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-   -   An utterly daft question about aircraft carriers (https://www.pprune.org/tech-log/401594-utterly-daft-question-about-aircraft-carriers.html)

Senior Pilot 14th January 2010 03:05

Of course the much easier way was to have the Looker plot the thing on his radar and give you a steer ;)

Emcon we'd use the plotting board up front and always win against the back seat with his Doppler plot: the darn thing inevitably slipped enough to give us the edge :ok:

ReverseFlight 15th January 2010 13:23

Great stuff, thanks to everyone for their contribution. :D

The SSK 15th January 2010 14:07


Three Wire: So, no they couldn't aid the ship in going faster, but could help you get alongside. Oh, and the stokers were known to burn a bit of jet fuel in the ship's boilers as well!
I fail to see how it would *not* make the carrier go faster. Newton's Law and all that.

I once asked on the rowing newsgroup whether my old man's four could tow a warship - admittedly a small one - 100 metres in half an hour, as a publicity/fundraising stunt. Some serious mathematicians and hydrodynamicists came up with the answer that we probobly could.

The comment was also made that if you stood on the edge of the dock and pushed against the side of the Queen Mary (or the Nimitz) it would move ... eventually.

18-Wheeler 15th January 2010 22:51


I fail to see how it would *not* make the carrier go faster. Newton's Law and all that.
I agree - as I mentioned in the first post, it wouldn't be all that difficult to add a good 30,000hp to the forward thrust of the carrier, that'd have to give it another knot or two.

Tinstaafl 16th January 2010 15:02

Another daft question: Why is the angled deck positioned behind the superstructure, causing the approach end to be in the wake? Why not arrange the deck to be ahead of the superstructure (or move the superstructure further aft, or both) so relatively undisturbed air is presented to the landing deck?

Capot 16th January 2010 16:33

Don't be silly, old boy. The Royal Navy, just like every other Navy, prefers to stick to the tried and tested ways of doing things. Carrier superstructures have always been halfway along the side of the boat. That's where they go, see?

The superstructure could in fact disappear altogether. All you really need above the flight deck is a set of remote handling controls (retractable) for docking, and perhaps a place to mount the radar aerial(s). Otherwise the ship and flight operations could easily be managed from an office somewhere in its bowels, with sponsons on each side for those who simply have to look at the sea from time to time, as they are now.

But The Royal Navy has managed its ships from raised platforms since Samual Pepys was first appointed and the telescope was the best means of target acquisition and shouting was the only way of communicating, and who would be so foolishly revolutionary as to propose a change?

Intruder 17th January 2010 03:06


Another daft question: Why is the angled deck positioned behind the superstructure, causing the approach end to be in the wake? Why not arrange the deck to be ahead of the superstructure (or move the superstructure further aft, or both) so relatively undisturbed air is presented to the landing deck?
The superstructure has been moved aft. Look at pix of Midway, Forrestal, Kitty Hawk, Enterprise, and Nimitz (evolving classes).

The ship drivers also sit in the superstructure, so their needs weigh into the equation...

nomorecatering 17th January 2010 09:40

Why havent they made an aircraft carrier in the form of a catamaran or even a trimeran, 3 hulls would increase the usable space. and make it harder to sink with a torpedo. And the flight deck could be as wide as they wanted and i guess more stable.

Mike Oxbig 17th January 2010 10:05

Have you ever been on a carrier? I have only served on the RN CVS and getting around one of those 'baby carriers' is hard enough, without adding the extra hulls to get lost on :\! Also I would imagine the cost would be prohibitive - I think it would be cheaper to build one hull instead of two or three.

Mind you, you could keep all the fishheads in one hull and the wafus in the other............................:ok:

MB

3 Point 17th January 2010 16:17

Take a look at the designs for the RN's new CVFs. You will see two separate islands, one forward for the fish heads and one aft for flyco.

We came up with this idea and the logic was debated back and forth within the design team and found to stand up. Basically, the fish heads preferred a forward position to see better when coming alongside and the Air Department requirements favoured a more aft position to afford a better view of the approach and landing. Questions about communicating between the two were answered by using electronic means and the ability to have an emergency ship driving position in the aft island and an emergency flyco in the forward one gave good redundancy in the event of a hit in the superstructure.

Aircraft carriers do indeed need superstructure above the flight deck; where else would you mount the various antennae? Or where would you fly an ensign to lower it so dramatically during cocktail parties??

I pitched the two islands idea to the Navy at a design review meeting and expected to be shot down in flames however they were completely content (taken in!!) and the ship design today still has two separate islands!

So, looks like the RN is not too slow to adopt new thinking after all!

Happy landings (or recoveries)

mm43 17th January 2010 18:16

3 Point omitted to say that the RN CVF carrier design is for an inline flight deck, but thanks for sharing the info.:ok:

http://i846.photobucket.com/albums/a...alnavy-cvf.png

Obviously the design doesn't allow for multiple operations, e.g. Nimitz class angle deck landings, twin catapults fitted forward and two aft. Notwithstanding, this new class of carrier is quite a step up from the RN's current Invincible class.

I'm sure the French will come up with a bigger version!;)

mm43

Tinstaafl 17th January 2010 19:25

Looking at the Nimitz class: What I was questioning could be accomplished by angling the deck to the right instead of left so that it crosses in front of the superstructure. Superstructure on the left & 'behind' the present angled deck would also do it but with the penalty of occluding the deck during a left hand circuit.

There must be some reason why they're prepared to tolerate the wake from the superstructure?

D O Guerrero 17th January 2010 22:54

Unfortunately WAFU's aren't known for their knowledge of anything related to actual Ships...
The Navigation Bridge is generally positioned directly above the pivot point of the ship when under ahead propulsion. This is a useful feature when getting the thing into harbour (if you're going to navigate visually, which is often the case), which is occasionally desirable. Its nothing to do with Pepys, shouting or telescopes. Being high up is also quite nice too - you can see stuff. Which is why there are also windows. Being able to see stuff is quite good for avoiding other ships or big rocks and lighthouses.
Admittedly in carriers, the bridge is positioned by necessity in the island, which has to be displaced to one side. Moving it for'd or aft would completely bugger things up though... So its a bit of a compromise. I suppose parallel runways with the island in the centre would be the ideal solution. But then the FOD plod would really take forever, whilst being just as much a waste of everyone's time and effort.

mm43 17th January 2010 23:35

@Tinstaafl

Think about the following situations:-

(a) On a calm day and the ship steaming at 20 knots, the relative wind is across the line of the flight deck and any aircraft FU's will end up in the superstructure.:eek:

(b) On a day with a 25 knot wind, the ship when steaming sets a heading to provide a relative wind down the line of the flight deck. Any FU's and the ship is still effectively heading across the intended line of flight.:\

The angle deck carriers are designed to minimize the above situations, and furthermore the superstructure is on the starboard-side because that is the 'give-way' side and the Fish Heads prefer to see everything on that side.:ok:

mm43

Tinstaafl 20th January 2010 02:39

Ta. Hadn't thought about downwind effects of a crash.

3 Point 20th January 2010 20:45

The design for the CVF when I worked on it could accommodate either a straight deck or an angle; at that time the decision to go STOVL or CV had not been made and the design could easily have been built either way. When we persuaded the RN to accept the two islands we argued its merits for both the CV and STOVL case.

D O Guerrero is right, us WAFUs don't know much about ship driving but what he says pretty well explains why we ended up with the bridge in the forward island and flyco much further aft. The two functions demand entirely different positions relative to the hull/flight deck and all previous designs which co-located them were a severe compromise (usually in favour of the fish-heads).

Happy landings

Mike Oxbig 20th January 2010 21:43

Tinstaffi,

In the old days an angled deck also stops 50,000 tonnes of ship running you over when the catapult only goes whoosh instead of wwwhhhooooooossshhhhhhh!! Also if you fall off the end when landing!

Remember the Stig going over the ramp of Invincible and getting run over in his XJS?

Senior Pilot 21st January 2010 01:12


In the old days an angled deck also stops 50,000 tonnes of ship running you over when the catapult only goes whoosh instead of wwwhhhooooooossshhhhhhh
Stand fast those on the bow cat ;)

3 Point,

Reminds me of all those times sitting in the stack gas on 6 Spot while Ark's Flyco forgot all about us: until released from FW recovery with the wind at Red 90, out of limits, and then cleared for take off :ugh:

Tinstaafl 21st January 2010 04:48

I was aware of the angled deck's advantages. What I couldn't understand was the relative positioning of angle deck vs island, leading to turbulence for the landing.

D O Guerrero 21st January 2010 10:36

Tinstaffl - I explained it above.


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