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I found this hull at thingiverse last year. I printed the hull from a local shop and rest was handmade. Firstly I bought a 2426 4200kv brushless 2-3s which was too powerful and too heavy for the boat size. The length is 38cm. And the 30Amp esc was also too big for it's size. After that I tried small 180 brushed motor with 20A brushed esc w/brake. It was perfect (still it's heavy😂). The bridge and deck is made by 1.75mm pvc,torpedos are made of wooden pencil. Small battery space takes a 2s 500mah lipo. 30mm 3blade propeller. YouTube video link is here: https://youtu.be/KZdmZ8_Z0IE
Again, as not wanting to nick someone else's thread. Huntsman 31 currently has a geared (belt) brushed motor which was probably quite a good spec. many years ago. I don't remember how quick it was but having watched brushless boats running this morning in Southsea I have decided now is the time for change before I start painting. I've been reading various threads and gleaned some info but it is still a minefield. Whilst this boat (original) is twin screw I am not yet ready to go that far so will stay single screw. A thread suggested 3639 -1100KV which is fine as a spec. but there are a zillion different makes and models for that spec. Cornwall models seem to offer 6 or 8 so I am looking for more specific advise for make and model of each piece of the power system...motor, ESC, battery, charger. I'm not going to say 'money no object' just that I don't 'need' to buy bottom spec. I suspect there will be as many different suggestions as 'Cornwall' have motor makes but something good will come out of it. Many thanks Steve
The weather has quickly turned colder, giving an excuse to get back to this model. Stripped out much of the interior and the prop. shafts to replace the nylon propellers with brass. These items all needed removing for painting, so decided to paint the hull before reassembly and then moving onto the superstructure. Fortunately, examining similar naval vessels and several U Tube videos, confirmed the hull as light grey, the deck a darker one of the 50 shades of grey and the lower hull below the waterline black. Used thin Tamiya masking tape to define clean colour separations, followed by regular tape, masked the hull into colour sections and sprayed using “rattle” cans. After the colours applied a light overall Matt coat to subdue any shine. The results are satisfactory. Will now reassemble and move onto building the superstructure and the other fittings. Prior to the season closing decided to experiment with my new Flysky Tx/Rx package, shortly to be fitted to this model. This Tx has a servo limiting function, which was hoping could also be used to restrict ESC output. Would like to make the full speed motor response correspond to full Tx control position. Currently can over power the model; which lifts the stern, causing it to come off the plane and then dig the bow in. Was thinking that if full throttle could be set at around 90% forward control movement and 40% sternwards the model would retain adequate performance, but without being overpowered or very sensitive to control lever movement. As the Brave was not available, tried the idea on my Daman Stan 4207 model. This is brushed motor powered and a good performer. Obviously the settings for the Brave will be different, but at least could try to see if the idea would work – it did! This Tx function is easy to use and adjustments can be made whilst the model is on the water. Once the ideal settings are achieved they can be programmed and then retained in the Tx. Will try this on the Brave when back on the water next Spring.
Don't know what happened MOTOR COMPARISON Model Number Caldercraft CEM 900T MFA Torpedo 850 Nominal Voltage 12v 12v Operating Range 6-24v 12v Type Brushed Brushed Current Cons No Load 0.4A 1.9A Current Consumption Max Eff 5A 10,8A Stall Current 20.3A 40A RPM at Nominal Voltage 3000r/min 9778r/min Prop Caldercraft 75mm The Motor I am putting in this Sea Queen is a Torpedo 850. This is due to the Caldercraft motor only manages just above walking pace.
Hi John. Interested to know what kind of offers you have had. Boaty, yes Veron did an RTTL Rescue Target Towing Launch, they featured in the black and white film ' The sea shall not have them'. This though is their fast patrol boat. I believe it's called a 'Trinity class patrol boat and some were supplied to the Trinidad and Tobago navy. You will sometimes see the model bares the name Coureland Bay'. I have seen photos on this website of her. They were built by Vosper Thornycroft in Portsmouth. If I was building her I would put two meaty brushless motors n her which should bring a sprite lay planing performance. I have fitted two Graupner 900s in mine, which give her an excellent turn of speed. These are brushed motors but are not available any more. The hull space is vast so easily accommodates batteries with space for sound system working radar etc. Regards Kevin
Although have modeling experience, all my earlier vessels used brushed motors. This was my first brushless. The model is now running well, but thought, for the benefit of others considering this transition to summarize my experiences. Must stress the performance of a brushless motor is incredible when compared to a similar sized brushed; for a vessel such as this they are almost obligatory. They are worth the trouble! Had been advised that the best powertrain installation for a 37” Brave Borderer is either a single or twin screws, not three. This was good advice! Much heartache could have been avoided with a single screw installation. Unfortunately, that is not the correct layout for a scale builder. Tried three major powertrain iterations, with several variations within each group. All motors are 28mm O/D : 1) The original installation used 3 x 4600kV inrunner motors with 30 A ESCs. Had bought these items used. The motors were too fast and had little torque. The ESCs also did not have adequate capacity. The result was erratic performance, a high fuse failure rate and the eventual failure of an ESC and motor Picture #1. 2) First upgrade was to 2 x 2400kV inrunner motors, using 50A capacity ESCs. The centre shaft was fitted with a brushed motor. This combination did work, although suffered greatly from motor “squeal” and “stutter”. Eventually a motor burnt out and failed. Picture #2 3) Upgrade two: retained the 50 A ESCs, with 2 x 2600 kV outrunner motors, again with the brushed inner shaft motor. Reprogrammed the ESCs to soft start parameters. Much better, performance and reliability can now be considered acceptable. The squeal and stutter are largely corrected It has justified the challenges of getting here. Picture #3 Have tried both 2 and 3S Li-Po batteries, suggest use the minimum voltage needed to achieve the desired performance. Higher voltages translate into faster response and performance, but with less control modulation. The model can be easily overpowered. In summary, from my experience. For a marine application; chose low (under 2000kV) kV rating motors with an outrunner layout wherever possible (produce more torque than inrunners). Use ESCs with a ratings comfortably in excess of the motor ratings, fit fuses to supplement any ESC protections. Ensure the ESCs are programmed to “soft start” characteristics. Also, the obvious check of making sure shaft alignment is correct is even more important with the higher speed capability of brushless motors. In spite of the trails, cost and tribulations of getting here. Have enjoyed the challenge and the end result does justify the means. Also, do not finally fit the deck until you are satisfied with the performance. Making the changes described with limited access would have been very difficult and frustrating.
Just put up another vid showing the speed at around 2/3 throttle which looks reasonably scale for 38 knots (bit hard to scale water movement as we all know!) and it doesn't squeal too much at this speed. Just been back through my old info on the ESCs and found I may be able to change a few things (forgot due to approaching dotage and so many projects on electric (18 planes as well converted from ic to electric) I was thinking with your high kv motors that if you can get away with smaller props or some the scale diam bit finer pitch props, that would allow the motors to rev how they should, but give you finer control. As I mentioned before, on 8v per motor they will spin at around 16-18000 rpm and won't like a big load (you've no doubt heard those delta wings scream) . My props are 28mm x 3 blade on a 2000kv motor and are spinning at around 12000 rpm (probably around 8000 rpm in the vid at 2/3 throttle) The general rule with brushless is the higher the kv the smaller the prop/pitch and vice versa planes or boats (would also apply to brushed) If you have an in line amp meter/batt checker you can check the amps drawn in the water at full power (have someone hold the boat) and see if you are under max A for the motor. You can then prop to suit if necessary. This is the only way to check for correct load and is an absolute must for aeroplanes. After a run, motors should be around cool to almost too hot to touch (60-70deg C) There are backplate water cooling units available for using out-runners in boats if necessary eg pic.
If you are using 2 ESCs/BEC/UBECs with 2 plugged into 1 receiver you should remove the red wire from one of the plugs and tape it back to the lead, as both plugged in will possibly supply too much voltage for the receiver (you are getting double the voltage from 2 different sources) and this can cause the ESC to stutter . You should have no problems with Brushless out-runner motors as with the correct match with the ESC they should be as smooth as brushed. I have dual 2000kv 28/45 in-runners (with water jackets) and twin ESCs and 2 sound units using 1 receiver in my 64ft ASR model with no problems regarding proportional control (fwd or rev). I had a 28mm O/R in a Maiami ASR and it would crawl along (but the high noise was ear wrecking so have changed it back to brushed for now. I do have a similar slight high pitched squeal at certain speeds on one motor and this may be caused by the particular motor not 'syncing'properly with the ESC (Chinese cheap ESCs and HobbyKing /made in china motors) but short of changing that motor and ESC I am just putting up with it for now. The high pitched sync noise is fairly common and sometimes not fixable, (a number of my larger planes do it and its audible from 100m away (also amplified by a hull,-nice sound box). It can depend on the way a particular motor is wound (no 2 are identical) or even magnet placement/timing, as the may be hand wound by 2 very nice Chinese ladies at different ends of a bench ( just read some of the Hobby King motor reviews ) You could try changing the frequency on the ESC if it has that option as a higher motor Kv sometimes requires a higher frequency. Also make sure your ESC is set to the correct battery cell count. If it has an auto setting that should usually work best for general applications unless you are running fancy motors. Regarding interference, make sure you keep your aerial as far as poss from the motors and ESCs (even on 2.4 - I put mine right up in the bow) and there should be no problems. I have had 2 twin engined boats (my MTB & ASR) 1 brushed and 1 brushless running side by side 10" apart using the same radio for both (same type of Rec in each boat) with no problems at all. The bow down is probably prop shaft angle (the shallower the better) but if you are using counter rotating props you could try swapping props (inward rotation to outward) and motor rotation to see if it makes a difference. Also with 2800Kv motors you should be using small props (around 28-30mm diam 3 blade) as these motors are made to rev) as on a 2s battery they will be turning at around 20,000 dry and perhaps 18,000 wet (depending on prop) and if you load them too much they will cook with no cooling (assuming they are around 28mm dia ?) Only other thought - silicone couplings will squeal real loud if they slip.
Adjusted the transom flaps and reprogrammed the ESCs to the softest start settings, retested. Until now, the test runs did not have the duration or stability to really examine what was happening. Using 3 S batteries acceleration is rapid and a is plane quickly achieved. However, as the acceleration continues and speed increases, the bow digs in. A cloud of spray then surrounds the model as the plane is lost. Brushless motors do not modulate as smoothly as brushed and adjusting power tends to be erratic or exaggerated. This is a scale model and the propeller shaft angles are per the plans. The thrust from the propeller has two components, horizontal and vertical. The horizontal propels the vessel forward. However, the vertical component forces the stern upwards and, correspondingly, the bow down. Have moved as much weight as possible towards the stern to counteract this, limited by maintaining the correct displacement and waterline. The easiest solution is to reduce motor power, decreasing both speed and the lifting component. Decided to retry the 2S batteries as they give reduced power. A plane is again achieved, but as the motor response is more docile, it can be controlled. If the speed gets too high the bow lowers, as before, but the motor output can be more easily adjusted. Spent a pleasant half hour or so with the vessel accelerating onto and off a nice, controllable plane. Much less spray and drama than with 3S and much more controllable. Have now decided to revise plans and use 2S rather than 3 batteries. A further advantage is the motor noise is muted and now sounds more like a gas turbine than a dental drill! Finally feeling comfortable with the model. Will thus shelve further building until the late fall when sailing in Canada concludes. Want to enjoy the rest of my fleet in the meantime! Will summarize my experiences with brushless motors in another blog shortly for the benefits of others contemplating their use. After restarting the model will resurrect periodic build blogs to advise progress.
Shucks! An I was hopin' you'd build me a little 4 cylinder diesel for me to run a brushed motor as a Genny for all the lighting on my ships! Or for the diesel electric propulsion on my Type 45. Now wouldn't that be cool!?😁 BTW Some of Nick Carters tips an tricks showed me how to convert one of my tools to something that'll do what I want! So, out with the Proxxon mini-grinder😉 Cheers, Doug PS It wasn't a wrong steer cos it led me to all sorts of useful 'stuff' and above all helpful info👍
Mornin' John, agree re chromite, but still don't know what chroDite is! I only personally own the one Taycol Target. I got into this whole Taycol business while I was renovating Dad's old Sea Scout last year and decided I wanted a bit more Oomph so upgraded it to a 1000kV brushless, which gives goods results on a 3S LiPo. See the vids I've posted of the the 'Sea trials' (Lake Trials!?). So I decided to use the Target in the ancient Billing Boats Danish fish cutter I'm restoring and converting from static to RC. Figured the Target would cope OK with the plodding pace of a fish cutter😉 BUT, I wanted it to be reversible without cumbersome external switches or relays as recommended by Taycol / Keil Kraft in those days. After surfing around a bit a found a website where others had tackled the same problem. Looked at their solutions and refined them slightly. All I do is rectify the pulsed (square wave) signal from the ESC with a bridge rectifier (4 hi-current diodes in a bridge form in one package), apply the + and - outputs from the rectifier to the field coil so that it produces a constant magnetic field just like the permanent magnet of a canned motor. The two alternating (pulsed) outputs of the ESC are applied to the AC (~) inputs of the rectifier, which go + / - or - / + according to the command from the TX, I apply to the brush terminals just like a normal brushed motor setup. The output of the ESC is a train of either positive of negative going DC pulses. Pic 2 the positive train on the scope. Pic 3 the negative train. The larger and wider the pulse the higher and longer the voltage is applied and the faster the motor spins. So called Pulse Width Modulation (PWM). The gaps between the pulses are smoothed out by the inertia (flywheel effect) of the motor, and anything hanging on it - like a prop and a few million gallons of wet stuff 😁 Hey presto, a field coil motor that runs forwards or backwards on command 😊 Main thing is simply to separate the field coil from the armature coil (i.e. brush gear) so you can control each one independently. No rocket science but highly satisfying when it all comes together and works on the pond. OK, I'll look up Mr Lynch, wasn't he the Sarge in Z Cars 😁😁😁 Cheers, Doug 😎
Hi Boaty, The Taycols have fascinated me as well, ever since I dug the Target out of the Sea Scout my Dad built in the early sixties. I blogged my renovation of that and the conversion to run with a modern RC system and presumably that, and the converter boards I built for Martin (Westquay), is what triggered Colin to ask me to have a look at his Supermarine. How could I resist!? 😉 The 'smell of something electrical' is the ozone gas caused by the prolific sparking of the Taycol metal to metal brush / commutator combination. The other source of Ozone is on the coast wherever there is a strong surf! I agree, a nostalgic smell, which unfortunately disappears when the converter board is attached to make it run with a standard brushed ESC. The diode bridge kills almost all the sparks. 'Almost' so the usual suppression capacitors are still recommended. 0.1µF across the brush terminals, 0.047µF from each terminal to the motor can, or frame in this case. Earth to prop shaft tube as well if possible. The motor may not disturb the on-board electronics of your own boat, if using 2.4Gig, but could still affect anyone nearby using 27 or 40Megs. The power density of spark transmitters (e.g. unsuppressed E-motors, peaks in the upper HF bands and diminishes to almost zilch in the UHF bands. I.e. approx 300 MHz upwards. Like me and other submariners for instance; 2.4Gig is useless for subs cos it don't go underwater. Cheers, Doug 😎 But here! BTW Boaty: where are the pics of your Avanti? Harbour posts without pics are pretty dead 🤔 Cheers, Doug 😎
This is a restoration of a launch I was given that was found in a rubbish bin on a farm here in Auckland It is an old RCM ? plan built 'Fairacre' and was pretty rotten when I received it as it is made in balsa and had been wet for quite a while. I stripped it down, re 'planked' large portions of the hull and fiber glassed it, re- built the cabin, re- marked the deck planks, fitted lights, curtains (ex Graupner Commodore bits from the 70s I had kept), stern ladder, cleats etc. It is fitted with a 540 brushed motor (originally had an old Graupner monoperm) and 70s Graupner ESC and Using 2.4 Radio gear. I still have a few things I'd like to do such as a re-wire, fitting chine spray rails, better motor and maybe some safety rails, but for now it does the job.
IN THE BEGINNING there was what looked like a pile of rust😲 which got soaked in WD40 for 24 hours! After washing off with warm water and washing-up liquid, and drying in the sun for a few hours, the bearings (and copper wire brushes) were oiled, missing connecting links bridged, and 6V (with current limit 3A set) was cautiously applied. Lo and behold she rattled and protested BUT RAN! Oh! That nostalgic smell of ozone, and enough sparks to read a book by🤔 Next connections were changed, to separate field and armature coils (brush gear), and connected to a standard brushed motor ESC (Graupner Navy 30A) via my prototype converter board, and a Robbe Servo Tester to simulate TX and RX. lo and behold chapter 2; she ran forwards and backwards😊 and no sparks! Now dismantled (last 3 pics) to start clean up and replacement of corroded parts. Sorry Col, I broked your motor😁😁 Armature was cleaned up and commutator polished; surprisingly lots of 'meat' on it so motor has not been run much. Next stop; lathe to make some new frame spacers. After that new bearing bushes cos the old Paxolin end plates have worn so that there's about 1/32" slop! Will probably have to turn the drive shaft down from original 1/4" (6.35mm) to 5mm to remove last traces of rust and pitting. Cheers All, Doug 😎