F-35C wasted deck space?

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by tincansailor » 13 Nov 2017, 01:41

gergf-14 wrote:This seems to be wasted deck space.



I wouldn't consider it wasted deck space. Your talking about the aft end of the flight deck, that you primarily use for landing. The amount of deck space your losing, is about enough for parking two aircraft. In return your gaining a fine position for a NATO Sea Sparrow launcher. It has a clear field of fire on the port side. It looks like there's enough room to add a Sea Ram, or maybe a laser. In earlier carriers you had to have over hanging sponsons to mount defensive systems.

My only concern is a really bad landing could go off the deck, and hit the Sea Sparrow. It's an unmanned position, and that armored box it pretty secured vs. the warheads cooking off. I think it should work out fine.


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by h-bomb » 13 Nov 2017, 04:15

tincansailor wrote: I wouldn't consider it wasted deck space. Your talking about the aft end of the flight deck, that you primarily use for landing. The amount of deck space your losing, is about enough for parking two aircraft. In return your gaining a fine position for a NATO Sea Sparrow launcher. It has a clear field of fire on the port side. It looks like there's enough room to add a Sea Ram, or maybe a laser. In earlier carriers you had to have over hanging sponsons to mount defensive systems.

My only concern is a really bad landing could go off the deck, and hit the Sea Sparrow. It's an unmanned position, and that armored box it pretty secured vs. the warheads cooking off. I think it should work out fine.


I wish I could find the Youtube video of one of the officers from the design committee. He talks about the history from the late 1990's through early 2000's. He makes several statements, including the reduction of the radars to 3 systems cost an extra $1 billion, and it was his fault. He also stated that area is open and the NAVAIR members insisted you could not park on it as it would block the line of site for the LSO's. So they left it open. He talked about the location of the island was also an airwing request. And some history of the Enterprise to Nimitz to Ford changes in the reactor room watches and simplification. I knew the enterprise had 8 reactors, never knew she had a grand total of 32 steam turbines (drive and power).

I tried to find it in my history but I seem to have stopped watching youtube in 2015....


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by spazsinbad » 13 Nov 2017, 06:28

Good catch. I recall reading somewhere about aircraft parked in LSO line of sight used to be an issue on old USN non nuke driven carriers. Then it was a matter of not parking aircraft that did that during flight ops IIRC. F-35Cs won't be there eh.

However one needs to look at old aircraft carrier decks to see where LSOs stood on the flight deck, and / or in relation to the flight deck landing area. Some used to be on the side of the flight deck, often some distance from the foul line. In the photo provided we see them close to the foul line on the flight deck edge with the sponson now underneath them. So it all depends on a few criteria and I'm not going to look at various USN aircraft carrier decks over the last seventy-five years.


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by sferrin » 13 Nov 2017, 14:09

gergf-14 wrote:This seems to be wasted deck space.



It's pretty obvious why they left it. Those "unused" areas tend to get stuffed with things like weapons and antennas. Now they have somewhere to put them when (not if) more space is needed down the road. Nice click-bait / troll thread title BTW. :roll:
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by gergf-14 » 13 Nov 2017, 14:47

All that for LSO’s, isn’t the Ford class carriers a technological leap forward with a more automated approach to landing especially.

Perhaps a laser installation later on once ready? Who knows.


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by spazsinbad » 13 Nov 2017, 20:04

gergf-14 wrote:All that for LSO’s, isn’t the Ford class carriers a technological leap forward with a more automated approach to landing especially.

Perhaps a laser installation later on once ready? Who knows.

Thanks for playing. You seem to misunderstand the role of LSOs. LSOs monitored the X-47B robot auto landings, with the power to wave them off if those robots were not 'on speed, on glideslope and on line up'. Even robots are 'human'. Safety of flight - safety during a carrier approach is vital to all concerned on an aircraft carrier hence why they are practiced, monitored and graded. IF the LSO says you cannot deck land - you cannot - and you go back to the beach for more FCLP.

As mentioned by many others the space shown is NOT part of the flight deck like CVNs before this one. However the sponson can accommodate other things in future in the free space as mentioned by many others - laser weapons - yes.


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by 010137 » 14 Nov 2017, 00:45

gergf-14 wrote:All that for LSO’s, isn’t the Ford class carriers a technological leap forward with a more automated approach to landing especially.

Perhaps a laser installation later on once ready? Who knows.


All about new space “down below” in the hangar and work centers. Useful space up top is a non-player due to line of sight for the LSO’s.

This jet is very stable around the ship and will make the process much easier in the long run, especially compared to legacy jets. That being said, a pitching deck at night will never be easy in any aircraft. LSO’s are a must dance at the ship, regardless of aircraft type. Day, steady deck there isn’t a whole lot for them to do most of the time. Night, 0 illum, with a moving deck they will literally save lives regardless of aircraft type.


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by 35_aoa » 14 Nov 2017, 01:17

010137 wrote:All about new space “down below” in the hangar and work centers. Useful space up top is a non-player due to line of sight for the LSO’s.

This jet is very stable around the ship and will make the process much easier in the long run, especially compared to legacy jets. That being said, a pitching deck at night will never be easy in any aircraft. LSO’s are a must dance at the ship, regardless of aircraft type. Day, steady deck there isn’t a whole lot for them to do most of the time. Night, 0 illum, with a moving deck they will literally save lives regardless of aircraft type.


Yep......turns out you can still throw a turd pass with PLM/"Magic Carpet", and that isn't even a pitching deck MOVLAS recovery......in that scenario, getting aboard first pass is all about LSO skill, and timing/luck, automation has still not cracked that nut. PLM "rate" mode is the best way to do it in that scenario, but ultimately, you are still using the same technique you did with a manual pass, just a little more precise.


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by spazsinbad » 14 Nov 2017, 01:39

:roll: Geez I had to look up 'PLM' Precision Landing Mode. :doh: Still no mention by OP of significance of F-35C. 8)


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by rheonomic » 14 Nov 2017, 03:30

35_aoa wrote:"Magic Carpet".


I really hope the Navy gave whomever came up with that acronym some sort of medal.
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by 35_aoa » 14 Nov 2017, 03:31

spazsinbad wrote::roll: Geez I had to look up 'PLM' Precision Landing Mode. :doh: Still no mention by OP of significance of F-35C. 8)


Don't worry....some Paddles mentioned "PA CAS" the other day, and I was like, WTF are you talking about now? Turns out, that is the new name for the normal FCS operating mode the F/A-18 community has been flying since 1978.....ie CAS (Control Augmentation System) mode of the FCS.....which actually meant something in the legacy that also had DEL (both digital and analog backup) and MECH reversion modes .....but in the Rhino, you only have CAS....or you have "no longer flying" mode I suppose :)


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by spazsinbad » 14 Nov 2017, 03:51

:doh: Are you from HOLLAND because that is all DOUBLE DUTCH to me. :mrgreen: :roll:


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by botsing » 16 Nov 2017, 20:58

spazsinbad wrote::doh: Are you from HOLLAND because that is all DOUBLE DUTCH to me. :mrgreen: :roll:

The Netherlands you mean? :mrgreen:
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by spazsinbad » 16 Nov 2017, 21:24

:devil: :doh: Yep that is where my question came from: MY NETHER REGIONS (where the sun don't shine). :twisted: :roll: 8) :mrgreen:


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by spazsinbad » 13 Nov 2018, 07:26

Just guesswork based on the PDF cited, however the FILLET space under discussion may be designed to reduce BURBLE. The slimmed down island is thusly designed & moved aft but also for other reasons (free up deck space for etc.)
The Burble Effect: Superstructure and Flight Deck Effects on Carrier Air Wake
2010 BRADLEY E. CHERRY & MATTHEW M. CONSTANTINO

“The purpose of the present work was to qualitatively and quantitatively model the air wake created by an aircraft carrier flight deck and superstructure in order to understand how it affects aircraft on approach and landing. The “burble effect” is the name given by navy pilots to the velocity deficit and downwash field immediately aft of an aircraft carrier. This turbulent region of air has adverse effects on landing aircraft and can cause pilots to bolter, missing the arresting wires and requiring another landing attempt. The experimental approach involved using a five-hole Pitot probe rake system for mapping of the air wake of a 6 ft aircraft carrier model. Wind tunnel tests were performed at Reynolds numbers of 11,000,000 and wake maps of 288 point measurements each were generated for configurations with and without the superstructure. The experiment showed that the superstructure created a region of extremely low flow velocity and downward flow angle. While the hull/deck configuration produced velocity deficits as low as 17%, the presence of the superstructure increased this to almost 30%. Furthermore, the addition of the superstructure decreased the downwash angle at the deck edge from -5 to -8 deg. Under these conditions, an aircraft on approach will experience an increased descent rate as it passes through the burble region. The presence of strong downwash compounds this adverse effect, making it more severe closer to the flight deck. Results also show that the superstructure geometry affects the severity of the burble effect.

Introduction
HE superstructure and deck/hull features of an aircraft carrier are known to generate turbulent airflow behind the carrier. This region of turbulent air has become known as “the burble,” and it is often encountered by pilots immediately before landing. The burble causes planes to drop slightly, thus requiring a small amount of power to be temporarily added to maintain the glide slope though this region. The region is characterized by a downwards suction in the airflow and it is created by “the interference of the structure of the ship with the relative wind and its influence is felt mainly in the last half mile of the approach to the ship”. Additionally, sea state, crosswinds, and features such as raised jet blast deflectors and flight deck traffic contribute to the burble....

...The air wakes of ships which deploy aircraft have been the subject of numerous research programs, with the central focus to quantify the flowfield along the aircraft approach paths. Previous research has shown that subtle changes and protuberances in hull/deck/superstructure can have significant changes in the external flow characteristics and that these flow features can be severe. This has been shown for DDG, LHA, and CV ship classes. For the aircraft carrier (CV), the flow pattern is primarily characterized by the formation of free vortices. One of these can appear along the leeward side of the hull while others form at sharp edges of the deck-edge and superstructure. Cut-outs in the deck or sharp corners on the superstructure in general trap standing vortices which stabilize the wake structure in general and create a flowfield that is largely independent of the Reynolds number. The fact that the overhang of the deck is a major cause for flow disturbance was experimentally validated by Lehman on a Forrestal-class carrier. Durand and Wasicko also studied the effects of upwash and downwash on the glide path control of the approaching aircraft. More recently, the burble was modeled in CFD by Polsky and Naylor. They found that the geometry of the stern had a significant impact on the airwake qualities along the aircraft approach path. Other researchers have concentrated on the dynamic flowfield effects on the aircraft/ship coupling....

...A second feature that was investigated was deck fillets. Removable fillets were built to install in the two notches in the back of the deck. Increasing the deck space can be useful for taxiing aircraft and parking them on deck, therefore the effects of how rounding out the corners of the aircraft carrier’s deck would influence the burble was investigated. Figure 5 shows the two fillets and it is noted the fillet on the starboard side is the small fillet....

...C. Flight Deck Geometry Effects for Ford Class
Further analysis was conducted in order to study the possible effects of the flight deck geometry on the burble. These tests were conducted for the configurations listed below in Table 4. It was found that the flight deck geometry mainly affected the port side of the flow field behind the carrier and was independent of the type of superstructure installed. Therefore, this section seeks to characterize the deck/hull vortex for the Ford class aircraft carrier...

...D. Discussion/Conclusion
It is important to note that the study conducted on the effect of the fillets on the deck/hull vortex was conducted at a length of two feet behind the carrier. As previously stated, this length corresponds to distance of 380 feet aft of a real, full-scale carrier. Even at this distance, the vortex and burble appeared relatively intact. Due to equipment and wind tunnel mounting restraints, it was not possible to analyze the deck/hull vortex and burble effect immediately over and aft of the flight deck. The deck/hull vortex appears to be “sucked” upwards through the “notch” in the back of the carrier flight deck and subsequently rolls downstream behind the carrier. The addition of the large fillet drastically appears to reduce the intensity of the deck/hull vortex, even at a full-scale distance of 380 feet. Therefore, it would appear to be beneficial to fill in the “notch” in the back, port corner of the flight deck on aircraft carriers. Not only would this fillet reduce the deck/hull vortex and prevent it from rushing up and over the landing/approach area, but it would also provide room for aircraft and/or equipment storage.

The burble effect is caused by multiple factors such as - velocity deficits, upwash and downwash, and vortices that are generated from the superstructure and the deck/hull. All of these various aspects of the burble combine to produce the increased sink rate on approach that has been described by many carrier pilots. Additionally, an aircraft carrier’s superstructure and flight deck geometry both contribute to the burble effect. Since Nimitz class carrier construction has ended and Ford class carrier construction has just begun, the potential exists for future carriers to be designed such that the burble effect becomes reduced.”

Source: https://pdfs.semanticscholar.org/5433/b ... 62d40e.pdf (0.5Mb)
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TestFlightDeckLargeSmallFilletsBURBLE.jpg


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