Banner Ad 1

What if SEAVIEW???

Static Submarine modelers unite!

What if SEAVIEW???

Postby modelnut » Sun May 18, 2008 3:32 pm

What is the SEAVIEW had been an actual submarine?

What details would need to be added to make her more real?

Ballast/flood vents. An anchor.

What else? :?

Since I can't go the R/C route I want my Moebius to be the best static version that I can. I am not so much worried about being absolutely faithful to the FX model. I want to build her as if she had really sailed in the '60's and '70's.

Any suggestions???

-Leelan
User avatar
modelnut
SubCommittee Member
 
Posts: 424
Joined: Sun May 25, 2003 4:38 pm

Postby junglelord » Wed Feb 04, 2009 9:26 pm

Of course the SeaView is a SSNB type sub to begin with.

I have found the original plans on this thread
http://www.hobbytalk.com/bbs1/showthread.php?t=219645
and Seaview plans here as well.
http://www.nimr.org/seaview.html
and also done a search for cutaway models of the Seaview.
http://www.culttvman2.com/dnn/Default.aspx?tabid=976
http://www.vttbots.com/ted_koch_cutaway.html

One question is where are the nuclear engines located....that lead to this
Image

I was interested in the various design characteristics of the different subs that are available for RC.

Since I am interested in the Seaview, I thought I would submit what I have researched about this particular sub.

I thought I would start with work from Mr Merriman on the Seaview.

Design Flaws and Characteristics
Wedge shape bow and manta fins creates a downward pitch when submerged. This downward thrust can be countered with internal fixed vanes in the nicelles and also functional bow planes.

This peculiar architecture of the Seaview also creates something else.

A large Bow-wake = lots of drag

(Largest ever seen by Mr Merriman)

Certainly my own little piggyback PL Seaview on a Walmart USS Dallas showed a huge difference in bow-wake

Surface turning radius is average for the Seaview. But submerged it has some design flaws. Yaw stability increased by cadillac fins which makes submerged turns large. However, high speed underwater turns have a roll issue called "snap-roll".

Fast underwater turns have snap-roll due to the cadillac fins which is countered by the manta fins and according to Mr Merriman the sub would actually be non-functional without the manta fins.

the manta-fins produce a counter torque (outboard rolling moment, counter of the vehicles turn) that works to negate the de-stabilizing inboard torque produced by the SEAVIEW's sail and 'V' shaped 'Cadillac' fins at the stern. The manta-fins contribute to the dynamic roll stability of the SEAVIEW in a tight turn. As the submarines angle of attack about the yaw (turning) axis increases, and starts to 'skid' into a turn, a situation occurs at the manta-fin tips (those tips well below the vehicles longitudinal center of rotation) where the inboard manta-fin tip begins to generate an upward moment (force) and the outboard manta-fin tip produces a downward moment. These two forces induce a torsional moment that works to right the boat in the turn; the manta-fins improve the boats roll stability dynamically in a turn.

The significant maneuverability problems with this boat occur as a consequence of a turn while submerged. Sea-trails taught me to 'ease' the SEAVIEW into high speed submerged turns. To put the rudder hard over while running at any significant speed rolls the boat into an uncontrollable dive to the bottom. (American LOS ANGELES class attack submarines have the same problem). Other than that, and the SEAVIEW's woefully poor backing down ability, it handles pretty much like any other r/c submarine.

The only vice I can lay at the feet (fins) of the manta-fins is that they work to de-stabilize the boat in the pitch plane and contribute a great deal of flow and wave-making drag. The fix was to install permanent vanes within each propulsion nozzle, their job to direct the exhausted water upward, countering the pitching moment at the bow. In water tests verified that the fixed vanes countered the bow induced pitching problem throughout the SEAVIEW's speed regime, net angle change as a consequence of submerged speed was zero. Mission accomplished!

But, keep in mind that the two pitching forces (shape of the hull forward, the fixed vanes in the nozzles aft) are directed down; the net force on the vehicle is a downward one. However, this downward force acting on the submerged submarine is of low magnitude and is easily countered by operating the boat at a slight up-angle or simply by cranking in a bit of 'rise' on the sailplanes.

After installation of the fixed vanes in the nozzles depth control of the SEAVIEW became no more difficult than driving a 'traditional' type r/c submarine.

The SEAVIEW, as an r/c submarine, can be made to be dynamically stable in pitch and yaw as it travels submerged - without need of non-scale 'stabilizing' fins or control surfaces.


Some nice practical information on the dynamics of modern submarines and how that relates to the Seaview in particular.

Nearly all modern American combat attack submarines employ a set of downward canted (anhedral) stabilizers at the stern (situated between the horizontal surfaces and lower rudder). Their primary function is to serve as foundations from which either evasion devices or towed cables are launched or streamed clear of the propeller/pump-jet disc. The secondary purpose of the stern mounted anhedral stabilizers is to generate a torsional force (created as the boat's angle of attack about the yaw axis increases) to counter the boats tendency to roll inboard in a turn. On a 'real' submarine this unwanted inboard rolling moment originates solely with the sail and a big reason that today's submarine sail structures are kept as short and low of area as possible. Sail structures are either well faired in to the hull (as practiced by the Russian 'Ruben' design bureau) or are so shaped as to limit the structures ability to produce lateral 'lift' at a high yaw angle of attack (American LOS ANGELELS class).

With the SEAVIEW we are cursed with three surfaces that produce a unified torsional moment in a turn: the large sail and two upward angled fins as the stern.

The rolling, and reduced turn rate experienced by the SEAVIEW underwater was observed and noted. Like any other type submarine I drive, I first work out the maximum underwater speed I can attain and still maintain depth control once the rudder is put hard over. Same test and observations as I work the horizontal control surfaced to maintain or change depth. The objective during these sea-trial activities is to determine the submarines 'performance envelop'. I determine the edges of that envelop and try not to exceed them during normal vehicle operation. Sea-trials are more than working out the mechanical bugs and trimming the boat, it is also that initial period of operation where you, the Driver, learn what you can and cannot do with the vehicle above and below the surface.




Hope that stimulates some ideas.
User avatar
junglelord
Registered User
 
Posts: 347
Joined: Mon Jan 26, 2009 4:11 am
Location: Ontario Canada

Postby Crazy Ivan » Fri Feb 06, 2009 12:54 am

Leelan,
I share your philosophy of modeling the concept boat, rather than the shooting minatures. The front and back covers of Issue 15 of the Subcommittee Report feature the Seaview illustrated with exactly the type of realistic external details you are looking for. Here are some low res samples to give you the idea. You will need to purchase the actual back issue for the full res version.

Image

Image
George "Crazy Ivan" Protchenko
Image

“There are the assassins, the dealers in death; I am the Avenger!”-Nemo
"I'm disinclined to acquiesce to your request; means No!"-Capt.Barbossa
User avatar
Crazy Ivan
SubCommittee Member
 
Posts: 625
Joined: Sun Feb 23, 2003 2:42 am
Location: Rochester, NY, USA

Postby Scott T » Fri Feb 06, 2009 2:44 pm

Since the front fins are called Manta fins how about changing there action
to rotate up and down horizontally removing the up or down force when
moving forward. Manta rays move there fins up and down for propulsion.

-Scott
User avatar
Scott T
SubCommittee Member
 
Posts: 564
Joined: Fri Feb 21, 2003 2:01 pm
Location: Oklahoma City, OK


Return to Static Modeler

Who is online

Users browsing this forum: Yahoo [Bot]