Re: [PSUBS-MAILIST] Dive planes

["Sean T. Stevenson" <cast55@telus.net>]

With regard to "banked" turns, control surfaces which can impart a rolling 
moment on a large sub are not included so as to be able to effect such a turn, 
but rather to provide counter torque to the snap roll effect.  Snap roll occurs 
when the sub initiates a turn, and the change in angle of attack of the sail 
with respect to the water flow (since the sub "slips" in the water during a 
turn) pushes on the sail, forcing the boat to roll to the inside of the turn.  
Often, the natural snap roll will be to an extent that exceeds the angle of 
roll necessary to accommodate the centripetal acceleration and keep the 
apparent gravity vector perpendicular to the deck. Consequently, control 
surfaces are positioned to effect a torque in opposition to the snap roll.

-Sean


On September 12, 2009 09:42:22 ShellyDalg@aol.com wrote:
> Something that keeps coming back to me as I build my sub is the dive planes
>  and how they control the sub.
>    I've got the little "wings" on the sides but I keep wondering  if a pair
> on the stern would be useful. It wouldn't take much to add a pair back
> there and by adding another actuator, would be fairly simple to control.
>    The side ones have a Minnkota incorporated into them so even  at low
> speeds they should  push the sub up and down but I wonder how  effective
>  some dive planes at the back would be at changing the dive angle and  at
>  what speed they would work. With two sets of dive planes and running at
>  the  slow speeds our little boats go, it may not add much.
>    I've incorporated a sliding weight inside the sub to help  change dive
> angle and adjust for level while surfaced but using dive planes  while
> traveling submerged to change dive angle seems like it might be worth  the
>  extra effort to install.
>    The main reason I haven't done it yet is that I've never seen  anyone
> else do it so I'm wondering if it's not worth it or a waste of time and 
>  money. All the subs I've seen are designed to stay pretty level  front to
>  back and side to side but I keep wondering if making "banked" turns or 
>  angling the sub up and down is possible or even desirable.
> Dean's sub looks like it has dive planes at the back. Anybody had any
> experience with this or have any thoughts ? Frank D.
> 



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