ModelBoatBlog

Designing, Building, Operation and Discussion of Model Ships and Boats
To read article posts (Blog Style) select a Category in the main menu bar above.
Current Activity

- The Dauntless Project has been on hold as I stumbled between other major projects trying to to solve a late-in-life crisis. Being over the "standard" retirement age but still working, I was searching for an Idea on how to turn a hobby into a profitable business. Building a model boat didn't qualify.
- My primary employer "retired" me in early 2015 so now I have time to pursue other projects of interest.

Registration Not Required
Log-in is only required for contributors. All readers may browse and enter comments. However, you will be asked to provide some personal information when submitting a comment.

Dan Kautz

Johnson Motors

I am not sure if these motors are keepers yet. Well, I will keep them but not sure if they will get installed in this project. The specifications seem good (see below) but the motors, well… they seem so small. I did find some two inch diameter motors but I don’t think they are as plentiful as these Johnson brand motors. The price for the two Johnson’s was about $7.00 each. I have seen a conflicting price on the larger motors but all I see now is about $10.00. At that price it is worth experimenting .

I purchased these Johnson 9167AK from a seller on Ebay. There are quite a few sellers with this motor so it must be widely available. I didn’t see it listed under this number on the Johnson Motor web site. I assume it may be some kind of overstock for someone needing a small motor of these specification.

Johnson Electric 12VDC Motor (6 to 18V) – Model 9167AK

Extreme Torque of 2.2 in-lbs

Super Grip Serrated Shaft

This motor is quite a bit larger than most hobby types. It’s suitable for any model or experimental use where high shaft power and torque are needed. Please note that there are a couple of different Johnson model 9167 motors. The 9167AK is the biggest one with the highest power.

Runs very smoothly over the range of 3VDC to 18VDC.

                 Light load                Medium Load                Heavy Load

3VDC:     1,400 RPM                               850 RPM                         n/a

6VDC:       3,150 RPM                            2,100 RPM                      750 RPM

12VDC:   6,560 RPM                            4,900 RPM                   3,400 RPM

18VDC:   9,800 RPM                            7,350 RPM                   5,100 RPM

At 12VDC the motor has very impressive torque.

Starting torque is 2570 gm-cm = 36 oz-in = 2.2 inch-pounds, at 14 amps.

Operating torque at medium load is 440 gm-cm = 6.1 oz-in at 2.8 amps.

As the load is increased, the torque and current will increase correspondingly. Please check that the case temperature stays below about 100 deg C, in order to maintain long life.

On a dynamometer, the motor was able to generate a continuous 31 watts of mechanical shaft power, with a peak value of 46 watts (temperature limited). A typical small hobby motor can only produce 2-3 watts and a medium-size motor about 10-12 watts, usually not continuously.

Overall length is 3-1/2″ including terminals and shaft.

The body is 2-5/8″ long, 1-1/2″ diameter. Or 65 mm by 38 mm if you prefer metric.

The shaft is 3/4″ long. It’s 1/8″ (.125″) dia with a .130″ serrated end section that grips tightly to a suitable hub, pulley or shaft coupler.

The heavy duty self-aligning front and rear bearings are lifetime lubricated oilite bronze.

The brushes are low-friction and long-life graphite carbon, NOT just copper spring arms as in many small motors.

The armature is 5 pole and the spin is reversible by reversing the power wires.

The Remote Conning System (RCS)

This is a new concept of the Remote Operated Vehicle (ROV) or Remotely Piloted Vehicle (RPV) control applied to scale model boats. RCS is intended to provide realistic scaled control rather than real time instant response. That is why the term conning system is used. However, the concept can be utilized in any type of remote vehicle control when the human response time is not critical (fast). In this affordable system the display and use of the feedback will be generally too slow to be of use or value in any high speed real time application.

Reasonable application of  ROV control has been accomplished for explorer rovers both on land and under water and long range RPV aircraft of many types. The process is also well established in space and other distant world exploration but response is limited by radio signal delays. Low speed ROV’s are used to fulfill missions in the scientific, military, or hazardous investigation areas. All these applications are well established using the RCS type of feedback and are part of the inspiration for use of RCS in slow speed scale model boats.

Currently using RCS in the real time (speed and directional) control in standard R/C small field type model aircraft and all forms of high speed R/C model competition vehicles is not realistic. Scale slow operation is not desired. Data gathering and recording for later historical retrieval is the best application of RCS in these operating conditions. Speed and direction control must always be real time.

Operation of slow speed scale models could be made realistic in their rate of motion and directional control with RCS. In these cases, I am not proposing exact response scaling as I carefully selected the term realistic. The concept is the selective use of the RCS computer to introduce scale like response to commands from the com with complete override in panic situations.

This concept has been used in model train systems to provide realistic type locomotive and train operation for acceleration, drifting and braking.

A high tonnage warship certainly responds differently to helm and engine commands than a high speed personal sport runabout. The heavy ship will take a lot longer to power up, down and stop. Many boat and ship models can be grossly overpowered so they react with far better performance than the prototype craft.

With RCS it is possible to build “canned” effects into manual input and autonomous control sequences. Remember the sequences can be optional and turned off on on at will with proper programming (command) of the RCS computer.

My vision is the shore (captain’s) control will include a key pad as part of the interface. Any predefined control sequence can thus be sent to the TCS computer from the key pad via the data link to change on-board sequence of operations.

The key pad can also be used for control of any accessory or routines to control accessories. For example an entry code 789A might be used to turn on a mast light. Then code 789B used to start a computer sequence to blink the light on and off in one second intervals like a beacon. Finally 789C shuts the mast light off. It is all up to the imagination of the programmer and number of I/O pins with how they are programmed. That means there is almost no limit of the number or variation of realistic control functions available.

There are ways to extend control by using multiple processors to add additional I/O capabilities. That is far beyond the original scope of the RCS but certainly not unreasonable.

RCS – Remote Conning System

I have coined an acronym for the remote nautical control system I am designing and constructing for my roboboat project. I am calling it (as least for now) an RCS which stands for Remote Conning System. It has some precedence of use (display) in real ships control as can be seen in the following link:

http://www.syberg.no/conning-system/category179.html

There may be many others links to similar systems but this one provides an excellent presentation of what I am trying to accomplish with model boats and ships well before I discovered this link. I added the prefix term “remote” because of course, the Captain of a scale model must “take the con” remotely.

The link above is showing just the display of CON data but if you follow other links in the left column you will discover additional information about the IBS (Integrated Bridge System) and other control systems.

The reason I changed to conning instead of control is because it just sounds so much more a comfortable nautical term and as I stated, there is precedence. HA!

A Pretty Face

Dauntless

American Enterprise

American Enterprise

This thought is being generated from trying to decide what should be the water borne operations platform for the Roboboat project. I have been wishy-washy on my decision on how big and fancy the boat needs to be. The robot competition boats for autonomous operation built by students are almost always ugly looking floating boxes. No classic marine hull designs at all. Many look like pontoon houseboat platforms.

My intention from the start was realistic boat hull design. To that desire, my urge at this writing is to skip the ugly test platform stage I have briefly considered (the pointy box) and go back to my large hull original conception.

  • I want to get there (real hull design) anyway.
  • Saves the cost and time of “ugly duck hull”, as a “just get it on the water”, intermediate stage.
  • Kit boat saves all marine design work. Just build it. This takes hull design and performance out of the variable list.
  • The onboard electronics are very small so require little space. Access for experiments and alterations will not be an issue using a large hull.
  • Most experiments will be in software control functions.
  • Did I say reduces overall development costs?
  • Standard boat design has retained value if controls project is ever abandoned or sold as finished design.
  • Larger, heavier model boat projects perform much better in a wider range of water conditions than small, light, non marine designs.

So with all that considered, I have two prospect boat designs in mind. Both are made by Dumas. My top of the list is the Dauntless Kit #1211. Also considered is the American Enterprise Kit #1213. Both use the same running hardware, but I am considering sourcing the electric motors from other than Dumas.

The Dauntless is about 2.5 inches shorter than the 52 inch American Enterprise but is two inches wider in beam at 14 inches. It is also more expensive than the American Enterprise. However, the Dauntless looks a lot roomier due to its much larger freeboard.

Yet, the American Enterprise is sexier and faster looking. I’d take either but which one first? Ha!

This means I will soon be putting a face on this project. I’ll let you know when I decide.

 

Another Baby Step

It has been a great weekend. The weather in Texas finally broke this morning (Labor Day 2011) as it was 68 degrees on my back porch this morning. The wind had been blowing hard all day before and the night before so I knew something was changing.

At 7:30 AM I sat on the porch in my “got dressed” shorts, sippin’ a cup of fresh ground French Roast coffee, munching on my last chocolate walnut brownie, and freezing my a** off! I’m not conditioned to under 70 when it’s been 105 to 115 for several months straight. Never the less, it was a great day to work in the shop.

The picture shows the BS2 micro computer in the foreground with an LED, a photo transistor, a piezo speaker (squeaker would describe it better) and a servo motor all hooked up to the I/O pins. That is the Propeller behind it also with some I/O stuff on board. Both systems are capable of communicating both directions on the wireless XBee network.

My theory has been proven to my satisfaction. Now I will begin to design the real world component application so I can test how those components will really work, then do radio range checks before I switch to the prototype boards.

It sure was nice to have a cool day in the shop.