Guys, I have recently returned to the hobby and things have changed. I have been reading a bunch, so much so that it feels like my head is spinning. Before taking a break from the hobby I was working on a USN Pensacola class cruiser. Looking inside of it, it looks like I was originally going to go with two direct drive brushed 380 size motors. The motor mounts are an odd looking homemade mount that uses zip ties to secure the motors. Not sure what I was thing with this or where I got the idea. It looks a little suspect now. My other ship, a DKM Sharnhorst, uses roller switches glued to the throttle servo for forward and reverse. I assume I originally planned on doing something like this with the Pensacola. Now it seems like lots of people are using actual speed controls? Many are using brushless motors? I'd like to get back to work on the Pensacola, but, like I said, my head is spinning with all of the options. Does anybody have a similar sized ship that they could share their complete drive system? I need to know stuff like... What motors? What speed controls? What batteries? How are the motors mounted? Direct drive or gear reduction? I'm open to brushed and brushless options. Thanks, Jim
Been doing more digging... Looks like my Pensacola was set up to use 1.25" diameter props. Would two of these http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=33284 and two of these http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=35742 work for a direct drive brushless system? If that looks like a good start, what batteries would go well with it. Thanks, Jim
Both the motors and the ESC's should work well for direct drive. For batteries I'd go with a 5~8amp 2 cell LiPo. Something like these. http://www.hobbyking.com/hobbyking/store/__16224__ZIPPY_Flightmax_8000mAh_2S1P_30C.html http://www.hobbyking.com/hobbyking/store/__8578__ZIPPY_Flightmax_5000mAh_2S1P_20C.html I run one of those 8amp ones in my Suffren. I can make it through four sorties on one of them with juice left over.
Thanks for the recommendations Beaver. I'm trying to get current in all of my knowledge. Tell me if all of this is accurate. The big difference in those two batteries performance wise is 8000 vs 5000 mAh. The 8000 will run longer. The drawback to the 8000 is potentially the weight. I say potentially as each ship weighs a different amount. What might be too much weight for one ship might not be enough for another. The other difference is the C rating, 30 vs 20. If I remember correctly the C rating tells how fast we can pull power out of the batteries without harming the battery. Is this much of a concern with our ships? I know with R/C aircraft it was primarily a concern with high performance stuff. The voltages are basically the same, 7.2 vs 7.4. Is all of that fairly accurate? Any particular reason for 7.2 (or 7.4) volts? I see guys mentioning 6 volts, 12 volts, etc. I'm not doubting the voltage suggestion at all, just looking for some insight into voltage selection for future use on other ships. Thanks, Jim
Yes, the main difference is amperage. The weight difference (4.5oz) between the two isn't that significant as long as it fits in the boat. These LiPo batteries are much lighter than equivalent SLA's. You should be able to easily make weight with the 8amp one granted you aren't adding unnecessary weight. The C rating is the effective amount of draw you can take from the battery without destroying it. Multiply the stated C rating by the amperage to get the max draw. You shouldn't have to worry about the C rating since most of the batteries on HK are built for models with much higher draw than our boats.
The standard voltage for two cell LiPo is 7.4v. The 7.2v is just typo. You won't be able to power your receiver right off the battery, but those ESC's have a BEC (batter eliminator circuit) that can power you receiver.
I remember a little of this and thought maybe the 7.2 was a typo. When using two speed controls I need to disable to BEC in one of the speed controls, right? And, how do I do that?
Yes, if you don't, the BEC's will fight each other and cause problems. Just pull the center red wire out of the plug. Fold it back and tape it up just in case you might need it later. Piece o' cake.
Swampworks original directions had you make a cradle out of hardwood stock for a motor mount. Properly epoxyied in to the boat it made a great lightweight, low profile mount. Zip ties make it easy to maintain. I used them in my Admiral Scheer for a long time. Go to the battles. Put it on the water. See what works Good Luck Barry
