ML 1/10th Scale Newton 164/ MHR 9401 Kit

[Neal Hiland]

HI All

I have just finished building a 10th scale hydro as mentioned above and before i run it wanted to know a little bit about setup as i dont want to destroy the hull. all the info i have is below.

ML 1/10th Scale Newton 164/ MHR 9401 Kit built as the Budweiser
rear ride pads have been added
motor is a tenshock 2240 2300kv
esc castle x8s
single 4s 6800 lipo

My concerns are the cg as currently i am about 70mm behind the turn fin and from what reading i have done it seems i need to have this centre of the turn fin.

Attached are some photos of the build.

Any help would be apricated.

Neal

 

[Bradley Maglinger]

Beautiful build and boat, when testing a boat like this with wings, I normally take them off for testing so I can get the turnfin set and strut. Once I feel confident that it isn't blowing over, and the steering trim is set, then I put the wings back on and do final adjustments. Make sure your cowl has flotation, and I would get it out there and just see what it does. I don't run electric but on my Bert Dygert Hull 2 Wing Nitro Circus Circus, my CG is at the trailing edge of my turnfin. Good luck and I am curious what prop will start with on it?

 

[Mike Hughes]

With that vented hull and the CG so far back, you will need some prop to keep the back of the boat up. You are carrying lots of tail weight. Removing the tail feather will help with that to begin with. I would suggest a 3 blade prop. Something in the 1.7 inch range with that amount of KV. Did you build this boat to run counterclockwise? Right hand prop?

 

[RaceMechaniX]

I would agree with Mike on using a 3 blade prop to begin with, usually an Octura X series is the most forgiving. I usually would recommend a X440/3 to begin with and step up a X447/3. The new Tenshock 2240 motors have double the power of the older AQ motors. Log your data from the Castle controller and add prop/setup info in the notes section of the castle datalog. As a good rule for these motors, keep the peak current below 225A and the continuous average around 150A. That's conservative to keep the motor healthy for a long long time. The weak spot in the motor is the solder joint between the silver windings and the copper extensions. Keep an eye on these coming apart.

 

[Neal Hiland]

Hi all.

Thanks for the replies. So the boat is built to run clockwise and I was going to start with an x440, 1440 and m440 which I have. I have some other 40mm props to try also but are mostly just cnc ones.

I am not looking for outright speed to start with just a good running hull.

I will definitely take of the rear wing assembly to start and yest the cowl will have flotation.

When I put it on the bench to check cg I was surprised that it needed almost 1.2kg of weight on the front of the sponsons to get the cg at the turn fin. This was my biggest concern as I dont know how else to get the weight forward as there is simply no room.

 

[Hydro Junkie]

If you have to add that much weight, the easiest way would be to drill access holes into the sponsons. Not knowing how the internal framing is done on your boat, my guess would be to locate the hole into each sponson as close to the front as you can, drilling through the sponson insides.
What I would do is take the boat out for a couple of test runs to see if the boat is "flighty" or not, increasing speed each lap. If the boat seems to want to blow over, add around .1Kg with stick on style weights to the front of each sponson's deck and try it again. When you get to the point where the boat is stable, drill the holes and pour a mix of epoxy and small lead shot into the sponsons, standing the boat on the front of the sponsons, until the epoxy cures. Tape over the holes, for now, and test it again. If it appears stable, patch the holes permanently and install the tails & wing. At this point, you should be good to go, other than some minor wing and thrust angle adjustments.
One word of caution, try to keep the added weight to a minimum. You may find the boat doesn't need as much ballast as you think. Also, hydroplanes hate weight so every .1Kg you add can make your boat that much slower

 

[Neal Hiland]

Thanks for all the feed back guys.

So I finally go to take the boat out for its maiden run today. So from the advise I removed the wing and just ran it how it was with a x440/3. First attempt I put the boat in the water and it was just pushing the water. So I got my mate to give it a launch and was able to get it stright up on the plane.

The boat ran amazing turned perfect and was able to get it to full throttle and it was not to loose.

Bought it back in and put the wing on it and send it out again. Had my mate launch it for me again and it was just beautiful. Plenty fast enough and will give it some slight adjustments so I can keep it at full noise the whole lap.

So impressed with this boat and checked all my data logs. Only pulling 180amp and could prop it up but at a guess its doing low 90kph which is what I was targeting