What's the latest news of the V22 Osprey?
 

According to news report Osprey has been found suitable , which means it will move to next phase which I assume is Op Eval. Looks like it might make it into service despite the set backs.
Are the figures vs the H46 accurate 6 x range , 3 x payload and are the numbers additive ie 6 times the range with 3 times the payload or is range 6 times with min payload 3 times payload with 1 hr range ?.
What will slinging from the beast be like.

http://today.reuters.com/news/newsAr...-OSPREY-DC.XML

And your point is ???????????????

NEO

I think your keyboard is stuck expat .

BA609
 

I had a discussion with Nick not so long ago about the tilt rotors & he gave me the nudge to pose the question to the wider community.

So what are your thoughts on the tilt-rotor's pilot requirements, having spoken to Bell Augusta about the aircraft status & crew requirements, I began considering the nature of the beast & the combination of the skill sets.

I spoke to some people at the recent avalon airshow & asked about the BA609 & its progression, & pilot requirements, they indicated optimally the crew would need ATPL(H) & CPL(A).

Does anyone consider that it would be a benefit having too much time in either fixed or rotary wing-discliplines with this aircraft, or would you consider RW the primary requirement (ATPL) with fixed just a lesser but still required skill?

Would there be a potential benefit for a pilot starting on the aircraft , so that they don't perceivably pick up any motorskills that might be detrimental, or adverse to handling the tilt rotor?

Or the inverse, should only the most experienced pilots with both disciplines be considered/permitted to enter into the realm of tilt-rotor crew.

Unfortunately from the conversations with BA they indicated that arriving with both a CPL(H) & CPL(A) would still require around US$50K (+/- $20K) for the endorsement alone, a pretty cost prohibitive exercise. But there was an indication of orders for around 40 aircraft post-certification (which is now into fixed wing testing as RW has been completd). Whether that is reality of marketing hype I have no means of verifying.

Anyway - as i stated, would appreciate to know what you guys think, & whether you can see this type of aircraft taking a hold in EMS/SAR or surveilance/customs etc, given the cost & performance of the aircraft compared to a standard RW EMS aircraft.

Widge,

No offence mate, just taking the p**s a bit. Technical stuff just baffles me, that's all. Please don't take it personally.

Cheers,

NEO.

Well I am not a pilot type but I would have to say that this machine does present a challenge to go along with it's new capabilities. I wondered about this myself and I thought it might be best as a two pilot machine with one helo type and one fixed wing type driver to cover both regimes.

It is clear that BA has taken the "make an airplane that flies like a helicopter" approach rather than making a helicopter that flies fast like an airplane. This to me is interesting considering Bell is a helicopter manufacturer although they do have roots deep in the airplane world. I wonder if the requirements would be the same if they had gone the other way. I guess we may find out with Sikorsky looking at the coaxial configuration again. Will they have the same crew issues with a high speed rotorcraft?

Max

Being a Chinook pilot at heart.....I tend to ask the question...what can you stuff up the rear end of the thing? Seems to me it (the Osprey) has some shortcomings there. If so...one wonders how it will ever replace the Chinook and that Sikorsky thing....Sea Scallion or whatever it is called.

I do not see where comparing the Frog to an Osprey is a very fair comparison. Comparing Columbia's BV-107's to CH-46's makes sense but not an Osprey.

Cabin Seats:

Osprey 24
Chinook 44
Sea Stallion 55

Osprey cabin: 24 ft long x 5.9 ft wide x 6.0 ft high
Chinook cabin: 33 ft long x 7.6 ft wide x 6.6 ft high
Sea Stallion cabin: 30 ft long x 7.5 ft wide x 6.5 ft high

Humvee Dimensions: 15 ft long x 7.1 wide x 6 ft high

Osprey cannot carry the Humvee vehicle, has 50% litter capacity of the helicopters.

Cargo Hook capacity:

Single Hook Dual Hook

Osprey 10,000 15,000
Chinook 26,000 25,000
Sea Stallion 36,000


Why is it I think we are wasting a pot full of Taxpayer's money on the Osprey?

maxtork wrote:
I guess we may find out with Sikorsky looking at the coaxial configuration again. Will they have the same crew issues with a high speed rotorcraft?

My understanding is that there is no conversion with that Sikorsky coaxial. It is always a rotorcraft, it just goes like the blazes. And, with the little I know about disk loading, wing loading, inertia, vortex ring state, and autorotation, I'd rather keep my family out of tiltrotors in general.

-- IFMU

Top speeds:

Chinook: 159mph
Stallion: 195mph
Osprey: 316mph

Seems strange though not to have something that meets internal cargo standards that already exist.

CAS
 

isn't there also the issue of proving support for the osprey?

i.e: nothing else (RW; cobra's, apaches, etc.) can keep up?

seem to recall reading somewhere about consideration of an armed version of the BA609 for this role.

again unverified, maybe it was just a 'Furphy' :}

Ok...the Marines get the Osprey....for doing Vertical Assault from a ship way offshore....how fast they going to fly with underslung loads? They cannot load squat inside compared to the helicopters....carry half the troops. Anyone remember the lesson of Arnhem about lack of troop lift capacity?

For CSAR....it might be the cats meow...for taking off vertically and going fast and landing vertically...great. But to me ...the gain is wasted when you start acting like a real helicopter ...toting stuff. It is too small in capacity but too big as it is...to make it bigger to tote what you need.

Can you spell B-O-O-N-D-O-G-L-E?

(...Dons k-pot...)

To be fair, the V-22 is not designed to replace the Wokka or Stallion in the transport role - the CV-22 is replacing the AFSOC MH-53J/M in the CSAR role, where response time (i.e. penetration speed) and range is more important than off-loading capability, while SOCOM is retaining and upgrading its MH-47s.

Agree though that it's bizarre the V-22 (6ft hold width) wasn't designed to accommodate the 7ft Humvee, necessitating external carriage (for which there is presumably a dictated airspeed limit), but I guess if the Marines asked for a Frog replacement then that's what they're getting. While the Osprey is out-lifted by the Chinook (despite more installed power), it easily out performs the Frog (7.5 t vs 2 t), and the cabin size is identical.

(And you can pretty much guarantee Bell-Boeing has a design for a 'fat-ass' fuselage ready to be funded... :suspect: )

At this stage, the Corps is probably just glad to receive anything new - I've been told that the Frog's performance is so degraded these days (simply due to old age) that it struggles to lift a dozen grunts on a hot day, let alone a full complement.

The Marines are indeed interested in a high-speed escort (BA609, armed V-22, VTDP'd Cobra or - maybe? - an X2 type vehicle), but having just committed $4 billion to the AH-1Z program I doubt Congress will be overly impressed ! Once the MV-22 is into FRP, we'll probably seen attention focused back on the self-defense armament proposals (50cal nose gun, etc.).

:E

I/C

(Removes k-pot and runs for nearest trench)

I remember when I was a young boy my father worked for AM General on the hummer project. It was a long time ago and I'm not sure what year but I'm wondering if the V22 airframe dimesions were defined before or after the humvee entered service? This may explain why it isn't big enough to swallow a hummer.

As for the armed escort situation I read an article about the V22 some years ago and when the subject came up a high ranking Marine said something to the effect of "we already have that...it is called a harrier". I guess the escort roll requires a speed of 1.5 times that of the aircraft to be escorted as per this same article and that makes a 400 mph plus machine, squarely in harrier territory.

I don't know if I buy the whole thing at all. I think we may have been better off just designing a faster helicopter. This hybrid monster does some great things...but is it really the things we need?

Max

obviously if you want a helicopter you would get one and same with a plane but looking at the statistics above it looks to me like the v22 can deliver the same amount of cargo or pax to the same position as a chinook in the same time but faster from a to b than a sitting duck. somthing could be said about having all your eggs in one basket too. speaking of ducks and eggs, im off to feed the chickens......

id give it a go in a couple of years
:ok:

MV-22: Demo Ride As Tiltrotor Heads For Prime Time
New River, NC., July 13:- USMC pilots demo’d an MV-22 Osprey here for this correspondent taking their aircraft to the currently cleared maneuverability limits in a routine which seemed to re-write the rules of rotorcraft operational capability.
The 34-minute flight, into a practice area near the MCAS New River base for the Osprey test and evaluation squadron showed conclusively the Osprey is rugged, smooth and capable of almost jaw-dropping acceleration to cruise speed from a hover.
The flight – for officials, contractors and media – marked the successful completion of OT IIG, the intense series of tactical and operational trials carried out here to qualify the Osprey for full rate production, most likely beginning this September.
Pilots Lt Col Chris Seymour and Maj Logan Depue lifted Osprey tail number 6484 off the New River runway at 1426 today, immediately accelerating by bringing their proprotors to the full forward position in the early stages of the climb.
Our station in the back of the half-full cabin (fully loaded an Osprey can carry 24 troops) pre-empted seeing the data displayed on the MFD, but a pre-briefing suggested the aim was to reach 250 KTAS as quickly as possible after taking off from the seal-level, 92 deg F runway.
Ground run was minimal – 50 yards at most – but what followed was a thrilling sense of speed building up. Acceleration was linear and strong. A ‘clue’ that cruise flight mode was being set up was the lowering of proprotor RPM to about 85 percent of the take off revolutions.
This is an automatic aspect of tiltrotor flight – one of many new parameters that pilots (and observers) long used to the characteristics of large transport rotorcraft flight will have to get used to.
The aircraft was then put through a card of maneuvers that included an assault approach, numerous hovering exercises and a high speed ‘break’ over the field at 2,000 ft prior to (a similarly thrilling) approach to an approach speed of around 100 KTAS.
The Marines had pulled out the stops on this flight which was accompanied by a sister ship that performed various maneuvers to take up a variety of formatting positions on our aircraft. A lowered rear ramp – as well as an open side door at the crew chief position on the front right side of the aircraft - allowed photographers a unique series of shots of Osprey’s appearance in flight, up to now a commodity that could only be obtained through a controlled process involving program officials.
The new attitude of openness on behalf of these same officials marked a definite first for the Osprey program and was intended to mark – and celebrate – what Lt Gen Mike Hough, USMC Deputy Commandant for Aviation called a ‘great day’ for both aviation and the Corps.
In flight (in the cabin) the Osprey appears somewhat quieter than larger helicopters, but its most noticeable characteristic was its nimbleness.
Turns both left and right were reached at a rate of what appeared to be about 60 degree bank angles in less than five seconds - the higher forward speed contributing to a definite sense of ‘g’s felt.
The aircraft has been criticized for a lack of low-level maneuverability, but Seymour and Depue were having none of it: they racked their aircraft around at heights of between 100 and 200 ft AGL.
The aircraft was highly stable in air made gusty by on and off distant thunder storms. Ospreys are currently cleared to bank angles of up to 60 degrees and pitch attitudes of between 20 and 30 degrees, but these envelope limits will be expanded as a two-year program run by Navair at Pax River gets underway.
‘We want to make it more maneuverable – the word is for it to be more ‘evasive,’’ said Col Glenn Walters, CO of VMX-22.
A squadron pilot said the demo ride was ‘close to, but not actually at,’ the maneuverability limits the aircraft is currently capable of .
Following the overhead break into a short landing pattern, the crew slowed the aircraft by pulling torque back to about 30 percent, an act which immediately brought the speed down very noticeably. In the back, the feeling was that the aircraft had perhaps run into mud, so smooth and predictable were the deceleration forces. This writer – mindful of the challenge to yaw control such things present in a conventional helicopter – noticed the aircraft was very precise in this axis.
What more to say about impressions of Osprey flight at this point? Overall it’s clear certain thresholds set by generations of rotorcraft up to now have been decisively breached.
The Osprey flies faster, climbs faster, is smoother – and quieter.
Proponents have long said this was case but up to now have been unable to prove it to anyone outside the pilot/engineering fraternity.
Critics have stood their ground claiming maneuverability issues, inherent handling flaws and overall maintainability will make the Osprey case unsupportable.
OT IIG results – refute all these things and more. But if that’s not enough just one simple maneuver, pick-up off a landing site – like any old helicopter - followed by an immediate boost from zero to 250 knots in just a few seconds – should be enough to convince them a generational change in the way rotary wing aviation does business is at hand.
- David S. Harvey

The tiltrotor is a specialised role machine, optimised for high speed / low volume transport rather than high all-up mass / carrying capacity. It has relatively severe handling limitations in the low speed envelope when compared to a helicopter. Because of the very high cost, it is most unlikely it will ever have as large a market as the helicopter presently enjoys.

Rather than have a squadron of these, why not just use a large helicopter and set off a little earlier? ;)

I understand one of the fundamental design issues with tilt rotors in general is that there are currently only 2 engines certified to run vertically - the Allison in the V22 and the PT6 variant in the 609. That rather limits the sizing of the final aircraft.

Did I mention the HOGE number for the V-22 is 5400 feet?

The last Chinook shot down in Afghanistan was at 10,000 feet or so....where is the CSAR mission now?

80 Million bucks a pop and climbing for this piece of crap.

It is a great concept....the 609 might be useful for long offshore flights but the 22 is too expensive and cannot do the missions that the Sea Stallion and the Chinook can.

Maybe the Marines might get their heads out of their butts and buy Chinooks or Sea Stallions.....they could get a pot full of them for the same amount of money.

Self protection.....50 cals....at a hover....spell R-P-G? Think Blackhawk Down in Moga....think Chinook down in Afghanistan...

The bright side of this....by buying the 22....the Marines can justify keeping the Harrier....which has proven to be a very expensive CAS aircraft in its own right.

Airplanes and helicopters are just two different concepts that cannot be made into one and do well at both.

steve_oc,

The LTC1K-4K variant of the T53 (XV-15) and the T800 (US-2) are also vertical-capable. But as you point out, the sizing options are still limited.

I/C

http://i3.photobucket.com/albums/y73...yer/8xV22s.jpg

Time will tell how good V-22 is.

By the way, OGE ceiling of 5000 feet is at MGW.

Even Ch-47D does not hover OGE at 10K density at MGW!

Looks like Darth Vader's attacking. That lot should drop their cameras and reach for their Light Sabres.

zd,

I would love to see the what the 22 will hover out-of-ground effect at 10,000 feet would be...in the summer? Then....compare that to both the 47 and 53 both in raw numbers and as a percentage of MAUW for vertical takeoff at sea level.

"Allison in the V22 and the PT6 variant in the 609 ... LTC1K-4K variant of the T53 (XV-15) and the T800 (US-2) ... vertical-capable."

I'm suprised they haven't got a 3 or 4 engine version on the drawing board, to push up payload. This would also help with the eng-failure during transition problem, which i imagine could be a real problem with low speed low level work over unfriendly territory.

There is going to be some good competition once Sikorsky aim their coaxial development towards V-22 performance figures. A lot of research will be needed to get the rotors to be as efficient as a fixed wing at speed though, requiring active twist and variable RPM. Much better in hover efficiency though.

Mart

There once was a competition was there not....ABC versus Tiltrotor? Seems I recall hearing of some flying going on over at Mother Rucker or somewhere betwist the two machines.

As I recall...a kind of squatty, curly headed Greek looking fella was in the ABC.

Just testing the waters....."Mark Twain!" (In the mail Nick....)

The 4-engine version is the quad tilt rotor or QTR - a good summary is at AHS QTR page.

Lots of fun stuff on Bell's other tilt studies at AIAA unbuilt VSTOL. Pretty rare so see concept work like this released for public consumption.

I/C

Coincidentally I just got done reading a writeup about the V22 in the July Wired magazine (of all places!). It's actually a pretty good article, other than its title ("Saving the Pentagon's Killer Chopper-Plane"!).. It covers the program's history, some details about the four crashes that I hadn't seen elsewhere, and focuses on the work that's gone on since those accidents.

I have been very critical of the tiltrotor in the past - at least for tactical military stuff (I have to admit that I think the BA609 is a helluva nice looking ship and would love the opp to fly one!). I will still be watching with great interest as they deploy the aircraft in large numbers, but I came away from the article thinking that it's not *as much* of a boondoggle and terrible idea as I thought before. But at $105M per copy (this is GlobalSecurity.org's estimate of the *real* cost), every one they lose due to "whatever" is going to hurt.

Dave Blevins

The MH-47E...fanciest version and equivalent to the CSAR version of the Osprey goes off the lot for about 40 Million Dollars vice the 105 million Dollar price tag of the Osprey. Price creep is bound to happen on the Osprey....so we can assume about a 3:1 ratio of top line Chinooks for the price of one Osprey based upon purchase price alone. The Sea Stallion would be about the same price....and again about a 3:1 advantage in numbers.

In the first six months of the war against terrorism, Night Stalker Chinooks flew more than 200 combat missions totaling about 2,000 flight hours. The Chinooks flew as high as 16,000 feet (which forced crews to use oxygen systems) for as long as 15 hours. More than 70 of these missions, flown in the war's first three months, involved infiltration or removal of special operations troops behind enemy lines. Throughout, the Chinooks maintained a 99-percent mission readiness rate.



Again...know where my vote goes....sorry Bell....no Osprey for this guy.

"The 4-engine version is the quad tilt rotor or QTR"

With a shaft required from front wing/rotor set to rear wing/rotor set, that would have to be some drivetrain - unless they "assume" no total front/rear eng failure... :uhoh:

"Lots of fun stuff on Bell's other tilt studies at AIAA unbuilt VSTOL."

Interesting stuff here. I guess they opted early on for a distributed powertrain to keep drivetrain mass down (torque limit on one engine operation). I still bet that G/Box and Drivelines make up a significant proportion of the empty weight.

"MH-47E ... 40 Million Dollars vice the 105 (plus creep) million Dollar price tag of the Osprey"

Tandems have been around a while now since Piasecki's "Flying Banana". I imagine that time will (eventually) see this technology cheapen too, as it proves itself (or otherwise :hmm: ).

"Chinooks maintained a 99-percent mission readiness rate."

That's an impressive statistic!

Mart

Think of the engineering it took to design the Osprey for shipboard service....and either engine drive of the rotors...with rotor translation and blade fold capability. Someone probably has an ulcer by now.

One look at the CH-46 heads or the CH-53 heads with blade fold will give you headaches too.

The $100M price tag for a vanilla MV-22 sounds high - most estimates are closer to $71-74M, with NAVAIR demanding a reduction to $58M by 2010. The mission-equipped CV-22 is probably closer to the $100M mark (just as SOAR's birds cost $20M to upgrade from Ds or Fs).

The oft-quoted 99% mission readiness rate for the MH-47E (during 72 missions over a three month period in OEF) indicates a carefully-planned schedule and a hard-worked ground crew ! Publicly-released mission capable rates for the CH-47D in OEF are closer to 60%, and 80% for OIF.

That said, the Chinook’s achievements in-theater have been spectacular, and the uprated donks have substantially improved the fleet’s performance (it wasn't that long ago that Congress and the media were taking pot shots at the MH-47E for its lack of high-alt performance).

SASless - you're spot-on with the blade folding comments. While it does meet the Corps' spotting requirements, that little trick doesn't come cheap, and the weight penalty is significant.

Graviman - it'll really get interesting once the electric drive systems now entering mass production for automotive and marine applications begin to improve in efficiency, reliability and weight. That then opens up the possibility of a mission-optimized powerplant located on the aircraft's fuselage driving motor-driven proprotors, thereby doing away with the cost and complexity of individual powertrains on each wing.

I/C

Excellent presentation Nick....I feel vindicated on my comments about the Osprey versus the equivalent helicopters.

The one thing you did not address was the airspeed of the Osprey in the external cargo mode. How does that affect the numbers? Commonsense says the external load being carried will determine the airspeed the machine can fly (in general) and thus any airspeed advantage the Osprey had would evaporate like fried chicken at a family reunion.

Good point SaSless,
But how much forward speed does the V-22 need for it's wings to create the lift needed to stay in the air ?? 70-80knots maybe??
and that speed is over Vne of most external loads.

Is it only able to sling in "hover mode" then??

I think the number would affected then, increasing the helicopters advantage even more. just a thought:confused:

Can't help it but sometimes this whole tiltrotor thing reminds me of the movie "Pentagon Wars"
does anyone else remember that one ???

I may be wrong (do please let me know!) but I seem to recall reading somewhere that the V-22 did a slingload demonstration of 6,000 pounds to 220 knots. Impressive!

Regarding External Load Weight and Speed Capabilities...
 

OSPREY ESTABLISHES SEVERAL NEW RECORDS
By RICHARD R. BURGESS, Managing Editor
Bell-Boeing's MV-22B Osprey tiltrotor transport has set an unofficial load-carrying world record for rotorcraft by carrying a 10,000-pound external load at a speed of 220 knots. The load was attached to the Osprey's aft cargo hook by a Marine helicopter support team, using procedures developed during 15 prior hookups.
During a series of 20 flights in 10 days, the Osprey eventually had reached the required speed of 220 knots while carrying a load of 6,000 pounds. The 10,000-pound load was carried on a later flight.
"It was basically transparent that there was an external load once the V-22 was airborne from the hookup, into forward flight, and during the transition into the airplane mode," said Bill Leonard, a developmental test pilot. "The V-22 was remarkably easy to operate and handled the 6,000-pound load extremely well."
"The demonstration of the V-22's ability to carry external loads at very high speeds is a significant accomplishment," said John Buyers, Bell-Boeing's V-22 program director at Naval Air Station Patuxent River, Md. "This is the fastest airspeed any rotorcraft has carried an external load, no matter what the weight."
"What is significant about the V-22 external loads testing is not so much the weight ... [the tiltrotor] is carrying but the coupling of the weight and the speed," said Steve Grohsmeyer, Boeing's senior V-22 experimental test pilot. "Helicopters have lifted much heavier external loads but have not reached speeds of 220 knots while carrying these loads." The external load-carrying capability of the MV-22B is considered critical to the amphibious-lift requirements postulated by the Marine Corps for the 21st century.
In a later test flight, Osprey No. 8 carried a 6,500-pound HMMWV (high-mobility multiwheeled vehicle, or "Humvee") in an inverted V-sling at 120 knots and at a 60-degree engine nacelle angle. "The aircraft was very stable in the hover and forward flight," said Grohsmeyer, who flew the test mission with Maj. Bill Witzig. "It was well-damped following acroservoelastic and flying qualities excitations--both the aircraft and the load flew very well. We should feel very confident about taking this load faster if we want to."
"Like previous external load tests, this test went without a hitch and is a testament to the professionalism and efficiency of all those involved," said Phil Dunford, Bell-Boeing's director of flight test for the V-22 program.
Further tests will involve carrying--at 220 knots--15,000 pounds suspended from the forward and aft cargo hooks.
The first time a tiltrotor was used to carry external loads occurred earlier in the decade when an FSD (full-scale development) V-22A carried 4,000 pounds while reaching a speed of 174 knots.

Interesting presentation Nick. Puts the facts into perspective.

"Someone probably has an ulcer by now."

Certainly looks like some serious engineering has been required...

"... electric drive systems ... improve in efficiency, reliability and weight.... a mission-optimized powerplant located on the aircraft's fuselage driving motor-driven proprotors..."

I'm a complete convert of the hybrid helicopter, primarily for reasons of improved efficiency without mission compromise (generally through v-RRPM). Best power/weight is using NdFeB magnet technology, in a disk motor to reduce the iron reluctance circuit mass. Commercial units already exceed kW/kg by running at very high rpm (couldn't find an exact figure by googling).

My only concern is that you will always need to design for failsafe operation, primarily due to the controller complexity required for brushless DC motors (magnet rotates, while static windings are switched). In a tilt-rotor this means you always need the tip-to-tip driveshaft, in case one motor fails. You can triple up of course, but i will be interested to see which way the technology goes...

Mart

I think all the lifting, etc arguments are irrelevant - I can see a real niche market for this already and would be more interested in comparisons between a 609 and a 76, or any other typical corporate helicopter.

Phil

I understand that the V-22 is capable of carrying external loads at pretty high speed and that is fine but the question is can the load itself survive it? A humvee is not meant to go 200 mph! In fact I recall some problems in testing the Army's new FMTV vehicle doing sling loads. The chinnok pilots were able to cruise along at a pretty good clip with the truck in tow....so fast that it would crack the windshields from wind forces against it. It was decided that the truck should be carried backwards so as to reduce the wind force on the front. This may work for a planned mission but I doubt the marines would want to remove all their tarp and bow kits and put braces on the windows and doors to keep from ruining their vehicles just so the V-22 can sling them into a hot LZ or beach at 200 knots. This would leave a bunch of Marines sitting on the beach trying to put their wheels back together while being shot at....not a good scenario in my mind.

From the numbers I have read the 609 and the 76 have similar useful loads but the power required is drastically different. You can get (or used ot be able to get) a PT6 powered S-76 which has about 980HP each. The PT6 in the 609 puts out I think somethig like 1680 HP each. I would assume that HP increase would be needed in the helicopter mode but I'm not sure how much less it will be for the airplane mode.

Max

Diversion from the thread
 

http://www.unicopter.com/confused.gif http://www.unicopter.com/confused.gif

Graviman,

In the thread 'Future rotorcraft control systems' the question was;
"Why could not a reasonably large diameter, linear induction disk motor be an integral part of a special rotor hub...?"

Your reply was;
"Why not, but aerospace motors and generators run at 80'000 rpm regardless of shape. Any less and you are just introducing unecessary weight."


In this thread you say.
"Best power/weight is using NdFeB magnet technology, in a disk motor to reduce the iron reluctance circuit mass."

http://www.unicopter.com/chairshot.gif

Back to the thread

Dave,

That's easy: you need both! Since the application is aerospace propulsion i was making the assumption that the motor/gen would already be geared to run at as high RPM as practical. Having got the most power for a given torque, the ideal design then seeks to reduce the mass for that torque. This is accomplished by minimising NdFeB magnetic circuit length, which is the objective of disk motors.

To get partly up to speed check out www.uqm.com

I have read about higher performance developments for various applications, but couldn't find any of the ones i was thinking of in my quick google session...

For a rotor hub application you would still need to gear the motor down, requiring a serious epicyclic reduction gearbox. In a tiltrotor this drivetrain rotates into the airflow, in an interleaving heli the drivetrain would likely present a serious drag element. Notice i still state that a mechanical drivetrain would be required in the tiltrotor. Your application was also to try to remove the mechanical drivetrain, which i still believe to be impractical.

Mart

junglyAEO,
Your logic seems to be interesting. I think what you said is that when we find a cheaper, similarly sized vehicle that does better, we are wrong. Or does that mean when the USMC managed to find a machine that had half the efficiency at twice the price that they were wrong?

If your Doctor used the logic you use, he would amputate your feet to cure your hangnail.

With similar logic, several Marines said to me that the 53E is a "heavy helicopter" and a V-22 is a "medium" so they don't compare! Same deck spot factor, half the cost, twice the payload, 150% of the transport capability, but not a better choice.

Paco, Of course we should compare the 609 to an S-76, otherwise we would have no contest! How about comparing it to a 206 to be sure it looks good? Or maybe a Bell 47?