RCU 8th Scale Brushless Hydroplane Build

[kcpasco]

Hey guys I have a build going on another site but I decided to add it to here, it seems like there is a lot of knowledge on this site and I would appreciate any help you guys can give me on anything. I have done tons of boats both nitro and electric but this will be my first 8th scale hydroplane, and my first electric this big. We will be running with the nitro guys running .67s so the goal is to have a nice fair setup, which we have now I think. I have the registration for the 2009 Oh Boy Oberto and thats what I will be running. I have been an unlimited hydroplane fan for all 29 years I have been on this earth ha. I am on the Water Follies Board that runs the Columbia Cup race here in the Tri Cities and do anything and everything I can involved in the sport of hydroplane racing. So racing scale boats is an easy fit for me. Hope you guys enjoy the build and feel free to add any insight you may have on anything.

P.S.
If some of this is not making sense its because I am simply posting what was in the other forum thread so far, but I am only posting my posts nobody else's, I am trying to avoid posts I made that directly answered other peoples questions so it does not get too confusing.

[kcpasco]

Hey guys this is KC and I will be posting my build of my 8th scale brushless 2009 Oberto for the RCU Club. We will also have a number of other boat builds posted in this thread, including a 2008 U-3 piston hydroplane and a 2008 Elam. Look forward to visiting with all you guys.
Also due to the fact that it took a month to get accepted on here to post we will be starting our posts after lotsa work has already been completed, but we will try and catch everyone up on things we have already completed.

[kcpasco]

Hi guys I am trying to figure out where to start, I wanted to post pictures of the new boat, taking it out of the box and every step after. I think I have a couple pictures of the boat before anything had been done so Ill post those. I am doing the 2009 Oberto from Qatar. Steve at RC boat company came through with the T6 hull for me. The T6 can basically be every hull running currently and in recent years. Steve really impressed me with his Fiberglass work. The boat come fiberglass and carbon fiber, and the glasswork is so nice you can almost just prime and paint the boat with no sanding.

The boat has a lot of the scale features but is not 100% perfect. I think his is closer than any other boat makers boat. I looked at Phil Thomas hulls too but it is not even close to what I need as far as scale for my boat. Steve's has 90% of the scale look I need. The cowling had some issues as far as scale look so we are making a new cowling to go on our boats. Josh with his U-3 is doing a lot of hull modifications to make it even more scale. I am going to go with almost everything Steve did because I trust he did what he did for a reason. The ride surfaces of the boat have some very interesting ideas, not very scale but very interesting. So my plan is to set up the boat to run and run the boat before I even start on the paint job. This way I know if I want to change the ride surfaces or not. Here is a couple pictures of the boat with nothing done.

As you can see in the pictures the boat comes with a swim-step, offset bull-noses, over-sized outside sponson, and many other really nice scale features. Only thing I would change if I could have it redone is the rear shoes dont look scale and the real ones one is shorter and shaped different than the other. Also the front ride pads are not scale at all, but again I will trust his design features and hope it performs well.

[kcpasco]

Here are the first set of pictures

[kcpasco]

Ok guys got some pictures of a few of the things I have been working on the last week. As you can see from the pictures I added a block that I can add inserts and bolt my motor mount to. As you can see I will be putting the motor as far forward as I can, close to the radio box/cockpit. The batteries will be in the compartments on both sides of the motor, The 4s 5000 mah 40c batteries that we will be allowing in the club fit perfectly in the compartments that were built in for fuel tanks. The speed control will be going up front in the radio box/cockpit and all wires and waterlines will be epoxied into the wall of the radio box so I never have to worry about sealing it up. In the pictures all I have is the aluminum water tubes epoxied in the wall, the next pictures will include the wires as they are, as of last night completed.

Also in the pictures you can see the skid fin stabilizing bracket got epoxied in the hull. Also you can see the scale rudder bracket that has been welded up and mounted to the boat, I purchased a nice rudder with duel water pick-ups and the scale rudder bracket was designed to fit the rudder. Also as you can see I do not like bolts or screws mounted on the bottom of the hull so instead of mounting my strut to the floor of the boat like most I mounted it to the back inside of the transom, and the strut fits perfectly with just the drive dog ears behind the transom.

[kcpasco]

Also as you can see I am trying to cut into the hull as little as possible... I have so far only had to cut two small holes in the boat, one to add a piece of aluminum for one side of the rudder bracket to mount to, and the other to put the skid fin stabilizing bracket in the side of the boat. Everything I have mounted I used two layers of fiberglass and one layer of carbon fiber. Hopefully this will keep me from ever having to get back into these places due to the mounts coming apart. Also the motor mount block was mounted the same.

I am currently debating running my water lines through the engine bay, or through the unexposed hull, for the sake of hiding everything I will not need access to and keeping everything neat and organized. As everyone will see once I get everything in the boat, it will be very organized with no clutter. The engine bay will hold only my motor, and servo.

[kcpasco]

Hey there. Sounds like the setup we are shooting for is two 4s 40c 5000mah lipos ran in series. It will be about perfect for a set per heat. We first were planning on running a 10s setup with the NEU 1527 but it was a bit too fast to equal the nitro guys, so it has been changed to the 8s setup and that is about perfect for the speeds the club is shooting for.

[kcpasco]

The scorpion motor was tested but it got way to hot for my comfort and with no way to water cool it I wont be going that direction personally. I think it will be an available option for the club but when it was ran it was about 40 degrees outside with ice cold water and the motor came back after a 2 minute run on a 55mm prop with a temp of 155 and that was after it had about a minute or more to cool down, meaning it was much warmer than that when it was running. The NEU runs much cooler in our testing so ill personally be running that.
As far as the batteries, it seems in the club its somewhere around 15 seconds a lap at full speed, all heats are 5 laps, so the race will be 1 minute 15 seconds roughly, and around a minute mill time. All our testing we have been able to get 2 and a half minutes out of our runs, and the batteries still had some mah left, not much and not much room for error but it seems to work. With the 10s setup we would have had much more room for comfort but it was just too fast and that was with a 50mm prop so not much else we can do to slow it down.

[kcpasco]

1527 1.5y is what we are running

[kcpasco]

No we had heard it was a good setup.... the 1y is way too high a kv.... running that motor on 8s would be no different than running the 1.5y on 10s speed wise. The intent was to slow it down. We are trying to make a super safe setup and have it run 55mph to run with the .67 nitros and not have a speed advantage.

[kcpasco]

the scorpion motor worked it just ran too hot for my liking so ill stick with the NEU, however I think you are remembering incorrectly, when you guys ran the scorpion it was over 150 after some cool down time. 155 was the exact temp after the first reading. Either way thats fine for a brushless motor, but in the middle of a hot summer it will be even higher and heat is certainly the enemy.
As far as the mill period goes the reason it will be ran in RCU is because the club is all about scale racing. The unlimited hydroplanes run a mill period and fight for lanes. So the scale boats run a mill, the mill is just another part of the race. Many of the nitro boats get on the course at the 3 minute mark though and I doubt many of the electric boats will be spending that much time milling. I personally enjoy the mill as much as the race, its all about strategy.

[kcpasco]

Hey Bob just did some measuring and the boat seems to be right on, Steve did a good job.
Boat total length is 45.25 and RCU allows 43.25 to 45.25
Boat width is 23.25 and RCU allows 19.56 to 23.93
Tunnel varies a little but at its widest it is 11.50 and RCU allows 10.46 to 12.79
Sponson depth is 3.35 and RCU allows 3.04 to 3.71

As far as the Jones sponsons are concerned the small sponson is 5.25 and at the same point on the other sponson is 6.50 ... as you know it the rule book it states that Jones sponsons need to be approximately "1 1/4" difference which is exactly what the sponsons are.

So this boat from Steve follows all the rules and meets all the RCU requirements. As you know we are trying to allow people to get into the club that dont have the experience some of us have to help grow the club. This boat can be many different boats that have available registrations and not everyone can build a boat from scratch like you can. That takes a lot of skill and time. So this is a great option for all those that want to get involved but cannot build their own hull from scratch.
Looking forward to testing in a few months with all the new boats. Hows the progress coming on your guys end with the molding process? Hope its going great cannot wait to see all those beautiful new boats.

[kcpasco]

I keep hearing that about the scorpion. Maybe it was esc settings or maybe the x455 prop was too much or something I dunno but it got too hot for my liking. The way everything is going right now it seems like the scorpion will be an allowed motor in RCU, along with the NEU and maybe a couple others. The goal is to get as many more people involved in the club as we can and help it grow.

[kcpasco]

Ok guys got some work done, as well as made a list of what is still left to do haha... long list. Right now the plan is just to get everything mounted and in place to run. Then I will work on polishing and making all the hardware look good along with painting and the boat and what not. Since I am making everything from scratch the motor mount and everything else do not look that great now, but when I am done with the boat ready to go they will all be polished up and look good.
I got all the wires and everything ran into the radio box and epoxied up and all the connectors on them. I put brass inserts into the block I glassed into the hull for the motor mount, the inserts are threaded on the inside and outside, the outside so they screw into the hole in the mount and stay, then I can bolt my motor mount to the block. I also got my rudder cut down and in place. Stuffing tube has been bent to fit into place and line up with the motor correctly, I have not glassed the stuffing tube in place yet though. I also got the hole cut out the way I want it in the hull for the strut to fit through and move to the angles that I want it at. Here are some current pictures.
Not much to look at now but it will be nice a purrrrty soon enough :-)

[kcpasco]

A few more