Francois5

V-22 OSPREY

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A la place des boys, je ne serai pas à la fête si je devais me rendre dans une zone de combat à bord de ce truc. Mais bon, quel appareil militaire du type hélicoptère pourrait faire aussi bien??

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A la même vitesse aucun. Un NH-90 ou un Eh-101 pourraient éventuellement le faire, question capacités, mais pas question vitesse et altitude de croisière. un MH-60S aussi, mais avec moins de monde à bord et aucune possibilité d'embarquer un véhicule.

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Je sais pas trop ce qu'il s'est passé depuis le 2nd OPEVAL, mais bon...

http://www.cnn.com/2007/US/04/13/osprey/index.html

WASHINGTON (CNN) -- The military's controversial V-22 Osprey tilt-rotor aircraft will head to Iraq for its first combat tour later this year, Marine officials announced Friday.

After 18 years and $20 billion in development, the plane will deploy to western Iraq in September to support Marine Corps combat operations for seven months, Marine officials said.

The plane, which is intended to replace the Corps' 40-year-old fleet of CH-46 helicopters by 2018, can fly like a plane and land like a helicopter, giving the Marines more flexibility in the field, officials said.

The V-22 can carry troops three times as far, twice as fast and has six to seven times more survivability than the CH-46 widely used now in Iraq, the military says.

The Osprey's performance has also been noticed by the Air Force, which has plans to use it as a special operations aircraft.

The aircraft has been redesigned after two fatal accidents in 2000 that killed 23 Marines. Accidents in 1991 and 1992 killed seven other people, but Marines say the plane's problems are in the past.

"It's been through extensive operational testing and evaluation, and it is our fervent feeling that this aircraft is the most capable, survivable aircraft that we carry our most important weapon system in, which is the Marine or rifleman, and that we will successfully introduce this aircraft in combat," said Lt. Gen. John G. Castellaw, deputy commandant for aviation.

Critics say the tilt-rotor design may still be too unsafe for the complexities of flying in combat operations.

The Marine Corps maintains it is a much more controllable aircraft in those situations.

Since 2003, the Marines have lost seven aircraft in combat operations. The Marine Corps says the V-22 can better avoid being shot down because it can fly higher than the missiles that have been targeting helicopters. In addition, people on the ground cannot hear the aircraft approaching, giving insurgents less time to prepare to shoot as it flies at low altitude.

"I flown the V-22, and I have taken it and used it in a tactical manner," Castellaw said. "The ability to maneuver this aircraft is far in excess of what we have with the existing helicopters."

CNN's Mike Mount contributed to this report.

Va 3 fois plus loin, 2 fois plus vite, et une survivabilité 6 à 7 fois meilleure qu'un CH-46. Il vole aussi plus haut que les missiles qui ont dégommé les CH-46.

Bref, il partira en Septembre pour l'Irak, pour une période de 7 mois.

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Guest ZedroS

Je n'ai plus le site mais récemment j'ai vu un article sur un problème récurrent de ces petits V22 : des problèmes de fuite d'huile sur les rotors entrainant des départs de feu. Cela s'est déjà passé plusieurs fois, par chance à chaque fois que l'appareil venait de se poser, et ce encore récemment malgré les tentatives de réparation. L'article insistait sur le danger que présente un tel problème s'il se passe en vol : crash pur et simple. Au final, ce n'est vraiment pas un appareil qui inspire confiance je trouve, surtout en zone de combat où, malgré l'article dithyrambique que TMor vient de poster, un moteur peut être mis hors service. Et là paf le V22...

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Tu parles sans doute de cet incident ci. Il y a eu une fuite dans le systeme hydraulique d'un des moteurs, et le fluide a pris feu. Ce n'est pas la premiere fois qu'une fuite d'hydraulique dans les V-22 mene a un incendie.

A mon avis on aurait du abandonner le V-22 depuis longtemps. Pour le meme argent on pourrait remplacer tous les H-53 et H-46 avec des nouveaux modeles ameliores. Le fait que ni les forces speciales de l'USAF, ni celles de l'Army, ne veulent toucher aux MV-22, en dit beaucoup.

La plupart des qualites du V-22 dont on se vante ne seront pas utilisables operationellement. Par exemple, on parle souvent de sa vitesse superieure aux helicopteres qu'il va remplacer. En effet, a 18,500 pieds d'altitude, le V-22 peut faire 240 kts, donc a peu pret 80% plus vite qu'un helicoptere. Mais le V-22 n'est pas pressurise, et n'a pas de systeme d'oxygene pour les passagers, donc il doit en fait rester en dessous de 10,000 pieds en transportant les troupes. Aux altitudes typiques des helicopteres, il est limite a 185 kts, donc seulement 20% plus vite.

En plus de ca, il n'emporte que 24 troupes, compare aux CH-46 qui transporte 25, le CH-47 qui emporte 33, ou le CH-53 qui emporte jusq'a 55. Il n'a aucune provision pour les armements defensifs. Le souffle des rotors (le "downwash") est tellement puissant qu'il empeche l'utilisation des systemes fast-rope, produit des "brownouts" de poussiere et debris, abat les branches, etc. Et bien sur la complexite de ses systemes le rend bien plus vulnerable, aussi bien au tir du sol qu'aux simples avaries mecaniques.

Je voudrais bien croire que le V-22 a "une survivabilité 6 à 7 fois meilleure qu'un CH-46." Mais je crains q'on va apprendre autrement.

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Un long article très instructif tiré du New York Times : April 14, 2007 Combat, With Limits, Looms for Hybrid Aircraft By LESLIE WAYNE The Marine Corps said yesterday that the V-22 Osprey, a hybrid aircraft with a troubled past, will be sent to Iraq this September, where it will see combat for the first time. But because of a checkered safety record in test flights, the V-22 will be kept on a short leash. The Pentagon has placed so many restrictions on how it can be used in combat that the plane — which is able to drop troops into battle like a helicopter and then speed away from danger like an airplane — could have difficulty fulfilling the Marines’ longstanding mission for it. In Iraq, the V-22 will begin to replace the Vietnam-era helicopters that are increasingly facing enemy fire. The limitations on the V-22, which cost $80 million apiece, mean it cannot evade enemy fire with the same maneuvers and sharp turns used by helicopter pilots. As a result, the craft could be more vulnerable to attack, and may result in the Marines keeping it out of the thick of battle, using it instead for less dangerous tasks. “They will plan their missions in Iraq to avoid it getting into areas where there are serious threats,” said Thomas Christie, the Pentagon’s director of operations, test and evaluation from 2001 to 2005, who is now retired. The V-22’s debut in combatends a remarkable 25-year struggle for the Marines to build a craft they could call their own. Video More Video » In announcing the Iraq deployment yesterday, Gen. James T. Conway, the Marine Corps’ commandant, referred to those efforts as “a road marked by some setbacks, lots of sacrifices and the success of these Marines standing before you.” The V-22 has been the Marines’ top priority — the Pentagon has spent $20 billion so far and has budgeted $54.6 billion for it. The money has bought a craft that is half-helicopter, half-airplane and whose speed, say the Marines, will save lives. But the V-22 has also suffered some of the deadliest test crashes in Marine history. It has claimed 30 lives, 26 of them marines, in three test flight crashes. A fourth V-22 crashed, but there were no deaths then. Many more have been damaged in lesser incidents involving fires, stalled engines and software glitches. Critics say the V-22’s unusual design can create deadly problems that the Marines have minimized in their single-minded pursuit of the craft. “It’s like a bad poker hand, and the Marines have been investing in it for 20 years,” said Philip Coyle, the Pentagon’s top weapons tester from 1994 to 2001. “They might have been better if they invested in brand new helicopters.” The plane’s most widely cited design problem is that one of its propellers can get caught in its own turbulence as it comes in for a landing, and that can cause the V-22 to roll over and head into the ground. For that reason, V-22 pilots are trained to steer clear of their own turbulence by rules prohibiting them from making the quick maneuvers used by helicopters to evade enemy fire. Instead, the V-22 must land at speeds as slow as nine miles an hour and in a fairly straight line. A 2005 Pentagon report said these limitations “may prove insufficient” in protecting the V-22 from ground fire. As a result, that Pentagon evaluation said the V-22 was suited only for low- and medium-threat environments, and is not “operationally effective” in high-threat environments. Some critics say that in the heat of battle, V-22 pilots could forget these restrictions and move in ways that could bring the craft down. “The V-22 cannot do radical evasive maneuvers” said Lee Gaillard, author of a report critical of the V-22, “Wonder Weapon or Widow Maker” for the Center for Defense Information, which studies weapons programs. “But that’s what it will need for combat.” The Marines defend the V-22 by saying it provides a margin of safety a helicopter cannot because it can fly faster, farther and higher. They say it can get to wounded troops quicker and speed them to medical care in what is called the “golden hour” when life can hang in the balance. Because the V-22 flies with a lower “acoustical signature,” it can enter a battlefield less noisily than a helicopter. Officials add that the Osprey can do more evasive maneuvers than currently permitted — and further testing will prove that. “If flies twice as fast as the CH-46 that it is replacing,” said Lt. Gen. John Castellaw, head of the Marine aviation program. “It carries three times the payload; it goes five times as far; it’s six times as survivable. So what you’re deploying is an asset that increases the combat capability of the Marines.” “That’s what you want to do,” added General Castellaw. “Give them the best you can.” Col. Mathew Mulhern, the Pentagon’s V-22 program officer, whose Patuxent River office has an “Osprey Country” sign, says marines cannot wait to get on board. “Every marine who sees one, when they do, a light bulb comes on,” said Colonel Mulhern. “They say, ‘my God.’ ” Each V-22 costs about three times the price of a modern helicopter and nearly the same as a fighter jet. The Marines will get 360 Ospreys, Air Force Special Forces will get 50 and there will be 48 for the Navy. The program’s high cost and uncertain technology led Vice President Dick Cheney, when he was secretary of defense under President George H. W. Bush, to try four times to cancel the program. But, from 1989 to 1992, Mr. Cheney was beaten back by Congress. Work on the project — the Boeing Company and Bell Helicopter Textron are the main contractors — is spread across 40 states and 2,000 subcontractors, giving the V-22 broad support. More than 100 members of Congress even formed a Tiltrotor Technology Coalition to protect it. “We have proven conclusively that this is an extraordinarily fine craft,” said Robert Leder, a spokesman for the Bell-Boeing V-22 program. “It is a very safe craft and will be of tremendous service. ‘’ All new weapons have problems in testing. But critics say the V-22 is plagued with basic design problems. Should the V-22 lose power, it can not “autorotate” like a helicopter and allow the updraft of air to rotate its propellers for a hard, but survivable, landing. Because of this, according to the 2005 Pentagon report, emergency V-22 landings without power at altitudes below 1,600 feet “are not likely to be survivable.” “If you lose power on a V-22, you just burn and crash,” said one Pentagon official involved in testing the craft but who was not authorized to speak publicly. “There is no way to survive. ” The cabin is not pressurized, even though the craft can fly at altitudes of 10,000 feet and above, where breathing is difficult and it is not climate-controlled. Pentagon reports also say the V-22 is too cramped for the 24 marines it can carry. The marines are so packed into the windowless cabin that they can become airsick, their legs can grow numb and leaving the plane quickly is difficult. There is no bathroom on board and marines have criticized the “piddle packs” they are to use as insufficient. And, there is no place on board to store them once they are full. V-22 downdraft is so strong, and moves in so many directions that it can create “brownout” conditions, making it difficult for pilots to see and potentially knocking down marines on the ground. As a result, when rope ladders are used, the V-22 must hover at higher altitudes, making marines more vulnerable to fire. “Safety is a big issue,” wrote one V-22 crew chief, in a questionnaire filled out for the Pentagon’s 2005 operational evaluation. “If we had went down in the water we would have most likely lost at least 24 troops because of restricted egress. I felt like I was in a coffin.” These are more than theoretical concerns. On April 8, 2000, 19 marines were killed in a training exercise when a V-22 descended too fast and crashed near Tucson. It was the third V-22 to crash — seven people were killed in two previous crashes. In December 2000, four more marines, including the program’s most experienced pilot, were killed in a crash caused by a burst hydraulic line and software problems. These accidents led to program delays to make design changes. But as tests resumed, so have the problems. Three engine fires occurred recently because of problems related to hydraulic lines. In March 2006, a computer problem led an idling V-22 to suddenly take off on its own. It then slammed into the ground, breaking off its right wing. All 54 V-22’s were grounded for weeks in February because of a faulty computer chip. In preparation for deployment, the Pentagon ran tests last year in the New Mexico desert, similar to the climate of Iraq. In January, the Pentagon wrote about frequent failures with various parts and systems. The reason: “Extended exposure to the desert operating environment.” Because of these problems, Mr. Coyle, the former Pentagon weapons tester, predicted the Marines will use the V-22 to ferry troops from one relatively safe spot to another, like a flying truck. “They don’t want to have a ‘Black Hawk down,’ ” he said. “That would kill the program. Of course, it was not designed to be a truck. It was designed to be used in combat.” The Marines say the V-22 will prove the critics wrong. “Ask all the naysayers how many hours they have flown,” said Colonel Mulhern, the V-22 program manger. “They are just sitting around a desk and crunching numbers,” he added. “Go talk to the Marines. The V-22 has come of age. The first marine it saves makes it worth what we paid for it. And I have real confidence that the V-22 will do it.” Fans include General Castellaw, a Vietnam helicopter pilot, who has flown the V-22. “I came in at a high altitude and then did a tactical ingress,” said General Castellaw. “Yankin’ and bankin’ to avoid simulated fire, came in low, streaked into the zone. The aircraft is nimble, agile. You can yank and bank with the best of them. “I believe absolutely that this is the most survivable craft for the Marine Corps’ most precious assets,” he added. “ If I did not believe that, I would not deploy it. I have absolute faith in the craft to do the mission.”

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Tout a fait d'accord. Parmi ses fautes, j'avais oublie de lister qu'il ne peut pas faire l'autorotation, ainsi que sa tendence a souffrir du "vortex ring state" -- si il descend trop rapidement, les rotors rencontrent leur propre turbulence et perdent leur "lift"; du coup, les commandes ne fonctionnent plus et l'avion amorce une descente non controlee qui mene au crash.

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et pendant ce temps, dans les rangs de l'US Army, on doit bien se marrer. les UH-60M vont bientot arriver et eux pourront aller sans problème au combat. Les CH-47F aussi d'ailleurs.

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Les CH-47 sont les helicopteres de transport les plus capables globalement. D'ailleurs l'USAF a selectionne le une version amelioree du MH-47G pour remplacer les MH-60 dans le role de CSAR.

A mon avis une version du CH-47 adaptee a l'aviation embarquee, avec un train d'aterrissage en tricycle, serait ideal pour remplacer les CH-46. C'est quasimment cela que Boeing avait propose au debut des annees 80:

Image IPB

Le Boeing Model 360, un helicoptere a peu pres la taille d'un Chinook mais qui ressemble a un Sea Knight.

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oh à mon avis les CH-53 vont très bien pour les Marines. par contre, au lieu du V-22, ils auraient du prendre des MH-60S ou des S-92 (moyennant quelques grosses modifications), qui auraient étés beaucoup plus capables à mon avis...

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un moteur peut être mis hors service. Et là paf le V22...

En théorie (!) non: chacun des deux moteurs est capable d'entraîner simultanément les 2 rotors, grâce à un système assez complexe de tringles qui passent dans les ailes (c'était à peu près le même système sur feu le Bréguet 941).

Mais bon, dans les conditions du combat, ce n'est pas forcément réjouissant de perdre un moteur pour cette raison...

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Guest ZedroS
En théorie (!) non: chacun des deux moteurs est capable d'entraîner simultanément les 2 rotors, grâce à un système assez complexe de tringles qui passent dans les ailes (c'était à peu près le même système sur feu le Bréguet 941).

Mais bon, dans les conditions du combat, ce n'est pas forcément réjouissant de perdre un moteur pour cette raison...

J'pensais à une mise en service mettant ko les hélices perso (comme pour toutes ces images d'avions qui rentrent avec des réacteurs touchés par des missiles Sol Air). Il me semble que dans ce cas là c'est fatal pour le V22 non ?

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Yes Sir! C'est vrai aussi des hélicos: une destuction structurelle d'un élément du rotor ou de l'anticouple aboutit en général à un tas de feraille inutilisable - et malheureusement à d'autres dégats, humains et moins remplaçables...

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Yes Sir!

C'est vrai aussi des hélicos: une destuction structurelle d'un élément du rotor ou de l'anticouple aboutit en général à un tas de feraille inutilisable - et malheureusement à d'autres dégats, humains et moins remplaçables...

Tu connais pas la devise de l'EM américain? Le soldat est un consommable comme un autre.

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GI's, mon cher c'est pas pour rien qu'on les appelle comme çà... Cela dit, je suis de l'avis de notre AIM-9, certes le Tilt rotor est un projet d'avenir mais le V-22 est une vraie merde et l'USMC risque de payer cher sa collusion avec Boeing (Bruit que fait un Osprey quand il rebondit sur le tarmac avant de partir en miettes). Il aurait fallu bosser sur des protos pendant encore pas mal de temps et sûrement revoir en profondeur l'Osprey.

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là il coute aussi cher qu'un chasseur et probablement 4x plus cher qu'un hélico conventionnel type UH-60M/MH-60S, donc on est plus à quelque dizaines de milliers près...

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ce matin sur CNN il montrait obama en israel qui arrivait avec un V22, a croire que le gars a confiance en la machine

Ah les vilains,C'est un complot des républicains :lol: Les assassinats genre Kennedy,c'est trop visible,ça fait plein de bruit et c'est pas bon pour le business.ils se sont alors rabattus sur quelque chose de plus discret et plus habituel....... Un V-22 . Dans les coulisses ont dit même que c'est sa seule mission

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