Albacore continued

[bassplayer1]

Very well done sir!!! You must be really proud of your achievement!!!

[Subculture]

I think you'll get problems running it in the wet. Firstly the armature and magnets will rust like the blazes, the bearings won't like it either. Now I suppose at the end of each run you could flush the motor through with WD40, but it's a bit of a hassle. Secondly the motor will offer quite a bit of drag in the wet I would think, certainly more than you will get via a shaft seal.

I have seen brushless engines engineered to run in the drink, but they are a bit different to the type of thing you see commercially available.

[He Who Shall Not Be Named]

Here's your solution -- I learned this from the MK-37 torpedo in TM-A school in the 60's: Eliminate the gearbox, put the brushless motor in the wet (with slip-rings between the motor and the ESC leads) with the after face of the motor attached to a structural bulkhead through a roller-bearing that can also take thrust loads. Attach the outer propeller shaft to the motor case, attache the inner propeller shaft to the motor output shaft.

The output is counter-rotating shafts, a rotating motor (think old-style radial 'rotary' aircraft engines), and perfect torque matching of the propellers with a net hull torque force of zero (less the drag of the roller-bearings).

And Mark: the torque you will learn to fear is the torque produced by the sail as you radically change the boats angle of attack about the yaw axis -- that's what the active dorsal rudder was all about: not propeller torque, but foil-roll. An artifact of the sails size and location.

I have spoken, so let it be written!

David

[Subculture]

Bin the gearbox, and go direct drive with an outrunner style motor. I guess at the moment you're running at about 5-5500RPM. Perhaps you'd like to drop down about 1kRPM? If so you'd want a motor that does about 6-700kv on 7.4 volts (2S lipo).

[greenman407]

Manfred, no , the sail rudder is not powered. I didnt see the point of adding extra complications when the rudder would serve no purpose. In the real Albacore the rudder was used to keep the boat from torqueing or snap rolling due to torque. Especially not necessary with contra-rotating propellors.
Hobby Lobby sells drop in Speed 400 sized brushless motors. Seems like the shaft size is different, but im sure something could be done.

[He Who Shall Not Be Named]

Thanks, Andy.

David

[Subculture]

Time to think brushless me thinks.

Hey, Andy: can we parallel two brushless motors off a common ESC?


David

No, electronically commutated motors must have one ESC per motor. Very cheap from places like Hobbyking.

[MFR1964]

Mark,

You did a great job on rebuilding your boat, it's good to see her in the water, only question i have is, the rudder at the sail, did you make that also functional?

Manfred.

[He Who Shall Not Be Named]

Thanks Dave, but how will the new 3" bulkheads help? More powerful motors or greater gear ratio? OR some new evil idea that I had not yet contemplated?

Time to think brushless me thinks.

Hey, Andy: can we parallel two brushless motors off a common ESC?


David

[trout]

Congratulations!

[greenman407]

Thanks Dave, but how will the new 3" bulkheads help? More powerful motors or greater gear ratio? OR some new evil idea that I had not yet contemplated?

[He Who Shall Not Be Named]

Congratulations, sir! You deserve it!

Leave those wheels alone!

I'll have new 3" bulkheads to you soon.

David

[greenman407]

[greenman407]

[greenman407]

Ive never went out on a maiden voyage before that something didnt go wrong......................................until today. It worked great! I hit the nail right on the head, the first time. Apparently the balance was just right because I could run flat out with only the slightest oscilation and that with the ADF2 set at the least sensativity.I had the front to back balance point set at 1" in front of center of the sub. The advantage to this was seen in another way as well. Before, you couldnt go very fast on the surface or it would nose dive on you and the stern planes wouldnt help you. Now with the balance set as it is you can go much faster on the surface before it trys to dive. Also you can adjust the stern planes for "Riding on the step" as they say. In one of the pictures you can see it doing just that with the bow high. As you go faster and faster the water spilling over the deck gets further and further back toward the sail until it reaches a point where it just slips under but the tail comes up in the air and you grind to a halt. How fast did it go did you say? NOT SO FAST! You have to listen to my entire speel first. As youll see in the pictures I used my world famous chicken stick(red and white striped) as I was afraid that it might get away from me. My fears were unfounded. It was completely controlable at all times. Periscope depth was easily achieved. Remember, ive had this boat down to 30 ft. before with the reserve bouancy set "in the wild" and it would come right on up at a fast clip. Nothing has changed in that department. She still turns on a dime. Im glad that I painted her a dark, dark grey instead of black. Makes visibility easier. It leans slightly to port but I think thats because the battery was shifted somewhat to port in the front compartment. We will see.
OK.......OK......She was very fast. The single prop Albacore with the D&E 3" Cylinder was pretty fast. A fast walk was required to keep up with it. Now to keep up with it you have to walk very briskly. A good work out for sure. Im pretty sure that the props are too big for the Speed 400 motors and the 3:1 gear reduction. Im thinking of reducing the pitch of the props by grabing each one at the tip and twisting somewhat to reduce their bite. That should give me more RPMs. What do you think Dave(HWSNBN). I offer these pictures in evidence. The light was kinda low. I will enhance some of them Monday. No video as driving and taking video was not on my list for today. Also I took know pictures of her underwater. I was kinda pushed for time. I gotta get my camera man. AL NUCI! Where are you???