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© KYODOU.S. Air Force grounds Ospreys over safety concern, including in Japan
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Sh1mon M4sada
The sprag clutch has been a constant source of problem for this airframe. Intended as a redundancy measure, so each of the two engine can either either / or drive the either of the two rotors in case of an engine out on either engine. But it has turned out to be a very high maintenance item.
Amazing in its own right, specially made by Formsprag (of Zlotek fame), the sprag clutch is an amazing bit of kit. Think bearing that in one directions spins freely, whilst in the other direction transfer huge amounts of power. A bit like the clutch used in a motorcycle that enables the starter motor to turn the engine over but spins freely once the engine has started.
Eastmann
"best army in the world "can be defeated by own "reliable" aircraft...
how abt you pack all your things and go back to Iowa and take care your own business at home guys?
war has ended here in sep 1945....
Desert Tortoise
Sprag clutches have been used in helicopters for 65 years at least. It is the standard means to decouple a failed engine from the rest of the rotor system so it doesn't add drag to the driveline. The V-22s engines are however more powerful than any used in a US helicopter so maybe that is a factor.
The Marines are not grounding their V-22s. The claim pilot training can ameliorate the problem. In their view the USAF pilots are exacerbating the problem by using high power settings transitioning from hover to forward flight. The Marines are avoiding using a more gentle transition and claim this reduces the occurrence of sprag clutch slip.
Sh1mon M4sada
The sprag clutch rotates with the rotor (90degrees) which makes it a challenge in terms of lubrication. In any case, like you say I think the USAF got a Ferrari but they treat it like a tractor.
Rodney
Ospreys and F-35s are dangerous to civilians so should based on artificial islands away from schools.
Michael Machida
Great to see the American Military Machine taking care of people by being innovative and move to action minded and staying here in Japan to protect and serve the people of Japan while not going back to Iowa.
Sh1mon M4sada
Ah, is that why China made all those artificial islands in the SCS? Their planes are all unsafe?
BeerDeliveryGuy
Overall, the Osprey has a lower incident/flight hours ratio than every other rotary wing in the US military, and China Airlines.
Pukey2
And this country wants to start a war with China? Gimme a break. These aren't the only incidents involving American hardware.
Harry_Gatto
I'm just wondering why you mention China Airlines, the national carrier of Taiwan?
TokyoLiving
Send them back to the junkyard..
Best comment of the day!!..
Taking care of people, or taking care of geopolitics and interventionism??..
BeerDeliveryGuy
No particular intent.
Just the first airline on an alphabetical order list of airlines that have a higher incident/flight hours ratio than the M/CV-22.
Keep in mind that an “incident” can be anything from a crash to a loose bolt.
wtfjapan
Ospreys and F-35s are dangerous to civilians so should based on artificial islands away from schools.
and thats what eventually will happen in Okinawa when Futenma base is moved
Joemusic1980
Kumagaijin
It just wouldn't be a normal discussion about the Osprey without someone (typically US or former military) defending the aircraft and comparing it to others in developing countries.
Eastman
its good that dangeorus life threating rubbish is grounded.now its time to pack it and get out of here folks...your mommies are waiting you home
voiceofokinawa
It was last June 4 when five Yokota-based CV-22 Ospreys left Yokota Base in Tokyo for Kadena Air Base on Okinawa, but only three were confirmed to have arrived at Kadena. What happened to the other two? At about 15:00 it was reported that two U.S. military aircraft made emergency landing at Amami Commercial Air Port. Apparently, they were part of the five CV-22 Ospreys that had taken off from Yokota for Kadena.
Has the U.S. Air Force discovered something very serious in the makeup of these aircraft, thus grounding all CV-22s operating all over the world?
Aren't the Marines' MV-22s basically the same as the Air Force's CV-22s in the makeup? If so, some measures must be taken with Futenma-based Ospreys, too.
englisc aspyrgend
From the headline, not sure how they will get the birds to stay on the ground?
Perhaps he thinks Taiwan West is an inalienable part of Taiwan?
quercetum
A China Airlines flight on its way to Hong Kong from Taiwan crashed killing some 200 passengers in the early 2000’s.
Desert Tortoise
Based on mishaps per 10,000 flight hours, the F-35 has had the fewest mishaps of any new fighter the US has ever developed. In fact it passed through its entire development cycle and entered fleet service without a single F-35 being lost, something no other fighter aircraft can claim.
The V-22 for a few years was also the safest aircraft in the Navy / Marine Corps inventory. The aircraft with the highest mishap rated in the US Navy / Marine Corps inventory will surprise you. It is the C-20. What's that? It's a Gulfstream business jet that is used as a transport aircraft. The next most dangerous airframes are the AV-8B (no surprise ) and the legacy F/A-18Cs and Ds. All of these are worn out from years of combat. Interestingly while the Navy and Marine Corps manage to have their worst safety experience with the C-20, the Air Force has never lost one in the 20 some years they have been in service.
Desert Tortoise
As I said earlier, the Marines are using their Ospreys differently than the AIr Force does. and has trained their pilots to add power gradually when transitioning from hover to forward flight. They have experienced sprag clutch slippages and found a way to prevent them basically by being gentle during the transition phase.
An aside, but for years I flew the CH-46. One of our "Land as soon as possible" emergencies was something called "Rotor Weave". I never experienced this in the Navy but we had to understand what it was and treat it as an emergency. Rotor weave happens when the blade dampeners can't keep up with the power loads. There are three blades on each rotor, each with a blade dampener and each blade should be 120 degrees apart at all times If the dampeners can't keep up the blades are not the same number of degrees apart and the aerodynamic and mechanical centers of the rotor system diverge. When I went to work at Columbia Helicopters we used the civil version of the CH-46, called the BV-107II. Several of these were made by Kawasaki btw. including one I flew a lot that was used in a famous James Bond movie. They had the old metal blades and older, weaker blade dampeners the Navy had long ago replaced. We used them for aerial logging and every second or third lift we entered violent rotor weave. When this happens it feels like you are sitting on top of a giant orbital sander. We are talking an oscillation of as much as a meter that is throwing your around in the seat. It's pretty exciting the first time! For the grizzled old logging pilots at Columbia rotor weave was hardly an emergency. It was normal and expected to them but the Navy considered it an emergency that required one to land as soon as possible.
Long story short, I read stuff like this and take it with a grain of salt. The military, especially the Chair Force, are very gentle with their aircraft and maybe over react to small problems, making them bigger than they are.