Thursday, July 5, 2012

V-22オスプレイはどう言う問題ですか? What about the V-22 Osprey?

Well, I have just heard that the first 12 V-22 Osprey aircraft have been shipped to Japan, to arrive in Iwakuni.  Despite the Governor of Yamaguchi Prefecture's protests.


Recent crashes have raised more fears about the Osprey, and the US government has promised not to fly them until investigations end.  But it seems that they will arrive in Japan anyway.


A crashed Osprey

So what is it about this aircraft?  Well here is an excellent report from the "Wired, Danger Room" website.


First of all, let's talk about the Marine Corps.  I, myself, was a US Marine.  And can tell you that the central concept of Marines is amphibious landings.  This is landing on a beach with an assault force.  But not only that, the US Marines have refined this tactic with helicopter assaults 2 or 3 kilometers inland.  This traps any defending force between the beach landing force, and the heli-borne force.


The result is supposed to be that the US wins.  For years, the helicopter used by the Marines has been the CH-46 Sea Knight.


A CH-46 helicopter


I flew on those things when I was a Marine, and they saw a lot of use in Vietnam.  That is how old they are.  There is no question that the Marines need a new aircraft.


So the Marines have been the driving force behind the Osprey, even though the Air Force also uses them.  However, the Marines have special needs.  Their aircraft must fit on an aircraft carrier.


With the CH-46 helicopter, you just fold the rotor blades, very simple.  But the V-22 Osprey has wings, there must be folded.  The engines are on the tips of the wings, so all hydraulic lines must also be folded.  Very complex.


Also, the rotors are too short.  So the engines must generate extra power.  6,200 horsepower, compared to 4,400 horsepower CH-53 helicopter.

それと、ローターは短か過ぎです。それで、エンジンは余分の力を作り出す必要が有ります。それは、6,200馬力、比較する為に、CH-53ヘリコプターは4,400馬力しか必要有りません。(《単位》馬力◆米国では、1 hp=約745.6999 W(watt)。)

And this means the engines run hot.  So hot in fact, that when taking off from an aircraft carrier, the pilot must jiggle the engines back and forth, he cannot keep them over the same spot.  This is because the engine exhaust will melt the steel deck of the ship.


These are very dangerous procedures, with a lot of accident potential.


A landing Osprey causes a lot of hot dust and debris


In a practice landing a few years ago in South Carolina, the Osprey started a brush fire with it's engines.


So what we have here, is a tilt rotor, which is by nature an unstable aircraft design, with engines running very hot.  These hot engines also have high potential for catching fire in flight.


Video of an Osprey crash


This link gives us a list of serious defects in the Osprey.


I will briefly list these problems:


1  Cannot autorotate.  In the Vietnam war, around 80% of helicopter crashes came on approach to landing.  Autorotation saved half of the crews.  The V-22 Osprey has auto rotated in test conditions, but the test was conducted under very easy conditions.  In realistic flight conditions, autorotation is impossible.


2  Vortex Ring State.  This occurs because of the side by side placement of the rotors.  What this means that in case of serious maneuvering, the aircraft rotors will lose symmetry, creating a vortex, and then uncontrolled flight.  To put it simply, the aircraft will crash.


In a combat situation, you do not fly in straight lines at steady speeds.  The enemy is shooting at you.  You dip and turn all over the place, land your plane, disembark the troops, and get back to base or ship.


Of course, pilots must practice combat maneuver flying.  They will be doing this in Japan.  And aircraft will crash.


3  Tendency to PIO.  I am not sure what this is, but in certain landing conditions, it seems to be a roll that could put the aircraft into a crash.


4 Effects of vibratory loads.  This aircraft will vibrate a lot, and this can cause hydraulic, electrical, and mechanical cables to break and fail.  Also, because of the need to fold the wings in a carrier hanger, the cables must be long and flexible.  This increases complexity, and possibility of failure.


5.  Susceptibility to wake and tip vortices.  Any aircraft flying thorough the air leaves a wake. 


In the case of the V-22, there have been three cases where the aircraft went into a sudden roll when encountering the wake from another aircraft.  The FAA recommends 2,000 feet of separation from other aircraft in flight for the Osprey.  Of course this is meaningless for a combat aircraft, so the pilots will practice flying close together.  And some will crash from this.

V-22オスプレイの場合、別の飛行機の空跡に入って、突然回転が始まったケースが3回有りました。FAA (連邦航空局)の案内で、V-22オスプレイはこれにもろいから、別の飛行機から2,000フィート(約610メートル)を離れて飛ぶべきとしています。勿論、軍機にこれは意味がなく、近くで一緒にグループで飛ぶ事を練習します。いくつかの航空機は墜落します。

6  High downwash velocity.  We have mentioned how the engines have started a brush fire while in rotation in preparation for landing.  What this danger is, the engines throw up so much dust and debris, the pilot cannot see where he is in relation to the ground, and crashes.


In any case, from 1991 to 2000, the V-22 proved it's reputation a "widow maker", killing many people.  From 2001 to 2005, it was redesigned.


Another photo of an Osprey crash.


The Marine Corps and the manufacturers now say that the aircraft is safe.


But is this true?  The link below lists many serious accidents since then.


But the military only considers an accident involving $1 million damage or a fatality serious.  Yet in four or five incidents in the link above, it was only pure luck that the aircraft did not crash.


And the Marines have revised their standards for $2 million as being a serious crash.  And they don't count Air Force accidents with the V-22, and only count accidents in flight, or in intent to flight.  That means a problem that occurs while taxiing or in maintenance is not considered an accident.  So there is no need to record it as an accident.


So according to the Marines, following incident which occurred in North Carolina on March 27, 2006, was not an accident.  3 men were working on the aircraft when it suddenly took off by itself.  It rose about 6 meters into the air, and crashed back down, with major damage to the right wing and engine.  The 3 crew members were unhurt.  What happened was that the computer flew the plane itself.


But to the Marines, this was not an accident, as there was no human intent to fly the aircraft.  So there is no need to report it.


The Air Force is doing the same thing.  When a very experienced V-22 pilot attempted a landing in Afghanistan on April 9th, 2010, he attempted a landing which the aircraft flight manuals said was possible.  It wasn't, the pilot and three others died.


The flight manuals are written with figures that were the original goals for the aircraft, not what it can actually do.


In effect, they are lying about the problems with this plane.


This is a word game.  Unfortunately, this is still a highly dangerous aircraft.


A series of websites listing problems with the V-22.  The blogger of this site, Carlton Meyer, is a former Marine officer.

色々なV-22オスプレイの問題についてのサイトです。このサイトを書いている人、Carlton Meyerさんは、元海兵隊士官です。

Test flight routes in Japan


Looking at the proposed flight routes for Japan, my guess is they are for "nap of the earth flying".  What this means, you practice flying in close formation at very low altitudes, about 100 to 200 meters.  You fly up the sides of mountains and over them, and through river valleys.  This is to evade enemy radar.


In the list of defects I have written above, the V-22 Osprey is particularly dangerous in formation flying and at low altitude.  This deployment, and the idea to use the aircraft in this way, is insane.


Is the Japanese government helpless?  And if there is a crash, what will the Americans do?


America has the geographical wide open spaces to conduct such flying.  ANY operation of the such a complex and troubled plane such as the V-22 in Japan is very dangerous.  A crash is only a matter of time.


This plane seems more dangerous than an enemy attack.


What is the Japanese government doing?



Unknown said...


ASH.K said...

This seems like an example of what will happen if F-35 enters service. *facepalm*