Albacore continued

[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]

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.

[bassplayer1]

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

[He Who Shall Not Be Named]

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.

Buzz-Killer!

[Anuci]

Sweet ride, Mark. Nothing like the feeling of a finished project which ends up a success. Bravo Zulu!

[Slats]

David,
what Andy said.

Also, I thought the plan for the 3" SD was to go ahead with the same 540 type basic motor used in the 3.5". Please DO NOT go brushless. I don't want to be having to buy new ESCs for brushless motors. There is nothing wrong with the geared grunt that you have in the 3.5" setup and the efficiency of that setup is great. Its not broke, it doesn't need fixing!

J

[Slats]

Mark
A superb build, I can't wait to get my hands on a phase 2. I love this little boat.

J

[Slats]

Mark
quick question -I might have missed this...why the large red and white mast? Is it your aerial? Are you running in salty water?

Thanks
J

[He Who Shall Not Be Named]

David,
what Andy said.

Also, I thought the plan for the 3" SD was to go ahead with the same 540 type basic motor used in the 3.5". Please DO NOT go brushless. I don't want to be having to buy new ESCs for brushless motors. There is nothing wrong with the geared grunt that you have in the 3.5" setup and the efficiency of that setup is great. Its not broke, it doesn't need fixing!

J

Not to worry, John. I only advocated the brushless is a specific situation. No plans to go brushless with the production stuff. Not at all. I'm with you, we have all the power we need with brushed motors. Secure from General Quarters.

David

[greenman407]

John, that red and white staff is my chicken stick. On the very top I drilled a hole in it to attach some fishing string and a bobber. That way if this thing were to get out of control in Inky Black water, i would know where it is. I wont be using it again as she is VERY stable and predictable. Im sorry that it got into the pictures. At all ahead flank it is the fastest submarine I have ever seen except for "Aquadeeps" Graupners tiny yellow sub with a brushless. I am completely satisfied with the subs extreme speed. Just for the sake of conversation and thinking about "What Ifs". If we want to take this sub to its potential, we would go Brushless.

[greenman407]

So Dave, is it true that the 3" motor bulkheads that you are coming out with will have (2) 540 motors? If thats true, how did you squeeze them, in there?

[greenman407]

Check these out. Why couldnt I run two of these thru the existing gearboxes. There is a wide range of winds to chose from. If I read it right, they will bolt right up with t
he same screw bolt pattern as the Graupner speed 400.

http://search2.hobby-lobby.com/psearch/svc/search.php?uid=2&q=400+brushless+inrunner+motor

[greenman407]

I was also thinking that two speed controls in the front compartment would be too much for the conduit to pass those 6 large wires back to the motors in addition to everything else going thru there. What If I put the speed controls in the back compartment with the motors and servos and put everything else up front? That would be better. Maybe this will be the next phase of modifications. Maybe.

[greenman407]

From the research that I have done thusfar, there are brushless motors that will drop in. However, I need a speed control that will operate also in reverse. Most ESC for brushless wont. The ones that do are pricey. Castle Creations makes them but the smallest one still in production is the Hydra V60 amp at $249. I would need two of them. The motors from Hobby Lobby are $89.00 each. Hobby King might, maybe , possibly have something for less but my experience with their products is that the price is not the only thing thats less. So after some more reseach I found it. The Graupner Speed 480 Ball Bearing race motor. According to the specs its quite a jump in performance over the Speed 400. They are currently out of stock until mid January which probably means late March. So I will keep checking back and order me a set.

http://www.v-eastonline.com/products/SPEED-480-BB-RACE-7,2-V.html

[greenman407]

Here is a useful link. It compares many of the commonly used brushed motors with many of the Stats. Print you out a copy of both the Mabuchi motors or the Graupner ones or save the link.

http://homepage.ntlworld.com/edward.matthews/motors.htm