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Model Boats Website Team
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Hi. The HK controller is an Aquastar 120Amp water cooled which has suffered all of the burn outs and never failed. SKU: 9052000008. The failed motors were all 2848SL 3900kv Brushless Inrunner (WaterCooled) SKU:3900-2848SL. I have my doubts about the specifications as their watts and amps do not add up. I have a temperature sensor on the motor sending info back to the TX and usually after a full charge and a fast run it would get to 60°C, then I would cool it to 45°C before the next run it burnt out at 85°C when I wasn't paying attention. The new motor runs at about 45°C how ever hard it is pushed. Still using the 120A ESC. The new motor was in the HK sale and I don't think they do it now SKU:S2858-2630. It just happend that the water jacket for the failed unit fits it.
Thanks for the info. I thought maybe something like vinegar and baking soda in the DCs them might make them produce loads of bubbles. Making them blow off at a certain depth would be interesting. As for RC on the torp, looking at maybe a tethering system so it homes.
Hi. It is a scale model of a Formulaboats.com sponsord jet turbine powered hydroplane. I think this livery was from 2009. They can be seen racing on Youtube https://www.youtube.com/watch?v=A4HPB4PtT0k .As for the burning out motors that is sorted. Nothing to do with my cooling system but the unit I had from Hobby King seems to have a number of complaints about them burning out. So replaced it with a different model. HK have been very good and replaced all 3 failures. I will keep the latest replacement for another boat.
[Score: 10/10] 49" KD Perkasa MTB Single Propellor (2 Blade S Type 50mm) Direct Drive to a Turnigy AquaStar 4084 620Kv (2 Blade S Type) Powered by LiPoly (14.8v) 12Amp/h Batteries Controlled Through Turnigy AquaStar (150Amps) ESC - Comments: Plywood 1:24 scale MODAV kit from 1976.
Well after loads of messing around I eventually bought all new gear. So I now have a 160 Amp ESC, brushless motor and LiPo batteries. The 48" Perkasa runs like a dream. https://www.youtube.com/watch?v=s9Y850Y_o1w Not sure if the hyper link works. Noise from out of balance prop but sorted now.
Hi. I have tried an Acoms 27Mhz RC and a 2.4Ghz RC both do the same thing. I have given up with Mtronik. It looks like they have buried their head In the sand maybe because they do not know. So moving forward I am going to build my own speed controller based on an article on www.pt.boat.com. For what It's worth this Is what I sent to Mtronik: "Sorry but this made things worse on both Viper ESC the 25A and 40A have the same problem so does my cheep Chinese Import. I have set them up on my bench now with the digital scope coupled up to confirm what Is happening and have come to the conclusion there Is something In the software causing the problem. This Is my test method. Two 6 Volt gel batteries coupled In series feed the main power to the ESC. A separate 6 volt supply powers the servo tester. A 4 Watt 12 Volt bulb Is connected to the ESC output (this Is to give load and make sure there Is no EMC) The servo tester Is giving out 0.945 to 1.926ms with centre off around 1.452ms. At 1.087 and 1.85ms the ESC's output switches hard off and on. This Is what causes the flickering on the bulb. All that happens when I use the left or right mid point to set the travel Is the problem moves In proportion. Which makes me think It Is a software glitch. Would It be possible for you to set this up and replicate It?"
Just to let you know I have received this reply from Mtroniks and It made matters worse. "Have you tried reducing the throttle end pints on your transmitter? This would bring the throttle end points closer together and stop the controller from seeing the spurious signal at 75-80%. Dong this would not effect your feel or proportionality In any way. Let me know how you get on. Best regards," I have replied to them with the outcome and await their reply. 😀
Thanks for response Dave. I did some more checks yesterday (Sunday) and ran the ESC from a servo checker. I put a 4 watt 12 V bulb on the output of the ESC. Coupled It to my digital scope and sure enough the wave form Is very clean but switches off and on at around 75% throttle. The PWM looks like 1Khz so It makes the bulb flicker rather than switch off and on. As soon as the throttle gets to 90% It clears up and at 100% full voltage Is applied. I did this on all three ESC and the result Is the same. I have written to Mtronik as my conclusion Is the ESC cannot resolve the change In mark space well enough. It looks like the system thinks there Is a loss of signal so It shuts off. From what I can gather most ESC use the same embedded software In the PIC. Just as a matter on Interest I did all the usual suppression things Including running a large separate negative wire to the RX. Will post what Mtroniks have to say to the site If I get a reply.
Hi. I came across this site while browsing for Info a problem I have with my brushed ESC's. I am running a Viper Marine 40 with an MFA850 motor from two 6V 10Ahr gel batteries. The boat performs well enough but I get Intermittent motor cut out at around 75% throttle (froward or reverse) This has already caused the ESC to blow up. This was replaced FOC. However I now have another new Viper Marine 25 on a smaller boat running from NiCad cells and this does the same thing. To cut a long story short I have replaced the 40A ESC with another make, replaced the TX-RX with a new 2.4Ghz system and I still get the same thing. Being a bit of an electronics engineer I coupled the kit up to my digital scope to see what was going on and It looks like the problem Is with the ESC. The Input from the RX Is a good 1 - 2ms steady signal but the output of the ESC switch off and on around 75 - 80% throttle. I have emailed Mtronik on the the subject but no reply. I just wandered If anyone else has had a similar experience? I might go back to glow motors.