Navys new toy

Discuss life, the universe, and everything with other members of this site. Get to know your fellow polywell enthusiasts.

Moderators: tonybarry, MSimon

paperburn1
Posts: 2484
Joined: Fri Jun 19, 2009 5:53 am
Location: Third rock from the sun.

Navys new toy

Post by paperburn1 »

http://widget.newsinc.com/_cfvp/playlis ... ternal_url
first test of a drone from a catapult

GIThruster
Posts: 4686
Joined: Tue May 25, 2010 8:17 pm

Post by GIThruster »

It's not loading for me though probably because I'm on an acient, crawly computer. I would just note the old steam catapults used in previous carriers cannot launch drones becasue they're too light and this would damage the catapult. The new EM cats for the Ford class can be easily adjusted to various weight vehicles, and they take up far less room, have better mantanance and require fewer sailors to tend them.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

KitemanSA
Posts: 6179
Joined: Sun Sep 28, 2008 3:05 pm
Location: OlyPen WA

Post by KitemanSA »

GIThruster wrote:..., and they take up far less room, ....
Say wha??? Where did you come up with this tidbit of inanity?

Stubby
Posts: 877
Joined: Sun Aug 05, 2012 4:05 pm

Post by Stubby »

The story is about the X47B.
Everything is bullshit unless proven otherwise. -A.C. Beddoe

Stubby
Posts: 877
Joined: Sun Aug 05, 2012 4:05 pm

Post by Stubby »

KitemanSA wrote:
GIThruster wrote:..., and they take up far less room, ....
Say wha??? Where did you come up with this tidbit of inanity?
Are you doubting the validity of the statement or whether it is relevant to the thread?
Everything is bullshit unless proven otherwise. -A.C. Beddoe

GIThruster
Posts: 4686
Joined: Tue May 25, 2010 8:17 pm

Post by GIThruster »

KitemanSA wrote:
GIThruster wrote:..., and they take up far less room, ....
Say wha??? Where did you come up with this tidbit of inanity?
The steam cats use boilers that have been removed from the Ford class design, and retrofits are planned for the Nimitz class. The new reactors and power generation on the Ford class that replaces the steam boilers for the Nimitz cats are much smaller and lower maintanance. I believe all this info is available on Wiki under the section for the Ford class carriers.

From the EMALS link on the Ford page:

"Compared to steam catapults, EMALS weighs less, occupies less space, requires less maintenance and manpower, is more reliable, and uses less energy. Steam catapults, which use about 614 kilograms of steam per launch, have extensive mechanical, pneumatic, and hydraulic subsystems. EMALS uses no steam, which makes it suitable for the Navy's planned all-electric ships. The EMALS could be more easily incorporated into a ramp.

Compared to steam catapults, EMALS can control the launch performance with greater precision, allowing it to launch more kinds of aircraft, from heavy fighter jets to light unmanned aircraft. EMALS can also deliver 29 percent more energy than steam's approximately 95 megajoules, increasing the output to 122 megajoules. The EMALS will also be more efficient than the 5-percent efficiency of steam catapults."

So basically, the system can launch both heavier and lighter aircraft. Also the acceleration profile is much gentler, so it puts far less strain on the aircraft it launches and since cat launch is one of the driving causes of metal fatigue in Navy aircraft, the EMALS will likely extend the lifetime of some craft it launches.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

ladajo
Posts: 6258
Joined: Thu Sep 17, 2009 11:18 pm
Location: North East Coast

Post by ladajo »

FYI GIT, They have been known to launch pairs of boots with steam cats. I would imagine that boots weigh less than a drone or light aircraft.
As for boilers, I don't know where you got that idea. Steam cats draw steam from the nuke plant.

All that said, Emals are a better rig. Although there are some concerns about battle damage ease of repair.

I guess if we keep the "don't get shot" philosophy, it'll never be an issue.
The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)
What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)

kcdodd
Posts: 722
Joined: Tue Jun 03, 2008 3:36 am
Location: Austin, TX

Post by kcdodd »

Yeah I don't understand why you couldn't control a steam catapult. Could you not just put a valve on there.
Carter

GIThruster
Posts: 4686
Joined: Tue May 25, 2010 8:17 pm

Post by GIThruster »

I'm just reporting what I've read. Steam cats supposedly cannot launch very light craft becasue this does damage to both the cat and the craft. Also, steam cats use something like 600kg of desalinated water on each launch which has to be replaced. The EMALS doesn't need any desalinated water so it saves the space of the desalinization system which can then be far, far smaller, and it saves the energy needed for this as well. It's all in-win and one of the biggest improvements in the Ford class.

The Wiki article on the Ford is very interesting. Though it lacks some detail, it gives a very good idea of why a new class is called for. It's the same hull IIRC, but they moved the elevators, the tower and extended the flight deck to significantly improve the number of sorties that can be flown in a day. All based on traffic patterns on the flight deck, etc--the kinds of stuff you would never know about until you had Nimitz class carriers working for decades. Sounded like a lot of very smart upgrades that will result in a couple hundred fewer sailors aboard.
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

ladajo
Posts: 6258
Joined: Thu Sep 17, 2009 11:18 pm
Location: North East Coast

Post by ladajo »

Steam cats are fully adjustable.
The Air Boss gets his boots shot off as an end of cruise tradition.

Not sure where you saw what you think you saw.

Image
The development of atomic power, though it could confer unimaginable blessings on mankind, is something that is dreaded by the owners of coal mines and oil wells. (Hazlitt)
What I want to do is to look up C. . . . I call him the Forgotten Man. (Sumner)

KitemanSA
Posts: 6179
Joined: Sun Sep 28, 2008 3:05 pm
Location: OlyPen WA

Post by KitemanSA »

The EMALS has an energy storage unit that is about the same size as the Nimitz but it also has rooms and rooms of power shaping and control electronics that a steam cat doesn't. It also requires gensets that are quite a bit larger than Nimitz class. I'm not sure how they could claim it is smaller. I suppose that the cabling may be enough smaller as to compensate? It IS a whole lot more capable though, being able to shape the launch thrust much more precisely.

Of course it has been about three decades since I last saw the accumulator for a steam cat and I MAY be mis-remembering it's size.

ltgbrown
Posts: 198
Joined: Mon Jun 22, 2009 11:15 am
Location: Belgium

Post by ltgbrown »

I had my boots launched when I completed my tour as an Air Boss. Steam catapults can launch UAVs.
Famous last words, "Hey, watch this!"

KitemanSA
Posts: 6179
Joined: Sun Sep 28, 2008 3:05 pm
Location: OlyPen WA

Post by KitemanSA »

What is that phrase about "no matter how hard ya try, ya can't sailorproof nothin'".

KitemanSA
Posts: 6179
Joined: Sun Sep 28, 2008 3:05 pm
Location: OlyPen WA

Post by KitemanSA »

ltgbrown wrote:. Steam catapults can launch UAVs.
You can shoot a rowboat with a Mk45 but a Mk38M2 is a much more reasonable choice.

GIThruster
Posts: 4686
Joined: Tue May 25, 2010 8:17 pm

Post by GIThruster »

My mistake. It's only the smaller craft that are damaged by the steam cats, not the cats themselves. From wiki with my bolds added:

Launch and landing systems

The Nimitz-class aircraft carriers use steam-powered catapults to launch aircraft. Steam catapults were developed in the 1950s and have been exceptionally reliable. For over fifty years at least one of the four catapults has been able to launch an aircraft 99.5% of the time.[24] However, there are a number of drawbacks. “The foremost deficiency is that the catapult operates without feedback control. With no feedback, there often occurs large transients in tow force that can damage or reduce the life of the airframe.”[25] The steam system is massive, inefficient (4–6%),[26] and hard to control.

Control problems with the system results in minimum and maximum weight limits. The minimum weight limit is above the weight of all UAVs. An inability to launch the latest additions to the Naval Air Forces is a restriction on operations that cannot continue into the next generation of aircraft carriers. The Electromagnetic Aircraft Launch System (EMALS) provides solutions to all these problems. An electromagnetic system is more efficient, smaller, lighter, more powerful, and easier to control. Increased control means that EMALS will be able to launch both heavier and lighter aircraft than the steam catapult. Also, the use of a controlled force will reduce the stress on airframes, resulting in less maintenance and a longer lifetime for the airframe. Unfortunately the power limitations for the Nimitz class make the installation of the recently developed EMALS impossible.

Electromagnetics will also be used in the new Advanced Arresting Gear (AAG) system. The current system relies on hydraulics to slow and stop a landing aircraft. While effective, as demonstrated by more than fifty years of implementation, the AAG system offers a number of improvements. The current system is unable to capture UAVs without damaging them due to extreme stresses on the airframe. UAVs do not have the necessary mass to drive the large hydraulic piston used to trap heavier manned planes. By using electromagnetics the energy absorption is controlled by a turbo-electric engine. This makes the trap smoother and reduces shock on airframes. Even though the system will look the same from the flight deck as its predecessor, it will be more flexible, safer, more reliable, and require less maintenance and manning.[27]
"Courage is not just a virtue, but the form of every virtue at the testing point." C. S. Lewis

Post Reply