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Nov 07, 2011



Just as an interesting note, the Santa Ana winds that have so violently ripped through the Southeastern US this week have been caused by 2 counter rotating wind masses. I'd blame the V-22 for these winds, but even it can't screw things up that badly. I saw a picture like the one I linked to on the local news and thought it would be an interesting object lesson in what can happen when two rotating masses of air collide as they do under the V-22. This is one of the key reasons Bell abandoned the XV-3, 2 rotor configuration of VTOL aircraft for the X-22, quad rotor approach.


I certainly wish I did have it. That's one of the ways they make these things difficult to get via a freedom of information act request. They claim not to know what you are talking about when you request a study that you know exists but you don't have the name or document number for. From the rumors I heard back when they were looking for someone to do this study, I doubt even if you had the name they would release it or acknowledge it in any way.

It is sadly ironic that they classify data like this based the claim that by releasing the information it would expose a weakness of the aircraft that could be exploited by an enemy. In reality, they are only covering their own asses and covering up data that should have resulted in the cancellation of the V-22 program. I have seen this done many times before, and I've often wondered why pilots themselves do not stand up against this practice of covering up aircraft problems by trashing the lives and reputations of the pilots.

There seems to be this pilot psychology, though, that makes them want to deny anything bad will ever happen to them. They will literally turn on a fellow pilot in a heartbeat because they feel like if they isolate that pilot as being "bad" and "not like them" then nothing bad will ever happen to them. This must be some sort of false bravado that is backed up by an aspect of their training. "There but by the grace of God go I" would be a much better attitude. It is by the acumulated exploitation of many small character weaknesses that this current status quo is allowed to survive. Anyway, my apologies for not being able to help this cause with more information.

Bryan Rahija

Dfens -- can you provide any more info about the study (or studies) you mention? Would be great to know the name / title of the study, date of publication, the office that published the study, and / or any other details. Thanks to you both for your insightful comments!


So now you see why I make the distinction between the asymmetric vortex ring state (AVRS) and the standard vortex ring state. It is so the program bureacrats don't confuse those concerned about this brave pilot who was killed and his good name that has been trashed with irrelevant issues. The fact is, the flight rules for the V-22 have changed significantly since the studies were done that showed the dangers of this AVRS that is unique to the V-22. Whether they release that study or not, it is obvious to anyone that these flight rules have changed and there is no doubt they changed due to some kind of new finding. Hopefully the congressman and his staff will not allow the V-22 program bureacracy to side track their efforts and they will keep the AVRS issue their focus.

It is a shame these program bureacracies are so willing to destroy the lives and reputations of our brave young soldiers just to keep the taxpayer's dollar flowing their way. One of the best reasons to reform our defense procurement system such that we no longer pay contractors to do development is so we can drive a stake through the black heart of these faceless, unaccountable bureacracies. The soldier should not serve the weapon. The weapon should serve the soldier.

A.A. Cunningham

The misunderstanding of VRS and the Osprey continues. HROD testing conducted in 2003 confirmed that the V-22 is less susceptible to entering VRS than any other rotary winged platform and when encountered, recovery from same is accomplished much quicker and safer in the Osprey.

"In August 2003, the V–22 Integrated Test Team completed a thorough investigation of the V–22’s low-speed / HROD flight
characteristics. Testing defined an operational envelope for the aircraft and demonstrated flight regimes free from vortex ring state (VRS). Tests also probed deeply into fully developed VRS to determine precise flight conditions where it may be encountered, and to confirm the ability of the V–22 to recover from the condition. The ability to tilt the nacelles proved to be a powerful and (in every case) reliable means for rapidly regaining aerodynamic function of the rotors, even when operating in VRS beyond the point of having sufficient controllability.In an operational sense, the test results show that the V–22 has a significantly higher rate of descent margin for avoiding VRS with respect to the published NATOPS limitation than conventional low disk-loading helicopters. Furthermore, dynamic maneuver testing of the V–22 showed that VRS cannot be initiated outside the steadystate VRS boundary. Simple engineering analysis is used to show that the V–22’s steady-state VRS boundary is predictable by simple methods that work for conventional helicopters. High blade twist, and the side-by-side rotor configuration of the V–22 do not play a significant role in defining the VRS boundary."


The fact of the matter; which is lost on Walter Jones, amongst many others, is that had Brow and Gruber been flying any other rotary winged platform that night in Marana the results would have been the same. Egregious violations of the 800/40 rule, abandoning basic airmanship skills and losing situational awareness; all of which occurred that night by the aircrew in question, often have fatal results.

'“Anyone familiar with the accident agrees that the pilots were not at fault,” Jones told POGO in a recent interview.'

Jones speaks only for himself. Those of us who are intimately familiar with the Marana incident disgree with the conclusion of yet another congressional neophyte. Instead of lauding Jones for his futile attempt at rewriting history he should receive the scorn he deserves.


Quoting from the complete article:
"Lawrence's concerns were backed up by the three Marine investigators who were responsible for establishing findings from the crash. According to their investigation, the "asymmetric vortex ring state" (VRS) -- a hazardous condition encountered in helicopters, which can derail a controlled landing—was the cause of the crash. The report said that there was no warning of VRS in the pilots' manual, and Bell/Boeing didn't fully test for this "dangerous design flaw."

"The accident aircraft was under control until the moment the right prop-rotor lost lift, after which the roll was unrecoverable," said the investigators' report.
Though this statement is mostly true, there is one key point that is not true and that has been hidden by the Marines and not disclosed as a result of their investigations. Although helicopters do experience a "vortex ring state" that can cause them to crash, they do not experience an "asymmetric vortex ring state" (AVRS) as the V-22 does. Partly this is obvious because helicopters typically only have a single rotor and therefore cannot experience a wild rolling maneuver due to losing lift in a single rotor since they only have the one.

The rest of this AVRS phenominon is not so obvious, but I had a hypothesis about its nature, a hypothesis that was confirmed when I saw the way the rotor flow influenced the surface of the ocean in a photograph of the V-22 hovering over water. The air coming off the rotors has a tornado like twist imparted to it by the rotor blades, with the exception that these twin tornados blow down, not up (see the red arrows added to the picture). That twist causes a big plume of air to be blown aft of the aircraft (notice how the surface of the water is white and frothy well aft of the V-22 in a corridor between the drawn green lines). If something on the surface under the V-22 causes that plume to be deflected up it will be sucked into one or the other rotor (see the cyan arrow), causing a significant loss of lift on whichever side the plume is attracted to. Since this uncommanded roll maneuver happens close to the ground, there is no way to get out of it before the craft strikes the ground in an accident that will likely be fatal to the occupants.

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