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| Science & Technology | |
| Navy Probes Multiple V-22 Surges, Stalls | |
| 2006-07-22 | |
In addition to the compressor stalls that recently caused a V-22 Osprey to make an emergency landing in Iceland, other V-22s last week experienced compressor surges that were imperceptible to pilots at the time and officials are investigating whether all of these problems are related.
Also, officials learned that another V-22, which had been in Goose Bay as a backup aircraft, similarly experienced an imperceptible compressor surge during its return flight to New River, NC. Like a compressor stall, a compressor surge is a disruption of the air flow to the compressor, but it is not as serious, said Darcy. There may be a link between the problems experienced by these various V-22s. At press time, however, Darcy said the investigation is ongoing and would not comment further. The Osprey that landed in Iceland June 10 had its right engine replaced before flying to Farnborough, where it landed safely July 13 in the early afternoon, said Darcy. Officials are still investigating what caused the problems that forced the landing in Iceland. Darcy said the first sign of trouble was a compressor stall in the right engine, but he had no details on when this happened. The compressor stall led the right engine to flame out, meaning it stopped providing propulsion, he said. Both of the aircraft's two proprotors continued turning under the power of the remaining engine, he said. After about “10 seconds,” the pilot was able to relight the engine, said Darcy. Subsequently, however, the same engine experienced another compressor stall, prompting the pilot to land in Iceland at about 2 p.m. Greenwich Mean Time. Bell Helicopter Textron and Boeing make the Osprey, which can take off and land like a helicopter, but can also fly like a plane. Bell spokesman Bob Leder downplayed the July 10 incident that led to the landing in Iceland, which he called “a common event with turbine-powered aircraft.” But the Iceland incident was clearly not what V-22 program officials had in mind last month when they issued a press release boasting the Osprey was “writing the book” on long-range deployments. The statement predicted two V-22s would fly July 10 directly from Goose Bay to Farnborough, along with two tankers. “This will be the first time that an assault support aircraft has ever flown across the Atlantic,” said V-22 program manager Col. Bill Taylor, in the press release. “Unlike conventional rotary wing aircraft, which must be transported into overseas theaters of operation aboard amphibious shipping or heavy lift transport planes, the V-22 can self-deploy thousands of miles over water to get itself to the fight,” Taylor said in the statement. Both Ospreys participating in the air show are part of the Marine Corps V-22 squadron based in New River, NC. The V-22 that stopped in Iceland is production model No. 59, known in the squadron as Osprey No. 23, Darcy said. The other aircraft is production model No. 58, known in the squadron as Osprey No. 22. | |
| Posted by:Steve |
| #16 Sounds like a variable stator vane or variable bleed valve problem disrupting airflow through the compressor. |
| Posted by: tzsenator 2006-07-22 22:48 |
| #15 No worries. The real issue is that the Marines, who from my Army perspective deserve nothing but the very best. I'm afraid they will get the V-22 instead. We can all do better than this. |
| Posted by: 49 Pan 2006-07-22 21:00 |
| #14 Ooopss I also see that the article I was referring too...was talking about the CH-46s and not the CH-47's which are a lot larger... man I got to quit drinking so much coffee. |
| Posted by: Blackvenom-2001 2006-07-22 16:49 |
| #13 http://www.navair.navy.mil/v22/index.cfm?fuseaction=news.detail&news_id=148 Well this is where I got my info from... maybe I shouldn't believe everything I read... hmmmmm... what a novel idea |
| Posted by: Blackvenom-2001 2006-07-22 16:46 |
| #12 I think the combat roll will slide away from Direct Action to Logistical Support Interesting. Thanks for sharing your experience. |
| Posted by: ed 2006-07-22 15:20 |
| #11 Nope, I flew MH-6's. But I've been blown aroud by them on many occasions! The inlet on the V-22 looks to me like an airplane design with that bottom inlet, and your right a giant dirt sucking device. Your right on the second point also, a barrier filter would be a monster. Time for the engineers to get back to work. I would expect until they can fix it they will limit the bird to hard stand take offs and landings. I heard they are going through compressor sections at a surprising rate. I really don't think they will ever kill this aircraft program. I think it will take a few generations of engeneering to get it combat ready and I think the combat roll will slide away from Direct Action to Logistical Support. |
| Posted by: 49 Pan 2006-07-22 15:00 |
| #10 49Pan, do you fly CH-47s? I'm not sure the compressor blade erosion problems can be fixed. The engines looks like they have such large air requirements that they cannot use filters, unlike helicopters. During low hover or landing the engines have to be sucking in mass quantities of bad things. |
| Posted by: ed 2006-07-22 14:44 |
| #9 Huh? CH-47s: 70 miles and the time required is 2 Hours and 15 Minutes = 31mph. Cruise speed is listed as 143knots. Did you mean 28 minutes? V-22s will only take 17 minutes = 247mph. Cruise speed is listed as 240knots Also, the CH-47F lists a higher gross vertical takeoff weight (54,000 lbs, http://www.boeing.com/rotorcraft/military/ch47d/docs/CH-47F_overview.pdf) than a V-22 (47,500 lb, http://www.fas.org/man/dod-101/sys/ac/v-22.htm) For the cost of 8 V-22s, 24 CH-47s can be bought. That means twice as many troops landed in the same time, or money left over to buy equipment to suppress enemy defenses. Maybe I am naive, but we seem to be getting to point where we have so few assets can no longer afford losses, whether combat, accidents or maintenance down time. |
| Posted by: ed 2006-07-22 14:32 |
| #8 BV, probably need to redo your math. 70 miles is a hop in both airframes. More like the difference between 20 and 30 minutes here. The real safety issue is when they get to the objective site. The 47 you can fast rope from. CV-22 is still a must land event, this takes time and under fire is critical. The 22 can not get into the confined spaces that a 47 can, I know were talking confined spaces for giant aircraft here. But it can not land on a two lane road and can not let the Marines fast rope from it either. |
| Posted by: 49 Pan 2006-07-22 14:22 |
| #7 V-22 will be like the CH-47. Deployed by ship and self deploy only in an emergency, both V-22 and MH-47 can self depoly. After all those hours for self deployment the scheduled maintenance will ground both aircraft and take nearly as much time to repair as it would to ship it. Only in a crisis event where a few could be sent ahead and others to follow will work for this self deployment myth. As for the compressor stall/surges these are really not as big a deal as it sounds. It is common and they will figure out the inlet or bleed air issues with it. The engines seem to have some issues with compressor blade erosion requiring frequent engine replacement. This is something that can get fixed. The aircraft still has fundemental flight control issues. These will not get fixed as easy as the engine issues. My vote goes with Ed. We could by a number of 47's for the cost of one V-22. Once the V-22 gets into theater it is limited in mission profile, HUMVV wont fit in it but they will fit into a 47. I believe a 47 will haul more troops as well. This thing is going to turn into an herring. |
| Posted by: 49 Pan 2006-07-22 14:15 |
| #6 It takes 12 CH-47s to move 180 marines 70 miles and the time required is 2 Hours and 15 Minutes. It will take 8 V-22s to move the same 180 marines and will only take 17 minutes to cover the 70 miles... Less time in the air means less death for our boys on the ground... |
| Posted by: Blackvenom-2001 2006-07-22 14:13 |
| #5 Great. But it isn't going to assault over thousands of miles. The land assault range is listed at 200nm, amphib assault range 50nm, remarkably similar to the CH-47F. |
| Posted by: ed 2006-07-22 14:07 |
| #4 #2 Is a V-22 really worth 3 CH-47s just to get a 50% speed increase? “Unlike conventional rotary wing aircraft, which must be transported into overseas theaters of operation aboard amphibious shipping or heavy lift transport planes, the V-22 can self-deploy thousands of miles over water to get itself to the fight,” Taylor said in the statement. |
| Posted by: Idiom Police 2006-07-22 13:53 |
| #3 gold plated dead bird but no new anti-IED HUMVV replacement |
| Posted by: Clerert Uneamp2772 2006-07-22 13:43 |
| #2 Acquisition costs of a CH-47 is $35-40 million. A V-22 is $100+ million. Is a V-22 really worth 3 CH-47s just to get a 50% speed increase? |
| Posted by: ed 2006-07-22 13:06 |
| #1 I'd rather go to Iraq then get on one of these things. |
| Posted by: tu3031 2006-07-22 12:47 |