|
Hi Paul. I welded together some shapes ( using old propane tanks from my
barbecue ) and pulled them through the water with a cable and a spring
scale ( actually a fish scale ) to see how much difference a particular shape
pulled on the scale. The saucer shape took a little more force than the tube and
hemisphere, but they were both pretty close. I then took the tube and hemisphere
model and cut a section out making it sort of like a fish shape and it was an
improvement in required thrust. The problem was that it was pretty small on the
inside and I thought if a guy built one that was big enough to get in, it would
need to be very large ( and consequently heavy )
This isn't very scientific, but it did give me an idea as to what the
difference in shape makes in required force.
For the money, the tube and hemi shape is the best. The saucer
shape was unstable and tended to roll so I added a fin and that took most of the
roll out. The fish shape had a similar problem so I added some weight to the
inside making it travel in a more vertical orientation and that worked
well. I would like to try adding the ballast tank shapes to the saucer and
try it again. There should be some improvement there.
These were small models, and had no tanks, hoses, or anything else on the
outside to interrupt the flow around them.
Frank D.
|