Disney Nautilus RC Submarine

More math about the Nautilus than most would care to know. http://www.rcgroups.com/forums/member.php?u=40728 7ft web page http://home.comcast.net/~byourk/7footaa.html Up until the last two times I've conducted speed tests I thought the nose dive effect was possibly an artifact of the model not applicable or insignificant to the full size or large replica. However, now, I am convinced that a larger model or full scale could not escape this effect. I've concluded that it's inherent in the shape of the hull. On the last test I was certain the sub would stay afloat. But contrary, down it went of its own accord. This indicates to me that the effect (nose dive) is related to speed. What I don't know is, if, on a larger sub the effect is relative to speed (increase to a greater speed proportional to size), or if the speeds I achieve with the model are absolute for the effect to take place. In other words once this speed (or slightly faster) is reached the sub (at any size) will nose dive. In the speed test video any scenes showing the sub submerging (beginning and end) are at 24 volts set up (greater speed). Otherwise it's rock steady and smooth at 12 volts (lesser speed). In the first frames showing the sub submerging, setup at 24 volts, I cut the power as soon as it went under, you can see (possibly) that it levels out and then I sent it straight out at about 2-3 ft under water. To see what the effect would be without releasing the forward controls I sent it out straight. This is seen in the last part of the video. It hit bottom in about 15-20 ft depth, about 150 ft from shore. I started the run again from this point (where it's seen submerging again), and it came up on the other end of the pond. If it were not for the upward curve to the side rakers it would have leveled off and traveled straight across at some (unmeasured) depth without surfacing.