V22 Osprey discussion thread Mk II
Show of Force?
Hopefully that "show" was dropping a pair of 1,000 pound bombs....or a CBU drop! Then I am all into such "shows".
Hopefully that "show" was dropping a pair of 1,000 pound bombs....or a CBU drop! Then I am all into such "shows".
Pretty sure "show of force" can refer to a strafing run in the vicinity, or even a line up without actually firing. Both of which would be successful in scaring the pants off of the guy holding the duct-taped AK-47.
C'mon SAS, youre all about saving the taxpayer money! This should make you happy they aren't spending $40,000 a pop to drop JDAMs right?
C'mon SAS, youre all about saving the taxpayer money! This should make you happy they aren't spending $40,000 a pop to drop JDAMs right?
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Show of Force?
Remember from your Bristow's days SAS that this is "British English," not "American English"! They tend to be a bit more reserved in their commentary.
Lexington Institute
Misleading Metrics Understate Readiness And Versatility Of MV-22 Tilt-Rotor
Author: Loren B. Thompson, Ph.D.
Date: Tuesday, March 06, 2012
Over the last five years, the MV-22 Osprey tilt-rotor aircraft has demonstrated its operational value in 17 foreign deployments while becoming the safest rotorcraft in the Marine Corps fleet. The aircraft has performed raids in Iraq, disaster relief in Haiti, casualty evacuation in Jordan, counter-insurgency operations in Afghanistan and combat rescue in Libya. Operational commanders are clamoring for more of the unique airframes because, in the words of one Marine briefing, it flies "twice as fast, carrying three times the payload, at four times the range of the legacy helicopter it replaces."
You'd think that after 140,000 safe flight hours, often in harrowing circumstances, critics would begin recognizing that the MV-22 is everything the Marines promised it would be -- agile, versatile, reliable and affordable. Well, no such luck. Even though transition from the ancient CH-46 helicopter to the MV-22 is now more than 50 percent complete, some so-called experts continue to spout misleading information about the aircraft's price and performance. They say the Osprey costs too much to build and operate, and has not demonstrated adequate levels of readiness in combat operations.
No doubt about it, $68 million is a lot of money to pay for the production version of a rotorcraft. However, the performance characteristics of the Osprey make it the operational equivalent of two or three conventional helicopters. The CH-46 that the MV-22 is replacing can carry 12 troops to a combat radius of 75 nautical miles (nm.) at a top speed of 145 nm. per hour. The MV-22, in contrast, can carry 24 troops to a combat radius of 325 nautical miles at a top speed of 260 nm. per hour. The range differential alone is a huge force multiplier. For instance, a CH-46 stationed in Baghdad can't even make it to the Iraqi border and back without refueling, whereas an MV-22 stationed at the same base can reach the Persian Gulf, the Mediterranean Sea or the Caspian Sea -- and then turn around and fly back without refueling.
The contrast in performance underscores why picking any airframe other than Osprey for combat search-and-rescue is irresponsible (as the Air Force should have learned when MV-22s rescued a stranded U.S. fighter crew in Libya during the recent conflict there). But it takes time for people to appreciate the full potential of a revolutionary airframe, so it is no surprise that as Canada puts together its own solicitation for a new combat search-and-rescue helicopter, it is making the same mistakes the U.S. Air Force did -- applying dated metrics and assumptions that favor a solution sure to leave some personnel stranded forever in hostile territory. The simple fact is that any solution other than a tilt-rotor can't fly far enough or fast enough to save some endangered warfighters.
In that regard, the critics are doing warfighters a real disservice by citing misleading comparisons between Osprey and various conventional helicopters. For instance, they complain it costs about $10,000 per flight hour to operate the MV-22 compared with about $3,000 per flight hour for the MH-60, the Marine helicopter most closely resembling what the Air Force uses for combat search-and-rescue. However, this ignores the superior speed, range and carrying capacity of the MV-22. When the metric is changed to cost per mile flown, the MV-22 only looks about 60 percent more expensive, and when the metric is passenger seat miles, the MV-22 looks twice as efficient ($1.53 versus $3.21). After all, it can carry three times more people than an MH-60, which like its greater speed and range might come in handy in some rescue operations.
It is also worth noting that the MV-22's computerized reporting system depresses apparent readiness rates compared with the older, manual system used for the legacy CH-46s it will replace. The Osprey actually has high mission-capable rates, but the way the new system measures availability makes it look less ready than it really is. Eventually these matters will all be sorted out, and it will be obvious the MV-22 is far, far superior to a conventional rotorcraft in just about any imaginable scenario. That's why even the Army, which has no formal plans to buy tilt-rotors, is taking a close look at its medical-evacuation potential. Let's just hope the rest of the world wakes up to the revolutionary potential of tilt-rotor technology while there is still time to leverage economies of scale off of a warm production line.
Author: Loren B. Thompson, Ph.D.
Date: Tuesday, March 06, 2012
Over the last five years, the MV-22 Osprey tilt-rotor aircraft has demonstrated its operational value in 17 foreign deployments while becoming the safest rotorcraft in the Marine Corps fleet. The aircraft has performed raids in Iraq, disaster relief in Haiti, casualty evacuation in Jordan, counter-insurgency operations in Afghanistan and combat rescue in Libya. Operational commanders are clamoring for more of the unique airframes because, in the words of one Marine briefing, it flies "twice as fast, carrying three times the payload, at four times the range of the legacy helicopter it replaces."
You'd think that after 140,000 safe flight hours, often in harrowing circumstances, critics would begin recognizing that the MV-22 is everything the Marines promised it would be -- agile, versatile, reliable and affordable. Well, no such luck. Even though transition from the ancient CH-46 helicopter to the MV-22 is now more than 50 percent complete, some so-called experts continue to spout misleading information about the aircraft's price and performance. They say the Osprey costs too much to build and operate, and has not demonstrated adequate levels of readiness in combat operations.
No doubt about it, $68 million is a lot of money to pay for the production version of a rotorcraft. However, the performance characteristics of the Osprey make it the operational equivalent of two or three conventional helicopters. The CH-46 that the MV-22 is replacing can carry 12 troops to a combat radius of 75 nautical miles (nm.) at a top speed of 145 nm. per hour. The MV-22, in contrast, can carry 24 troops to a combat radius of 325 nautical miles at a top speed of 260 nm. per hour. The range differential alone is a huge force multiplier. For instance, a CH-46 stationed in Baghdad can't even make it to the Iraqi border and back without refueling, whereas an MV-22 stationed at the same base can reach the Persian Gulf, the Mediterranean Sea or the Caspian Sea -- and then turn around and fly back without refueling.
The contrast in performance underscores why picking any airframe other than Osprey for combat search-and-rescue is irresponsible (as the Air Force should have learned when MV-22s rescued a stranded U.S. fighter crew in Libya during the recent conflict there). But it takes time for people to appreciate the full potential of a revolutionary airframe, so it is no surprise that as Canada puts together its own solicitation for a new combat search-and-rescue helicopter, it is making the same mistakes the U.S. Air Force did -- applying dated metrics and assumptions that favor a solution sure to leave some personnel stranded forever in hostile territory. The simple fact is that any solution other than a tilt-rotor can't fly far enough or fast enough to save some endangered warfighters.
In that regard, the critics are doing warfighters a real disservice by citing misleading comparisons between Osprey and various conventional helicopters. For instance, they complain it costs about $10,000 per flight hour to operate the MV-22 compared with about $3,000 per flight hour for the MH-60, the Marine helicopter most closely resembling what the Air Force uses for combat search-and-rescue. However, this ignores the superior speed, range and carrying capacity of the MV-22. When the metric is changed to cost per mile flown, the MV-22 only looks about 60 percent more expensive, and when the metric is passenger seat miles, the MV-22 looks twice as efficient ($1.53 versus $3.21). After all, it can carry three times more people than an MH-60, which like its greater speed and range might come in handy in some rescue operations.
It is also worth noting that the MV-22's computerized reporting system depresses apparent readiness rates compared with the older, manual system used for the legacy CH-46s it will replace. The Osprey actually has high mission-capable rates, but the way the new system measures availability makes it look less ready than it really is. Eventually these matters will all be sorted out, and it will be obvious the MV-22 is far, far superior to a conventional rotorcraft in just about any imaginable scenario. That's why even the Army, which has no formal plans to buy tilt-rotors, is taking a close look at its medical-evacuation potential. Let's just hope the rest of the world wakes up to the revolutionary potential of tilt-rotor technology while there is still time to leverage economies of scale off of a warm production line.
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Osprey to star at RIAT
9 March 2012 | UK
A unique aircraft that is both a helicopter and an aeroplane will make a rare appearance in the UK when it takes part in the Royal International Air Tattoo at RAF Fairford this summer.
The US Marine Corps MV-22B Osprey stole the show at the Air Tattoo 2006 where it marked its UK flying display debut. It is the world’s first tilt-rotor aircraft and makes a welcome return to Fairford on July 7-8 2012.
A cross between a helicopter and a fixed-wing aeroplane, the Osprey’s rotor blades can tilt mid-air enabling it to take off vertically and then reconfigure to fly like an aeroplane. This allows it to reach speeds twice as fast as a helicopter and carry heavier payloads at higher altitudes.
In 2007, the aircraft was deployed operationally for the first time, supporting routine cargo and troop movements in Iraq. Two years later, the aircraft performed its first offensive combat mission, Operation Cobra’s Anger, transporting US Marines and Afghan troops into Helmand Province to disrupt the Taliban’s communications and supply lines.
In 2010, Ospreys performed their first humanitarian mission, operating in Haiti as part of Operation Unified Response following an earthquake in the country.
The US Marine Corps plans to send two MV-22Bs, one for the flying display and the other for the static park.
An Air Tattoo spokesman said few other modern aircraft have been so revolutionary in terms of their design and operational capability. He added: “In musical terms, adding the Osprey to the flying display is a bit like Glastonbury adding Jay-Z to the bill – it’s sassy, has lots of good moves and looks downright cool.”
9 March 2012 | UK
A unique aircraft that is both a helicopter and an aeroplane will make a rare appearance in the UK when it takes part in the Royal International Air Tattoo at RAF Fairford this summer.
The US Marine Corps MV-22B Osprey stole the show at the Air Tattoo 2006 where it marked its UK flying display debut. It is the world’s first tilt-rotor aircraft and makes a welcome return to Fairford on July 7-8 2012.
A cross between a helicopter and a fixed-wing aeroplane, the Osprey’s rotor blades can tilt mid-air enabling it to take off vertically and then reconfigure to fly like an aeroplane. This allows it to reach speeds twice as fast as a helicopter and carry heavier payloads at higher altitudes.
In 2007, the aircraft was deployed operationally for the first time, supporting routine cargo and troop movements in Iraq. Two years later, the aircraft performed its first offensive combat mission, Operation Cobra’s Anger, transporting US Marines and Afghan troops into Helmand Province to disrupt the Taliban’s communications and supply lines.
In 2010, Ospreys performed their first humanitarian mission, operating in Haiti as part of Operation Unified Response following an earthquake in the country.
The US Marine Corps plans to send two MV-22Bs, one for the flying display and the other for the static park.
An Air Tattoo spokesman said few other modern aircraft have been so revolutionary in terms of their design and operational capability. He added: “In musical terms, adding the Osprey to the flying display is a bit like Glastonbury adding Jay-Z to the bill – it’s sassy, has lots of good moves and looks downright cool.”
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"Shows of force" are a pretty common thing. Not as effective as actually engaging, but it's enough to make them put their heads down for a bit.
Dropping bombs over there is taken as something of a last resort under current ROE, for better or worse.
Dropping bombs over there is taken as something of a last resort under current ROE, for better or worse.
After this last bit of force showing.....we might really really think about bringing all our Lads and Lasses home!
The 64 Dollar question....Will there be as much rioting, mayhem, and noise over the murder of 16 Civilians as there was over the accidental burning of a hand full of Qurans?
I bet not! Which to a reasonable person does really make one wonder how in the hell we can ever relate to such folks!
The 64 Dollar question....Will there be as much rioting, mayhem, and noise over the murder of 16 Civilians as there was over the accidental burning of a hand full of Qurans?
I bet not! Which to a reasonable person does really make one wonder how in the hell we can ever relate to such folks!
How it flies
For those interested
Flying the V-22 | Vertical - Helicopter News
An Air Force major describes some of the handling characteristics of CV-22.
Osprey Driver may or may not wish to comment.
Flying the V-22 | Vertical - Helicopter News
An Air Force major describes some of the handling characteristics of CV-22.
Osprey Driver may or may not wish to comment.
The Marines are still acting like Cats covering up poop......and defaming two Good Marines in the process....all to hide malfeasance at senior levels of command.
http://http://thehill.com/blogs/defcon-hill/marine-corps/218913-jones-widows-seek-exoneration-for-marine-pilots-in-2000-osprey-crash]Rep. Jones, widows seek exoneration for Marine pilots in 2000 Osprey crash - The Hill's DEFCON Hill
Talk about looking out for the Troops.......yeah right!
Just as a side note.....this McCorkle fella.....well at least he knows who butters his bread....and would upon his retirement!
http://http://thehill.com/blogs/defcon-hill/marine-corps/218913-jones-widows-seek-exoneration-for-marine-pilots-in-2000-osprey-crash]Rep. Jones, widows seek exoneration for Marine pilots in 2000 Osprey crash - The Hill's DEFCON Hill
Jones said the Marines’ investigation report actually exonerates the pilots — it was the Marines’ statement about the investigation that sparked the “pilot error” blame.
“Unfortunately, the pilots’ drive to accomplish that mission appears to have been the fatal factor,” the release said.
That statement led to years of press accounts that said pilot error was the cause of the crash, Gruber and Brow say. They are asking the Marines to issue a statement that says the two pilots “were not at fault” and include it in the accident report.
As Jones stepped up efforts to clear the pilots’ names last year, he solicited letters from the three crash investigators, all of whom wrote that the pilots should not be blamed for the crash.
Documents reviewed by The Hill and interviews with those involved show the circumstances surrounding the accident do not lead to simple conclusions. While the pilots took actions that contributed to the crash, they and their superiors did not yet understand the flight condition called “vortex-ring state” (VRS) that caused the Osprey to roll over and crash.
“Unfortunately, the pilots’ drive to accomplish that mission appears to have been the fatal factor,” the release said.
That statement led to years of press accounts that said pilot error was the cause of the crash, Gruber and Brow say. They are asking the Marines to issue a statement that says the two pilots “were not at fault” and include it in the accident report.
As Jones stepped up efforts to clear the pilots’ names last year, he solicited letters from the three crash investigators, all of whom wrote that the pilots should not be blamed for the crash.
Documents reviewed by The Hill and interviews with those involved show the circumstances surrounding the accident do not lead to simple conclusions. While the pilots took actions that contributed to the crash, they and their superiors did not yet understand the flight condition called “vortex-ring state” (VRS) that caused the Osprey to roll over and crash.
The Marines remain unconvinced. In his last letter to Jones in 2011, Amos wrote: “I cannot prevent outside observers from using unflattering characterizations about these pilots.”
But some who were involved don’t think the Marines should change their report. Retired Lt. Gen. Fred McCorkle, former Marine aviation chief, said while the crash was heartbreaking, the pilots’ actions still led to the tragedy.
“To me, it was human factors,” McCorkle said in an interview. “That’s what I’ve told the family, and that’s the way it’s going to stay.”
“To me, it was human factors,” McCorkle said in an interview. “That’s what I’ve told the family, and that’s the way it’s going to stay.”
While the V-22 was considered for cancellation in 2001, there was heavy political lobbying to save it. The Boeing effort was led by General Richard Hearny, the former head of Marine Aviation, who retired in 1996 and is Vice President for business development at Boeing. The lobby effort for Boeing's partner, Bell Helicopter, was led by its Vice President for government relations, General Terrence R. Dake, who retired from the Marines in 2000 after heading Marine Aviation. The effort at Headquarters Marine Corps was led by the head of Marine Aviation, General Fred McCorkle (left). Soon after retiring from the Marines in October 2001, McCorkle joined the board of directors and as a senior advisor for GKN Aerospace Services (V-22 fuel tanks). He also serves on the Rolls-Royce North America board of directors (V-22 engines), and is a member of the board of directors of Lord Corporation (V-22 components). In addition, he has served as a consultant for Boeing Aerospace (V-22 maker) and Optical Air Data Systems (V-22 low airspeed indicator).
While these Generals receive an $8000 a month retirement check from the Marines, a tradition has emerged in which the head of Marine Aviation is financially rewarded after retirement for not rocking the boat. Questioning the progress of the V-22 is difficult since the current head of Marine Aviation must challenge his former bosses working for defense contractors. This was revealed during a December 2000 news conference when a reporter asked General McCorkle if the Corps might abandon the V-22. McCorkle replied: "that would be something above my pay grade, quite frankly." At that time, McCorkle was a three-star General and head of Marine Aviation, yet he considered the future of Marine Aviation to be in the hands of others. McCorkle saw himself as a just a salesman whose loyalty to the V-22 program would make him a wealthy executive.
While these Generals receive an $8000 a month retirement check from the Marines, a tradition has emerged in which the head of Marine Aviation is financially rewarded after retirement for not rocking the boat. Questioning the progress of the V-22 is difficult since the current head of Marine Aviation must challenge his former bosses working for defense contractors. This was revealed during a December 2000 news conference when a reporter asked General McCorkle if the Corps might abandon the V-22. McCorkle replied: "that would be something above my pay grade, quite frankly." At that time, McCorkle was a three-star General and head of Marine Aviation, yet he considered the future of Marine Aviation to be in the hands of others. McCorkle saw himself as a just a salesman whose loyalty to the V-22 program would make him a wealthy executive.
Operating a vehicle outside the defined NATOPS would be grounds for a determination of "pilot error" would it not?
A great comment posted on the article itself:
A great comment posted on the article itself:
Descent limits were in place. All rotary winged pilots are trained to observe the 800/40 rule. When ground speed is 40 knots or less rate of descent is not to exceed 800 feet per minute. The NATOPS manual that existed for the Osprey at the time included the 800/40 rule. Brow and Gruber were both trained to observe the 800/40 rule. Gruber himself was an experienced CH-53E pilot. The fact is that if Brow and Gruber had flown any rotary winged platform in the same manner that they flew the Osprey that night, the results would have been the same.
HROD testing of the V-22 showed that the Osprey is less susceptible to entering VRS than any rotary winged platform and when encountered, recovery is achieved much quicker in the Osprey.
http://legacy.vtol.org/pdf/test-60.pdf
"causing one of the rotors to enter VRS and stop rotating,"
Jeremy Herb doesn't know what he's talking about. Due to the high rate of descent one of the proprotors lost lift due to the "dirty air" beneath it; it did not stop rotating, causing the aircraft to roll due to the asymmetric lift.
Walter Jones has been repeatedly rebuked by the Department of the Navy for this crusade of his. He needs to accept that this accident was indeed caused by pilot error and move on. His constituents deserve a Congressman who doesn't spend his career beating a dead horse.
Were John Brow and Brooks Gruber here today they'd admit that they made a number of errors that night in deviating from NATOPS: descending at nearly 3500 feet per minute at ~100 knots, losing situational awareness and violating basic airmanship guidelines. They screwed the pooch and ended up killing 19 Marines in the process. Any other explanation is simply revisionist history.
HROD testing of the V-22 showed that the Osprey is less susceptible to entering VRS than any rotary winged platform and when encountered, recovery is achieved much quicker in the Osprey.
http://legacy.vtol.org/pdf/test-60.pdf
"causing one of the rotors to enter VRS and stop rotating,"
Jeremy Herb doesn't know what he's talking about. Due to the high rate of descent one of the proprotors lost lift due to the "dirty air" beneath it; it did not stop rotating, causing the aircraft to roll due to the asymmetric lift.
Walter Jones has been repeatedly rebuked by the Department of the Navy for this crusade of his. He needs to accept that this accident was indeed caused by pilot error and move on. His constituents deserve a Congressman who doesn't spend his career beating a dead horse.
Were John Brow and Brooks Gruber here today they'd admit that they made a number of errors that night in deviating from NATOPS: descending at nearly 3500 feet per minute at ~100 knots, losing situational awareness and violating basic airmanship guidelines. They screwed the pooch and ended up killing 19 Marines in the process. Any other explanation is simply revisionist history.
40/800 rule and 53E's
Sans,
Don't know the source of the article, but the section professing that the 40/800 VRS boundary applies to 53E's ( implying all helicopters ) and that a 53E, if flying the same profile, would have encountered the same result, is simply incorrect. Reminiscent of the old saw about the " Big Lie ".
Thanks,
John Dixson
Don't know the source of the article, but the section professing that the 40/800 VRS boundary applies to 53E's ( implying all helicopters ) and that a 53E, if flying the same profile, would have encountered the same result, is simply incorrect. Reminiscent of the old saw about the " Big Lie ".
Thanks,
John Dixson
John is exactly right.....especially when one considers the 53 is single rotored...and thus not possibly susceptible to differential Vortex Ring State.
Despite the three Accident Investigators clearly stating it is their separate and jointly held opinion the two pilots were not responsible for the accident....I would suggest they are much closer to the issue and thus have a basis upon which to make that statement.
Sans....I really do object to you saying what you just did about the Pilots....both in tone....and more specifically as it is directly opposed to what the Accident Report and the three Accident Investigators had to say.
It is a USMC Press Statement that laid the blame on the pilots.....not the Accident Inquiry.
I submit both you and the USMC are wrong in what you are saying.
It is because of that fatal crash that more testing had to be done and the true dangers of VRS in the Osprey became known.
The two dead men did not have benefit of all that later data.....did they?
Despite the three Accident Investigators clearly stating it is their separate and jointly held opinion the two pilots were not responsible for the accident....I would suggest they are much closer to the issue and thus have a basis upon which to make that statement.
Sans....I really do object to you saying what you just did about the Pilots....both in tone....and more specifically as it is directly opposed to what the Accident Report and the three Accident Investigators had to say.
It is a USMC Press Statement that laid the blame on the pilots.....not the Accident Inquiry.
I submit both you and the USMC are wrong in what you are saying.
It is because of that fatal crash that more testing had to be done and the true dangers of VRS in the Osprey became known.
The two dead men did not have benefit of all that later data.....did they?
Thread Starter
V-22 ≠ H-53E
John Dixson is absolutely correct. One cannot compare the V-22 to the H-53E. One of my first test flights in the H-53E was a pitot system calibration flight. There were two end points to the test, a 40 KIAS autorotation and a Vne (170KIAS) autorotation. At 40 KIAS and the VSI pegged at 6000 FPM rate of descent our recovery was accomplished with collect alone. To quote the Chief Program Pilot (Frank Tefft) when he instructed me to just increase the collective, he said “that the machine wouldn’t like it but it could take it.” Sure enough, 13,000m ESHP dug us out of the descent with no signs of VRS. Later in my career I was provided with an opportunity to fly in an H-53E with Brooks Gruber. He was a consuement professional and a Great pilot. If there were any mistakes made by the flight crew, it was assuming that the V-22 would perform similarly to the H-53E.
Sans....I really do object to you saying what you just did about the Pilots....both in tone....and more specifically as it is directly opposed to what the Accident Report and the three Accident Investigators had to say.
And, as nobody has deemed it necessary to respond, Ill repeat my question from the previous post.
Does or doesn't operating an aircraft outside NATOPS warrant a "pilot error" determination? Simple question.
http://legacy.vtol.org/pdf/test-60.pdf
7. In comparison to the published NATOPS descent rate limitation, it is shown that the V–22 has significant margin for avoiding VRS.
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Did the manner in which the meat servo manipulated the controls play a significant role in the mishap? Yes? Then it's pilot error. Stop beating a dead horse. Pilot error is a term of art in the aviation community. I'm sorry if some civilians are butt-hurt by it.
Let's put it another way. Say you're in a King Air taking off and you have a single-engine failure. You goon up the abort and ball the plane up at the departure end. PILOT ERROR. But if the engine hadn't failed you wouldn't have crashed. Tough. It doesn't mean you're a bad person, or even, depending on the circumstances, a bad pilot, just that someone who had applied procedures properly would've not crashed the plane.
Whether "VRS" caused the crash or not, the Marana crew entered a high ROD profile at low airspeed close behind another aircraft. That's bad juju in anything.
BTW, the 40KIAS VRS limit doesn't exist because VRS starts there--it starts there because pitot-static instruments don't give accurate indications below 40KIAS, so that's why most r/w manuals say to avoid high RODs below that airspeed. If one can recover from VRS with power, per the 53 example above, one wasn't in VRS to start with.
Let's put it another way. Say you're in a King Air taking off and you have a single-engine failure. You goon up the abort and ball the plane up at the departure end. PILOT ERROR. But if the engine hadn't failed you wouldn't have crashed. Tough. It doesn't mean you're a bad person, or even, depending on the circumstances, a bad pilot, just that someone who had applied procedures properly would've not crashed the plane.
Whether "VRS" caused the crash or not, the Marana crew entered a high ROD profile at low airspeed close behind another aircraft. That's bad juju in anything.
BTW, the 40KIAS VRS limit doesn't exist because VRS starts there--it starts there because pitot-static instruments don't give accurate indications below 40KIAS, so that's why most r/w manuals say to avoid high RODs below that airspeed. If one can recover from VRS with power, per the 53 example above, one wasn't in VRS to start with.
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JD
No has stated the 53E would enter VRS at less than 40 Knots and less than 800 fpm sink rate. The statement you object to is that a 53E put into the same (or really lessor) extremes seen in Arizona would have actually entered VRS. Fact is one of the investigating board members took a 53 into VRS as part of the investigation and stated he would never do that again. You can read that for how he meant it.
Truth is truth, physics is physics. The only great lie is the 53 is safer than a V-22.
TC
No has stated the 53E would enter VRS at less than 40 Knots and less than 800 fpm sink rate. The statement you object to is that a 53E put into the same (or really lessor) extremes seen in Arizona would have actually entered VRS. Fact is one of the investigating board members took a 53 into VRS as part of the investigation and stated he would never do that again. You can read that for how he meant it.
Truth is truth, physics is physics. The only great lie is the 53 is safer than a V-22.
TC
Flight Manual Restrictions?
Originally Posted by Osprey Driver
BTW, the 40KIAS VRS limit doesn't exist because VRS starts there--it starts there because pitot-static instruments don't give accurate indications below 40KIAS, so that's why most r/w manuals say to avoid high RODs below that airspeed.
Let me attempt to explain an aerodynamic reality that occurs in slow, relatively steep descents that I believe several in the forum have incorrectly believed to be the edge or onset of VRS (there are other members whose reports are clearly VRS).
In descending flight at speeds in the 15-30 kt range and at rates of descent in the 700-1500+ fpm range, the advancing tip penetrates the tip vortex from the preceding blade (one can immediately see how the flight conditions for this effect are affected by weight, altitude, temperature), and the instantaneous angle of attack change on that tip results in a lift, drag and pitching moment change that effectively "rings" the main rotor at N/rev and can produce, if air conditions are stable enough to stay in this situation, very high vibration levels at N/rev frequency. One has to consciously try varying the ROD and airspeed to find this effect (in day to day flying we usually we fly right on thru it), but it is there if one goes looking, or if the combinations are just right. SA has always used this manoeuvre (at least since before I started doing engineering flying in 1969), called a "rough approach" as a flight loads survey manuever, as the associated vibrations may impact engine mount loads, or perhaps electrical, hydraulic, or other hardware that is mounted on the transmission deck (they are typically far higher than the N/rev vibrations associated with VRS as discussed below). The blade stress guages clearly reflect what is happening here. HOWEVER, it is key to this discussion to realize that when in this condition the vehicle is rock solid in pitch, roll, yaw ROD and airspeed.
Finding the right combination for a "rough approach" as described above is a piece of cake compared to getting VRS data. Since you are looking for 2500 fpm (ballpark) and a stable situation, one starts at 6-8000 ft. The vehicle has to be coming down exactly vertical relative to the airmass, so on the most recent vehicle we did this on, the S-92, we thought that since we had a super new, state of the art low airspeed system onboard it would be easier than usual, but it wasn't to be, and thus we were forced to use the sides of clouds etc. Once VRS is found, the effect upon the vehicle is dramatic, with rather sharp excursions in the pitch and roll axes, some smaller excursions in yaw due to the power changing (at fixed collective) as a result of non-steady inflow, and increased N/rev vibrations. If not ready for the ride, one can understand the reference offered in Tcabot's posting:
"Fact is one of the investigating board members took a 53 into VRS as part of the investigation and stated he would never do that again. You can read that for how he meant it."
In the case of fully developed helicopter VRS, the vehicle is hardly rock solid.
Two very different rotary wing aerodynamic situations.
Misconstruing a "Rough Approach" situation with the profile necessary for a VRS event can create unneeded restrictions. I mention that because some friends have heard unconfirmed "buzz" about possible regulatory restrictions (civil) on steep approach profiles.
Thanks,
John Dixson
Bummer.....inconvenient facts again! Yet another learning opportunity from SA and Captain D! Thank you John....always good info from you.
I take it then....when you say "exactly vertical" that means an actual relative wind of "Zero" no matter what IAS is "clocked".
How much leeway does that allow for airspeed variance in actuality before you lose the effect?
Also....in the larger aircraft....it has been said one can simply "power" your way out of VRS without resorting to the CW of "flying" out of the situation.
Is that true....and if so....how much would that apply to the Osprey where only the one Prop Rotor is in VRS?
I cannot recall ever getting into VRS in a Chinook....though when doing a Training Demo it was possible to get some instability and vibration but never ever anything that would have remotely have been described as scaring my socks off.
Any memories of Chinook days you can add?
I take it then....when you say "exactly vertical" that means an actual relative wind of "Zero" no matter what IAS is "clocked".
How much leeway does that allow for airspeed variance in actuality before you lose the effect?
Also....in the larger aircraft....it has been said one can simply "power" your way out of VRS without resorting to the CW of "flying" out of the situation.
Is that true....and if so....how much would that apply to the Osprey where only the one Prop Rotor is in VRS?
I cannot recall ever getting into VRS in a Chinook....though when doing a Training Demo it was possible to get some instability and vibration but never ever anything that would have remotely have been described as scaring my socks off.
Any memories of Chinook days you can add?