Seaview

[greenman407]

WHAT A PAIN! Digging out the old motors. I had them in there good.

[greenman407]

Thanks, thats what I thought. Anyway I just ordered the four 12 volt motors. Also, I picked up another digital fish scale like I used to have. Ill use it to compare pull on various boats to determine whether a modification was successful or not.

[He Who Shall Not Be Named]

No, that's a miss-print -- they're all three-pole motors, Mark.

M

[greenman407]

I was thinking about getting a couple of 35 turn crawler motors but all those modified motors have really short shafts and that wont work. I need a longer shaft because of the shaft seals installed in the motor bulkhead. Some of the aftermarket motors also have a flat spot on the shaft for the setscrew ,that runs the whole length of the shaft. That wont work either because the shaft seals wont seal around half a shaft,....ya know. The bad part is now Ive got to dig those motors out of the bulkhead. They are covered up and glued in somewhat. Too Bad I guess. Heavy sigh...................

[greenman407]

According to the specs on Caswells motors, the 7 volt 540 motors are 5 pole(unusual) and turn 17,000 RPMs and have a stall of 11 amps. The 12 volt 550 motor has an 23,000 Rpm speed and a 28 amp stall. Based on this I would say that the 12 volters are twice as powerful, If these figures are accurate. I think I will order 4 of them considering they are so inexpensive and the Skipjack Subdriver has the 12 volt motor installed and I know what a good performer they are. I need two for the Seaview and two for the Albacore.

[greenman407]

Well then, these are the 7 volt motors, and Im running them on 12 volts. I guess Mike sent me the wrong motors(garage Sale). I can switch over and run these on 7 .4 volts(Lipo). From what you have seen, is there any advantage to running the 12 volt motors over the 7.2s as far as Torque is concerned? If there is Ill buy a couple of 12 volt motors.

[He Who Shall Not Be Named]

The 12-volt motors have internal capacitors -- look for the wires coming out of the plastic back-plate that wrap around the terminal lugs. No wires, it's likely an old 7-volt motor.

M

[greenman407]

Dave, how do you tell the difference between the 12 volt 550 motors and the 7.2 volt 540 motors? Is there some kind of mark on the case? I ask because there is a possibility that I got 7.2 volt motors installed instead of 12 volt.

[greenman407]

I neglected to say the other day that although the Seaview was moving along faster than she has ever gone before, there was no tendency to nose dive. She behaved well. I just ordered the shafts and thrust bearings from Mcmaster & Carr, and when they get in we will put them in and note the difference. Before I cut down the empellors, Ill probably install some 27 turn 540 motors with adjustable timing and all that good stuff. Im looking for more torque. Ill have to go to 7.4 volts for the motors. But to keep the weight nearly the same Ill use two 2s Lipos in parallel.

[greenman407]

[greenman407]

[greenman407]

Finally, into the water. Very enjoyable. A healthy increase in speed. Buoyancy is about the same, despite lowering the Subdriver in the submarine by 5/16" and the added buoyancy of a 3&1/2" cylinder in the stern. However, the 550 motors get pretty hot after a while.
The first thing were going to do is buy another digital fish scale and measure the thrust as is. Then Im going to lengthen the 1/8" Empellor shafts and install on them some thrust bearings. The reason being is that when you turn the drive shafts you can feel some resistance. Gotta get rid of that. After measuring the thrust again perhaps we will cut down the empellor blade width to reduce pitch. We will see.

[greenman407]

Now that the dogbones finally got here, I cut and built the new drive shafts. I did that because everytime I make a drive configuration change the lengths change. The last time I cut and spliced them. Since I believe that this configuration will likely remain , I started out fresh with brass tubing so that there would be less chance of out of balance shafts. Once that was done I needed to seal up the ever increasing size of the slots in the empellor covers where the drive shafts exit. With the increase center to center of the drives, its almost a straight shot down to the empellors. Then to modify again the shape of the foam insert. Now on to the kiddie pool and the final trimming.

[crazygary]

Lookin' good, Sir!!

Good call with the double click-ons for the pushrods!! Very cool!

CG

[greenman407]

Today I got the gear reduction on and running. Now I need to make two new drive shafts out of aluminum tubing , so Ill need to order new Dumas Dogbones.