PIP Bittburger (Re) Build

[keithbradley]

Just picked up this beautiful hull/hardware. It has a mount in it for a XL size motor, but I am going with a Leopard 4082/1600kv on 6s2p so I will be making some changes there. Initially Im just going to use the rear part of a mount for the Leopard motor on the mount that is already in the boat so I can run it and decide if I need to make any changes. I have a carbon fiber mount to go in it once I decide how I want to mount the motor. I may end up mounting the motor a little differently as I dont like the amount of bend in the stuffing tube.

[keithbradley]

[keithbradley]

[johnf]

Sweet, what esc is that?

[keithbradley]

I went ahead and put it together tonight...I'm not sure where I am going to want the center of gravity yet, mostly because I am more familiar with monos and Im not sure how cats are done...A couple inches of the rear really never even touch the water. If I start my measurements from the back of the ride pad my CG is about 30% so hopefully its pretty close. Its about at the center of the motor. I can easily move it by doubling up the batteries instead of placing them spread out like they are in the pic.

[keithbradley]

Sweet, what esc is that?

Its a Swordfish 240HV. The one in the boat is a ICE 160HV, which I will be running initially to take advantage of it's data logger when setting up the boat.

I plan on starting with a s220 prop and going from there.

[keithbradley]

Anyone have any thoughts in regards to prop? I would like to run something a little larger but I think at 35,000RPMs the s 220 will be a good strarting choice. If the amp draw is low enough I have a s225 and s230 here I can try. I am looking for a lot of speed out of this boat! Any help will be appreciated.

[JMSCARD]

Nice Boat Kieth!! where ever did you get it... LOL... glad it got there safe... and it looks like its gonna be covering the pond a little quicker then when it was in my possesion....

[keithbradley]

Took her out today. Ran on 6s2p with a knife-sharp prather s220. I wasnt sure how well this hull would stay in the water at heavy throttle with this setup.
It turns out this hull has better feet than any boat I have ran around this size to date. It was a little bouncy at light throttle, but she ran smooth across the water full out. Never had a threat of blowing over or flipping, and I was going pretty fast. I would say easily into the 50's without GPS-ing it. It "hops" when turning (i took most of the turns at lower speed because of this) so it isnt a killer there but it definitely runs well in a straight line. I will be making some SAW style runs with this hull for sure. I'm hoping it still stays on the water this well with a larger prop.

The only problem I ran into was after running it for a little while, it started acting strange (radio issues, motor cogging). I brought it in and it had a lot of water in it. I was a bit puzzled, being that I checked it in the bathtub and sealed up any problem areas I found before I ran it. The esc was cool, the batteries were cool, and the motor and water jacket were pretty hot. All of this due to the fact that the water inlet line had popped off the motor mount cooler. I guess that gets the inside of the boat wet pretty quickly! Now Im having issues getting it to work properly. The motor seems to cog or shutter when giving it certain amounts of throttle. Im thinking my pistix (that was laying in a pool of water) may be giving me some issues.

[keithbradley]

[keithbradley]

Ran her today on 6s2p with a s225 prop. This thing is fast and the straight line handling is awesome. I havent GPSed it yet but I've got to be close to 60mph and she just glides across the water nice and flat. I couldnt be more pleased with the straight line handling.

The turns, however, leave a bit to be desired. It hops like crazy when you turn. It loads and unloads the prop and just keeps smacking the water. It handles like a mono with no turn fins. Do I need to put turn fins on this thing to get it to handle in the turns? Its a very narrow cat and it handles alot like a mono...

[Rumdog]

Most narrow cats will do this in the turns. Scale looks equals scale handling. That is why with the scale boats, especially cats I go for all out straight line performance. Same issue with my Drifter.

[keithbradley]

Most narrow cats will do this in the turns. Scale looks equals scale handling. That is why with the scale boats, especially cats I go for all out straight line performance. Same issue with my Drifter.

I love the straight line handling, and Im pumped about the fact that she can take some more speed...I would love to push this hull to 70!
Its a big transition going from hairpin turns at 60+ with that 40" mono to hopping around at 15mph when turning with this boat.

Is there anything I can do to get it to handle or did this just become my new SAW boat? Ive tried changing the rudder angle but theres no way the rudder is going to keep it down.

Im also noticing that at higher speed it turns to the right quite a bit when I lift on the throttle. Im guessing its from the drag of the rudder...It's ofset to the right a lot.

[Rumdog]

look at my thread for the Drifter to see what I said earlier about the pulling to the right.

Turn fins don't work well on cats. On a mono, when it banks, the outside fin is out of the water. Not so on a cat. A little extra width goes a long way on cats. My Sprintcat was the best turning boat I've ever seen. 70 plus mph, right into WOT turns, and WOT all the way through.

[keithbradley]

look at my thread for the Drifter to see what I said earlier about the pulling to the right.

Turn fins don't work well on cats. On a mono, when it banks, the outside fin is out of the water. Not so on a cat. A little extra width goes a long way on cats. My Sprintcat was the best turning boat I've ever seen. 70 plus mph, right into WOT turns, and WOT all the way through.

You are refering to the prop lifting the left side under power though right? I am talking about a shrp turn to the right when I LIFT on the thottle. I think the drag of the rudder is making it go right when there is no prop thrust in front of it...you think? That or I could have a servo that gets scared at high speeds.