miss geico bouncing problem!

[4343]

would extending the battery trays fix bouncing with more weight forward?

[tlandauer]

No.

[4343]

can you explain why please? what is causing this bouncing?

[tlandauer]

Sorry, had to step away for a moment, didn't mean to be abrupt. I wish I can explain, all I can tell you is that i put a 6 cell Ni-Mh battery in front of the motor to weight it down, did not make a difference, you know how heavy a 7.2v, 5000Mah pack is? lol...
I think the thrust angle of the prop and of course the where abouts of the strut is of utmost importance, plus i looked at my ride pads, they are not uniformed and the hull is also twisted some what. I put the hull on glass table top w/o the stuffing tube touching/jacking up the hull, I looked carefully and the L/R sponsons don't look the same as far as clearance to the glass is concerned.
I think with stock motor these problems get hidden, but as we push the limits of the hull, it flairs up and becomes more obvious, mine has a Leo 4082, 2200kv spinning a M445 prop ( also tried x642, same problem).
I just don't have the time next two weeks to do anything, now that I have done a complete build myself, I am no longer afraid of truing the hull and other things, will see what happens when I get done with the pads.
Have fun and keep us posted also!

[Make-a-Wake]

4343, sometimes the weight is too far forward................. move the batts back toward the rear of the trays. Many Cat experts have done this and it has worked, i had a friend try it and it worked for him too.

Too far forward means the tunnel is first catching air, then the front is too heavy to keep it up, so it goes back down til the pressure can build up again and lifts it.............then down................

[4343]

do you angle the strut down or just raise it to keep nose down on a catamaran?

[swanny454]

I have the same problem with the infamous "bounce" but I also have the left side of the boat skipping the backend out of the water. I am running a Ammo 1800 and a 120 swordfish esc. The boat screams and I have moved the driveshaft up/down and moved batteries forward and back and nothing helps. I have debated about Adding some ballast to the back end of the boat to see if i helps at all

[tlandauer]

do you angle the strut down or just raise it to keep nose down on a catamaran?

I feel this is one area where there is some confusion: I assume when people said "raise the strut" they mean to raise it w/o altering the angle. ( neither positive nor negative). I had to enlarge the long adjustible hole (make it wider, length wise is ok) on the strut so i can move up and down w/o being forced to tilt it. Get the strut height correct then make minor adjustments with the angle. ( positive or negative).
I remember one post suggested to shorten a tiny bit of the stuffing tube where it mates with the strut---same purpose. It is to do away with having to tilt the strut. Reason being that the movement is like an arc, to maintain the strut going straight up or down requires a bit of tinkering.
Now, as I always said: I could be dead wrong.This is not a disclaimer, but I realize I am not in the league with alot of the people here and could be giving wrong info.

[maxmekker]

Seems like just a few manage to hit the sweet spot on this boat and get a smoot ride. I'm not having any luck with it. Tried adjusting the stock strut,and then got the Kintec (v2) but I feel like it was little to zero help.

I did get it to run smooth once after the Kintec was on : With some big hardcase lipo's

http://www.youtube.com/watch?v=h9mL7OzMTE8&list=UURNlga8sE0qJBcPb_5FFovQ&index=31&feature=plpp_video

Here I'm testing diff strut levels affter the kintec was on.

http://www.youtube.com/watch?v=Pd0rElsUsZY&feature=relmfu

All I can tell is if I go wot straight it will bounche, but if I make a really big wide wot turn (almost no steering input, just a hair) it will run smooth, Let go, and straight run, it will bounch.

Also I feel like when I try to adjust the strut the tension from the (what do you call it) part that's on the boat, brass tube , (for the flex cabel) is so hard it will make a gap almost at once ( see pic , don't mind the text ) between the tube and strutt part, and I have a 'helluva' time sorting out my water issue wich I belive enters either there ore at the back of the prop.

http://www.youtube.com/watch?v=75ONVwNFm_o&list=UURNlga8sE0qJBcPb_5FFovQ&index=22&feature=plpp_video

but that's another story.

My friends stock Mystic ( only with the prather 220+ T180 esc) runs better than my geico do (bounch that is).

Not that I have not have any good runs with my boat. I have :-)

http://www.youtube.com/watch?v=O8zKMwrqEl0&feature=autoplay&list=UURNlga8sE0qJBcPb_5FFovQ&playnext=1

http://www.youtube.com/watch?v=v5SiQkL3XqM&feature=relmfu

http://www.youtube.com/watch?v=qXOKMOIRO-U&feature=relmfu

[Boat guy]

I made some home made trim tabs and it took out the bounce. Then moved batts and trimmed it out and it now screams w no bounce. If you adjust the strut to much it will bounce. W trim tabs you don't have to move strut way down to pull the nose down.
Think real boat, it you trim the motor down it pulls the nose down and stops bouncing but you lose speed. If you trim the motor up it bounces but goes faster until the bouncing slows you down. W the tabs I can play w the strut to get the best top end w little or no bounce. When I removed them, bounce came right back. Will be ordering real ones to be able to better adjust them. I bent a thin pc of alum and hot glued to back to see how it worked and bounce was gone. Then you can adjust batteries and strut to get top end back.
My 2 cents.

[4343]

hi, will you screw the tabs in to geico? will water come in back then? I thought when you raise the strut, it should bring nose down or angling the strut down will do the same?

[dana]

trim tabs are a band aid for poor setup. moving batteries forward is a waste of time….
the boat should be aired out and ride on the last couple of inches of the sponsons. sure burying the nose of the boat till bouncing stops will work, but is it rite? not really. you may be able to trim it out with tabs to get the most out of it with tabs, but it will never be as fast as it can be without them. just my two cents

[maxmekker]

Just wanted to show my friends pnp Mystic I set up for him. No honky tonky, just a prather 220 + T180 and some Nano's. It's a joy to drive it , no bounch , and fast with stock motor, and it has good run times.

I have only layd it flat agains the dinnertable and adjusted the strut then, batteris just place where I felt they would fit the best , with equeal space on each side of the battery tray, and it a good runner.

45-90c first, then 65-130c later in the clip. Abitt narrow, only had my 30mm on the dslr, but you get the idea how it runs. I really like the strut on the mystic, the kintec on my geico makes a lot more spray than the Mystic do.

http://www.youtube.com/watch?v=N55GDspMSXc&list=UURNlga8sE0qJBcPb_5FFovQ&index=1&feature=plcp

[Boat guy]

That may be true but it is much faster and stable now w the tabs, proof is in the speed. It was much slower bouncing and no amount of battery placement helped. Geico and mystic are not the same. Mystic has the off set rudder that some have said takes the bounce out of the geico also. To me it just seems to make drag, same as if you slightly turn the rudder and bounce goes away but you also lose speed. The strut placement will also chane depending on if you use different batts. Unless you want to always play w the strut tiny tabs solved all the issues. For those who give no advice other than tabs are for a poor set up, or did you have any "helpfully advise"?
Make some and use double sided tape that is how I started to see if it worked it did, try them see what happens. If you have tried every other thing and bounce is still there what do you have to lose.
As of now mine are just hot glued on back, will mount real ones when they get there. Will get back on that one. May keep what I have I can bend one more than the other to make up for the torque w the single motor. I also found I lowered the batt trays so the sit lower and angled to the outside. Mainly for bigger batts but think it made it turn a little better as well.

What worked for me only.

[maxmekker]

Do you have a pic of you're tabs on ? Maybe that is the key.

I will try to run my MG today, changed the inner tube + new flex last night to se if the water stay's out then , and then if it do, on to cure the bounch.
Glad my friend has no time running his Mystic Pnp right now, so all the lipos and boat are at my place , cure the geico and have fun with the mystic :-)