Some problems on 5S.

[Eggy]

Just went out for some runs with the fullers hardware. The water was crystal clear so i was hoping for good runs.

At 4s the boat looked good, and where stable even with WOT doing around 30Mph.
But when changing to 5S i encountered some problems.

First of i am not able to hit full trottle right away, when giving full trottle the prop starts spinning for about a sec and then stops, i have to gently press the trottle and then slowly start building revs. This problem happend after changing to the fullers hardware. Workes like a sharm on 4s but not 5s.

Also when passing 40Mph the boat starts to get realy unstable. Before changing to the fullers i where getting good and stable runs at 45Mph, but not anymore.
It looks like the right side is sticking lower into the water than the left, even when having slightly heavier lipos on the left (added some lead to the 2S packs so they are about 60grams lighter than the 3s) I might think that the rudder may couse the boat to be unstable. The rudder is a bit loose so might be the problem, any other ideas?

[domwilson]

Is this the Stock ESC? Are you running a receiver pack? Do you have pics of the new installation from the back and side?

[Eggy]

Stock ESC, temp never been above 110F on the ESC it self and 120F on the Caps.
Using the Castle BEC. Will get some shots from the transome in some hours.

[domwilson]

Try reprogramming the ESC. I've heard others say that they sometimes need to be reprogrammed with 5s.

[Eggy]

Ok, will try that. How do you other guys using fullers hardware sort out the rudder? Do you run with it when its a bit loose or have you done something to tighten everything up?

[Eggy]

Got some pics of the transom. They are not the best, taken with my phone becouse the other camera was out of power. Let me know if you spot anything and tell me if i should get the other camera to get some better pics.

[Flying Scotsman]

One thing, I note is no gap between the prop and the strut, you should have at least a 3mm gap.

Douggie

[domwilson]

One thing, I note is no gap between the prop and the strut, you should have at least a 3mm gap.

Douggie

I noticed that too. And you may want to raise the strut up around 3/16" and make sure it is parallel with the bottom of the hull.

[Eggy]

Ok, will sort out those things, there is a small gap between the strut and prop, but only 1mm and not as much as 3mm.

But can this two things couse the boat to get unstable at 40Mph as far as i can see this things is only preformance issues and will not couse the boat to get unstable.

Have also tried reprogramming the ESC to sort of the trottle issue on 5s, but did not work. Will try to set the Low Voltage Cutoff to Low to try if this might be the fault.

[domwilson]

The strut height and angle can affect stability as well as performance. On the rudder being loose, is that up and down or wobble. Somebody else on here had the same problem and said that a couple of washers on the rudder shaft fixed the problem. Have you tried running without the turn fins?

[Eggy]

The rudder wobbles a bit, think i have sorted this now by placing a small spring washer between the rudder and the mount for it.

Have not tried running without the turnfins. But i dont think that is the case here, ran a stable 48Mph run with the outdrive and turnfins once and after that i ran several Mid 40 runs so the turnfins should be fine.

[LiPo Power]

Higher the speeds, more precise your turn trim angle have to be. I noticed that you have them bent inwards. Make sure they are the same angle. My fullers rudder was loose on its mounting point, bushing, when my boat was doing exactly what yours is doing on high speed. It was sent to Mr. Huller for rework and right after rebuilt there is no more crazy bouncing left to right. Eliminate any play on your rudder to servo connection. All of the above will get you 50.
My 3 cents.......

[Eggy]

As i said above, ran a stable 48Mph runs and several stable mid 40 runs on the turnfins with the outdrive so they should be fine. The angle on them are the same.

I will work on the rudder, i will bet that's what's making the boat unstable.

[Flying Scotsman]

Another point remove the dual water pickups and go with the rudder method

Douggie

[6S HYDRO]

to much disruption of flow off the prop with those big water pickups- i agree the rudder pickup is not enough flow- it only flows in turns. but yours are too big- use one and line it up w/ the rudder so you only have one drag point not 3

[6S HYDRO]

T it off if you need 2 seperate cold hoses

[Eggy]

I have raised the water intakes about 1" so that they are at level with the top of the prop now. Will try it like this before going down to 1 intake. Temps are a OK now, getting tops 120F on the caps, but i think that if i reduce it to one intake the temps might climb a bit and could be seeing 130F on the caps.

[6S HYDRO]

add a 50v 1000uf cap from radio shack and your caps will stay cool as a cucumber

[Eggy]

Will look into that later, will first try some runs with the intakes raised and tighten the rudder so it does not wobble.

[Flying Scotsman]

to i agree the rudder pickup is not enough flow- it only flows in turns.

Bollocks!!

Douggie

[6S HYDRO]

Bollocks!!

Douggie

english please

[Eggy]

The rudder is for sure picking up water on the straits as well. When i dont block the top of the rudder i see a clear stream of water standing about 7-10" up from the rudder. I will try some different options and see what workes the best:

- Two pickups and forget about the rudder pickup
- One pickup in addition to the rudder pickup
- Only the rudder pickup split with a Y.

english please

Bollocks = BS, BullS***

[6S HYDRO]

try taking off the tubes and running the strait pickups open and watch how high they spew, guarantee 4-5 times the height. hence way more flow in the straights

[Eggy]

Did some runs today and looked good. The water was nice and clear and almost no wind.

Did tighten up the rudder with a washer, raised the water pickups about 1" and raised the strut about 1/8", worked like a sharm. Clocked the boat in at a topspeed of 48.4Mph so i'm back on track now. It was dead stable at that speed, some playing with COG and strut and 50Mph should be next.