The US seems to be forging ahead with a number of vertical lift innovations.
Moving on from the Sikorsky X2 demonstrator is the Light Tactical Helicopter
Boeing is not standing still either and building a reduced scale telescoping-blade disc-rotor model for wind tunnel testing next year under DARPA’s DiscRotor program to demonstrate technology for a high-speed VTOL combat search-and-rescue aircraft.
http://www.youtube.com/watch?v=pg6LuwyNIxk
Meanwhile, the first Merlin HM2 upgrade has taken to the sky. Of the 44 Merlin HM1 purchased, 2 have been lost in accidents and 4 are in storage.
In January 2006, Lockheed Martin UK was awarded the contract for the Merlin capability sustainment plus (CSP) upgrade programme. The programme is planned to sustain capability until the planned 2030 out-of-service date.
The upgrades include: the introduction of open systems architecture, improvements to mission system processing, new touch-screen flat-panel flight displays and upgrades to the Blue Kestrel radar and sonar systems. Entry into service for the upgraded helicopter is planned for 2013.
Only 30 of the remaining 38 aircraft are being upgraded to HM2 level, no news yet on what is happening to the 8 not being upgraded and the 4 in storage but it is expected that some will replace the Sea King ASaC Mk7 and the remainder may be used for SAR, if the SAR PFI deal is stopped.
It’s good to see Sikorsky taking the initiative with the S-97, as for the DARPA design, is does make AgustaWestland’s BA609 look somewhat simple!
Re: the BA609, does anyone know how well development is fairing? It first flew circa 2003, but I’ve very little about production.
S-97 will be flying (in prototype mode)just in time to piss over the chips of the wildcat, oh great!! not sure about retracting blades etc etc I can’t understand why the big helo companies aren’t playing with the rotordyne technology. on the AW page it just says 609 WILL be this and will be that although it has been flying with at least 2 test aircraft, would like to see that doing ASW instead of merlin on the CVF as it is small enough to fit onboard better height and range than merlin
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The ’4 Merlins in storage’ aren’t they are used as test airframes by Westlands, i dont know about the other 8 airframes but they are not used at the moment and could be attrition reserves and these are kept in storage.
not sure Ian, Richard might know
I can’t resist this subject any longer VTOL transport and the history of attempts to improve it are a real hobby (even Hobby Horse) of mine.
A lot of wounderful sounding pipe dreams, computer graphics design proposals, etc etc fill the histories of all the aviation companies. It is vastly harder than it looks even to aeronautical engineers to actually make one work (Keep it stable when flying throughout its envelope, AND make it practical to build and use.
Osprey was supposed to be in wide service in the US by 1990, and of course it cost huge amounts of money, and if the rumours are true it still is ‘tricky’ to fly, with a number of work arrounds required. And some deaths during the trials which were blaimed on ‘pilot error’. Much vaunted attack versions were not proceeded with, seem to recall specificaly the LHX proposals specifically said no Tilt Roters.
I’ll Believe any of the above when they flie in full scale prototype!
The Cheyanne was relativly simple idea, (mechanicaly) compared to some of these proposals and it prooved a failure even the sainted Rotodyne had its fault.
It was to noisy, the Jets on the end of the rotors actually likely to damage the hearing of those nearby Fairy was working on it whe it was cancleed.
The clutches etc in the drive system heavy and complex
etc.
Yes I know the sun shone out of it’s exhaust pipes as far as many are concerned, Just saying it wasn’t THAT good.
I’ll have to rise to Ixion’s bait on the Rotodyne – I too have a long-term (although not very technical) interest in all the different attempts to achieve VTOL.
Sure, the Rotodyne wasn’t perfect – but it was vastly more capable than contemporary heavy-lift helos, in terms of speed, range and payload. It was simply in a different league. Just think what it could have been by now, with half-a-century of continuous development behind it.
Even without that, the work of the Groen Brothers demonstrates that it could still offer advantages in some applications. Above all, it’s relatively simple and low-tech compared with tilt-rotors, for instance.
quote taken from rotordyne insert
The one great criticism of the Rotodyne was the noise the tip jets made, however, the jets were only run at full power for a matter of minutes during departure and landing and indeed, the test pilot Ron Gelattly made two flights over central London, and several landings and departures at Battersea Heliport with no complaints being registered. There was also a noise-reduction program in process which had managed to get the noise level down to the desired level of 96 dB from 600 ft (180 m) away[6], less than the noise made by a London Underground train, and at the time of cancellation, silencers were in the pipeline which would have reduced the noise even further. In the end though it was funding and not noise that killed the Rotodyne
bear in mind that when this was flying, the britains most powerful computer had the same memory as a novelty talking greeting card has today, and the centurion was a “super tank”
OK I recant about the Rotodyne.
Tony you are of course right with 50 years of development by now they would be fantastic.
But my main point remains. A lot of the of the VTOL craft projected, even from serious aircraft manufacturers, are subject to some serious problems. Even my own favorite ‘nearly was’ the XC142 Tiltwing had problems.
None of them will work without serious cash and time and rescources, and even when that has been spent, they still tend to get cancelled, just as they are ‘ready for production’.
Pity the Dragonfly never got going.
http://en.wikipedia.org/wiki/Boeing_X-50_Dragonfly
Come to think of it, that DiscRotor thingy looks familiar too…
http://en.wikipedia.org/wiki/Sikorsky_S-72
Reinventing the rotor blade?
the xc142 vids are amazing each engine was only 3000 shp imagine what you could do with the A400′s engines!!!
Ixion, I promise not to keep banging on about the Rotodyne, but I think that key point about it is that it was very simple and low-tech so very low risk, and it seemed to work remarkably well straight out of the box. Most alternative VTOL approaches had major technical problems; even with modern computer-aided design, the V-22 Osprey had a long and troubled development.
As I understand it, the limiting factor for rotary aircraft speed is the tip speed of the main blades. Once these pass into the transonic region (at about the speed a Lynx AH1 at full whack), the whole thing becomes unstable. Thats why those rather fetching “boomerang” ends were put on the Lynxes, to delay the compressibility effects of the rotor tips travelling so fast (I forget the proper name for them, sorry).
I don’t see how the Sikorsky X2/LTH gets round this, given that the rotor will be powered at all times – even with the pusher-prop. The Darpa design does seem to be “son-of-x-wing”, and should get around the problems of stopping a fast rotating main rotor at the correct position (i.e. 2 blades symmetrically forward and 2 rearward) 100% of the time, which was the insurmountable obstacle at the time – but surely the retraction gear on the main rotor hub has a huge weight penalty?
I still think that tilt rotors are the easiest way to increase tactical speeds. More effort has been put into this form of development over the years than any other, and the problems are all surely just engineering ones, not with the theory? ALso, the theory can be applied to other powerplants. I believe BAC was working on a Tilt-jet fighter proposal at the time it merged with HSA, P.103 I think was the project designation, though I’m not sure and am away from my copy of Buttlers “British Secdret Projects” at the mo’
The problem with the tilt rotor is that the proprotors (I think that’s what they call them) involve significant compromises, being too big to be efficient propellers and too small to be efficient rotors. Their payload is therefore quite limited relative to their power. They are best suited for missions which emphasise high speed over high lifting ability, which is of course how they are being used by the USMC (which has the big CH53 Sea Stallion for the heavy lifting).
All of the so far tried fixes for fast vstol have problems.
Apparantly Proprotors on Osprey, Vibrate and resonate like hell, and a lot of the money spent on it was to stop it tearing itself appart at various stages in the transition process.
BTW the tilting jet engines are a favorite of scifi etc, but what hapopens if one engine malfunctions during transitions, or in vertical flight mode?
Usuall result is a spinning crash to the ground, ordinary flight control surfaces require an airflow; stop the aircraft you loose yaw and pitch control, unless you have an articulated rotor.
Above all, power required for vertial flight means that unless the most efficient form (rotor) is used, it leads to stupidly overpowered aircraft in horizontal flight.
XC142 still rocks if it had been continued by now we would have c130 sized vertical lifter that could go further faster
don’t forget catercopter http://www.cartercopters.com
Ixion said: “XC142 still rocks if it had been continued by now we would have c130 sized vertical lifter that could go further faster”
It’s an interesting design, but wouldn’t the proprotors have suffered the same weight-lifting limitations as the V-22′s?
Tony.
The xc142 had props (yes they were even less efficient in hover than Osprey, the LTV Co simply went for the no shit approach to power and piled it on.
Unlike the Osprey it worked very well as a conventional transport.
The performance on take of was described as “dragster like” it worked very well as STOL transport.
With one of the inevitable stability problems at some point in the transition as with the Osprey.
Pilots had to be told not to fly slowly near the ground with the wings partialy tilted. As with a lot of unconventional vstol craft, it leads to flying into rotor/prop wash/ similar to ring vortex which rendered it unflyable.
Hi, in the leading story this quoted part ties up with the discussion on Navy Matters (blog): “it is expected that some will replace the Sea King ASaC Mk7″
Sea King airframes currently 25 yrs old, and no funding for a viable alternative as a replacement in sight before maybe 2022? This is where the Boeing model quoted starts to look interesting.
Consider the likely scenarios emerging between now and 2022: Engagements most likely to be in littoral environments, facing not only sea-skimming missiles but also supersonic cruise missiles, designed to be used in anti-shipping mode. Answer: Have to have the ASaC capability at a higher altitude for enough response time and coordination.
Costs for alternatives so far (these are nominal US $ so both inflation and FX rates make comparisons a matter of orders of magnitude only):
- take the kit from existing airframes and put into Merlins (opportunity cost for each airframe 21 million)
- take Ospreys with a pressurised cabin (and all the problems quoted), $67m a pop
- going for a proven solution (Hawkeye 2000 at $80m each) not an option(?) bacause the catapults are to be maglev, not steam
So, none of these sound very good? Merlin upgrade perhaps the best (as a stop gap and works with or without carriers) so that the solution can be matched to the likely threat level.
There’s an interesting article in the latest (December) Jane’s International Defence Review about unconventional VTOL designs currently being worked on, and helpfully explaining for laymen the basic problems of getting high speed from rotorcraft.
The most bizarre project, which I’m struggling to get my head around, is the FanWing. It looks like a fixed-wing plane with a couple of combine harvester cutters spinning around along the leading edges of the wings. The company’s website is here: http://www.fanwing.com/
ACC, why shouldn’t maglev catapults be able to launch Hawkeye? They are actually far more controllable than steam catapults, so acceleration can be kept constant instead of peaking.
Hi Tony, (before I revert to helos}, I am sure you are right. Until the SDSR outcomes the RN insurance policy (design contract) ran at a £ 1m/yr funding level. I have not been able to find out what the capability exactly will be. I am just agnostic as to anything not proven in use. I took a 250 meter ride on a maglev train in 1987 – and now they are building them! From another source I picked up that we are on par with the US as for going over to maglev catapults. How could that be (without backroom technology sharing), considering the relative investment priority up till now?
About helos (and Merlin specifically): You can consider the machine itself and the “kit” that does the job. Leaving the latter aside, with rotary wing solutions, the problems will be altitude and endurance.
I consider altitude critical for the reasons I stated, and even more so going into the future (and the threats evolving). UAVs controlled from an airborne manned platform may be able to mitigate (I can’t quote the service ceiling for those already experimented with).
Endurance is easier: you control a swarm of UAVs from one (at a time) airborne helo. Launching UAVs at sea is easier than recovering them, though. And the Merlin development with stub wings was discontinued, so I guess what we will have are going to be “standard issue” as for the flying side of it.
Compared to a pure helo (cum UAV?) solution, Hawkeye 2000, Osprey and the Boing covered in the leading-in article also provide some COD capability (rapidly getting onboard some critical supplies or staff, from a distance). Of course this part will only happen when the carrier(s) is in service. But, is also secondary to ASW (in good shape, with alternative platforms) and area AA (falling behind even with T45s because there are only so many of them).
As this discussion seems to be drying up, an x-ref to the Future of the Royal Navy thread:
- …is about maritime ISTAR and littoral combat, including littoral ASW (NOT by me)
Hmmm, I would like to see more discussion on this latter point
- yes, that was me