coopers shocker build #2

[Cooper]

Hey sirslash did you have trouble with your cc 240 speedo? If so what? The only problem I have is with one of them the motor rpm has a spike in the log, I know it's mot the motor running, bench testing confirms that, no matter what it always has a spike, run rps up to 48000 and the spike will read 80000! Looking at the throttle input, output, amps, voltage they are all flatlined. So I just figured it's a glitch in the logging graph? Everything else seems normal/fine, as for the speedos I love em! Really great to dial everything in. Did you try and waterproof them in anyway?

[srislash]

Look into the # of poles it is set for.I remember I had an issue with that.My speedo problem started with why I rebuilt my Geico,now Miss behavin'.I hit a stick in the water and logged a 450 amp spike.Not knowing this (or the damage to the hull) I ran again,on 5s this time and blew it over.I believe it got wet though didn't appear to be.I sent it in and they said they'd cover it .That was August as I recall.I will waterproof the new one as when I do that I never get water in the boat

[RCKong]

is this rudder going to be too far back for this cat? the leading edge of the rudder is 1-1/2 behind the trailing edge of the props. or should i use one that is closer to the boat?

I would say yes. I've always had better handling boats with the rudder up closer to the transom.

[srislash]

I would say yes. I've always had better handling boats with the rudder up closer to the transom.

And that's two whom have said this today.That saves me some experimentation.Thanks Kong.

[Cooper]

This boat is going to be used for sport and speed runs, saw, so with that info I'm not worried about handling as much at straight line stability, so is it still better to be closer to the transom for the rudder or further back for straight line?

[RCKong]

I always try to keep the rudder out of the prop wash. Also with it sitting back that far, it will put alot of stress on the transom where it is mounted. If (when) you wreck at speed it can act like a lever when the rudder hits sideways and snap it off or bend ( depending on what gives first ) at the transom.
just sayin...

[Cooper]

Ok makes sense, I have same rudder that is 1-1/2" from transom, probably use that one then. As for the transom it is modified with support. Epoxy with glass filled the 1/4" depression in rudder pad, 2mm carbon fiber plate across entire back transom, then 3/16" aluminum plate drilled and taped for rudder bolts. Not disagreeing with you about a target for damage from crash, I just thought being slightly past props it would be more stable. Leading edge of rudder is 2-1/2" behind trailing edge of prop and this is a wide boat so the rudder is 3-1/2" left/right from center of shaft, I thought that might be out of prop wash or just at the side cone of prop wash .

[Cooper]

Oh and look back in my pics of the rudders, which one would be better, longer or shorter, can always make it shorter, I think there is an inch or 1-1/2" that can be removed before it inter fears with water pickup.

[srislash]

If it were me I'd try the short one and see how it is,I'm curious.Tiqueman was seeking a large one when he had the first Shocker,but that was a single.That is Why I got the one I did.If your short one works fine I'll be a little quicker to start cutting mine.

Looks like good weather for the weekend here so I put out the boating call on the local forum.Maybe I'll step it up to 5s.

[Cooper]

Let me know, yea weekend looks good here too, bad thing is I have to go to Florida for awhile, too bad I couldn't take some toys!

[srislash]

Seems there is a boat club in every town down there.Is this weekend the swap meet at Ackerman?Where abouts are you headed?

[RCKong]

From what I've seen, some twins like alot of rudder for stability. I would use at least 130mm even for a SAW boat. Also if those motors are Ben's 1970kv Out runners, yull want more than 4s power for sure. Put 5 or 6s on em'... I ran Gens Ace 5300s 4s2p with CNC 445's, and tried 447's too. I pulled the set of motors I had out of my boat due to lack of speed. The class we invented to race these is limited to 4s power. Soooo, I installed CC 1515's 2200kv in my DF explorer cat, and now see the speed I'm looking for. I think these OR motors will probably rip with more power.

Is this weekend the swap meet at Ackerman?

Nope, the swap meet is on the 12th.

[Cooper]

Yes, i have run them with 8s also, with smaller props, forget what size, but she spins fast, almost 60000 rpm's! Motors are rated for 60000, that's not a setup that I run regular, just wanted to see what she would do, had to set the speed controllers to 80% throttle! Didn't get a speed on that but I might play around with that again, excessive cavitation , again that was just for fun once, I usually run that on 6's set up with 442 or 447's , have some 450 three blades in the works too, when I get back from Florida I will be finishing the shocker build and post more pics,

[Cooper]

rw boat shocker hull 057.jpg

while i was down in florida i stopped at graves rc, wow lots of planes on the ceiling! i decided to get another rudder so now i have the option of two cooling lines or one,

[Cooper]

also some pics of flotation, im not set on using noodles may use two part foam . have to wait to see what final weight will be.