Comments on: Osprey Ready for Primetime? Part Two

By: rotorhead146

rotorhead146 — Sun, 25 Feb 2007 08:59:43 +0000

You guys are not seeing the big picture. The political winds are shifting. Massive budget deficits in conjunction with ever increasing entitlement expenditures will soon have a crushing effect on defense bugets. Forget VRS. Forget the fact that the H46 has done a fantastic job in Iraq (even if senior Marine leadership has it flying around at unacceptably high altitudes making it vulnerable to MANPADS). Forget the fact that H-53 operations are restricted in the Sunni Triangle do to its vulnerability to MANPADS (makes me wonder what the V-22 will be relegated to). The simple fight for scarce defense dollars will kill the V-22. Someday when we are starving to feed that beast, the Marines will awaken to a catastrophic mistake. So argue over VRS if you like. The almighty dollar killing the V-22 will be the best thing that ever happens to the Marines.

By: Gordon

Gordon — Fri, 02 Feb 2007 23:32:47 +0000

It is always sad to see technolgy overwhelm common sense. There are so many reasons to NOT go forward with V-22 they could probably fill a few college blue books.
From its lack of ability to protect itself, to its cost, to its questionable ability to survive a combat environment, the stresses of combat on its components, its maintenance cost/component costs and a litany of other problems, it is difficult to imagine the 22 becoming a successful combat aircraft.
Why would DOD want to develop a multi-billion dollar aircraft that will be utilized for troop insertion/extraction, med-evacs, and resupply missions? Granted, its speed is an advantage but it appears to be the only advantage the 22 has over a standard helicopter. The claimed altitude advantage was a canard as it does not have a pressurized cabin. Consequently, its speed advantage and claimed reduced fuel operating expenses are out the window.
I certainly do not want to anger anyone but sometimes, people involved in developing a widget become so determined, so adamant they lose sight of what they are actually trying to accomplish and consequently begin to ignore relevant evidence. I hope this is not the case and I do hope the 22 does succeed…God knows, enough Marines have paid the price to get this bird in the air. Let’s all hope the disciples of the 22 are correct and we doubters wind up with egg on our faces.
S/F Gordon

By: helodriver

helodriver — Fri, 02 Feb 2007 14:55:13 +0000

rjsquirrel said
“The typical helicopter has no such restriction on its rate of descent at low speeds, and would certainly not flip upside down should a pilot chose to descend faster.“
…I don’t know what you fly but for the past 15 years of flying RW aircraft I’ve been taught to stay out of VRS. Having spent 14 of those years flying USMC helicopters I can tell you that EVERY USMC helicopter NATOPS limits them to 40kts, 800 fpm rate of descent in order to stay out of VRS, so no, the V-22 is no different. Yes most helicopters can exceed that limit, just as the V-22 can, it is a conservative number which doesn’t affect your approach into a landing zone. A well executed tactical approach won’t have you doing 20 kts and a 1000 fpm rate of descent close to the ground and most approaches into a hot LZ aren’t very vertical in nature.
At altitude VRS is recoverable by BOTH a TR and helicopters. Close to the ground getting into VRS in either platform can be deadly. That’s why you train, plan and execute.
As far as maneuverablilty is concerned, I’m sure you think you’re laying on the g’s at slow speed but you’re lucky to get 1.3 g and that’s with very large control displacements.

By: skiddriver

skiddriver — Fri, 02 Feb 2007 14:04:34 +0000

rjsquirrel couldn’t be more wrong. All helicopters have a similar power settling limit related to VRS. I’ve not only flown them for over two decades, but I’ve conducted flight tests on them, graduated from USNTPS, and like Tom (who I know) am a member of SETP. The average restriction is 800 FPM below 40 knots. Use you RFM/NATOPS/-10 for individual discussion on the machine you happen to be guiding through the air on any given day.

By: Jim

Jim — Fri, 02 Feb 2007 04:09:11 +0000

A quick correction first off…VRS was responsible for the April 2000 crash. The Dec 2000 was in part, caused by a hydraulic leak. After the April 2000 crash, the VRS envelope for the V-22 was thoroughly tested as well as procedures for avoiding and if necessary flying out of VRS
As for VRS and the V-22, the article above said it best…it is less of an issue than critics are making it out to be, a lot of smoke and no fire.
Having been a crewmember on a USAF special operations helicopter for eight years prior to coming to the CV-22 three years ago, I remember having VRS warnings in my Dash-1 for the MH-53M that I was a flight engineer on. In particular, it highlighted the conditions for VRS as being a vertical velocity of more than 800fpm, airspeed less than 40 KIAS, and power applied to the rotor system. The procedure to exit VRS in a helicopter was to INCREASE AIRSPEED, while decreasing power to the rotor system.
In contrast, the V-22 does have the same issues with a vertical velocity at or above 800fpm and airspeed below 40 KCAS. However, the difference between helicopters and the V-22 lies in both crew alerting of VRS and the procedure to fly out of it. The procedure for the V-22 to fly out of VRS involves “beeping” the nacelles forward for two seconds. What is unique for the V-22 is that power does not need to be decreased and the aircraft attitude does not need to change. We can in essence, fly out of VRS, with out trading anything for it. .
The V-22 has four tools for combating VRS; extensive flight testing following the 2000 crash, training, visual cues of the dynamic VRS threshold and finally an audible warning of SINK RATE. At 40 KIAS and above the limit is 800 fpm. Additionally, with an air data system failure the crew warning system defaults to 800 fpm as the VRS limit. At airspeeds above 40 KCAS, the VRS threshold is dynamic with the limit increasing with airspeed, topping out at 1100fpm. The absolute edge of the VRS envelope for the V-22 has been determined to be 1800fpm.
All of this said, I fly on the CV-22 at least three times a week. Having been doing so for three years I am very comfortable with the safety factor of the V-22. Additionally, I believe that for the both USMC and the USAF the V-22 will meet and exceed expectations that we currently have for the aircraft.

By: BT

BT — Thu, 01 Feb 2007 21:00:30 +0000

It’s going to be a PR disaster the first time the V-22 crashes into an Afghan mountain, or is shot down in Iraq. I would only be impressed by the V-22’s performance, if it could rescue people on the top of Mt. Everest, or is armored like an A-10. Since that is not the case, I think it’s waste of money; it’s a good idea, but not for combat ops.

By: Skeptic

Skeptic — Thu, 01 Feb 2007 20:37:30 +0000

I agree that such a diagram would be invaluable in understanding the phenomenon, but fortunately detailed plots of military aircraft performance are generally classified. I say fortunately because that information is just what an enemy wants to have to find out where the vulnerabilities of a system are. All the armchair Quarterbacks will just have to pontificate without all the data as usual and pooh-pooh the decisions of those who both have all the information and will have to bear the cost of any error. The fact that the Marines are so hot to get this bird into service ought to indicate to any reasonable person that they believe that whatever drawbacks the design may have are more than made up for by the increased capabilities that come with it as well.

By: rjsquirrel101

rjsquirrel101 — Thu, 01 Feb 2007 19:43:12 +0000

The typical helicopter has no such restriction on its rate of descent at low speeds, and would certainly not flip upside down should a pilot chose to descend faster. The comparison of TR VRS to helo VRS is a chilling one. The TR loses control, flips upside down and creates a disaster when it is flown into the VRS region, which is close to its operating regime. Close enough so that it was found by the earliest OTE flights, disasterously.
Regarding helicopters and descent rate limits, no helicopter has such restrictive limits on approach. The “limits” that TR folks have quoted for helos to say they have “similar” limits are the landing gear structural limits based on ground contact, and have nothing to do with this discussion. They are a distraction that TR folks use to cover for the obviously poor capabilities of the TR.
I have flown at thousands of feet per minute descents in many helicopters at speeds near zero knots, and so have most helo pilots. To say that this is a forbidden zone is absurd. To know that doing so will flip you upside down should be a warning that the air vehicle that has this limit is not fit for combat insertions.
Furthermore, the small maneuver capability of the TR at lower speeds, less than 1.3 g’s in helo mode, is a severe impediment to combat landings, and makes the TR a sitting duck on any contested landing. Helos have a much larger envelope, and are much more nimble at the close-in approach and departure regimes.

By: Nicholas Weaver

Nicholas Weaver — Thu, 01 Feb 2007 18:13:36 +0000

Glad to see this.
However, I think a figure would be worth 1000 words, and would probably HELP the osprey case:
On the Y axis, have “Descent rate (FPS)”.
On the X axis, have “Forward Rate (MPH)”.
Graph both the Blackhawk’s flight envelope and the Osprey’s, for both the recommended “Do not exceed” profile and where vortex ring state kicks in (the “you’re F@#)($*ed”) profile. Yeup, basically the “descent” portion of the flight envelope.