Model Boat Mayhem - Forum

Please login or register.

Login with username, password and session length.
Pages: [1]   Go Down

Author Topic: what are pitch controllers  (Read 1529 times)

kraftykid

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 373
  • Location: portsmouth
what are pitch controllers
« on: April 07, 2012, 10:42:35 AM »

what are pitch controllers , are they for dynamic    or static what do they do   

                                                                   thanks
                                                                      kk
Logged
its the wolf you cannot see that you should fear

hollowhornbear

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 108
  • Location: new haw, surrey
Re: what are pitch controllers
« Reply #1 on: April 07, 2012, 11:05:38 AM »

Logged

Subculture

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,906
  • Location: North London
    • Dive-in to Model submarines
Re: what are pitch controllers
« Reply #2 on: April 07, 2012, 11:40:12 AM »

They work on static and dynamic boats. You need a boat with stern hydroplanes for them to work, they don't work well with front hydroplanes.

Submarines will, in general, not remain straight and level when travelling underwater, dynamic forces acting on the hull tend to tilt it upwards or downwards, and these problems get worse as the boat travels faster.

The operator of the boat will try and compensate for this, but generally we do a poor job and tend to over control the boat, leading to the boat porpoising.
Submarines with hulls optimised for operation on the surface tend to be worse than more streamlined designs in this respect. However the latter tend to travel faster which offsets that advantage.

A pitch controller adjusts the rear planes automatically to help keep the boat stable underwater. Earlier designs were based on pendulums, and you'll still see some of these in action. They tended to be a little bulky, and were time consuming to produce (hence expensive) so weren't at all well suited to smaller models. That all changed with the advent of accelerometer based pitch controllers, essentially a pendulum mechanism on a microchip.

How do they work, well think of our pendulum. With the boat travelling straight and level, the pendulum is undisturbed. If it starts to take a dive to the bottom, the pendulum will move as it's referenced to gravity. Sensors detect this and via circuitry a signal is sent to the servo controlling the rear hydroplanes to move them upwards by a certain amount and hence bring the boat level again. If the boat then begins to to travel to the surface the pendulum will swing the other way, and the opposite will happen.

This cycle constantly repeats itself, so you can appreciate the servo controlling the rear hydroplanes is kept as busy as a bee.

kraftykid

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 373
  • Location: portsmouth
Re: what are pitch controllers
« Reply #3 on: April 07, 2012, 11:45:55 AM »

thanks for the info       

and why dont they work well with front hydro planes       as 2 of my subs have them and only 1 have aft hydro planes
Logged
its the wolf you cannot see that you should fear

Subculture

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,906
  • Location: North London
    • Dive-in to Model submarines
Re: what are pitch controllers
« Reply #4 on: April 07, 2012, 02:07:17 PM »

Front planes tend to be less effective than rear planes, and they also behave slightly differently. Some people have mooted the idea of a leveller for forward planes, so it's probably feasible but I have yet to see it done in practice.

If your boats don't have rear planes, then you'll have to operate them without a leveller, or consider fitting some rear hydroplanes. Most boats with front planes tend to be non-scale 'fun' subjects like the Deep Dive VI or the Graupner Shark. These type of boats work quite happily without levellers, as they're designed to be driven in an aquabatic style.

kraftykid

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 373
  • Location: portsmouth
Re: what are pitch controllers
« Reply #5 on: April 07, 2012, 03:31:34 PM »

i have a deep dive but also my type 7
Logged
its the wolf you cannot see that you should fear

Subculture

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,906
  • Location: North London
    • Dive-in to Model submarines
Re: what are pitch controllers
« Reply #6 on: April 07, 2012, 04:43:26 PM »

Best thing is to concentrate on making them reliably watertight and functional, well trimmed etc. A leveller can be seen as icing on the cake.

kraftykid

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 373
  • Location: portsmouth
Re: what are pitch controllers
« Reply #7 on: April 07, 2012, 09:25:22 PM »

will do thanks
Logged
its the wolf you cannot see that you should fear

redboat219

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 49
  • Location: Philippines
Re: what are pitch controllers
« Reply #8 on: April 08, 2012, 02:58:34 PM »

So a leveller is NOT ABSOLUTELY needed?

 I  read In another forum  that some modelers do away with them preferring to drive by the seat of their pants.
Logged
"Better is the enemy of good enough"

Subculture

  • Full Mayhemer
  • *****
  • Offline Offline
  • Posts: 3,906
  • Location: North London
    • Dive-in to Model submarines
Re: what are pitch controllers
« Reply #9 on: April 08, 2012, 03:28:42 PM »

If you drive your boat in a crazy aquabatic style, then levellers are a little less important. If you want to drive at anything beyond a dribble, and maintain good trim near the surface then they become far more important. It's possible to fly a helicopter without a gyro, but they're a lot nicer and easier to run with one fitted.

For ultimate control you use a leveller and a depth controller, but most submariners are happy with the control a leveller offers.
Pages: [1]   Go Up