depth keeping as solo and diveplanes up or down?

[commandosolo2009]

I would like to know if the aft dive plane should be slated up or down to accelerate the dive. I know that the forward plane is tilted up to dive but the aft plane? Should both planes be parallel when diving or surfacing? I'm a one man crew so I would like to also keep depth while conning and listening. Its my understanding that the two - - is the zero bubble on the indicators but also zooming in to notice trend. Is this a sound tactic?

[derstosstrupp]

Set aft about 5-10 deg down, fore full down for a dive. You can use the forward planes to keep depth, but we’ve found it useful to use the negative tank as a regulator tank. When at depth, put 0.5 in the negative tank (halfway to the first mark, tiny bit) and that helps trim you too.

Historically the forward planes corrected small depth changes and the aft planes were used to correct small pitching tendencies.

Surfacing hard up on forward, 5-10 up on aft. Blow ballast when at periscope depth.

[Pisces]

To correct/more precisely define the instruction:
The negative tank should be filled to 0.05 cubic meters to be almost perfect neutral buoyancy and thus maintain depth when without forward movement. Half of the first mark on the left dial. But if you are moving and tilted, also consider the following.

B̶o̶t̶h̶ ̶p̶l̶a̶n̶e̶s̶ ̶t̶o̶ ̶t̶h̶e̶ ̶s̶a̶m̶e̶ ̶s̶i̶d̶e̶ ̶c̶o̶u̶l̶d̶ ̶l̶i̶f̶t̶ ̶u̶p̶ ̶o̶r̶ ̶p̶u̶l̶l̶ ̶d̶o̶w̶n̶ ̶t̶h̶e̶ ̶h̶u̶l̶l̶ ̶b̶u̶t̶ ̶i̶t̶ ̶i̶s̶ ̶l̶e̶s̶s̶ ̶e̶f̶f̶e̶c̶t̶i̶v̶e̶.̶ F̶o̶r̶ ̶t̶h̶e̶ ̶q̶u̶i̶c̶k̶e̶s̶t̶ ̶d̶i̶v̶e̶/̶r̶i̶s̶e̶ ̶y̶o̶u̶ ̶w̶a̶n̶t̶ ̶t̶h̶e̶ ̶p̶l̶a̶n̶e̶s̶ ̶i̶n̶ ̶t̶h̶e̶ ̶o̶p̶p̶o̶s̶i̶t̶e̶ ̶d̶i̶r̶e̶c̶t̶i̶o̶n̶.̶ C̶o̶n̶s̶i̶d̶e̶r̶ ̶t̶h̶e̶ ̶d̶i̶r̶e̶c̶t̶i̶o̶n̶ ̶o̶f̶ ̶t̶h̶e̶ ̶f̶o̶r̶c̶e̶ ̶e̶a̶c̶h̶ ̶d̶i̶v̶e̶p̶l̶a̶n̶e̶ ̶ ̶c̶r̶e̶a̶t̶e̶s̶ ̶t̶o̶ ̶t̶u̶r̶n̶ ̶t̶h̶e̶ ̶h̶u̶l̶l̶.̶ ̶I̶f̶ ̶y̶o̶u̶ ̶w̶a̶n̶t̶ ̶t̶o̶ ̶r̶i̶s̶e̶ ̶w̶i̶t̶h̶ ̶t̶h̶e̶ ̶s̶t̶e̶e̶p̶e̶s̶t̶ ̶a̶n̶g̶l̶e̶,̶ ̶y̶o̶u̶ ̶w̶a̶n̶t̶ ̶t̶h̶e̶ ̶f̶o̶r̶w̶a̶r̶d̶ ̶p̶l̶a̶n̶e̶ ̶p̶o̶i̶n̶t̶i̶n̶g̶ ̶d̶o̶w̶n̶ ̶(̶u̶p̶ ̶f̶o̶r̶c̶e̶)̶ ̶a̶n̶d̶ ̶t̶h̶e̶ ̶a̶f̶t̶ ̶p̶l̶a̶n̶e̶ ̶p̶o̶i̶n̶t̶i̶n̶g̶ ̶u̶p̶ ̶(̶d̶o̶w̶n̶ ̶f̶o̶r̶c̶e̶)̶.̶ ̶I̶f̶ ̶y̶o̶u̶ ̶w̶a̶n̶t̶ ̶t̶o̶ ̶d̶i̶v̶e̶ ̶q̶u̶i̶c̶k̶e̶s̶t̶ ̶t̶h̶e̶ ̶b̶o̶w̶ ̶p̶l̶a̶n̶e̶ ̶s̶h̶o̶u̶l̶d̶ ̶b̶e̶ ̶p̶o̶i̶n̶t̶i̶n̶g̶ ̶u̶p̶(̶d̶o̶w̶n̶ ̶f̶o̶r̶c̶e̶)̶ ̶a̶n̶d̶ ̶t̶h̶e̶ ̶a̶f̶t̶ ̶d̶o̶w̶n̶ ̶(̶u̶p̶ ̶f̶o̶r̶c̶e̶)̶.̶ ̶W̶h̶e̶n̶ ̶y̶o̶u̶ ̶a̶r̶e̶ ̶m̶o̶v̶i̶n̶g̶ ̶i̶t̶ ̶i̶s̶ ̶t̶h̶e̶ ̶h̶u̶l̶l̶ ̶i̶t̶s̶e̶l̶f̶ ̶t̶h̶a̶t̶ ̶d̶r̶i̶v̶e̶s̶ ̶i̶t̶s̶e̶l̶f̶ ̶u̶p̶ ̶o̶r̶ ̶d̶o̶w̶n̶ ̶p̶r̶e̶d̶o̶m̶i̶n̶a̶n̶t̶l̶y̶.̶ ̶T̶h̶e̶ ̶p̶l̶a̶n̶e̶s̶ ̶a̶r̶e̶ ̶t̶h̶e̶r̶e̶ ̶t̶o̶ ̶t̶u̶r̶n̶ ̶t̶h̶e̶ ̶h̶u̶l̶l̶.̶ [EDIT: Apparently the game does not work like it should or like I thought. See replies below] The angle is shown by the blue water collumn; note the scale is upside down. Because with extreme angles of the hull you can partially break the surface, (when near it) you would not want to use these all-out diveplane angles. So like derstosstrup explained you keep the aft plane centered when diving. If you follow real life procedure (there should be a link to translated contemporary RL German Uboat diving procedures in the stickies somewhere) you would have the negative tank filled at that point to aid you in a quick dive time. And once submerged empty it again while shallow, as it takes more precious pressured air to do so when deeper.

[gurudennis]

Originally Posted by Pisces

For the quickest dive/rise you want the planes in the opposite direction.

This is demonstrably incorrect within the current implementation of Wolfpack, and an often repeated misconception. As a matter of empirical fact, at least as of the moment of writing on version 0.16a, both planes up gives the most upward momentum, whereas both planes down gives the most downward momentum.

[Pisces]

Originally Posted by gurudennis

This is demonstrably incorrect within the current implementation of Wolfpack, and an often repeated misconception. As a matter of empirical fact, at least as of the moment of writing on version 0.16a, both planes up gives the most upward momentum, whereas both planes down gives the most downward momentum.

Oh my, this is embarrassing. You are absolutely correct. My statements came from subjective experiences. And extrapolating from how the model should work. I should have known better not to take this for granted.

After having counted the seconds per 1 and 10 meters rise and dive (from 15m to 25m and back, and 15m to 16m) at 2 speeds (4.45kts and 1.4kts) and combinations of maximum deflections of the diveplanes it appears only the forward diveplane deflection have an effect on dive and rise rates (seconds per meter).

Before testing everything I tried to set buoyancy to neutral by filling the negative to 0.05 ish. With no speed and neutral diveplanes it dived 1m in 7m35s. At 1,4 kts it took 7m30s. At 4.4kts it took 7m25s. That seems to be a pretty stable baseline, with a slight speed affect to rising.

The both the fore and aft diveplanes affect the tilt angle of the hull. But the tilt angle itself does not seem to have any appreciable affect to climb and dive rates. I was very surprised to see no depth change with neutral forward diveplane deflection and either aft dive plane deflection. Well the effect was minor, comparable to both planes set to neutral. At 1.4 kts forward speed forward neutral and aft down took 6m50s from 15m to 16m. Aft up took 8m30s to go from 15m to 16m. Maybe the slight up tilt angle with up aft planes caused the fore dive planes to get a minor angle of attack and slowed the intrinsic dive due to my slight negative buoyancy.

P.S. I consider this a bug. Knowing how wings and elevator surfaces work on airplanes, where even the hull has a non-zero contribution to lift, tilt angle of the boat must have an effect. I can't find the reference but I remember reading it in one of the translated German Uboat documents or maybe Uboat Commanders handbook.

[ljqcn101]

Originally Posted by Pisces

P.S. I consider this a bug. Knowing how wings and elevator surfaces work on airplanes, where even the hull has a non-zero contribution to lift, tilt angle of the boat must have an effect. I can't find the reference but I remember reading it in one of the translated German Uboat documents or maybe Uboat Commanders handbook.

I also think so. Neutral dive planes should only (at least) keep the current pitch attitude IMO. In Wolfpack it seems to me that the boat will inherently return to zero pitch if dive planes at neutral.

[Pisces]

I'm just reading this document and it says the fore and aft diving planes angle ranges in the game are back-to-front also:

http://www.uboatarchive.net/Manual/Manual.htm

Dive planes installation.
The forward and aft dive planes are mounted on common shafts. The maximum deflection of the forward planes is 30° up and 30° down, for the aft planes 25° up and 35° down. The spindle driven by an electric motor moves the pushing rod either in or out and through the connection with the rudder shaft lever deflects the dive planes. The aft dive planes each have an area of 2.25 m², each of the the forward dive planes area is 2.4 m².

[ljqcn101]

Dunno much about the submarine, but from an aerodynamics point of view, I always imagine it as a canard and elevator configured aircraft, like the Su-37.

With the forward plane pointing down (leading edge down), the angle of attack at the dive plane is decreased, resulting in a decreased lift, so the bow will sink.

With the aft plane point down (trailing edge down), the angle of attack at the dive plane is increased, causing an increased lift, so the stern will rise.

A common misconception comes from how you define up and down. Also from an aerodynamics point of view, we use leading edge/trailing edge to describe elevator/canard position. There's also a convention in body systems whether leading edge/trailing edge should be used. From the look of dive plane indicators in Wolfpack, it seems that the forward plane uses leading edge and the aft plane uses trailing edge to describe up/down angles.

[Superesse]

In Wolfpack, the hull angle is limited. So even with max plane settings, the tilt never goes further than maybe 20-30 degrees. Is this realistic? Or would a real submarine eventually do a loop on full speed setting?

[Pisces]

Originally Posted by Superesse

In Wolfpack, the hull angle is limited. So even with max plane settings, the tilt never goes further than maybe 20-30 degrees. Is this realistic? Or would a real submarine eventually do a loop on full speed setting?

This document is the translated real diving regulations for German Uboat during the war.

http://www.uboatarchive.net/Diving/D...egulations.htm

Loops are pretty much out of the question. Even if they can develop enough torque in all attitudes, they are too long compared to the available depth. And the turning circle would extend beyond crushdepth most likely.

But the text does speak of extreme down angles in case of crash dives:

126. In most cases, crash diving at the front depends not only on getting away from the surface as quickly as possible, but also on reaching a greater depth as quickly as possible. For this purpose from 20 meters the boat is to be vigorously tilted (as appropriate with a change of course) and quickly driven deeper at down angles of 15 to 30°.

Remember that going beyond that might be physically possible with the diveplanes, but longitudinal or lateral stability might be lost in certain circumstances. Getting it into an angle might be one thing. Keeping it steady and under control might be another. There is the center of gravity of the boat. But also the center of buoyancy, which can be considered as the center of mass of the displaced water. These are not in the same spot. The center of buoyancy should be above the center of gravity to have the boat automatically level itself. At extreme angles this might invert (depending on if there is a forward/backward offset too).