Aircraft Carriers II (Closed to posting)

As I stated earlier...the Navy already had a very good handle on this and has addressed it as they said they would.

Sometimes people hear of "issues," or "problems," through press reports and start jumping to all sorts of conclusions.

The people working on these things are VERY bright, VERY talented, VERY smart people.

This does not mean that they cannot make mistakes, but generally they are being checked and rechecked by numerous others. Then when an error is found, they address it as quickly as possible from a position of very strong knowledge about what they are dealing with. Those checks are requirements of such engineering projects.

Generally people out on internet forums who want to second guess these folks have no idea the level of schooling and...more importantly...the level of real-world experience these people have who are designing these systems.

They do not take people fresh out of school, no matter how impressive their grades and performance in a scholastic environment may have been, and put them into any senior design or engineering positions. It almost always takes years...decades...of experience in the real world before that happens.

strehl said:

If you refer to Jeff's catapult specification table (https://www.sinodefenceforum.com/modern-aircraft-carrier-catapult-systems-including-emals.t7115/), the longest steam catapult is only 307 feet long (actual shuttle track length). If there are g limit problems with EMALS, they would be present for existing catapults as well. Also, top end speeds are listed at only 140Kts so your 200Kt Hornet will be in trouble even allowing for another 30Kts of carrier/wind speed.

In any event, the specification table indicates EMALS matches the steam catapults in top end speed and track length. From the CGI renderings of Ford, it doesn't look like the catapults are any shorter than existing systems so it is unlikely that the EMALS designers screwed up and forgot about g limits. This whole story seems to be another concoction of the professional naysayer crowd.

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Read the table - for Nimitz , shuttle run 306 ft 9 inches , track length 324 ft 10 inches . For Gerald Ford , track length 300 ft - therefore actual equivalent of shuttle run is well below 300 ft I made simplified calculation, if we calculate with shuttle run results would be even worse .

As for 200 kts, I didn't invent that . I suppose it is USN requirement . Looking at videos of Super Hornets taking off with current steam cats, they don't utilize all off hardpoints to the maximum capacity. Now they probably want that , and coupled with shorter run it means more acceleration .

As for "software" fix, do you really believe it would take until 2017 to correct few parameters in software to allow lower maximum acceleration for aircraft with fuel tanks ?

P.S. I forgot one tiny detail . We are talking about Super Hornet - fine aircraft that needs around 140kts to successfully launch from carrier with reasonable payload . And what about our little joy wonder F-35 C , with its relatively small wings and squat fuselage ? That could be the answer of our 200 kts enigma .

kwaigonegin said:

Yes, I would say the red navy was probably at it's peak just before the collapse of the Berlin Wall and official end of Cold War. At that time they also had 4 Kirov class battle cruisers,3 Slava class, Kara class not to mention a bunch of Udaloys, Krivaks and Sovs... and that's just the major surface ships.
They have even more subs of various kind including 6 Typhoons and more Delta SSBNs than I can count.

Also all of the carriers were built at Nikolayev Shipyard in Ukraine so I would assume those experiences and knowledge are extremely limited today or died with many folks. The youngest folks who built those carriers are probably in their 50s, 60s now and the older more experience workers probably 70s and beyond. To add to that, I would assume only very very few workers were Russians. Most were probably Ukranians so there's that.

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OT
Many of the people living in Nikolayev have as mother tongue Russian.

thunderchief said:

Read the table - for Nimitz , shuttle run 306 ft 9 inches , track length 324 ft 10 inches . For Gerald Ford , track length 300 ft - therefore actual equivalent of shuttle run is well below 300 ft I made simplified calculation, if we calculate with shuttle run results would be even worse .

As for 200 kts, I didn't invent that . I suppose it is USN requirement . Looking at videos of Super Hornets taking off with current steam cats, they don't utilize all off hardpoints to the maximum capacity. Now they probably want that , and coupled with shorter run it means more acceleration .

As for "software" fix, do you really believe it would take until 2017 to correct few parameters in software to allow lower maximum acceleration for aircraft with fuel tanks ?

P.S. I forgot one tiny detail . We are talking about Super Hornet - fine aircraft that needs around 140kts to successfully launch from carrier with reasonable payload . And what about our little joy wonder F-35 C , with its relatively small wings and squat fuselage ? That could be the answer of our 200 kts enigma .

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I don’t know what the form factor of the shuttle to track length is for an EMALS catapult but I assume it is different since the drive mechanism is much more compact. If you do, please post the specification table and the source for it.
I don’t know what the Navy prioritization schedule is for EMALS and where fixing the acceleration profile for external tank g limits fits into it. If you do, please post the schedule and the link to it.
You say you didn’t invent the 200 Kts takeoff speed for the F-18 with external tanks. I did a quick Google search and came up with nothing. Since you know, please post the source (official source please, not a discussion board).
If other Navy’s are more open in showing their development programs along with all the glitches they encounter along the way, I am unaware of it. Perhaps there are discussion boards in Chinese commenting on revelations of technical deficiencies encountered with various military programs but I have not seen anyone referencing them.
US military hardware is subjected to extensive negative commentary and disparagement until a war comes along and then the results are seen on video. This was true for every major program I can recall (M1 tank, AH64, F-117, laser guided munitions, etc etc). None of them worked, until they did.
Finally, that F-35C with its’ little wings:

thunderchief said:

Read the table - for Nimitz , shuttle run 306 ft 9 inches , track length 324 ft 10 inches . For Gerald Ford , track length 300 ft - therefore actual equivalent of shuttle run is well below 300 ft I made simplified calculation, if we calculate with shuttle run results would be even worse .

As for 200 kts, I didn't invent that . I suppose it is USN requirement . Looking at videos of Super Hornets taking off with current steam cats, they don't utilize all off hardpoints to the maximum capacity. Now they probably want that , and coupled with shorter run it means more acceleration .

As for "software" fix, do you really believe it would take until 2017 to correct few parameters in software to allow lower maximum acceleration for aircraft with fuel tanks ?

P.S. I forgot one tiny detail . We are talking about Super Hornet - fine aircraft that needs around 140kts to successfully launch from carrier with reasonable payload . And what about our little joy wonder F-35 C , with its relatively small wings and squat fuselage ? That could be the answer of our 200 kts enigma .

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thunderchief said:

Read the table - for Nimitz , shuttle run 306 ft 9 inches , track length 324 ft 10 inches . For Gerald Ford , track length 300 ft - therefore actual equivalent of shuttle run is well below 300 ft I made simplified calculation, if we calculate with shuttle run results would be even worse .

As for 200 kts, I didn't invent that . I suppose it is USN requirement . Looking at videos of Super Hornets taking off with current steam cats, they don't utilize all off hardpoints to the maximum capacity. Now they probably want that , and coupled with shorter run it means more acceleration .

As for "software" fix, do you really believe it would take until 2017 to correct few parameters in software to allow lower maximum acceleration for aircraft with fuel tanks ?

P.S. I forgot one tiny detail . We are talking about Super Hornet - fine aircraft that needs around 140kts to successfully launch from carrier with reasonable payload . And what about our little joy wonder F-35 C , with its relatively small wings and squat fuselage ? That could be the answer of our 200 kts enigma .

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Your 200 kts is way high, please post a link to the requirements of the USN, as to your observation that not all the hardpoints on the wing are filled, they could still very possibly be at or even above gross weight??

I was thinking that you said you are a pilot??? so you are aware if you fill the Cessna 172's four seats and fuel tanks you will be overgross?? same with the F-18 or the Super Hornet depending on your fuel and what your are hauling on those hard points. You also know that at gross weight your aircraft performance drops off noticeably, that's why we see those kool old movies with P-51s and F-86s dropping those external fuel tanks as the spot the bogies or prepare to "roll in" on a target. You never carry more ordnance or fuel than might be required to complete the mission with a legal reserve on fuel.

INS Vikramditya's maiden visit to Kochi after the conclusion of TROPEX-2015

and btw there is news that a foreign aircraft will be using india's SBTF facility soon
wonder which?

Air Force Brat said:

Your 200 kts is way high, please post a link to the requirements of the USN, as to your observation that not all the hardpoints on the wing are filled, they could still very possibly be at or even above gross weight??

I was thinking that you said you are a pilot??? so you are aware if you fill the Cessna 172's four seats and fuel tanks you will be overgross?? same with the F-18 or the Super Hornet depending on your fuel and what your are hauling on those hard points. You also know that at gross weight your aircraft performance drops off noticeably, that's why we see those kool old movies with P-51s and F-86s dropping those external fuel tanks as they spot the bogies or prepare to "roll in" on a target. You never carry more ordnance or fuel than might be required to complete the mission with a legal reserve on fuel.

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Master Strehl beat me to the draw here by a few minutes?? The F-35C or Charlie has MUCH larger wings and horizontal stabs than the A or B, that's why the Charlie is rated at 7.5 max gs to the USAF A's 9 g max?? I know you knew that?? The Charlie's must come aboard ship at NO MORE than 145 kts, why the flaps were recalibrated to help fly the aircraft down the glide path, there is no doubt reserve lift or you wouldn't be able to reduce flap deflection in order to accomplish that?

I will once again repeat that the EMAL's acceleration will have to be dialed back??? to provide lower initial g loading with a more gradual acceleration to around 3 to 4 gs. Like a light switch you get it all at once, and that very high initial acceleration is very "stressfull on any underwing fuel or ordnance hung on a plyon due to its much great moment arm acting to twist the wing leading edge downward from that front attaché point?? I would also note that the F-18s or Super Hornets max g loading is in the 7.5 range.

@strehl @Air Force Brat

I don't have official USN requirements for EMALS , but you could put two and two together . For example

All prospective EMALS designs must be capable of launching present and future naval fixed wing aircraft from the deck of an aircraft carrier. Design goals for the program are: 30% reduction in manning, 20% reduction in life cycle cost, 20% improvement in operational availability, and up to a 50% reduction in installed size and weight when compared to the current steam catapults. The performance goals for the EMALS are:90,000,000 ft-lbs. of energy capability, an end speed range between 55 and 200 knots, a peak to mean acceleration of 1.05 for all aircraft launches (including light weight aircraft such as Unmanned Air Vehicles and Unmanned Combat Air Vehicles), and a cycle time of 45 seconds.

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or this from 2010

“The future Electromagnetic Aircraft Launch System (EMALS) full-scale test catapult went operational for the first time at NAVAIR Lakehurst, N.J., and has since demonstrated max speed of 180 knots, or 207 miles per hour. The program is scheduled to launch its first test aircraft later this year.”

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As for F-35C , landing speed is one thing, launch speed with external stores something completely different .

Air Force Brat said:

I will once again repeat that the EMAL's acceleration will have to be dialed back??? to provide lower initial g loading with a more gradual acceleration to around 3 to 4 gs. Like a light switch you get it all at once, and that very high initial acceleration is very "stressfull on any underwing fuel or ordnance hung on a plyon due to its much great moment arm acting to twist the wing leading edge downward from that front attaché point?? I would also note that the F-18s or Super Hornets max g loading is in the 7.5 range.

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Acceleration is second derivative of displacement (length, road ...) , speed is first . You are talking about first derivative of acceleration (speed of acceleration) , which would be third derivative of displacement . Third derivative of displacement is not significant in physics. To put it simple , when a mule kicks you its second derivative of displacement (acceleration) that knocks your teeth out Acceleration going rapidly from 0 to 3g would not harm you (you could experience this in fast car for example). But steady acceleration of 5g is harmful for average person.

without being kicked by a mule LOL I figured out what you guys're talking about:
a = v*v/(2*S)
so for v=145 knots (number from AFB's post) and S=90 m (the deck length) a is 2.94g