Plastic equivalent of dog bones. I never liked the fidgety-ness of a DIY gear box. So I thought I’d try something different. The motors have internal gearing. The plastic “dog bone” can be cut to exact length. The couplers really bite into the plastic. It was very simple and quick to install, and so far feels pretty solid. We’ll see after a couple battles if I feel the same.
…then I’ll move to metal dog bones. If I’m still not happy, then it return to a classic DIY gearbox setup in mk2 of the ship. I am under no elusion this version will be perfect.
SEATRIALS! The 'geared motors' were a complete DISASTER. They are no where near fast enough. She needs more weight too, especially in the front. Mark2 will be using the classic gearbox we all know will work.
Hmm ... yeah, she's mighty light. You want her around 12-13 lbs. I think. Also, I'm not sure what the "standard gearbox" is, but ... maybe I need you to remind me. Does this gearbox use 500 or 400 size motors? That would be a start.
This style, but maybe not quite as fancy: https://rcwarshipcombat.com/resources/3d-print-traxxas-villain-gearbox.146/ I'll let you know after you text me back with a recommended model or [amps/rpm/torque]. haha... EDIT - Keeping it to 1" - 1.25" diameter would be ideal. So 550s are out, anyway....
I use 555 motors at 12v direct drive for mine and am very pleased with performance, they have plenty of torque without gearing
Hokay, so it looks like you want something in the 380-400 range. Once upon a time, we would use something like a classic Tamiya 380 direct drive in our cruisers, but it was honestly too fast (for 1985). Recently, as in the last decade or so, I've used a geared 390 flat can motor in my French cruiser, like you saw yesterday. I wish I'd shown you in more detail. So, the thing is, I'm used to running a 6V system, not 12V. The standard Tamiya motor (link to follow) appears to be a 25 turn motor. I think that even geared down, it would be too much power for your Lutzow, as even at 6V, it made my old cruiser blazing fast (for the time). Interestingly enough, thanks to R/C rock crawlers, lots of motor flavors are available. I'd be very tempted to try something like this: https://amzn.to/3KuJTIp To get a cheap baseline. They list it as 10K RPMs at 12V, and geared 1.5:1, that should give you a nice baseline. Actually, it would probably be fine for small gun use. Hopefully you'd be too fast, and could use your ESC to adjust your speed. Oh, and I just realized a point of confusion - I thought your motors were brushless because you were running 2 ESCs. With brushed motors, you can run both (in parallel) off a single ESC. Anyway, back to the story - Dynamite "Tazer" 380 motors are available in a variety of windings. I'd be tempted to get the most windings available (37t, I think) and see how that works. https://amzn.to/40XIJu2 With any of these motors you're also going to want a gearbox. The Traxxas Villain clone gearbox is 550 sized, and too big for these motors, but if you wanted to, I'm sure you could make a scaled down version for 380 motors. Maybe someone else already has. When I needed one for my French cruiser, I just made it from a sheet of .060 aluminum that I bent 90 degrees, and drilled/ground some holes and a slot in with my drill press/dremel. It was tedious, but they worked fine. Anyway, I have to scoot, but hopefully that will be enough info to get/keep you going.
Updated the drive system for the 'standard' gearboxes that I've seen on most people's ships. - Roughed in for the recommended 380s. - Motors are angled along the prop axis. - Mounting bracket is tall enough that it can fit gears too. - Cut into the hull so the drive gear could have as much space as possible: - Cut away from hull so the 380s could fit direct drive:
I'd like to start with the obligatory reminder that this is for Big Gun, which goes by scale waterline rather than weight. So make sure you're ballasting appropriately. Secondly, I'll second the vote for 380's. I used direct-drive RS-365SH motors turning two 1.25in props in Tegetthoff and Prinz Eugen (VU class battleships), and they reached the low 30-knot range during sea trials. Without checking my radio, I think they needed around 70% throttle to reach their allowed speed of 25kts. The Deutschland is a lighter, more efficient hull so 380's will do great. Those motor mounts look fantastic. I can't wait to see this thing fighting!
Today's update - Flattened the bow and stern deck for easier printing. - Added lip under bow and stern, so the deck can just slip under without needing a magnet. - Extended the aft deck to cut into the 'deck step', to give easier access to parts underneath.
After meeting @Commodore and the Texas fast gun club this weekend, I learned that I'm cutting my window too close with my prop shaft. It would be a nightmare to glue the balsa sheet. I've updated it with my understanding of their recommendations. Everything below the highlighted blue line will no longer be a window cut in the hull. For orientation; that 0.5 x 0.625 block I where the prop shaft is mounted. The fallout from this simple change is going to be enormous. I'm going to go for dinner before I attempt to commit that change. Please review and comment! Let me know if it can be higher as well please.
That took me way too long.... I hate waiting for filets to compute, one at a time, while I fix whatever was broken... Next Steps - Make space for a full size rudder servo. Finish electronic & ESC trays. Give the CO2 bottle a better cradle. Double check the motor fit, once they arrive Wednesday. Consider how to add an upgraded motor, if needed (I am NOT reprinting this thing again!) Increase the prop shaft for a larger stuffing tube. Check full full size servo can fit in the turret rotate position Add tie-down for the floatation cord. @Commodore - Did I miss any other notes from this weekend?
This may drive you nuts but I am starting to CAD up a 3d-printable Big Gun triple. It's primarily intended for my Viribus Unitis class, but guess what other ship gets 7/32" triples with identical barrel spacing... If it works, I will probably ask to print a couple of your lovely pocket battleships.
