All the bulkhead parts are made ready for assembly. I decided at this point modify CF2 and B2. B2 to enable easy access for further detailing of the cabin at a later stage and CF2 I cut out what will be the door opening into the cockpit. Each of the bulkheads had 2 x 12 mm holes drilled just below deck level for future wiring runs; they also needed support to secure them at 90 degrees so I made a number of right angle squares to support them squarely and at equal height at each side, these were secured with a temporary brass pin. The spacing at the keel was pre-determined when building the keel components, however the tops need correct spacing by dry fitting the cabin sides and just checking that each side measures the same height, finally the back end of the keel needs supporting to keep everything square. Each of the cabin sides and bulkheads can now be dismantled and reassembled with epoxy resin. NOTE at this stage only the bulkheads are epoxied to the keel, the cabin sides and CF2 are only there to ensure the bulkheads are square and correctly spaced at this stage.
Hi Spitfire Glad to hear that you will be supporting the site's running costs. Stephen (Fireboat) runs this free site entirely on donations so every little bit helps. Doug has answered your question re wiring the brushless motor to the ESC. I would just add that you should not swop any wires whilst the battery is connected. I would also advise that you fit a fuse between the main battery and the ESCs. Brushless motors can draw very heavy currents when stalled or overloaded. A fuse rated just above your running current and no more than 50% of your ESC rating. I am assuming here that your wiring is capable of carrying this current? If you haven't got one I suggest you purchase a wattmeter so you can measure the current drawn under load (hold the boat in water and run at full wack). This must not be greater than the Motor or ESC rating. A smaller prop will reduce the current. Please keep us posted
Before the funnel could be installed wanted to fit a working radar scanner, navigation lights and the batteries. Decided to use sub C NIMH batteries in plastic holders, they should have the target endurance and provide some ballast. Fitted two sets of 4 cells, one at the forward end of the superstructure and the other at the rear, both at keel level. These were inserted into wooden battery trays to hold them in place. A dry test run showed a full speed motor run time well exceeding the hour target, so will try on water. Also took the opportunity to fit the Rx and then adjust the rudder before finishing off the wiring. Both the navigation lights (LEDs) and the radar scanner work. The radar is driven by a servo with the potentiometer removed and a magnetic drive shaft run up through the superstructure from below the deck. The motor requires about 9 volts to run at what would seem to be something approximating to scale speed; fitted a voltage reducer to allow the lights and the radar to work on less than 6 volts. The mast lights are to be installed in a separate circuit after the masts are added. As I get more into the detail it is evident the GA drawing and the photographs of the vessel in service differ. Fortunately the component locations seem consistent, although the equipment is not. This most apparent in the hold ventilators. The GA shows the standard cowl vents, but the photographs show a mixture between an vertically squeezed oval vent (which am advised is more typically German) and ventilator columns with cylindrical caps. The column style vents with cylindrical caps were easily made from two different sizes of styrene tube with the cap tops made from styrene offcuts. The squeezed oval style vents were more difficult. Broke them down into the major parts of the cylindrical vertical tube and, from a larger tube cut a small ring and filed one end to straddle the tube once it had been squeezed oval. Glued it into place whilst restrained in a small hand vice. Once set, removed and sanded the the two to give a smooth transition, closing the rear aperture off with styrene offcuts. Then resorted to wood filler, filed down to give a smooth, oval vent.
Hi Charlie, don't mention it, glad to help. 45 years electrical & electronic engineering must be useful for something 😉 I'm also new to brushless and not sure yet how they behave when stalled. Must do some tests soon.🤔 Remember: fuses are essentially there to stop wiring bursting into flames and igniting the surroundings; house, boat, plane, model - whatever! So make sure ALL your wiring (including battery leads) is at least as thick as that on the ESC and motor! 👍 Good luck, and have fun, Doug 😎 PS I'm also single and nearly flooded the bathroom a while ago getting my 5 foot Graf Spee to float to check ballasting!! 😁
Props by ChrisG Chief Petty Officer Posted: 22 days ago
Many thanks to Mark, Doug and Roy for the information on prop rotation. I will now be confidant that each prop is on the correct side of the boat, wiring the motors and connecting the ESC correctly is a task for the future to say nothing of connecting the R.C. Thanks again👍
Thanks for that. I have picked up one or two references elsewhere that coating all connections made in wiring and servo connections is a good precaution. Also coating exposed circuit boards would benefit them. It is extremely unlikely that I would ever wish to make alterations to such boards, so if it does no harm and may be of benefit then I will have a go. You were right on the rudder links Mark. Better now that I have given them some 'slack' so will just use 3 in 1. All the best. NPJ
To be honest, I have never heard of the stuff, hence no comment!!! I will only advise if i have used the item or product. Do you think you will need that? Possibly WD40 would work just to dispel any moisture, If you spray sealed the circuit boards it might make it difficult to alter the wiring etc, only a thought as i said i have never used the product Mark
Yes I am sure you are quite right. I can see I have much to learn and it is interesting. So many different aspects to address.......so few brain cells functioning. Hope to do more on the wiring Saturday. Cheers all. NPJ
The motor units are Robbe EF76 with fitted gearboxes, rated at 6 - 8volts, superb units and very reliable, did you strip and clean the gearboxes as well???? were the photos taken before you cleaned the motors??? The battery space looks to have been fitted with 4 x 6v 4ah batteries, probably giving 6v drive power, might have been 12v. Is there an ESC fitted?? that would give us the final key, apart from the red and black wire in the 4th photo is there any other wiring??? Mark
This time I will try to remember to put in the ‘source’ information on the bits and pieces I use........... In the most recent piece I should have included exciters/transducers are Dayton Audio DAEX 25VT -4, 4 Ohms – 20 Watt pair, obtained from Sound Imports Netherlands and very quickly as well. The sound unit is a Mtroniks Digisound 5M diesel sound, available all over the place. Now to look at where I am at. Exciters are in place as high up the Hull as possible, but remembering the Deck level. Used the adhesive pads as supplied after wiping that part of the Hull with Meths and Silicone adhesive to keep in place as well as using the wiring tidies from Modelsport Ltd., for the cabling. (Pic 1+2) Before I start the motor and controller wiring I changed the platform ‘up front’ (pic3) with a piece of thin ply which I have given a couple of coats of varnish to waterproof. Then I thought to myself “why am I waterproofing this when, if it gets that wet, it will have gone to the bottom and be useless anyway”! (Pics 4) However, the platform gives a little more choice in terms of layout of other components and my plan for them is not really settled yet. I am concerned about the stern and possible swamping, but it currently seems the best place for the upgraded battery. (Pic5 ) Whilst talking batteries, I have gone for a separate battery supply for the receiver and hope to use the Bec supply for running other less critical items. Also the fitting of the battery in the stern bay drew my attention to the rudder servo for a couple of reasons. First is I am still considering increasing the size of the rudders and I am assuming that will increase the strain on the servo. The servo supplied is a standard issue and not water resistant so I have gone for an upgrade as shown(Pic6) That gives torque increase of 17Kg/cm over the Hobby Engine S1040C and has metal gears, metal control arm and waterproof for 20grams extra weight. Second is the closeness to the new battery position. So I was going to alter the servo arm setup anyway and the new metal arm suits this well. Maybe my ‘tutors’ will consider all this to be a little ‘over the top’ but I do so enjoy messing......................... New Servo DS 3218 by AYANI from Amazon. (Pics 6/7 ) Following that distraction, back to the front end and the Motor/Mixer placing and wiring. Now a little time ago I drew a plan to see what could go where and it came out that most of the ‘bits’ would go in the front bay with motors to be wired once power was brought forward, followed by the Esc/Mixer. (Pic 8) At that time I bought a P94 dual esc/mixer from Action Electronics and got the 20 amp version to be on the safe side................. My ‘guardians’ did point out this was ‘over-kill’ but I had already got it. Now, when placing the unit on the mounting board I found that the heatsinks made it too high to fit in the Hull! So being a spoilt brat only child I ordered the 10 amp version and as usual it came very quickly from up here in Bangor. ( Will keep the other one for the next project............Happy Hunter??) Unboxed it and it looked just the same, heatsinks and all. (Pic 9/10 ) So at that moment there was a bit of a set-back so I rang Component Shop at Bangor, they said “take the heat sinks off and you have a P94 lite”! Such a simple answer and such a nice chap. (Pic 11 ) Now a quick 'measure up' before I have a glass of wine (Pic 12) and does it all fit...? Well it appears to at the moment! (Pic 13) Next time really going to screw down the components under the forward hatch and wire it up. NPJ
Thanks for that stuff on the PM. I am assuming the white wire from the motor is positive........... As you can see I an working in a very tidy fashion.............. Need to first finish the temporary sound set up on the build blog and then move to the battery/motor wiring on there. All the best. NPJ
Hi John Glad to hear you have a working boat. The new wiring and ESCs have clearly removed any previous faults in the connection between the battery and the ESCs. It was a beautiful calm day at Boundary Park, Cheshire and I sailed my Perkassa so must have been a good day for fast patrol crafts.
Reilly, I stand corrected I see what you are saying, the speed of the boat is just about right, if I fit a smaller prop then I will need a much faster motor to keep it at that speed then I presume the battery will not last as long, in fact that is something I would like to work out, although I am ok with wiring and working out loads at mains voltage etc. my ohms law is useless with DC voltage and mAh Haverlock I had a look at that motor but I see the recommended motor mount would block of the front air holes again (same mout as I have) Canabus thanks for that sounds expensive besides which I have spent out nearly, my pension does not really extend to this hobby, but enjoyment is important. I wonder if the last three words of the previous paragraph is a quote from some famous person I could add to the bottom of my posts😁
This is sounding more and more like interference and low voltage. Can you post a few pics of your setup, showing all the wiring, motors, ESCs, Rx and battery. Are you using Tamiya connectors by any chance? Also are all your connections good - no green verdigris on any?