V-22 Osprey Air Refuel F-35Bs for CVFs? + other stuff

[LowObservable]

N-a-B... not to mention the fact that the brakes on an Osprey are of the parking variety. Still dubious about the tanking value of a vehicle with a VTOL payload of 10000 lb at 200 nm radius, though (and shipboard STOL so far has been tested experimentally, not demo'ed operationally).

The OV-10 stuff is interesting. So why is the Navy suddenly interested in the only fixed-wing combat aircraft, other than a STOVL, to have been tested on an LHA/LHD?

[SpazSinbad]

Osprey on the Truman, Fishing for COD

Osprey on the Truman, Fishing for COD 18 Apr 2013 Amy Butler

Osprey on the Truman, Fishing for COD

"...The aircraft is onboard the deck of the carrier USS Harry S. Truman in preparation for trials to validate whether it is suitable to be considered as a replacement for aging C-2 Greyhounds.


The first phase of the assessment Starts April 19, when operators will be “conducting palletized cargo and cyclic operations” using the MV-22 on the Truman’s deck, says Rear Adm. William Moran, Navy aviation chief. This will include transfer of passengers, cargo and “cyclic flight operations...."

[Not_a_boffin]

I'm sure it'll do VTOL COD just fine. It's the MROL nonsense or whatever it's called that worries me.....

[SpazSinbad]

V-22 Brake/Park Brake Description

V-22 Brake/Park Brake Description seems reasonable. What are the issues for MROL (apart from more testing required). Seems to me a CVF will provide sufficient deck length for braking (subject to further US testing).

Bell/Boeing V-22 Osprey Overview
Eaton’s Aerospace Group's Product Capabilities July 2009

http://www.eaton.com/ecm/groups/publ.../ct_195937.pdf (5Mb)

"...The hydraulic brake master cylinder functions as a boosted brake valve assembly when the aircraft hydraulic system is pressurized. The unit directs flow and pressure to the wheel brake cylinders. The brake pressure delivered is a function of pilot input force, which is proportional to the brake displacement. When there is no system pressure, the unit reverts to manual braking, utilizing a two-stage piston arrangement.

The Sterer brand park/lock valve provides isolation of fluid between the pilot and co-pilot's master cylinders and the brakes. It also has a lever and poppets so that when actuated, hydraulic pressure is locked in the brakes for parking. The unit contains free maintenance accumulators to provide fluid for thermal compensation when the unit is in the "park" mode. Pressure switches are incorporated in both the right and left brake pressure indicators...."
_________________________

Bell Boeing Tiltrotor Team
OSPREY FACTS Volume 11, Issue 7 Sept. 14, 2000 page 4

http://www.boeing.com/rotorcraft/mil...imes/sep00.pdf (0.4Mb)

"...-The V-22 has difficulty remaining parked on rolling aircraft carrier or assault ship decks.
Correction: This is not true. Initially there was a problem with the parking brake when the aircraft were moved on deck because the brake rider in the cockpit needed improvement. This fix was made in three of the four aircraft that were used during the recently completed Operational Evaluation and in all production aircraft since...."

Nolan Schmidt, COL USMC, V-22 Program Manager

[Not_a_boffin]

What are the issues for MROL (apart from more testing required). Seems to me a CVF will provide sufficient deck length for braking (subject to further US testing).

This...



Plus this..



Equals this



(which is the International Sign For Panic).

Might be a bit easier on QEC with the initial pitiful number of cabs, but two 11m+ rotors coming at you at say 20 kts relative with only brakes to stop them is likely to require a fair bit of safety clearance.....

[SpazSinbad]

V-22 MROL Technique Proves Safe - Benign Even

'Not_a_boffin' thanks for the scary 'Edward Scissorhands' V-22 photo. At the risk of boring youse all - these text extracts and graphics are from the post here:

http://www.pprune.org/military-aircr...ml#post7792460

MV-22B OSPREY SHORT TAKEOFF AND MINIMUM RUN-ON LANDING TESTS ABOARD LHD CLASS SHIPS 26 Feb 2009
Virginia T. Mitchell & William P. Geyer V-22 Ship Suitability Engineers
Naval Air Warfare Center Aircraft Division Patuxent River, Maryland

http://www.f-16.net/f-16_forum_download-id-17415.html (1.1Mb)
http://www.vtol.org/f65_bestPapers/t...Evaluation.pdf (original download not working)

"ABSTRACT
...The V-22 also demonstrated that MROLs are a new and safe technique for landing on LHD 1 class ships at an appreciable ground speed across the spectrum of GWs [Gross Weights] bands...."
&
"...The MROL technique involved the aircraft performing a stern approach to the ship targeting touchdown on spot 9, rolling along the longitudinal “crow’s foot” lineup lines, and fully stopping just prior to the aft end of the island. The touchdown and braking zone is shown in Figure 16. Prior to sea trials, stopping distances were predicted for 15 to 20 kt ground speeds based on STOLCOMP which was validated by landbased test data. Based on these predictions, there was sufficient deck space available to stop the aircraft from a 20 kt Touchdown Speed Relative to the Ship (TSRTS). TSRTS is defined as the difference between aircraft ground speed and ship ground speed.
The MROL procedures develop as follows:
• Turn base at 2 nautical miles and 800 feet and begin to slow to 60 nacelle/120 kt indicated airspeed
• Landing checks complete
• Turn final and slow to 50-60 kt indicated air speed at 83-85 deg nacelle [see photo]
• Intercept glideslope at 1.1 nautical miles
• Maintain a 7 deg glideslope and establish recommended airspeed
• Confirm WOD and Ship’s speed over ground to determine landing touchdown speed
• At 0.2 nautical miles rotate nacelles aft 2-3 deg, use longitudinal stick as required to capture touchdown speed
• Prior to crossing the deck edge, transition from indicated airspeed to groundspeed. Target aircraft ground speed was ship’s ground speed plus TSRTS as determined from touchdown predictability tests
• Target spot 9 mainmount markings for touchdown
• Maintain 0-5 deg nose up until MLG touchdown
• Reduce TCL to aft stop at touchdown
• Smoothly lower nose wheel to ground
• Apply hard braking
• Adjust nacelle angle to full aft at maximum rate
• Select nose wheel steering when the gear is firmly on the ground if desired
• Terminate maneuver by adjusting nacelles forward to prevent aircraft from rolling aft...
&
...The landing airspeed was limited to no less than 30 kt based on simulation results. The difference in aircraft and ship ground speed was mathematically equivalent to the difference in aircraft and ship wind speed....
&
...MROL Envelope Expansion
A total of 11 MROLs were conducted completing 6 of the 52 planned MROL test points with required repeats. Due to limited test time at sea, only MROL touchdown predictability and GW expansion tests were conducted....
...Performance
MROL testing began with touchdown predictability to determine the pilot’s ability to touchdown within the touchdown zone and determine what the appropriate touchdown speed relative to the ship (TSRTS) would be to safely stop within the braking zone. Figure 26 presents stopping distance as a function of TSRTS for both touchdown predictability tests as well as GW expansion. Note that touchdown predictability test points for TSRTS from 12 to 15 kt [not below 30 KIAS] resulted in stopping distances from 89 to 121 feet.... Test results demonstrated that MROL ground roll distances with TSRTS up to 22 kt could be achieved with the flight deck space available aft of the island. The touchdown positions relative to the target touchdown point are presented in Figure 27. Aside from the one outlier, pilots were able to accurately land the aircraft within the touchdown zone....
...The general pilot sentiment was that MROLs were a benign maneuver for the GWs tested. In addition, the pilots commented that maintaining ground speed relative to the ship during a MROL actually created an easier approach than attempting to decelerate to a hover, reducing lateral workload as the aircraft crossed the deck edge. The MROL technique was validated in the shipboard environment....
...CONCLUDING REMARKS
...MROL demonstrated to be a revolutionary and safe way to land aboard ship at GWs heavier than VTOL capability and will continue to be developed and tested. An MROL envelope was not recommended due to insufficient test data; however when more can be gathered, the possibility of granting an envelope to the fleet exists...."

[Not_a_boffin]

Nobody doubts you can do it on a ship - that's self evident. It's the amount of emb8ggerance you cause to the deck park and subsequent operations in doing so.....

That raises the question of why you'd want to do it operationally, if you have to clear the entire aft end of an LHD, or reduce the safe parking area on a CVN. That's why statements like "The MROL technique was validated in the shipboard environment" are a little disingenuous and ought probably to say something like "validated in a shipboard trial environment".....

[SpazSinbad]

In the context of the 'never mind the quality - feel the width' of the CVFs that 'making space' would seem to be less of a problem. After all - CVF is what this thread is about - not USN/USMC flat decks.

[Not_a_boffin]

Correct. Which brings us back to post #37

QE is a slightly different kettle of fish with double the flightdeck beam, but it's still a huge swathe of real estate to surrender. Any concerns about brake failures with F35 and SRVL are going to be dwarfed by those where you've got two 11m rotors, spinning at several hundred rpm coming down the deck at you. Very definitely not for the faint-hearted.....

and post #45

Might be a bit easier on QEC with the initial pitiful number of cabs, but two 11m+ rotors coming at you at say 20 kts relative with only brakes to stop them is likely to require a fair bit of safety clearance.....

[SpazSinbad]

So 'not a problem' then for MROLs onto CVFs? Cool.

[Finnpog]

Would it not be easier to have left the 'extension' on the side of the CVFs to enable an angle deck for landings, regardless of whether there was going to be arrestor gear or not?

Then these type of landings become even safer in the event of an overrun,.

[Not_a_boffin]

So 'not a problem' then for MROLs onto CVFs? Cool.

Unless - as planned - you intend to have a few cabs parked aft or down the port side or some of our nice large helos with rotors spread. Then, not cool.

Would it not be easier to have left the 'extension' on the side of the CVFs to enable an angle deck for landings, regardless of whether there was going to be arrestor gear or not?

The extension was there to cater for a particular run out case for no 4 wire, so not necessary for an unarrested landing - ship is still fitted for an angled deck. Problem is that you'd end up causing even more havoc on the deck parking arrangements and if you didn't stop, you're unlikely to end up airborne, more likely swimming.

[Engines]

For what it's worth.....

It's always a bit of a mystery to me how any news of a development in using STOVL aircraft is met, on this site at least, by a chorus of posts pointing out how 'it's not going to work', or how 'it's not worth it anyway', or 'it's going to be too hard to do on a ship'.

Firstly, the usual disclaimer that, hey, it's a free thread, and all and any posts should be welcomed. No-one, in my view, should ever be criticised or ridiculed for their posts. But the best posts (and there are plenty of them) are the ones that offer hard facts and informed opinion. So here's my go on V-22 STOL and MROL....

Firstly, the reason you'd want to do rolling landings and takeoffs is simple. Payload. Fuel and stores. People. You always want more of these. If you can get it, you'll take it.

For most vectored thrust aircraft (and that's what the V-22 basically is) a STOL is invariably a better way to get off the ground, or deck. You get lift out of the wing, and for the V-22, tilting the props forward reduces the downwash on the wing, further improving TO weight. On board ship, it also delivers a massive benefit in reducing the time spent before you reach 'safe single engined' flight. (This isn't news. I know for a fact that the USMC were looking at STOs back in 1998)

The same goes for landings - using the wing (and the V-22 has a very thick, highly cambered wing with full span flaps that gives lots of lift at low speeds) allows you to come back on board with more stuff - useful for a COD sortie.

I believe that a good STOVL aircraft should always be capable of exploited to optimise TO and landing payloads by trading powered lift, thrust and wing lift against the available operating area. That's what's happening here.

On the safety aspects, USN and the USMC have been doing naval aviation for many years, and they are really very good at it. There is simply no way they would try these manoeuvres on a ship without having decent brakes and an acceptable level of control on launch and recovery. Why anyone would think that the V-22 doesn't have proper brakes is a bit of a poser. Have a little faith, guys.

Integrating these manoeuvres with the ship and the deck - again, some people might not have noticed that the whole science and art of naval aviation involves working out how to do the business of aviation, in its many forms, from a small patch of steel in the middle of the ocean. Clever professionals do the working out, just like in all other areas of aviation. If MROLs and STOLs are of use, the USMC and the USN wil work out how to do them safely and effectively.

As far as I know, the CVF still has the extension on the side of the flight deck. I also know that doing F-35 RVLs 'on the angle' was looked at.

Now for my bit of speculation. The USMC have been firmly wedded to VTO operations , but the payload advantages of V-22 STOs could, in my view, lead to a change in the deck ops cycles and methods on the L class ships. And if that happens, the next possibility is adding a ski jump. At present, the USMC are throwing away around 4,000 lb free extra payload for every F-35 launch. I don't know how much longer they want to go on doing that. I wonder (and would love to hear anyone else's view - especially JF's) whether a V-22 could possibly use a ski jump?

Best Regards as ever to all those pushing forward with powered lift

Engines

[LowObservable]

Engines,

One of the things that they did not think of in terms of V-22 STO was the nose gear design, which had some problems on less-than-smooth surfaces.

Clearly, STOVL has advantages over VTOL. I am not sure in what circumstances the SL bit would help the V-22. Surely that only applies with a larger payload than I can VL with, which I think is quite a lot of payload and means a short range. Reading the report on the STO trials, it looks as if they cleared SL so that they could make repeated STOs at high weights without dumping fuel for VL and then refueling.

Also, note that it was Mr Boffin, who does seem to know whereof he speaks, who raised most of the issues about SL...

[Engines]

LO,

Good points - the V-22 nose gear wasn't an instant success - but landing gear design is, as I learned on the F-35 programme, one of those pesky niche areas where even good people can get caught out. (Nimrod MRA4 had some monster issues with its main gears). In any case, where shipboard ops are concerned, flight decks are, thankfully, usually pretty smooth. I'd hazard a guess that the V-22 landing gear design (small wheels) was driven by weight considerations, like Puma and Merlin.

Repeated STOs at high weights might help for 'VERTREP' type scenarios, where they need to move lots of stuff quickly between two decks. It might also help in extreme high temps. At the end of the day, the USMC/USN will have a need for it, or they wouldn't be investigating it.

Best Regards as ever

Engines

[Finnpog]

Engines,
I am supportive of the idea. It seems to make some sense (purchase & operating cost of the Ospreys aside).
On post 3320 of the Future Carrier thread, GreenKnight posted a graphic of the two deck layouts for CVF.

My understanding was that for the angled deck, there was an extra attachement which was fitted to the port side of the deck to provide the necessary width.

My thoughts were that an angled deck in addition to the ski-jump allows for more flexibility and provide for STOL options, even with no catapults or arrestor gear fitted. This might also enable the RVLs for the F-35s as well.

I was trying to think outside the dogma of it only being angled if CATOBAR configured or Invincible style layout if not. AFAIK an angled deck does not prohibit VL or ski jump launches.

[John Farley]

Engines.

The simple answer is I don’t know whether the V-22 could use a ski-jump. However anything that can do a runway STO can use a ski-jump providing the gear will take the associated g loads (of order 2-3g depending on desired end speed and ramp shape).

As a vectored thrust aircraft the heavy Harrier is able to do its run up to the ramp with aft thrust of order .9 T/W which allows a short distance before the nozzles are lowered to 40-45 deg at ramp exit. If it had to do its deck run using 40-45 deg from brakes off it would need a considerably longer run.
Clearly the V-22 (u/c permitting) would accelerate for a ramp STO at only some .5-.6 T/W so would need a fair bit of deck.

However the important bottom line is if any aircraft gets more weight off doing a flat deck STO from the space available when compared to a VTO, then it will always do even better from a ramp if the gear will take it. Much better.

[SpazSinbad]

V-22 Factoid

Thanks for the input all - shuffling aircraft around is a flat deck stock in trade - no big deal. Here is a V-22 factoid for youse....

Software Change Gives V-22 Pilots More Lift Options 20 Oct 2011 Renee Hatcher V-22 Public Affairs

V22 Osprey Web

"A test team from the V-22 Joint Program Office spent about six weeks in Logan, Utah [4,400 foot elevation] confirming that a small software change will result in more lift capability for the Osprey.

The actual change, which is barely observable to the eye, calls for the V-22 rotors to be tilted about four degrees outward. This change reduces the air flow from the rotors over the wings, which allows the V-22 to carry more weight and achieve greater overall performance in hover mode.

“We did see the performance gain from the software change that we expected,” said Trevor Strand, V-22 flight test engineer. “It gives the pilot more options. He can either carry more fuel, more troops, go to higher altitudes, or some combination of the three.”

Strand led the 30-person integrated test team (ITT) during the off-site test at the Logan-Cache Airport during July and August. The ITT flew 25 test flights in 31 days. This effort was the result of about two years of work by NAVAIR engineers to improve the hover performance of the V-22.

The software change that was measured and confirmed in Logan has already been implemented into some MV-22s. The plan is to upgrade all V-22s by the end of the year. The test team is currently updating performance documentation for V-22 operators...."

V-22 Performance Graphic from: http://www.navair.navy.mil/v22/index...45373924,d.aGc (PDF 3.4Mb)

Click thumbnail for big pic:

[Engines]

John,

Thanks so much for coming back. As ever, an elegant and understandable answer.

My guess is that at some time in the near future the USMC will take a long hard look at the ski jump for the L class ships to generate more payload per launch for F-35 - if V-22 can use that as well, then the deal should be done.

They are building a ramp at Pax for the F-35 - watch out for V-22 activity off it. That would be a clue....

Best regards as ever to those brilliant people who think of ideas like the Harrier, the V-22 and the ski jump,

Engines

[SpazSinbad]

NAS Patuxent River Ski Jump

Jump De Ski is there now....

EAF enables JSF landing anywhere, everywhere Jun 29, 2009

EAF enables JSF landing anywhere, everywhere | NAVAIR - U.S. Navy Naval Air Systems Command - Navy and Marine Corps Aviation Research, Development, Acquisition, Test and Evaluation

“...Although the AM-2 matting is serving its purpose as vertical take-off and landing (VTOL) pads and a 1,900 x 96-foot runway for the EAF/STOVL testing, it also doubles as the run-up for a test “ski-jump” used in conjunction with JSF testing for the British Royal Navy. The AM-2 matting and the 12-degree ski-jump ramp were installed at the centerfield area last month [May 2009]....”
__________________

NAS Patuxent River Ski Jump July 2012 BBC? Video [no longer available on YouTubie]

https://www.youtube.com/watch?v=9dX4PyA2428

“The mock ski-jump is 150-feet long, with a 15-foot high “lip” for aircraft launch. These shore-based ski-jump takeoffs will be conducted at varying airspeeds prior to the first UK ship detachment with the F-35B.”
&
The BBC? Talking Head said: “Ski Jump Testing 2014”

Click for Big Pic BBC Video Screenie:
_____________________

JSF programme to proceed with UK-specific land-based carrier trials - Farnborough 2012 | IHS Jane's

The ski jump is a replica of one that will appear on CVF soon (not as indicated erroneously in the 'Janes' report above).
________________

Note the Ski Jump in the distance in this PaxRibber Photo: