Hi Seafarer, a few basic questions! Mast for what boat/ship? Dimensions / pic or sketch of the mast? Space for drive motors/gears/pulleys etc? Hint: for the radar on my 1:72 destroyer I used an old servo; disconnected the feedback, and removed the mechanical end stops so it rotated continuously and drove it with a single 1.5V dry cell (alkaline), lasts for years😉 But in my case the scanner aerial sat on the director tower on the bridge, not on a mast, so simple direct drive coupled to the servo (hidden in the ridge) output shaft with shrink sleeve. Does a sweep in a little under one second. What type of radar are you trying to simulate? Cheers Doug 😎
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"The brain is not intended to store facts. It is for thinking, and for knowing where to find the facts !" Albert Einstein. 😉 cheers Doug
Thanks Doug,the boat is the Ayton Cross Tug which has the scanner supported from a shelf projected from the main mast.the scale is 1:32. I'm thinking it's an impossible task but just maybe there's a nano motor somewhere waiting for the task!
Thanks Dave, you've set me off on another adventure into the unknown but I think I'm learning....do I need the Arduino UNO controller and could I control two motors off it (it doesn't matter if the speed is the same ) . If I don't need the controller ,could you explain a bit more about using the POT (presumably a potentiometer?)
Hi Seafarer, I have a few ships with rotating radars I have a few of these motors per the link below. They rotate quite well with one cell (1.4 volts) Gear Motor 3 - 224:1 90 Degree Shaft https://solarbotics.com/product/gm3/
I also have some of these, but they require a bit more vertical space. MFA 951 Series Motor and Gearbox 298:1 6volt (from CMB in the UK). I run these on 3 volts.
Both are quite small. I have also used old servos in a couple of places.
Hi seafarer You do need a four wire stepper motor driver. I used my Arduino as I have one. The pot varies the speed thro the Arduino so it can't be used on its own. I have some ic chips that can be used as drivers but I have not had time to program and develop so far. I have used geared dc motors but if in a quiet display area they can be noisy, which is why I intend to use this type of motor. I will do some more research and get back with possible alternative forms of electronic drives.
Thanks Mark, the wire would be a solution if the scanner was on the mast centreline but it is off-set half way up and on a shelf so that it can rotate. The 6mm motors suggested by Trillium appear to be a possible solution fitted underneath the shelf.
I have used the kits from Mr rc World he has option of motors and the controller that comes with it gives you the fine control to set the speed of rotation to what you want and powered by your receiver pack
You can find him on flea bay or on the Web
I have recently constructed a rotating radar mast for my 1:48 scale paddle tug "Forceful" I have used a geared 6 volt 60 RPM motor which gives a realistic scale rotational speed. It is a little noisy but only when close up. it is driven by a direct shaft running up the centre of the mast not prototypical but gives a pleasing effect. I may rebuild this at a latter date to eliminate the noise
Hi seafarer, I've scratch built a Type 21 frigate and managed to find motors for the radars. I got them from a company called Precission Microdrives, web site https://www.precisionmicrodrives.com/gearmotors. They don't come cheap, the three on the mast cost £45 - and then there's the replacement for the one I 'lubricated' with super glue. That said the effect is fantastic and they just make a slight whirring noise when running and go all day on the 6 volt battery (I needed to fit resistors to them to get the speed down a bit). Hope this helps. Graham PS The service was very good. PPS The film of them working doesn't appear to be working so I've posted a still, the motors are 20mm long to give an indication of the size. The air traffic control radar on the bottom platform shows the full length of the motors. PPPS Web address changed, thanks Dave.
Hi smiggy I have a couple of these motors and they are good and mine run off a 1.5v battery (max3v). Planetary gears but relatively quiet at low revs (volts). Mine came from http://www.gizmoszone.com/shopping/agora.cgi and cost about £6 ea. Your link should be https://www.precisionmicrodrives.com/gearmotors. Well worth a look. The stepper motors I have are 10x14mm (including the shaft) and are direct drive. I will be posting a thread soon showing more details Nice scale model Dave
Some great ideas and many options! what I thought was "no hope" to "every hope" of resolving the problem. Need to start to make some decisions and looking forward to Dave's forthcoming thread with more details.👍