Hi All,
If you have been reading my posts on the Comment Wall you are aware that I am building a fairly large R/C racing boat for autonomous offshore competition.
The R/C boat I have selected is the Zippkit VBox 2013 edition that is 46" long and 17" in beam. The boat is normally powered by a 26cc gas engine of around 5 - 7 hp, however I plan to use a brushless electric motor in place of the gas engine.
Since I do not need speeds of 50 - 60 mph for the kind of competition that I envision, I feel that a brushless electric motor of around 3 hp will be sufficient to drive the boat at around 25 - 30 mph. Therefore I have identified a Leopard 5692 1000kva 3000 watt 56 mm dia brushless motor as being a suitable candidate for my purposes.
I have decided on using twin 6S 10,000mahr LiPo batteries in parallel to power the motor. So now I am researching high current, water cooled ESCs with 180 - 220 amp capacity to control the motor.
After the propulsion and steering hardware have been installed in the hull, I plan to integrate a Pixhawk navigation controller and associated components into the hull to provide autonomous navigation.
I will begin the Project Discussion with the installation of the propulsion and steering hardware and then move on to the integration of the navigation controller platform.
Regards,
TCIII AVD
Replies
Hi Richard,
Thanks for the kudos, much appreciated.
Since this was my first attempt at building a wooden hull of this size, it has taken me much longer than someone with boat building experience.
Once the hull was together, I had to figure out a way to mount the brushless electric motor since the hull is designed for a 26cc Zenoah gas engine. Fortunately OSE had a nice motor mount for the Leopard motor that I was able to adapt the gas motor mounting rails. The ESC is mounted on top of the motor mount which is very convenient as far as the wiring and cooling lines go.
I have completed the support for the Parallel Battery Circuit Board Adapter so I can cut the battery to ESC interconnecting cables to length and attach the 8mm connectors to the Circuit Board Adapter end of the cables.
I have completed a hatch cover for the motor opening in the deck and have selected an airtight food container that is large enough to easily house the Pixhawk and its associated components.
Regards,
Tom C AVD
Hi Richard,
I will do preliminary ballast and propulsion testing in my Association's mini lake and then may see about using the mini lake at Vista View.
I think that Irv is probably too busy with his Pixy/Mini Arduino project to help out at the moment:-)
Regards,
Tom C AVD
Hi All,
Today I finished installing the ESC and its water cooling lines. I then started on installing mounting points in the corners of the hull motor opening to support the navigation controller hatch plate and provide hard points for the hatch plate hold down locks.
I will order a Pixhawk, a GPS/Compass module, and a PPM encoder tomorrow and begin a layout of the navigation controller components on the hatch plate.
RMRC is still on back order for the 6S 10,000mahr batteries and have stated that they do not know when their supplier will deliver them. I have therefore decided to buy two 6S 5000mahr 45C batteries to be able to test the present configuration. They will probably only provide around five minutes of run time, but that will be enough time to assess the performance of the configuration.
Regards,
Tom C AVD
That's a beautiful boat Tom,
I used to race outboard single engine runabout class in a Switzercraft semi-hydro in the Intracostal Marathons and off shore.
I can tell by your design it is seriously designed for max speed and rides with very little of the hull in the water at speed.
Your biggest problem will be to keep it from lifting in the front and taking off, (I very nearly did exactly that once at about 60 miles per hour and went to beyond vertical before the transom caught and slapped it back down.)
And even though your boat is big for an RC boat it's small in comparison with real boats and the waves that launch it into the air are the same size.
That's a very interesting prop, not the cleavers I am familiar with, but looks like it's supposed to perform the same way.
I expect they don't allow controllable wings.
However if they do allow real time controllable trim tabs, you might be able to do some interesting tweaking while running.
In any case, should be exciting, please record video of it when you can, can't wait to see it in action.
Best Regards,
Gary
Hi Gary,
Thanks for the kudos, much appreciated.
Unfortunately the trim tabs are only manually adjustable:-(
The prop has around a 4 in pitch and is designed for semi-surface running as the prop shaft transom support (stinger) is adjustable in the vertical plane.
I have selected a motor/prop combination that will keep the max speed at around 30mph which is still really quite a respectable velocity:-)
The designer/manufacturer of the boat has given me a laundry list of recommendations about how to ballast and trim the hull to prevent front end lift. The boat is designed to ride on the back 12 inches of the hull. It is definitely a plaining hull:-)
I have ordered the two 6S 5000mahr 45C LiPo batteries I mentioned in my last post and they should be here by the end of the week. In the meantime I will wire up the ESC/battery cables so I will be ready to go when the batteries arrive. I have a setup where I can use a garden hose to provide cooling water to the motor and ESC water jackets.
I am presently building a navigation controller housing on the motor hatch cover to house a Pixhawk and associated components.
Regards,
Tom C AVD
Hi All,
Between Thursday and today of this week I completed cutting the propeller drive shaft to the correct length, installed the cooling lines and fittings, installed the motor water jacket, and have attached the cooling lines to the motor water jacket and have sized the cooling lines to the ESC. I have also attached the ESC mounting fixture to the top of the motor mount, however it does not appear in this set of pictures.
I am still waiting on the batteries, but I can solder the 6mm connectors to the ESC motor cables and attach the ESC battery power cables to the Hifei Capacitor Bank for paralleling the two 6S 10,000mahr LiPo batteries.
While waiting for the batteries I will move ahead with installing the Pixhawk navigation controller and associated supporting components.
Regards,
Tom C AVD
Hi All,
I have applied the black racing stripes to the deck and have proceeded to attach the propulsion, rudder, trim plates and turn fin to the hull transom.
I have installed the Leopard brushless motor back in its motor mount in order to size the length of the propeller drive shaft. The drive shaft is presently inserted in the motor adapter collet and the propeller and drive dog has been positioned on the stub end of the drive shaft. I have measured the distance from the front of the drive dog to the back of the prop stinger support to determine how much I need to shorten the drive shaft. I will need to subtract 1/4" from the distance between the front of the drive dog and the back of the prop stinger support to allow for the flex drive shaft rap up when it is being driven by the motor.
I will shorten the drive shaft tomorrow and then proceed to add the water jacket cooling lines, hull fittings, and install the water jacket on the brushless motor. The ESC will be mounted above the motor and only needs to have its water jacket cooling lines attached to it.
I am still waiting for the RMRC 10,000mah 6S batteries to be back in stock. I can then wire up the battery wiring harness to the ESC. I will be running two 10,000mah 6S batteries in parallel and have purchased a Hifei Capacitor Bank (http://www.offshoreelectrics.com/proddetail.php?prod=hef-h%230007) with connections for running parallel battery packs to help simplify the battery to ESC wiring.
The following pictures are what I have accomplished this week:
Regards,
Tom C AVD
Hi All,
Made some good progress this weekend.
I built a boat cradle out of schedule 40 PVC pipe and refrigeration insulation.
I also completed spraying the hull and deck with a final coat of clear matt protective spray.
I am now at the point of applying the racing stripes to the deck. I purchased a racing stripe kit that consists of 24 ft of 6 in wide vinyl striping that has a 1/2 in stripe on either side of the main center stripe. I have prepared the surface of the servo/radio box deck access hatch by first sanding the hatch surface with 220 grit sandpaper and then finishing with 800 grit sandpaper. The surface of the hatch is now very smooth in the area that the stripe will be applied. If I am successful with the hatch cover stripe application tomorrow, I will then do the rest of the deck and the transom.
After I complete the application of the racing stripe to the deck, I will then size the prop drive shaft, attach the propeller to the drive shaft, and then bolt the prop stinger, rudder, trim tabs, and turn fin to the hull transom.
Regards,
Tom C AVD
Hi All,
Today I wet sanded the primer coat on the deck and cleaned both the deck and the sides of the hull with alcohol in preparation for painting the deck and the sides with the real orange color coat. Like the pictures of the hull with real orange color coat, this is the first of two color coats which will be followed by two coats of crystal clear spray.
Here are a couple of pictures of the deck and sides of the hull with the first of the real orange color coats:
Regards,
Tom C AVD
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