me, in teoria qualsiasi aereo potrebbe effettuare una manovra del genere. Limiti strutturali permettendo,
"think positive, flaps negative!"
-
I-FORD
- B777 Captain
- Messaggi: 547
- Iscritto il: 11 luglio 2006, 1:43
Prima che qualcuno si faccia male suggerisco questa lettura, è in inglese, se avete difficoltà posso anche aiutare nella traduzione:
A Lomcovak is NOT an inverted spin. It is NOT a non-precision maneuver. The pilot is NOT "just along for the ride". Recovery does NOT just occur at random without any control by the pilot. It is NOT a single maneuver, but rather an entire family of maneuvers, all of which are very precise and controlled from beginning to end IF they are properly done.
The key element in a Lomcovak is that the airplane's attitude and motion is controlled by four primary flight controls rather than the usual three. The fourth attitude control in this case is gyroscopic precession from the prop, controlled via the throttle.
There are five main types of Lomcovaks. There are also variations within each type. All are performed under negative "G".
The one most folks are familiar with is the "Main" Lomcovak. This begins from an inverted climb. As airspeed decays to near zero, the pilot initiates something initially resembling an inverted snap roll, so that the aircraft has a rotation rate about the pitch, yaw and roll axes as it reaches zero speed. The aircraft performs three foward tumbles, each one at 45 degrees to the plane of the previous tumble. At the end of the third tumble, the aircraft recovers into a vertical dive.
The "Cap" Lomcovak begins like a hammerhead, but as the airplane rotates to the halfway point, with the fuselage horizontal and the wing vertical, a combination of gyroscopic precession (caused by the yawing rotation from the vertical entry) and down elevator cuases the airplane to perform a single forward tumble, with the plane of the tumble horizontal. As the plane returns to its initial position, throttle is closed and the aircraft yaws the rest of the way to a vertical downline for recovery. I haven't done a complete true Lomcovak myself, but I once did part of a positive "G" variation of this by accident in a DeHavilland Chipmunk, which is how I discovered that Chipmunks do not like to do hammerheads to the left! It's a really weird feeling the first time.
The "Positive Conic" and "Negative Conic" Lomcovaks describe a cone shape in the sky, with the airplane pointed upwards as it sweeps out the cone shape with its underside. The point of the cone is at the prop for the positive conic, and at the tail for the negative conic.
Finally, there is a version resembling the "Main" Lomcovak, but entered from knife edge rather than inverted flight. This one is particularly violent.
The pilot is near the center of rotation for most Lomcovaks. These maneuvers are very disorienting, but not generally too stressful in terms of "G" forces on the pilot. However, since Lomcovaks use the precession forces from the prop as one of the flight controls, as you might imagine, the forces on the prop, crankshaft, engine mounts and engine are extremely severe. The centrifugal forces on things like wing panels can also be surprisingly high, and usually totally different from what the engineers were thinking when the airframe was designed. It is prohibited in a number of aircraft, and results in severe life limits on the rotating components in a number of other aircraft.
Shortly after the maneuvers were invented by the Czechs, some of the top Russian pilots started trying them in their Yak 18's. Shortly after that, there were a series of prop, crankshaft and engine fractures on Yak 18's, including one where the entire engine was yanked off of the firewall by its roots! Right after that, the word went out from "upstairs" to the members of the Russian aerobatic team that anyone caught doing Lomcovaks in a Yak could expect his address to be changed to a gulag in Siberia IMMEDIATELY.
There are a number of other manuevers that also impose severe stress on props and engines. Snap rolls and flat spins are some of the worst. However, nothing can break a crankshaft quite so well as a good Lomcovak. One project I was involved in during my previous career was assisting development of a Kevlar-bladed prop for aerobatic aircraft that would have the strength to tolerate this sort of abuse, and low enough inertia to protect the engine as well. It was well received by the aerobatics enthusiasts, a number of whom had already been through the harrowing experience of landing an already sensitive and tailheavy aerobatic aircraft deadstick, with a few score pounds of aluminum missing from the nose.
In più, se volete qualche cenno storico andate qui:
http://www.aerobatics.org.uk/repeats/ladislav_bezak.htm
A Lomcovak is NOT an inverted spin. It is NOT a non-precision maneuver. The pilot is NOT "just along for the ride". Recovery does NOT just occur at random without any control by the pilot. It is NOT a single maneuver, but rather an entire family of maneuvers, all of which are very precise and controlled from beginning to end IF they are properly done.
The key element in a Lomcovak is that the airplane's attitude and motion is controlled by four primary flight controls rather than the usual three. The fourth attitude control in this case is gyroscopic precession from the prop, controlled via the throttle.
There are five main types of Lomcovaks. There are also variations within each type. All are performed under negative "G".
The one most folks are familiar with is the "Main" Lomcovak. This begins from an inverted climb. As airspeed decays to near zero, the pilot initiates something initially resembling an inverted snap roll, so that the aircraft has a rotation rate about the pitch, yaw and roll axes as it reaches zero speed. The aircraft performs three foward tumbles, each one at 45 degrees to the plane of the previous tumble. At the end of the third tumble, the aircraft recovers into a vertical dive.
The "Cap" Lomcovak begins like a hammerhead, but as the airplane rotates to the halfway point, with the fuselage horizontal and the wing vertical, a combination of gyroscopic precession (caused by the yawing rotation from the vertical entry) and down elevator cuases the airplane to perform a single forward tumble, with the plane of the tumble horizontal. As the plane returns to its initial position, throttle is closed and the aircraft yaws the rest of the way to a vertical downline for recovery. I haven't done a complete true Lomcovak myself, but I once did part of a positive "G" variation of this by accident in a DeHavilland Chipmunk, which is how I discovered that Chipmunks do not like to do hammerheads to the left! It's a really weird feeling the first time.
The "Positive Conic" and "Negative Conic" Lomcovaks describe a cone shape in the sky, with the airplane pointed upwards as it sweeps out the cone shape with its underside. The point of the cone is at the prop for the positive conic, and at the tail for the negative conic.
Finally, there is a version resembling the "Main" Lomcovak, but entered from knife edge rather than inverted flight. This one is particularly violent.
The pilot is near the center of rotation for most Lomcovaks. These maneuvers are very disorienting, but not generally too stressful in terms of "G" forces on the pilot. However, since Lomcovaks use the precession forces from the prop as one of the flight controls, as you might imagine, the forces on the prop, crankshaft, engine mounts and engine are extremely severe. The centrifugal forces on things like wing panels can also be surprisingly high, and usually totally different from what the engineers were thinking when the airframe was designed. It is prohibited in a number of aircraft, and results in severe life limits on the rotating components in a number of other aircraft.
Shortly after the maneuvers were invented by the Czechs, some of the top Russian pilots started trying them in their Yak 18's. Shortly after that, there were a series of prop, crankshaft and engine fractures on Yak 18's, including one where the entire engine was yanked off of the firewall by its roots! Right after that, the word went out from "upstairs" to the members of the Russian aerobatic team that anyone caught doing Lomcovaks in a Yak could expect his address to be changed to a gulag in Siberia IMMEDIATELY.
There are a number of other manuevers that also impose severe stress on props and engines. Snap rolls and flat spins are some of the worst. However, nothing can break a crankshaft quite so well as a good Lomcovak. One project I was involved in during my previous career was assisting development of a Kevlar-bladed prop for aerobatic aircraft that would have the strength to tolerate this sort of abuse, and low enough inertia to protect the engine as well. It was well received by the aerobatics enthusiasts, a number of whom had already been through the harrowing experience of landing an already sensitive and tailheavy aerobatic aircraft deadstick, with a few score pounds of aluminum missing from the nose.
In più, se volete qualche cenno storico andate qui:
http://www.aerobatics.org.uk/repeats/ladislav_bezak.htm
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Blood
- 02000 ft
- Messaggi: 331
- Iscritto il: 8 giugno 2006, 17:04
Grazie Mille I-FORD sei stato utilissimo....
graaaaaaaaaaaazie ancora.... e ancora... e ancora....
graaaaaaaaaaaazie ancora.... e ancora... e ancora....
[font=Comic Sans MS]In un Mondo regolato dalla legge causa/effetto ogni coincidenza è quanto meno sospetta N.W.[/font]
------------------------------------------------------------------------------
Staff
http://www.italianvipers.com
------------------------------------------------------------------------------
Staff
http://www.italianvipers.com
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Er_Dete
- 05000 ft
- Messaggi: 645
- Iscritto il: 27 giugno 2006, 18:07
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I-DISA
- 02000 ft
- Messaggi: 429
- Iscritto il: 16 settembre 2006, 13:43
- Località: Roma
Come si pronuncia:
Una cosa del tipo:
'Lamcevac' ???
Una cosa del tipo:
'Lamcevac' ???
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Er_Dete
- 05000 ft
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