2 Fast & 2 Furious Apparition cat going 82mph http://www.youtube.com/watch?v=Ote0y

[ALIENALESSIO]

New lipos on my Apparition Cat but having stability problems and rx interference, the run before this flip series registered
82mph with radargun but couldn't keep full TH, lake is too short.
Problems need help:
You can hear the motors cutting off and on, why ??
LVC cut off is at 2,8 volts, using a separate BEC
Stabilty problems, it flips over too easy, move CG forward more, give neg strut angle 2°, or air dam ??
Any suggestions will help maybe reach 85 mph

http://www.youtube.com/watch?v=Ote0yOIulxU&list=UU7tnMgDdaOI_gAUfyaLcfbw&index=1

[Fluid]

I set SAW records with mine, although it was a single drive. Fastest pass was 89 mph with a Castle 1515/1Y motor through official timing traps - not radar or GPS. Your lake is plenty big enough for well over 120 mph, you just need to learn to use it all.

I need to see what your transoms look like and this info:

Motors
ESCs
Packs (exact description)
Props
Current CG (from sponson transoms not the extreme back of the boat)
How high above the sponson bottoms are the bottoms of the stingers?




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[martin]

Fluid on a separate question on the Apparition that uses negative angles on the ride pads, is this a good idea over altering them to be in line from front to rear. Thanks Martin.

[ALIENALESSIO]

Hi and thanks for any help,

the motors are 4168 Trackstar 2560kv car motors milled to fit Leopard water jacket
Esc are Turnigy Marine 180amp ESC timing on 15°
Lipos are 2x 4500mah 65C A-spec
Props M447
will have to measure the CG distance from transom, it's about 30% total hull length, the stingers are at 0° and aprox 2mm from bottom of sponson
Will have to check measurments as you requested, never really have taken those measurements
I can take a picture of the transom and enclose it, any particular spot ??

[ALIENALESSIO]

I noticed the steps on the Apparition are not level, the first one starting from the front is as high as the last step, the middle one is lower. Is it designed like that for any
reason or a fault in the fiberglass stamp processing.
What do you mean to be in line from front to rear ?? Negative ride pads, maybe I measure mine wrong but mine seem 0° in line with the stingers.

[ALIENALESSIO]

Oh I know the lake is big enough, I was really joking on the size of it, but buoys distance we usually ride the boats between seems really short at those speeds.
It was kind of unexpected to go that fast, fast yes but I'm not used to that fast. Is radar gun not accuarate ?? Only point is that my gun takes speed only really close

[martin]

If you sit a straight edge from front of the hull along all the ride pads the middle & rear pad has negative angle (higher at the front of the pads ).

[ALIENALESSIO]

If you sit a straight edge from front of the hull along all the ride pads the middle & rear pad has negative angle (higher at the front of the pads ).

So you are telling me to change the ride pads to be straight from the first to the last.
Glue 1mm wood strips to ride pads and sand them so they are straight front to back ?? I have to fill the gap in the middle pad
since it's higher than the othet 2 pads or should I sand the other 2 to make those higer and leve to the middle ??

[martin]

No im not telling you to do this, that is why i asked fluids opinon on making the pads in line.Theirs an interesting disscussion ongoing at the moment where tigueman on this forum debated on in line pads against angled pads. Different hull i know as it was a Cheetah cat that he was not happy with its handling & thought it may be the angled pads. So altered them to inline & said the improvment was very good, theirs a vid of his boat with the mods done.

[Fluid]

Fluid on a separate question on the Apparition that uses negative angles on the ride pads, is this a good idea over altering them to be in line from front to rear. .

While in theory they should be flat from side to side, but in practice it doesn't seem to matter. Most I've seen have negative dihedral (highest in the center), but my hull has positive dihedral! I'd just make certain they are flat and smooth and let the dihedral be unless the boat just doesn't work.

You DO NOT want to change the step angle front-to-back or change the depths! To work steps have to have an angle of attach, and the angle on these hulls works.


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[martin]

Fluid how critical is the pads being flat on the Apparition accross the width, the hull i have has a high spot across the pads. High spot is in the middle of the pad when a straight edge is layed across the width of the hull.

[Fluid]

LVC cut off is at 2,8 volts, using a separate BEC.

The T180 controllers are notorious for cutting out. Disable the LVC completely, you won't be running long enough to over-discharge your packs.

Esc are Turnigy Marine 180amp ESC timing on 15°

If the motors are Y winds, go to 20* advance. If they are D winds, drop back to 0-4*.

Lipos are 2x 4500mah 65C A-spec

How many volts? 1P or 2P?

Props M447

Stock L+R? Detongue them.

will have to measure the CG distance from transom, it's about 30% total hull length

This may be the blow-over cause, the CG is probably too far aft for the prop position. I never used an air dam but no reason you couldn't if needed.

I can take a picture of the transom and enclose it, any particular spot ??

A few side views showing the stinger and prop positions would be good.

Practice starting your runs near the end of the lake, not hundreds of meters short of the ends. Stand in an elevated position to see the boat better. It can take awhile for the props to fully hook up as the boat accelerates.


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[Fluid]

Fluid how critical is the pads being flat on the Apparition accross the width, the hull i have has a high spot across the pads. High spot is in the middle of the pad when a straight edge is layed across the width of the hull.

The pads must be flat both across and front-to-back if top performance is desired.




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[Chilli]

Stabilty problems, it flips over too easy, move CG forward more, give neg strut angle 2°, or air dam ??

Probably yes to all of the above. The water you were running in was a little choppy when you crossed the launch area and over your wake. When you get to a certain speed anything that lifts the bow such as small waves, a roller or gust of wind going to result in a blowover. Stay out of the chop. When you get that glitch taken care of where you can get a solid run up, you'll probably find you have some more speed in her without doing anything. Try using a reciever battery if you are not already and disable the low voltage cut off (BUT KEEP YOUR RUN TIMES SHORT)

On my SAW Fightercat River 32,I started with a CG of about 35% (measured as Jay described) and neutral on the strut. Once I hit mid 70's I added an air dam. As I went faster, I had to keep moving the CG forward. Strut height was dependant on what prop I was using. When I hit mid 80's I went a degree negative on the strut. All these adjustments were made over a dozen trips to the pond, two SAW events and probably about 30 blow overs. Keep going to the pond and experimenting.

[ALIENALESSIO]

Thanks I will give it a try starting from CG more forward, no BEC and no LVC. How high and where evntually goes the airdam, I rwead its just a lexan 90° strip glude to the transom side to side but have no idea how high and wher I should position it.