F-35B USMC 2017 "not going to stay the same"

Variants for different customers or mission profiles
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by weasel1962 » 30 May 2018, 02:16

Global security has a few pics of what appears to be flooded well decks with helo ops.
https://www.globalsecurity.org/military ... 5m-109.jpg
https://www.globalsecurity.org/military ... 0s-030.jpg

Whilst APAN had this on page 1 but probably AV-8 landing.
https:// community.apan.org/cfs-file/__key/groupfiles/00-00-00-31-52/AMW-Handbook-OCT-2016.pdf


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by spazsinbad » 30 May 2018, 03:28

APAN link has a dud space in it - this is the link to 11.6Mb PDF: JPG attached has AV-8B VL on page 1 as noted above.

AMW Handbook OCT 2016.pdf https://%20community.apan.org/cfs-file/ ... T-2016.pdf

Then for 'GABRIELE' a ZERO LENGTH CAVOUR AV-8B HARRIER TAKE OFF! :mrgreen:

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LHAwellDeckOpenHarrierOpsVL.jpg


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by gabriele » 30 May 2018, 09:37

Thanks. That is in line with what i thought. No reason why air operations should stop when docked down.


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by XanderCrews » 30 May 2018, 21:47

The air ops really CAN'T stop considering these operations go on for hours and hours with multiple waves.
Choose Crews


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by spazsinbad » 13 Jul 2018, 13:30

Essex Amphibious Ready Group Quietly Deployed on Tuesday with Marine F-35s
12 July 2018 Sam LaGrone

"THE PENTAGON — The three-ship Essex Amphibious Ready Group and the 13th Marine Expeditionary Unit left San Diego, Calif., on Tuesday with little fanfare for an expected Western Pacific and Middle East deployment, a defense official confirmed to USNI News on Thursday.

The big deck USS Essex (LHD-2)… departed for an routine deployment with a squadron of Marine F-35B Lighting II Joint Strike Fighters from the “Wake Island Avengers” of Marine Fighter Attack Squadron (VMFA) 211, the official confirmed to USNI News.

“The Essex Amphibious Ready Group with embarked 13th Marine Expeditionary Unit got underway from San Diego, Tuesday,” Pacific Fleet spokesman Capt. Charlie Brown said in a Thursday statement to USNI News. “For reasons of operational security, we are not publicly disclosing any additional details.”…"

Source: https://news.usni.org/2018/07/12/essex- ... rine-f-35s


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by spazsinbad » 22 Jul 2018, 01:56

World’s first supersonic short-takeoff and vertical-landing fighter trains in Hawaii
21 Jul 2018 William Cole

"There’s a whole lot of amphibious assault training and stealth fighter flying going on in Hawaii. Marines and sailors with the 13th Marine Expeditionary Unit and Essex amphibious ready group out of California arrived in Hawaii for final training as the unit heads out on a Western Pacific and Middle East deployment.

The training marks the first appearance of the Marine Corps F-35B short-takeoff and vertical-landing fighter in Hawaii, the Corps said. The amphibious force, which includes the Essex, USS Anchorage and USS Rushmore, is not part of Rim of the Pacific exercises....

...The F-35Bs are operating with Hawaii Air National Guard F-22 Raptors — another stealth jet — far out at sea, the Marine Corps said. The advanced jets would lead the air campaign in a conflict in the Pacific. On Friday amphibious assault vehicles from the group hit Bellows, and big troop and equipment-carrying hovercraft landed on the Marine Corps base. A long-range “raid” was practiced using MV-22 Osprey tilt-rotor aircraft, with a landing at Bellows.

“We’re moving Marines ashore doing training across Oahu, but mostly at (Kaneohe Bay) and Bellows,” said Capt. Diann Rosenfeld, a spokeswoman for the 13th Marine Expeditionary Unit...."

Source: http://www.staradvertiser.com/2018/07/2 ... -hawaii-2/


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by mixelflick » 23 Jul 2018, 14:51

Any VTO is going to take gobs and gobs of fuel though, correct?

Was that the reason for external tanks? I'd imagine the internal fuel and external stores would also be at a minimum. If a VTO affects things like I think it does, the Russian and Chinese carriers with a "ski jump" look like better solutions, LOL.


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by spazsinbad » 23 Jul 2018, 17:14

mixelflick wrote:Any VTO is going to take gobs and gobs of fuel though, correct?

Was that the reason for external tanks? I'd imagine the internal fuel and external stores would also be at a minimum. If a VTO affects things like I think it does, the Russian and Chinese carriers with a "ski jump" look like better solutions, LOL.

What is VTO in relation to which aircraft and why? The Italian Harrier was demonstrating a VTO - that is all. Otherwise a few discussions about F-35B VTOs have noted they have limited use. What do Ruskie/Chicom ski jumps do for them?


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by wrightwing » 24 Jul 2018, 00:49

mixelflick wrote:Any VTO is going to take gobs and gobs of fuel though, correct?

Was that the reason for external tanks? I'd imagine the internal fuel and external stores would also be at a minimum. If a VTO affects things like I think it does, the Russian and Chinese carriers with a "ski jump" look like better solutions, LOL.

Short take off. Vertical landing. STOVL.


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by quicksilver » 24 Jul 2018, 02:10

“Any VTO is going to take gobs and gobs of fuel though, correct?”

Nope. From brake release to wing-borne flight, about the same as other TOs.

The reason that VTOs are not used more often is 1) laws of physics (lift vs aircraft weight) and, 2) aero effects of powered-lift (takes more power to VL or VTO than to hover OGE).


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by usnvo » 24 Jul 2018, 03:29

quicksilver wrote:“Any VTO is going to take gobs and gobs of fuel though, correct?”

Nope. From brake release to wing-borne flight, about the same as other TOs.

The reason that VTOs are not used more often is 1) laws of physics (lift vs aircraft weight) and, 2) aero effects of powered-lift (takes more power to VL or VTO than to hover OGE).


The physics part is the most important. Vertical Take-off will give you the same payload as Vertical Landing allows you to bring back since hovering is hovering and you have to have a reserve of lift available. Just for discussion, say you had 40klbs of vertical thrust and the F-35B weighs 32klbs empty, you only get to add 8klbs of pilot, fuel, and ordnance before you don't get off the ground. Since the plane can carry over 13klbs of fuel, even clean you are taking off with only slightly more than 50pct fuel and no other stores.


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by quicksilver » 24 Jul 2018, 05:41

usnvo wrote:
quicksilver wrote:“Any VTO is going to take gobs and gobs of fuel though, correct?”

Nope. From brake release to wing-borne flight, about the same as other TOs.

The reason that VTOs are not used more often is 1) laws of physics (lift vs aircraft weight) and, 2) aero effects of powered-lift (takes more power to VL or VTO than to hover OGE).


The physics part is the most important. Vertical Take-off will give you the same payload as Vertical Landing allows you to bring back since hovering is hovering and you have to have a reserve of lift available. Just for discussion, say you had 40klbs of vertical thrust and the F-35B weighs 32klbs empty, you only get to add 8klbs of pilot, fuel, and ordnance before you don't get off the ground. Since the plane can carry over 13klbs of fuel, even clean you are taking off with only slightly more than 50pct fuel and no other stores.


"The physics part is the most important."

Yes.

"Just for discussion, say you had 40klbs of vertical thrust and the F-35B weighs 32klbs empty, you only get to add 8klbs of pilot, fuel, and ordnance before you don't get off the ground."

Actually, no. Search, "suckdown effect” (or try this — https://ntrs.nasa.gov/archive/nasa/casi ... 024374.pdf)

Vertical thrust creates areas of low pressure (think "lift" in the opposite direction) underneath the aircraft while it is in proximity to the ground; the closer the aircraft is to the ground, the greater the effect. During a VL, that effect only has to be partially mitigated -- in practical terms, as the jet descends into ground effect, by increasing thrust sufficient to keep the rate of descent within the aircraft structural design limits for rate-of-descent at touchdown. Additionally, there is thrust that has to be booked for control margin. For a VTO, the same control margin has to be booked, but suckdown has to be completely overcome by a thrust margin sufficient to get the aircraft off the ground, and up and above ground effect (something like 10-15' AGL). There may be some accomodation for HGI (hot gas ingestion) as well. I don't know exactly what any of those margins are for F-35 but I do know they are not insignificant.
Last edited by quicksilver on 24 Jul 2018, 11:57, edited 2 times in total.


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by spazsinbad » 24 Jul 2018, 05:59

Not a lot of actual figures/detail in this PDF however some issues are spelt out for STOVL for the F-35B:
F-35 STOVL Performance Requirements Verification
13 Apr 2018 David G. Parsons and Daniel E. Levin & David J. Panteny & Michael R. Rask & Brad L. Morris

"page 15 ...Having an aircraft gross weight capability in hover in OGE [out-of-ground effects] conditions does not necessarily directly indicate having a VL capability. Hot gas ingestion (HGI) is a significant factor affecting performance and operability during VL. It reduces total propulsion system thrust, potentially influencing aircraft descent rate and handling qualities and reducing engine and LiftFan stall margins. When executing a VL, the aircraft must not experience excessive un-commanded acceleration or adverse handling qualities during the landing as the jet enters ground effects.

HGI has two main mechanisms of action: ground sheet roll-up ingestion and fountain ingestion. These two mechanisms are visually depicted in Fig. 13.

The aircraft exhaust plumes impinging on the ground form a ground sheet that flows away from the aircraft in all directions. Ground sheet roll-up occurs when a strong environmental wind picks up this buoyant layer of gas and turns it back toward the aircraft. Due to the well-mixed nature of the flow returning to the aircraft, the HGI experienced from this mechanism is of a low magnitude. Usually, it is only seen near the ground in the last stages of a VL. The flight-test-measured levels of HGI from this mechanism have not been significant and do not require mitigation through performance limitations.

There are certain heights above ground where the propulsive jets do not merge before impacting the ground. There, the ground sheets from the individual exhaust plumes of the LiftFan, core nozzle, and roll-posts flow inward toward one another under the aircraft. An upward fountain is formed where they collide, and it then impacts the undersurface of the aircraft. Under certain conditions, exhaust gas from the fountain can enter the main engine inlets and LiftFan inlet. HGI in this scenario can result in a high temperature rise and high-temperature inlet distortion. This leads to concerns for both aircraft performance and engine/LiftFan operability that must then be mitigated.

For the F-35B, the amount of HGI is a function of height above ground, aircraft relative wind, aircraft fuselage station center of gravity (FSCG), and ground slope. Fountain HGI is typically only seen with tailwind or crosswind conditions relative to the aircraft and not with headwind conditions relative to the aircraft. For the aircraft to remain stationary in the hover in the environmental wind, the exhaust plumes must be directed aft for a headwind and forward for a tailwind. Additionally, the environmental wind acts on both exhaust plumes as they travel toward the ground and on the fountain as it returns. Therefore, a headwind tends to angle the fountain aft away from the inlets, reducing HGI levels. By contrast, a tailwind tends to angle the fountain forward toward the inlets, resulting in potentially higher levels of HGI.

An aft aircraft FSCG increases the trim TS required. Higher TSs [ratio of core nozzle thrust to LiftFan nozzle thrust] result in greater exhaust flow from the engine nozzle versus the LiftFan nozzle. This reduces the strength of the ground sheet from the LiftFan exhaust, compared to the ground sheet from the engine nozzle exhaust that forms the fountain. With an aft FSCG, the point at which the fountain forms underneath the aircraft moves farther forward. Consequently, the fountain flow will angle forward toward the inlets, increasing the likelihood of encountering higher HGI levels for a given condition. With the ground sloping away from the nose of the aircraft (downhill), the fountain will also be angled farther forward toward the inlets. This increases the likelihood of encountering high HGI levels for a given condition.

Subscale wind tunnel testing [10] [Cook, R., Curtis, P., and Fenton, P., “State of the Art in Sub-scale STOVL Hot Gas Ingestion Wind Tunnel Test Techniques,” SAE International 2005-01-3158] was used to create an HGI database to use in six-degrees-of-freedom flight simulation tools. With these, we performed sensitivity analyses under piloted conditions and developed flight test HGI limitations for VL envelope expansion, allowing VL flight testing to commence...."

Source: download/file.php?id=27759 (PDF 2.2Mb)
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