Hello all.
I have a feeling that this will lead to a confusing post, as I can't currently draw a picture to explain it. if so, please let me know and I will post some tomorrow.
Background:
Many model boats have their motors in the middle of the hull, and the prop comes out of the back. The prop creates forwards motion, which acts on the area where the prop tube is glued through the hull, and partially on the motor itself, which passes these forces via the motor mount and into the hull.
The angle of the prop shaft has an effect on the forwards motion. If the tube/prop comes straight out of the back of the hull, then 100% of the force is used as forward motion ( it's not really, but good enough for now ).
If the prop tube faced downwards, then 100% of the force would be used to lift the hull out of the water, and 0% on forwards motion.
If the prop tube emerges at 45 degrees, then some of the force will create forward motion, and some will lift the hull.
Question.
The model I am kinda/sorta thinking about might be a bit front heavy. Also, it might not deal well with chop. So, my thinking is to mount the motor as far forwards in the hull as possible - right at the bow.
If I then angle the prop at say 30 degrees, there will be plenty of forwards force, but also some upward element, which would create dymanic bouyancy - the bow would be lifted by the some function of the motors force.
All well and good, but in a perfect world, there would be a way of altering the pitch of the prop with speed. When the hull starts to plane, and the imparted wake is supporting the body, then there is less need for the power train to be lifting the bow, and therefore, it would be good if there was some way to alter this angle so that there was more forward force delivered - the powertrain would tilt and move the prop closer to parrallel with the water surface.
This is a long way of asking: Is this possible? Have models which have previously been built ever had the ability to alter the angle of the power train, and so shift the upwards and forwards forces acting on the hull?
If so, does anyone have any details? i would be interested to see how everything was kept water proof.
many thanks
Steve