What's the latest news of the V22 Osprey?
SAS
Once again.....what could possibly be used as evidence here???
How does anyone "prove a claim"??? How does anyone "substantiate a claim"?
What is it you want to see posted? Give an example of what could be considered proof of anything. This doesnt cut it I assume.
Regarding the ISS, to me, its a system of shafts and your claim of a singular "shaft" being necessary is flawed.
Under normal, two engine operations, each engine delivers its power to its corresponding proprotor through the PRGB. Only a small amount of power (511 hp max) is transferred down the pylon mounted drive shaft, through the TAGB and down the interconnecting drive shaft to the MWGB. The MWGB contains the auxiliary power unit (APU), the constant frequency generator and the variable frequency generator. The MWGB transmits power between the left and right interconnecting drive shafts without changing speed or direction of rotation.
During single engine operation, power is distributed from the remaining engine to both proprotors through the interconnecting drive shaft. This diagram shows this condition with the right engine failed.
So basically outside of OEI conditions, there are a pair of shafts feeding the MWGB. If one is lost, APU and generators should still be fed by the other. If both shafts were lost, you would lose the generators, and I would assume there are other backups to keep the system airworthy (DC bus battery?).
Do you interpret this differently?
Once again.....what could possibly be used as evidence here???
How does anyone "prove a claim"??? How does anyone "substantiate a claim"?
What is it you want to see posted? Give an example of what could be considered proof of anything. This doesnt cut it I assume.
Compared to both helicopters and conventional turboprops, the Osprey has a lower acoustic signature due to the tiltrotor's reduced rotor rotational speed. It also uses very low thrust for cruise propulsion. The V-22 flying in aircraft mode produces a distinctive sound, described by observers as a "throaty and muted hum - more like a vehicle than a helicopter." The observers noted that, in combined operations, the steady buzz of the MV-22 was frequently masked until the last minute by the "whop-whop noise" of AH-1 Cobras and UH-1 Hueys that were supporting nearby. Overall, as compared to the CH-46, the MV-22 is less noisy while in the aircraft mode, and provides comparable acoustic acquisition cues while operating in the helicopter mode.
Regarding the ISS, to me, its a system of shafts and your claim of a singular "shaft" being necessary is flawed.
Under normal, two engine operations, each engine delivers its power to its corresponding proprotor through the PRGB. Only a small amount of power (511 hp max) is transferred down the pylon mounted drive shaft, through the TAGB and down the interconnecting drive shaft to the MWGB. The MWGB contains the auxiliary power unit (APU), the constant frequency generator and the variable frequency generator. The MWGB transmits power between the left and right interconnecting drive shafts without changing speed or direction of rotation.
During single engine operation, power is distributed from the remaining engine to both proprotors through the interconnecting drive shaft. This diagram shows this condition with the right engine failed.
Do you interpret this differently?
Last edited by SansAnhedral; 11th Aug 2011 at 19:31.
During its entire time with the Marine Corps and Air Force Special Operations Command, an Osprey has never been brought down because of hostile fire, Whittle says.
Now let's ask the same old questions.....what data is that comment based upon?
Is there a comparative analysis of exposure rates, numbers of flights in similar circumstances, has the Osprey been exposed to equal risks, have a study been done to critically examine the comparisons?
I think it is plain to all the Chinook and Black Hawk have borne the brunt of operations in Afghanistan and common knowledge also confirms the Marines have been transported by Army Chinooks as well as the Osprey.
To merely say no Osprey has been lost to hostile fire does not tell the whole story....after a thorough analysis of this particular event....one cannot make any valid claim to superiority of one airframe over another. If the Taliban did set a trap as has been suggested by some sources....perhaps the end result would have been the same no matter which aircraft was attempting to enter that valley.
By the way....I haven't lost the plot.....just suggesting there does in fact exist a "plot" to over-sell the Osprey for "political" reasons.
Sans,
You posted while I was writing this post. I just went back using the "Search" feature to locate the exact post Sultan made which kicked off this discussion of the "I Shaft's". Alas, I was unable to find that post either by going back through the thread here or while using the search feature. I wanted to quote that post so we could each see exactly what was posted and thus clarify the issue at hand.
Being unable to do that now.....for what ever reason the post is gone....I hope you will accept my recollection of what Sultan said that prompted my question about the validity of his very vague description of the Shaft System.
I understood him to be comparing the Chinook Synch Shaft, a single long shaft made up of several shorter shafts, that connect the combining gear box to each of the Main Transmissions whose purpose is to drive the main rotors and keep them from meshing....to the Osprey system and was suggesting the Osprey system of shafting was not really needed (or words to that effect) as if there was a failure of the shaft(s) or for reason, the only thing that happened was a cockpit caution/warning light would illuminate.
I am sure in the Osprey such a failure is far more significant than merely lighting up a caution light....which is why I took issue with Sultan's comments.
The Chinook does have a weak link in the the Synch Shaft as if it fails for whatever reason.....the aircraft will self destruct quickly, fatally, and catastropically. That being said.....the old girls have been around for a very long time and are remarkable helicopters.
Likewise, I am sure the Osprey has its Achilles Heels failures as well. Hopefully with the improvements in design and technology as many of these as possible have been elimaated as possible.
I will give your post a good read and get back with a response. No doubt but you have it right. By providing us with the diagram and explanation, you are advancing the discussion and I appreciate it.... I am sure others do as well.
Last edited by SASless; 11th Aug 2011 at 15:32.
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Sans
Are you saying that should a DS be severed, the other rotor would be able to maintain an RPM close enough to the other, via engine control, so that there would be no loss of flight control?
Are you saying that should a DS be severed, the other rotor would be able to maintain an RPM close enough to the other, via engine control, so that there would be no loss of flight control?
Looking at the diagram Sans provided....it appears each engine/prop rotor could mechanically operate individually without benefit of the I-Shaft system. Without both engines running and a failure of the I-Shaft system I can see the end result is not pretty....only one Prop Rotor being driven. Depending what mode of flight and Airspeed/Altitude combination it might be possible (I am assuming here....)to continue flight with the one remaining engine. If the aircraft was in the Hover Mode (Helicopter Mode) at a low forward airspeed...and less than about 1600 feet or so....it would be a very interesting proposition re surviving the Emergency Landing as we know the Height/Velocity Curve for that conditon of flight has lots of bright RED. (Hover Mode/OEI....Hover Mode/Both Engine Fail). The odds of both engines failing simultaneously/almost simultaneously are very slim. One engine failing after entry to Hover Mode and below the Minimum Safe Height for recovery to Forward flight in the Airplane Mode is the range of flight that needs explaining as well. Just how large a Red Area is there on the H/V chart for that flight condition.
Compared to the Chinook and its Synch Shaft....the Osprey would have a distinct advantage.
Now the question that is begged....how does the Crew controlled Prop Rotor Speeds, pitch settings and the like to equalize the Torque/RPM/Power output for the Engines with such a failure.....which is up to the Osprey knowledgeable folks here to answer as I have no clue. It sounds doable in theory...but in reality I wonder. Hopefully, someone will come forth and enlighten us.
Did find the post made earlier by Sultan that prompted this exchange about the I-Shaft on the Osprey as compared to the Synch Shaft on the Chinook.
Compared to the Chinook and its Synch Shaft....the Osprey would have a distinct advantage.
Now the question that is begged....how does the Crew controlled Prop Rotor Speeds, pitch settings and the like to equalize the Torque/RPM/Power output for the Engines with such a failure.....which is up to the Osprey knowledgeable folks here to answer as I have no clue. It sounds doable in theory...but in reality I wonder. Hopefully, someone will come forth and enlighten us.
Did find the post made earlier by Sultan that prompted this exchange about the I-Shaft on the Osprey as compared to the Synch Shaft on the Chinook.
Saturday Shows Crippling Flaws
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The Chinook: big, slow, noisy and with a critical flaw. If you hit the interconnect shaft game over as the rotors collide and destroys the aircraft. On the V-22 take out the interconnect shaft and you get a caution light.
The Sultan
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The Chinook: big, slow, noisy and with a critical flaw. If you hit the interconnect shaft game over as the rotors collide and destroys the aircraft. On the V-22 take out the interconnect shaft and you get a caution light.
The Sultan
Last edited by SASless; 11th Aug 2011 at 22:41.
Sas
Been around Chinooks and V-22's many times. These videos say it all (cannot cheat science):
Chinook, imagine sneaking up on someone with this:
V-22 or this:
In my extensive experience these are representative.
As to your other post on how a tilt rotor handles a failed interconnect shaft they are call standard inputs to cyclic, pedal, and thrust lever (collective to you)
The Sultan
Been around Chinooks and V-22's many times. These videos say it all (cannot cheat science):
Chinook, imagine sneaking up on someone with this:
V-22 or this:
In my extensive experience these are representative.
As to your other post on how a tilt rotor handles a failed interconnect shaft they are call standard inputs to cyclic, pedal, and thrust lever (collective to you)
The Sultan
V-22 Interconnect
Sultan, you wrote:
"As to your other post on how a tilt rotor handles a failed interconnect shaft they are call standard inputs to cyclic, pedal, and thrust lever (collective to you)"
Not quite the case OEI, is it?
Thanks,
John Dixson
"As to your other post on how a tilt rotor handles a failed interconnect shaft they are call standard inputs to cyclic, pedal, and thrust lever (collective to you)"
Not quite the case OEI, is it?
Thanks,
John Dixson
Again Sultan......same sound systems, same location, same distance from the sound sensors?
No.....thus apples and oranges as to being an empirical test.
Now tell us again how it is only a caution light that comes on after a failure of the I-Shafts? How does that work?
If Ali Taliban smacks an RPG into the engine nacelle of an Osprey....and takes out one end of the I-Shaft and the ass end of the engine at the same time...and the Osprey is at three hundred feet AGL and say fifty knots....thus rendering the aircraft OEI and no I-Shaft....how does the Pilot handle that situation?
An excerpt from an Aviation Technical Magazine article about the Osprey....
Seems to be pretty much like a Chinook at the same point, speed, and all when an RPG takes out the Synch shaft is it not?
No.....thus apples and oranges as to being an empirical test.
Now tell us again how it is only a caution light that comes on after a failure of the I-Shafts? How does that work?
If Ali Taliban smacks an RPG into the engine nacelle of an Osprey....and takes out one end of the I-Shaft and the ass end of the engine at the same time...and the Osprey is at three hundred feet AGL and say fifty knots....thus rendering the aircraft OEI and no I-Shaft....how does the Pilot handle that situation?
An excerpt from an Aviation Technical Magazine article about the Osprey....
Traditionally, autorotation is a required air-worthiness capability for military rotorcraft. High rotor disk loading and low rotor inertia places V-22 well outside the nominal autorotation envelope of existing rotorcraft. Basic rotorcraft engineering analysis indicates that the V-22 will have a difficult time achieving a stable autorotation following a sudden power failure at high power setting, and that the probability of a successful autorotational landing from a stable autorotative descent is very low.
Last edited by SASless; 12th Aug 2011 at 01:58.
Sultan, you wrote:
"As to your other post on how a tilt rotor handles a failed interconnect shaft they are call standard inputs to cyclic, pedal, and thrust lever (collective to you)"
Not quite the case OEI, is it?
Thanks,
John Dixson
"As to your other post on how a tilt rotor handles a failed interconnect shaft they are call standard inputs to cyclic, pedal, and thrust lever (collective to you)"
Not quite the case OEI, is it?
Thanks,
John Dixson
We talk about and basically verify the fact that the ISS does not need to be intact during normal flight/both engines operating. Therefore, the argument has now shifted to the fact that if the ISS fails, AND the V22 goes OEI, there will be trouble.
Gee, ya think so???
It is very much the case Sans.....as you quoted Sultan.....I now again quote him....care to address the issue now? His post is the reason we are having this discussion.....patently plain to see what he said and meant by his comment.
Now lets assume it is an RPG hit....and that hit whacks the I-Shaft and takes out the engine at the same time....which is quite possible with a lucky hit....same as a lucky hit on the Chinook. As they are both possible and certainly within the realm of consideration...how do you see it turning out for the Osprey on final for the LZ while in the "Hover Mode" used for landing and at whatever airspeed the aircraft would be at 300-400 feet agl (remembering our 800 FPM ROD restriction below 40 knots IAS)?
Or....to keep things in perspective....what if we take an engine slap off the side of a Chinook and do the same thing to an Osprey...Which aircraft is superior? The modern hot to trot Osprey or the ancient lumbering obselete Chinook?
If you hit the interconnect shaft game over as the rotors collide and destroys the aircraft. On the V-22 take out the interconnect shaft and you get a caution light.
Or....to keep things in perspective....what if we take an engine slap off the side of a Chinook and do the same thing to an Osprey...Which aircraft is superior? The modern hot to trot Osprey or the ancient lumbering obselete Chinook?
Seems to be pretty much like a Chinook at the same point, speed, and all when an RPG takes out the Synch shaft is it not?
The chinook fails catastrophically with a single point of failure. Rotor self annihilation, no autorotation.
The V22 needs to fail BOTH the engine and ISS shaft to be in a similar situation.
But a single hit at their common meeting point is the same as as single point isn't it?
There is only so many ways to separate critical bits....and I would assume the Osprey is prey to that problem if you introduce something like and RPG that can knock out a Tank and make huge holes in aircraft.
Dare we bring up the subject of autorotational capabilities of the Osprey?
Did not the Marine Corps say it wasn't really necessary as a dual failure of engines was a one in a billion chance.....shortly before an aircraft on a flight out west had icing problems that caused both engines to fail. Fortunately the aircraft was at altitude and in airplane mode and had time to restart the engines on its way downhill. Had it been in another situation it could have been a lot different.
There is only so many ways to separate critical bits....and I would assume the Osprey is prey to that problem if you introduce something like and RPG that can knock out a Tank and make huge holes in aircraft.
Dare we bring up the subject of autorotational capabilities of the Osprey?
Did not the Marine Corps say it wasn't really necessary as a dual failure of engines was a one in a billion chance.....shortly before an aircraft on a flight out west had icing problems that caused both engines to fail. Fortunately the aircraft was at altitude and in airplane mode and had time to restart the engines on its way downhill. Had it been in another situation it could have been a lot different.
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The crashworthiness and ballistic tolerance of the V-22 is literally decades ahead of the Chinook, basically because it was designed decades afterward. The Chinook meets the basic standards of a civil helicopter from 1965 or so, because the Army had no special standards for crew protection, crashworthiness, fire resistence or battle damage back then. The same can be said of the Huey, BTW. Literally all the changes that the Chinook has seen since then have been for performance or operational capability, but have done little in the survivability area.
The V-22 meets standards that are tough, similar to the Black Hawk or Apache.
That doesn't mean that either is able to take an RPG hit and keep on flying, but it does tell a bit about what would happen after the hit, regarding breakup and or fire.
The V-22 meets standards that are tough, similar to the Black Hawk or Apache.
That doesn't mean that either is able to take an RPG hit and keep on flying, but it does tell a bit about what would happen after the hit, regarding breakup and or fire.
Photo of a Chinook downed by an RPG while recovering a Cobra Helicopter. The FE was killed and the rest of the crew were hit by groundfire while exiting or outside the aircraft. The aircraft was hit while departing from a hostile LZ with the underslung Cobra...and was beginning to climb when hit.
The RPG killed the Port side engine, severed fuel lines, and wiring harnesses in the area of the engine after punching a hole through the fuel cell on the starboard side of the aircraft. At least one of the main transmissions lost all luubrication fluid.
Fortunately there wasn't anything solid enough to slow the round and the explosive charge went off after it had penetrated the starboard side of the aircraft (It was assumed.....) and there was only a flash fire. The aircraft was recovered by a CH-54 later and was sent back to the factory for rebuild. It is very likely it wound up being a "D" model and could still be flying today.
Last edited by SASless; 12th Aug 2011 at 23:22.
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Although many details about its operations in Afghanistan and "other countries" are not much public, the fact is that the people using it, just love it.
Since this is the first kind of aircraft of a new class, I am sure there are is a lot of things to improve and learn, but I am sure that we are going to see a lot of Tiltrotors in short future in the military and in the civilian world.
For those of us flying maritime SAR, having such a platfform, with that range, speed and capabilities would be a dream and honestly if the hover perfomance and maneurability are like the one you can appreciate on the videos, I would trade my AW139 or the S-92 or the EC225 by such aircraft riight away.
I am wonder how long it will take to see US Coast Guard Ospreys.
And although the AW609 is a little bit small for my taste, it is expected to get its civilian certification shortly.
Since this is the first kind of aircraft of a new class, I am sure there are is a lot of things to improve and learn, but I am sure that we are going to see a lot of Tiltrotors in short future in the military and in the civilian world.
For those of us flying maritime SAR, having such a platfform, with that range, speed and capabilities would be a dream and honestly if the hover perfomance and maneurability are like the one you can appreciate on the videos, I would trade my AW139 or the S-92 or the EC225 by such aircraft riight away.
I am wonder how long it will take to see US Coast Guard Ospreys.
And although the AW609 is a little bit small for my taste, it is expected to get its civilian certification shortly.
Last edited by Furia; 13th Aug 2011 at 20:29.
For a single hit to take out both and engine would be a golden bullet as the nacelles and fuselage protect any critical point. As the V-22 travels so much faster this is really extremely improbable (not the extremely improbable that Sikorsky used to explain the S-92, but a real one).
On the Chinook you need not only to only hit one gearbox or the shaft, but can have total loss from a seemingly minor event (initiated by a chip light):
Daily Union - Google News Archive Search
As most who died were parachutist many lives could have been saved by ordering an immediate evacuation instead of trying to return to the field.
The Sultan
On the Chinook you need not only to only hit one gearbox or the shaft, but can have total loss from a seemingly minor event (initiated by a chip light):
Daily Union - Google News Archive Search
As most who died were parachutist many lives could have been saved by ordering an immediate evacuation instead of trying to return to the field.
The Sultan
Originally Posted by The Sultan
After the loss of our brave war fighters in one obsolete slow helicopter I believe the V-22 will surge ahead and the Army will begin buying.
The UH-60M seems to meet their needs. As I understand the program, eventually ~ 1200 UH-60M will flesh out the Blackhawk fleet, mixed in with UH-60L. I don't know if final AoB will closer to 2500 or 3000, since some of that is driven by how many divisions // RCT's remain after the next DoD belt tightening, and how TOE for Guard and Reserve units get restructured. There are a lot of unanswered questions on that score.
Originally Posted by Furia
I am wonder how long it will take to see US Coast Guard Ospreys.
Given its cost, see above on mission requirement.
Heck, I'm a bit surprised they keep Dolphin and Jayhawk. I am sure there's a reason, but for my money, Jayhawk is the better capability for the budget dollar. (We got any Coasties posting?)
Army Aviation takes up 7 percent of the Army's manpower and 20 percent of the Army budget. The Army spends about 7.5 Billion Dollars per year on Aviation. The Army is trying to organize its 13th Active Duty Aviation Brigade which is a five year project. Army Brass are waiting to see how deeply the Army's budget gets cut....to see what the future budgeting will allow them to do.
Top of the list for desired purchases is a replacement for the OH058 Warrior. The Army delayed the purchase while spending 250 Million Dollars converting 58D models to 58F models. The 101st Combat Aviation Brigade shall field a mixed unit of UAV's and 58F's for testing operational procedures.
The Army Blackhawk and Chinook fleets have seen an operational tempo five times planned due to Iraq and Afghanistan without a decrease in readiness or an increase in accident rates.
The Army is committed to building a new generation of helicopter by 2030 but have yet to finalize what the design shall be.
With budget cuts coming.....there is fat chance the Army will buy Ospreys due to the cost alone.
Top of the list for desired purchases is a replacement for the OH058 Warrior. The Army delayed the purchase while spending 250 Million Dollars converting 58D models to 58F models. The 101st Combat Aviation Brigade shall field a mixed unit of UAV's and 58F's for testing operational procedures.
The Army Blackhawk and Chinook fleets have seen an operational tempo five times planned due to Iraq and Afghanistan without a decrease in readiness or an increase in accident rates.
The Army is committed to building a new generation of helicopter by 2030 but have yet to finalize what the design shall be.
With budget cuts coming.....there is fat chance the Army will buy Ospreys due to the cost alone.
Mil Std 1290 Vs V-22
The Blackhawk and the Apache were both designed in the 1970s to meet Mil Std 1290. This was a very aggressive approach to ballistic and crash worthiness. Attributes included in Mil Std 1290 were: 32 fps crash attenuating landing gear, 42 fps crash attenuating airframe structure, fuel cells drop tested from 65 ft and a ballistic tolerant main airframe structure for up to 23 mm weapons. This capability was provided for at a significant weight penalty. The Blackhawk was procured to replace the 14 passenger UH-1H. The UH-1H’s empty weight was approx. 6000 lbs. while a similar 14 passenger Blackhawk has an empty weight of 11,500 lbs. Most of the weight difference was due to meeting Mil Std 1290. If you fast forward to the V-22 and Bell’s UH-1Y, both aircraft received wavers from Mil Std 1290 citing an inability to meet mission requirements at the higher weights required to meet spec. I do not believe that any aircraft subsequent to the Blackhawk and Apache have had to meet the requirements of Mil Std 1290. I am sure that the V-22 is a relatively robust machine but it cannot be compared to the Blackhawk or Apache for survivability.
Here is an interesting propaganda pamphlet about the Osprey. It does answer some questions but there are some "interestng questions begged".
I really enjoyed the deck space requirement diagram comparing the H-46 and MV-22.......as they orient the two aircraft cross ways.....which only shows the fact that the Osprey is as wide as the 46 is long. I don't think that is what they were trying to say....but then it is a sales brochure and not a fair discussion of facts.
They also mentioned a 3000 pound payload at 10,000 feet.....in helicopter mode....not bad for what....12,300 horsepower or something like that?
http://www.bellhelicopter.textron.co...0Guidebook.pdf
I really enjoyed the deck space requirement diagram comparing the H-46 and MV-22.......as they orient the two aircraft cross ways.....which only shows the fact that the Osprey is as wide as the 46 is long. I don't think that is what they were trying to say....but then it is a sales brochure and not a fair discussion of facts.
They also mentioned a 3000 pound payload at 10,000 feet.....in helicopter mode....not bad for what....12,300 horsepower or something like that?
http://www.bellhelicopter.textron.co...0Guidebook.pdf