56" Performance International Fountain Build

[b.mcdaniel.2009]

Hey guys, going to dive into my VERY FIRST BUILD so hang in there with me when I ask stupid and simple to some questions. Its a 56" Performance International Fountain with 5" rails. Thanks to OSE with there crazy fast shipping, most parts came today so I figured I'd start a thread and get some people's wheels a turning . Jim at South River is making the motor mount and water jacket for the build and it should be in by next week. I was also wanting to CF the floor and transom even though it doesn't need it by any means but the hatch could use a layer so it will also be done. I will be running this in very ruff water so I want It to tuff in case of a bad wipe out.

Motor-Castle 2028 780kv
ESC-Castle 240HV
Speedmaster 1/4 strut
Speedmaster Rudder at 5" set back
few OSE cooling tid bits
1/4" Cable turned down to 3/16" Prop shaft
Large tabs

I already have a few questions right of the ripe......

1. Where should I place the motor? More to the front of the hull, middle or near the transom?
2. How do I calculate the COG?
3. Is the CF from KINTEC any good?
4. Should I be using 5/16" stuffing tube? (no teflon)


Now I have enough Lipo's to either run 5-10s2p. Was thinking about 10s2p but the Castle motor is only rated at 30,000rpm. And what prop are you guys thinking? Thanks

[6sHyper]

Cog is calculated as the distance from the transom. Most people tend to say around 30% is a rough etsimate of where you want to be in a vhull to start and then move your weight/batts around to dial it in.

your boat is 56" so the calculation for 30% COG would be 56x30%=16.8 inches from the transom, get it?? To set the balance point i just take a pair of T fittings and replace 1 end of my stand with them and when your boat is at the balance point it will literally balance on that alone. Of course when you test your cog make sure the boat is full of batts and layed out exactly how you plan on running it!

Hope that helps I just learned the whole cog thing myself!!

[m4a1usr]

Nothing like a plan coming to action. You got a good setup going together. I have my own opinions about your questions, so without first hand build experience it only my best estimate.

Do not use a liner in the stuffing tube. Bare brass tubing. It enough.

Keep the stuffing tube as short as you think it can be. Within reason. Maybe not on the absolute shortest side but if you can,........ keep it short. The reason is the flex will want to twist due to the loading. The longer the flex the more binding even with lube. Its not going to be a problem, but anticipate this fact. If I was doing the build it would be about 14 to 16 inches forward of the transom.

Use the typical center of gravity rules to get the hull running loose. You wont need any special rules to follow. But leave room for the batteries to move in case you prefer a wetter running setup.

I'm not sure your going to need trim tabs. Maybe. But I am not convinced they are needed with the power you are going to use.

And lastly for the prop? I would be willing to bet your going to be in the 64 to 68mm range. Maybe even 70mm. Your going to be running right along the RPM's where the gas guys are. Just google or search what they are running. You will see.

Again all this is just my 2 cents. Much more will come from those guys already in the know.

John

[crrcboatz]

Larger boats don't always go that far on the cg, aka cog. It is so much different with fe from gas so I hesitate to comment. My old 56 apache cg was 28% but hey with the batteries and all I have no info for you on this.
The old broomstick method for locating cg will never fail you if you can get a cg from someone that has run this fe. I would definitely call aeromarine or ask Chris aka Dasboata. He is very tight with aeromarine AND I am sure he has built many apaches over the years because he owns more aero stuff than any gas guy I know of.

[Boaterguy]

Is the motor rated at 30 000 rpm? or the motor itself, I would think about upgrading the bearings if they are only 30 000

[Rumdog]

You'll be nowhere near 30,000 rpm under load. don't sweat it.

[m4a1usr]

Is the motor rated at 30 000 rpm? or the batteries, I would think about upgrading the bearings if they are only 30 000

The motor is rated to a limit of 30k rpm by Castle. Not the bearing manufacturer. I bet its due to rotor design and mass. But an email to Castle will certainly answer that question.

John

[b.mcdaniel.2009]

Cog is calculated as the distance from the transom. Most people tend to say around 30% is a rough etsimate of where you want to be in a vhull to start and then move your weight/batts around to dial it in.

your boat is 56" so the calculation for 30% COG would be 56x30%=16.8 inches from the transom, get it?? To set the balance point i just take a pair of T fittings and replace 1 end of my stand with them and when your boat is at the balance point it will literally balance on that alone. Of course when you test your cog make sure the boat is full of batts and layed out exactly how you plan on running it!

Hope that helps I just learned the whole cog thing myself!!

Sure does Josh. Thanks

Nothing like a plan coming to action. You got a good setup going together. I have my own opinions about your questions, so without first hand build experience it only my best estimate.

Do not use a liner in the stuffing tube. Bare brass tubing. It enough.

Keep the stuffing tube as short as you think it can be. Within reason. Maybe not on the absolute shortest side but if you can,........ keep it short. The reason is the flex will want to twist due to the loading. The longer the flex the more binding even with lube. Its not going to be a problem, but anticipate this fact. If I was doing the build it would be about 14 to 16 inches forward of the transom.

Use the typical center of gravity rules to get the hull running loose. You wont need any special rules to follow. But leave room for the batteries to move in case you prefer a wetter running setup.

I'm not sure your going to need trim tabs. Maybe. But I am not convinced they are needed with the power you are going to use.

And lastly for the prop? I would be willing to bet your going to be in the 64 to 68mm range. Maybe even 70mm. Your going to be running right along the RPM's where the gas guys are. Just google or search what they are running. You will see.

Again all this is just my 2 cents. Much more will come from those guys already in the know.

John

Your opinion is worth more than 2 cents to me lol....
14-16" is pretty far forward I think. This hull is very nose heavy John. Does that info change your measurment? My hands were placed around an inch back from the begining opening of the hatch with just the batterys, motor and esc (see pic), if they weren't around thaat area the hull would fall on its nose.
I plan on building CF trays in the centery of the hull with velcro and straps for battery placement there and velcro along the outside of the rails so I can figure out if the hulls rides better either in the center or futher out.

Larger boats don't always go that far on the cg, aka cog. It is so much different with fe from gas so I hesitate to comment. My old 56 apache cg was 28% but hey with the batteries and all I have no info for you on this.
The old broomstick method for locating cg will never fail you if you can get a cg from someone that has run this fe. I would definitely call aeromarine or ask Chris aka Dasboata. He is very tight with aeromarine AND I am sure he has built many apaches over the years because he owns more aero stuff than any gas guy I know of.

Sounds good. thanks

[m4a1usr]

14-16" is pretty far forward I think. This hull is very nose heavy John. Does that info change your measurment?
Sounds good. thanks

Sure does. I dont have any big monos so what your saying makes sense. Have you tried the "roller balance" method as suggested? All you need to do is put the hull on a large enough flat surface, probably the garage floor, and using a short section of 1" or larger tube see where the approx motor location should go. Its cursary at best but it puts you pretty close. To make a final location you really should have all the hardware installed. At least the stinger, rudder bracket, turn fins and if possible layout the batts too.

You can cut and tape some foam on the bottom or sides to keep the hull from wanting to roll when its flat. To make it easier to gauge with that size hull you can measure off the transom and using a black marker put some tick marks every 1" from say like 8" to 14". Its a PIA otherwise trying to bend down low enough to see while holding the hull and verifying exactly where your balance point is.

John

[b.mcdaniel.2009]

Little update, installed 1/4" sting and SpeedMaster rudder. Havent received the trim tabs yet. Also waiting for the motor mount and jacket from Williams Racing and some CF cloth. Fitted the huge HiTec HS-5805MG servo with 308 onces of torque at 6.0V into a mount centering the 5" rails. Why center it, well decided to add another rudder step up for twins. I'll cover the balsa tray with CF. Will be also building another battery tray in the center over the stuffing tube and covering it in CF as well.

[Brushless55]

bro, that motor is fine on 10s
it was mind for 8-10s boat use
glad this one is in the build thread....

[Make-a-Wake]

Gonna be real nice!! Went back to my order confirmation e-mail from OSE to make sure what props i ordered for my 51" mono 2028 10s2p build i am starting. Here's what i have coming for mine:

Prather S240 Stainless Prop $16.95
Prather S245 Stainless Prop $18.95
Octura x460 $15.95

[keithbradley]

Gonna be real nice!! Went back to my order confirmation e-mail from OSE to make sure what props i ordered for my 51" mono 2028 10s2p build i am starting. Here's what i have coming for mine:

Prather S240 Stainless Prop $16.95
Prather S245 Stainless Prop $18.95
Octura x460 $15.95

I tried a s240 on my mono and it was way too small. LOTS of cavitation. The x457 was better but still a bit small. I bet the x460 works well on your 51 sir!

[b.mcdaniel.2009]

Gonna be real nice!! Went back to my order confirmation e-mail from OSE to make sure what props i ordered for my 51" mono 2028 10s2p build i am starting. Here's what i have coming for mine:

Prather S240 Stainless Prop $16.95
Prather S245 Stainless Prop $18.95
Octura x460 $15.95

Hmmm I already have those props to trySaweet.

[b.mcdaniel.2009]

bro, that motor is fine on 10s
it was mind for 8-10s boat use
glad this one is in the build thread....

Thats what in the info says here on the site. I'll try 8s for the first run. Motor and mount shipped out today, but still havent received my order from KINTEC RACING, not really worried thought. They have treated me good in the past.