German PE build

I started a new German Heavy Cruiser PE build this last week, got 8 evenings in it so far. Making it for one of our future Air Force personnel. Josh just graduated from the AF academy, and wanted a smaller boat than his NC, or VV to haul around. Of course the PE is still pretty big for a cruiser.
I have it set up to use all brushless components since they are now cheaper than going with a brushed motor and good ESC. Mike M and I have been testing them, and so far they are looking good. But if for some reason they don't work out, they can be swapped out for a standard brushed setup easily enough. In the picture you can see the 2 motors, and the 2 controllers are sitting side by side, one each side of the stuffing tube.
This evening I will install the wiring, then I can finish installing the water channeling tomorrow and Thursday, the water channeling boarders are complete, just have to back fill with balsa, and seal it. Make the guns Friday and Sat, and I plan to hand it over to Frank the following week to make the Superstructure for it.
Windows cut out, with 1/8 stringer, subdeck and deck installed.

Aft to forward view.

Rudder setup, take out 1 screw, and the rudder servo and mount is removable, plus screw acts as a hold-down for the adjustment for the gears. Little resin to clean off the hull, but it pops right off. I went with a different rudder design, did not think the original shape covered enough of the prop wash to be very effective.

Brushless setup. 2 motors, and the ESC's are behind the gearbox, sitting side by side. They are 30 amp, 120 peak. I tested the 100 amp unit in my AH PE with a dual gearbox, twin 1 inch props. In the pond it was drawing 3.2 amps, so this should be close to the same. With the brushed setup in my PE, it drew right at 5 amps, so about a 30% current savings. I have a 1 1/2 prop on it, with 1 1/2 drag props, and if needed can go up to 1 3/4 for the drive.

ESC's, nice and small. The 100 amp unit is only a little larger, but the price more than doubles. Internal CO2 system.

 

WOW
Very nice job.
Mikey

 

Very nice. One question though? How are you going to waterproof the ESC's?

Kim

 

I have done one already, just remove the 4 screws, pull the Esc out. Fill the plastic case with West systems epoxy, put the ESC back into the case, and put the 4 secrews back in, done. You will have to wipe up the excess epoxy that gets displaced from the case when the ESC goes back in. Also do it over waxpaper to catch the spill.

 

Dave,
That is some great information.
Bobosan

 

Welp, the Erin battled all day today with it's newest brushless drive system. In a word: Awesome!

First thing I had to do was dial the speed down. The ship had so much power that it literally lifted the bow out of the water! After 15' at full power, the ship actually lost speed as the stern deck went under water and suction killed the thrust. Even so, it must have been doing sub 20 seconds. Heh. I ended up dialing the speed control from 100% power to 36% power to match speed with another 28 second boat.

Second most noticeable thing was the awesome acceleration the ship now had. Unlike a brushed motor that looses RPM under load, the brushless motor system had enough torque to maintain rpm under heavy loads such as starting and stopping.

Thirdly, I noticed that the ship looses less speed while turning ... in fact, it was barely noticeable. Again, the brushless motor torque under heavy load kept the props turning at full power even while turning. The brushed motor that was in the ship noticeably lost speed after more than 30 degrees turning.

Dave, the new 100 amp speed control worked perfectly. Even after finally getting sunk (nickle sized holes tend to do that), the esc worked without a hitch. Reverse was instantaneous and powerful. I'm thinking this series of speed controls is the way to go. And the price is right too!

I did NOT use the brushless pump. Curious about the amp draw on the pump that can empty the Erin in less than 30 seconds, I put a Watt Meter on it last night and was shocked to see it drawing 81 amps at full pump. Either the Watt Meter is wrong, or I picked the wrong motor for the application. Heh. I suspect the higher massive torque of the brushless pump motor actually contributed to the high amp draw by keeping the rpm up high vs the Titan's which drop rpm under load. We may have to rethink motor choice, but first I want to try something ...

 

You know, I just realized that I posted this in the wrong thread.

 

Not a problem Mike, we pretty much hijacked the other thread anyways. Better to use this one. I also wondered about the pump draw, but have not tried it as of yet. I plan on it this week. What was the draw on the drive motor, did you have a chance to check it?
I was also thinking that we may need to gear down the motor on the pump, just to cut the amps.

 

The brushless motor on the pump is a 4300 Kv (4300 rpm per volt) ... pretty substantial rpm on a 6.6 volt battery. I was trying for a motor with about 3000 rpm more than a Titan. What I forgot was the greater torque that a brushless can put out.

If I was going to buy another motor, I might go for a 3000 - 3250 Kv motor.

What I am going to do though is use the brushless esc that runs the motor and dial down the rpm until I get around 30 amps draw, then test the motor against the Titan setup. I suspect the brushless will still pump more than the Titan.

I didn't check the brushless drive system amperage ... forgot to take the Watt meter with me. Heh. Frankly, I'm not really worried about the drive system amp draw ... it should be equal or less than the brushed setup.

 

Mike, I got a 2600kv for the pump I was going to try. Hopefully by Thursday.

On the PE I made the guns, mounted the barbets, and installed the guns today. All that is left is mount the solenoids, firing card, and the receiver, and finish wiring up the 2 motors, hopefully I will be done on Tuesday.

Need Thursday and Friday to patchup the Benbow for this Sat battle.

Mike whats the status on you, are you making it Saturday. Josh Bruder emailed me yesterday, and is going to try to come also, he wants to see his new ship. Heck he should be able to battle it, all it will be missing is the super.

 

I haven't decided yet. Need to talk to my dad and see if he will be around. I would like to ... long drive (9 hours), but gives me a chance to see how he is doing as well battling.

By the way, the Erin turns much better now.

 

Did you try what ever it was on your pump?

 

Ok, got one of the motors hooked up to the pump. Had a little issue getting it to work at first with the car ESC, it would not work using the switch functions on the radio.

I programmed the ESC step 4 as forward only, and still it would not work. But then I used the programming on the radio, and reduced the negative end point gear adjustment from 100% down to (0) zero. Turned the ESC back on, and the pump then started working. Hope this helps others if they have the same issue. I plan on testing it in the water tomorrow. I plan on turning the forward gear endpoint down to like 20% to start, and monitor the current draw, and then slowly raise the end point adjustment. Since the ESC is a 30 amp, my plan is not to exceed a 20 amp draw.

 

Well I got the motors installed in the PE. They look and run very well. I did see 2 other small issues that need to be taken care of before you put it in the water, or let BB's get close to it.

1. The on off switch for the ESC. I tested the ESC with the switch shorted out, and it works fine. I don't think that little switch will last long when it gets wet. I'm just going to cut it off, and solder the 2 leeds together, and cover with heatshrink.

2. The fan leeds have 5 volts on them, and can easily be shorter out by a BB. I plan on just cutting the pins off at the base, and covering with some epoxy, don't want to short out the BEC.

I made a 5 mm pinion, by taking a 16 gear pinion, and drilling it out to 5 mm on my lathe, works fine.
Stern forward shot. Josh wanted tripple sterns in it, I would of done it a little different myself.

Bow to stern. Bottle, batteries, both only weigh 3 pounds total, with 20 amp capacity. You can see the looping plug just aft of the battery. Thats the on/off switch, I'm tired of switches going bad at the worst times. What you see in the center section, beside a mount to hold down the pump is complete. Easy access to the bottle, batteries, pump cleaning, and reloading.

The 2 brushless motors, I still need to come up with a mount of some type to hold the pump in place. The wiring and gas lines are buried under the resin. I ran the motors using a Spectrum system, with no cap, and I did not have any disconnect issues at all. The motors are 2250kv, so lower rpm, but after what Mike told me about his 2600kv, having to lower the ESC to 35%, these should have no problems at all.