Blog

Searchlight

The last gadget to be added to complete the Crash Tender refit is the searchlight. The body is made from a short piece of 15mm copper water pipe. A domed piece of copper soldered to one end closes off the body. The tube is just the right size to take a 1W LED and lens. The front cap was made from a ring of copper cut from a Yorkshire fitting which slides over the body of the light. Two small nuts (8BA) soldered 180 degrees apart on the circumference of the body provide mounting and pivot points. The body is mounted to a U shaped brass bracket which in turn is soldered to a brass tube. In addition to being able to rotate the searchlight, I wanted the challenge of making it elevate. A mechanism mounted under the wheelhouse roof provides both the rotation and elevation mechanics. A small servo provides the rotation function. Two plastic , salvaged from a defunct inkjet printer, couple the servo to the brass searchlight mounting tube. The gear ratio gives the searchlight a rotation of 270 degrees. To provide the elevation function, a pushrod passes through the centre of the searchlight mounting tube. As this pushrod is moved up and down, it adjusts the elevation of the light via a wire connected to an arm on one of the searchlight pivots. The pushrod is hollow and tapped with an M2 thread. A length of M2 studding threaded into the end of the pushrod is rotated by a small stepper motor. As the motor rotates the studding pushes or pulls on the pushrod, thus elevating the light. A small scratch built electronic module converts the demand from a receiver channel into step commends for the stepper motor. The motor was salvaged from an old floppy disk drive. The completed assembly was primed and then painted with Tamiya Gunmetal Grey. The LED is driven from an RC switch and constant current source and is quite bright, even in full sunlight. Graham93

4 years ago by Graham93

Forum

MFA 919D series geared electric motors

Hi Hugh, If they are metal yes - a few drops of light machine oil from time to time. Helps to keep 'em quiet as well😉 If nylon or plastic NO! But on the shaft bearings / bushes if metal YES! Cheers, Doug 😎

5 years ago by RNinMunich

Forum

Workshop

Perfect hobby machines, I'm in the wrong country!. We used to have a lot of small new lathes for sale here in machinery outfits for around $1200 NZ but I haven't seen any for a while. I could do with a small lathe especially for boat stuff. We had a Triumph 2000 (lathe not car) and a Bridgeport mill and all the gear when I was in the site services dept in the big woodworking co I worked for. I made good use of those, plus in my workshop I had 2 German RS2000 tool grinding machines which were great for touching up all your router bits and saw/ planer blades etc and a Chinese mill which I reco'd when the other guys didn't want to use it. Made my sons cars' frame and running gear (all 10 speed bike modified etc', -everything adjustable for growth) while I was there . Sure great if you have the gear!

5 years ago by jbkiwi

Blog

Stern Module assembly

This weekend I decided to do more work on the Gato Submarine. Now I am starting to realise how big this job to build the model is, let alone the WTC which I am thinking about and starting to plan in tandem. I have been working on the stern module today trying to get the rudder and aft planes in a working state. I have followed the video made by a kind soul on the internet which I am finding very helpful. To make them fit properly has resulted in a lot of filing and reshaping particularly on the rudder. All of the edges were interfering all over. After a considerable amount of adjusting, they now fit and work perfectly. A hole was carefully drilled right through the height of the rudder to allow for a shaft to be inserted for operation. Small holes were also drilled through some waste material to produce two running bearings for the rudder shaft. There has had to be a considerable amount of material removal inside the stern module halves to allow for the planes and rudder to work. This was done using a burr in the Dremel and files. Great care was taken not to remove too much and go right through the part. I am having a little problem with warpage of one of the stern halves. You can see the gap between the parts in one of the photographs. It might be that they will glue together without incident if I fix them well with bands during curing. Does anybody have a cunning plan to straighten this part before gluing? I have purchased the propeller shafts and tubes so further work on this module will continue when they arrive, probably towards the end of July. I have now purchased my chosen motors. They are MFA 360. I have also ordered the raw materials to make the motor mount and servo trays. I wonder if I have to put the usual three suppressors on the motors if running a 40Mhz transmitter. Next time I am going to work on the bow planes. I will have them working and retracting. I bought the for the retracting mechanism today but have found them to be too big on diameter to fit two side by side in the bow module. The are perfect in every other way so I think I will reduce them to quadrants which should fit nicely. More cad design work for me I think.

5 years ago by MouldBuilder