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Home Front: WoT
Oh, By The Way, We Need A New Engine
2008-03-19
This sucker should have been cancelled a decade ago.
The V-22 has made another bid for a Cleopatra award - presented by Ares to programs that are terminally snake-bitten - by the revelation, almost casually tossed out in mid-press conference at the Navy League show by program manager Col. Matt Mulhern, that the AE 1107C engines are not lasting long enough in service and that the Navy "could go as far as re-engining the airframe".

Swapping engines is not trivial. It involves redesigning the engine nacelle and all its associated systems and repeating much of the flight test program. Mulhern wasn't giving any cost estimates, but we're talking several hundred million dollars at the minimum. The fact that the Navy is even talking about such a move says that the existing engine is not performing acceptably and that nobody's quite sure how much it will cost to fix.

The problem has to do with lifetime. All engines lose performance with age, as heat, stress and contaminants take their toll on blades and seals. The result is that the engine gets less efficient and has to run hotter to produce rated power, and eventually temperatures reach a limit. Mulhern won't say how long the current engine is lasting, but it's somewhere between a few hundred hours - which the Navy feared was going to be the engine's lifetime in Iraq - and several thousand, which Rolls-Royce predicted and used as the basis for its power-by-the-hour contract.

Mulhern says that he's not sure that the government ever believed Rolls-Royce's estimates, which does raise the question of why program officials signed that contract in the first place. However, it's not hard to realize what would have happened if the need for a new engine had been disclosed a few years ago, when the V-22 program was reeling from a series of accidents and the need for an extensive redesign.

Fortunately, there is an alternative engine available - the General Electric GE38-1B, under development for the CH-53K. Which is ironic, because - as the few of us who were in this business when the V-22 got started will recall - the GE38's design roots are in a project called the Modern Technology Demonstrator Engine, which was originally intended to be the definitive V-22 engine. But the AE 1107C was sold, back then, as a lower-risk alternative.

Meanwhile, the Marines are saying very little about operational experience in Iraq - and won't until the first operational squadron crews return in about a month. Which, coincidentally, will be after the Pentagon signs a multi-year contract for 167 more aircraft.
Posted by:Steve White

#22  49Pan - What's stopping them putting on air filtration?
Posted by: 3dc   2008-03-19 23:22  

#21  They tested the existing planes to death nearly wearing them out before they could be field deployed. And needing a higher performing engine after initial deployment is pretty much par for the course for US aircraft. You get an underpowered version to keep costs down and get the airframe deployed and then you go back and get the engine you need for it once there are several in service.
Posted by: crosspatch   2008-03-19 18:25  

#20  Bobby. Jeffrey Quill -(Spîtfire's main test pilot) dissents about the laminar wing. According to him they tried it Supermarine and found
the thinge was very delicate as the slightest
asperity, or even wear and tear detractyed dramatically detracted from the laminar flow so he alleges that in practice Spitfiré's wing was better. Also in a diving contest in 1945 it was found that the Spitfire (1945 model) had a higher speed limit (ie in a dive) than the Mustang and much higher than Thunderbolts.

I would tend to think that it was more about the
fact that the Mustang design conformed to the
area law (discovered well after WWII) and also because she had a wholly enclosed landing gear
Posted by: JFM   2008-03-19 17:02  

#19  The engines have enough power. The issue is they are not lasting to TBO. The reduction in power experienced is largely due to the dust and dirt sucked into the engine during takeoff, landings, and hovering. This wears the compressor blades, forcing the engine to work harder to produce the same power thus wearing the rest of the enginge out in a downward performance trend. It does not matter what engine they stick on that aircraft, they will run into the same problem. They need to design a filtration system for the inlet, something other than that large scoop under the blades. Until they do this will continue to be an engine money pit.
Posted by: 49 Pan   2008-03-19 16:45  

#18  Thats one expensive caddy you got there.
Posted by: newc   2008-03-19 15:50  

#17  Is it possible that this aircraft has been "gold plated" by the Pentagon, with the result that it's now under-powered?

Not really. If anything, this craft could use some schtuff.
Posted by: Pappy   2008-03-19 14:32  

#16  I still don't trust rotary wings even though I rode in them for a living at one point (EH60B).

I could never trust an aircraft whose wings are moving faster than the fuselage.

Posted by: OldSpook   2008-03-19 13:57  

#15  Further to JFM in #13, per the Dogfights feature on the P-521, which I have watched several times now.

Laminar wing produced less drag, and more efficiency. Seems like that might have contributed to its turning radius and stall speeds. But the Merlin engine was 1600-1700 HP, another five or six hundred more than the original. That hadda count for something!
Posted by: Bobby   2008-03-19 13:28  

#14  I doubt the problem is with the original design. Is it possible that this aircraft has been "gold plated" by the Pentagon, with the result that it's now under-powered? It wouldn't be the first, or the last, unfortunately.
Posted by: Albemarle Grart8980   2008-03-19 13:11  

#13  Just a comment, and for those in industry they'll probably echo it. But if you thought dealing with Boeing and their arrogance (re the tankers, et al) was rough, then dealing with RR would put your head in a spin.
Posted by: bombay   2008-03-19 13:00  

#12  Nope the Allison engined P51s were not crap. She was much faster (I think it was 100 km/h, 60mph or at least 50km/h 30mph) than the P40 who used the same engine. The British also noticed that in a diving she accelerated faster than the Spit, (I think the it was the Mk V in those time) and, after returning to horizontal fly she kept her speed for longer.

Problem was the Allison engine, who had no supercharger lost power much faster than the Merlin with altitude. The P51 with Allison engine
would still have made a decent fighter (eg for countering the low altitude hit and run attacks
by FW190s) were it not that it had been named A36 and assigned to ground support despite the inherent vulnerability of her liquid cooled engine.

Also the Merlin Mustangs were not merely Allison Mustangs refitted for another engine. There were a number of aerodynamic improvements. It is probable that it was not only the engine but also
better aerodynamics who contributed to make the
Merlin Mustangs much faster than the Allison ones.

Original Mustangs had zero rearward visibility (a
no/no in a fighter) and it was the Mustang models
who benefited from the Malcom and later the bubble canopies. This was another important factor in improving the Merlin Mustang for the fighter role respective to the Allison Mustang.
Posted by: JFM   2008-03-19 10:28  

#11  Even the Chinooks that are allegedly old that are in service today are kinda like George Washington's axe... they have more new parts in them than old, or so I've heard.
Posted by: Abdominal Snowman   2008-03-19 10:16  

#10  "US designers seem to have a tradition of under powering both the engines and the weapons they develop."

Per a friend that's still in the business, that's intentional. They count on installing more powerfull engines once the project is underway.

Al
Posted by: Frozen Al   2008-03-19 10:02  

#9  Just reminder of the history of the Chinook, still in service from wiki -

The original Model 107/YHC-1A was rejected by the Army as being too small for its needs. The YHC-1A was then evaluated by the US Marine Corps, and ordered as the HRB-1 (CH-46A after 1962).

The Army then ordered the larger Model 114/HC-1B. The pre-production Boeing Vertol YCH-1B made its initial hovering flight on September 21, 1961. In 1962 the HC-1B was redesignated the CH-47A under the 1962 United States Tri-Service aircraft designation system.

There's been a long record of complaints, failures, and upgrades. It certainly isn't flying with the original engine design installed in 1962.
Posted by: Procopius2k   2008-03-19 09:36  

#8  Darth you have a good point and sadly this echos a Navy aviator decrying the performance of the F-14 on it's first roll out.

The quote was hard to forget. "This plane doesn't have enough power to get out of it's own way."
Posted by: Icerigger   2008-03-19 07:58  

#7  They have a lot of potential and the troops that use them like them. However, US designers seem to have a tradition of under powering both the engines and the weapons they develop.

However, the cost and development time of the V-22 is getting ridiculous.
Posted by: DarthVader   2008-03-19 07:17  

#6  Only seen them the once - two of them on night time maneuvers over the Thames a couple of years back. The river is the only flightpath allowed over the capital for aircraft that are liable to fall out of the any given reason - usually helicopters.

Got the neck hairs going though, I can tell you. I can understand why folks would be reluctant to bin them.

"Technical Glitches" aside, wasnt there an article on the Burg singing their praises in service in Iraq some time ago? Although their downtime is appalling, none lost in service so far?
Posted by: Admiral Allan Ackbar   2008-03-19 07:12  

#5  Off topic: The P-51 wasn't crap but there was a definite improvement to the aircraft and a change in mission once the RR Merlin engine was installed. It was a quickly developed low level and CAS aircraft that was not an outstanding performer.

It sounds like RR based their service life estimate on peacetime British, EU, US East Coast conditions (cool, humid, no sand. Instead they got combat conditions in the "sandbox". Pessimists probably knew what might happen but RR was living in a dream world.

No Surprise...
Posted by: tipover   2008-03-19 01:07  

#4  Sounds like the F14 TF30/F110 situation of 30 years ago. The more things change...

"Which is ironic, because - as the few of us who were in this business when the V-22 got started will recall - the GE38's design roots are in a project called the Modern Technology Demonstrator Engine, which was originally intended to be the definitive V-22 engine. But the AE 1107C was sold, back then, as a lower-risk alternative."

And no, I don't think that the variable geometry aircraft with the weak engine is "snake bit" except in the sense that Washington bean counters are snakes.
Posted by: F14 fan   2008-03-19 01:02  

#3  Ever hear of the P-51 Mustang?

Absolute crap until the Brits stuffed a Merlin engine in it.
Posted by: mojo   2008-03-19 00:48  

#2  
V-22 Engine Whine


Press Pic


Posted by: RD   2008-03-19 00:17  

#1  Fear not, AMERICA = AMERIKA, "the Boy" will super-improve upon what Daddy began. GOOD FOR GEORGE JETSON, "DA ARHNUUULD" SKYNET MACHINES, SPACE-WARP TRAVEL, AS WELL AS HEAVY LR AIR MECH.
Posted by: JosephMendiola   2008-03-19 00:10  

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