Conquest first run - thanks for ose help

[GRAEME LOUW]

After all the help I received from to mention just a few FLUID AND RACE MECHANIC I bought the 2028 as well as the SW 300 esc with all the goodies from Steve and spent the last week building the boat and it had its first run earlier today.
I only tried the 462 prop as time was short but was only able to clock 88 km/h in rough waters.I do need to get my CG back a bit as well as adjust strut as nose of the boat ran very wet. I also found that the boat was fish tailing and I think it is because the nose was to negative in the water. By getting CG back this will raise nose and I hope raise speed and stop fish tailing. AM I CORRECT WITH MY THINKING. The telemetery has not been set up properly yet but motor ran at 29 deg c and ESC was cooler as well as the batteries. After running for 4 min ,not flat out I had used 55 % of 8000mah. Running 10 cell .What should I set the timing at
Attached a few pics
Cheers
Graeme
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[Rumdog]

How deep are you running your strut? Where is the CG currently at?

[GRAEME LOUW]

Hi Rumdog
The CG is at about 30 % and I have played with the strut starting at the driveshaft level with the bottom of the sponsons and going up about 6mm higher and also pushed the prop out at bottom but not much difference. I went out again last nite after work and pushed the batteries right back in hull but still the nose was too low.
I managed to get 90 km/h with the 465 prop but now the torque steer is terrible To hold the boat straight at full throttle I need about 60 % left rudder. This same hull had a Leopard 5698 last year and I got 100 km from her with same drive,rudder etc so what has changed to do this. Also I was running standard motor oil in the drive cooler and you could smell the oil after the run. The shaft runs smothly with no friction and I have a 3/16 gap between dog and strut
Your help is greatly appeciated.
Thanking you
Graeme

[Fluid]

If you actually did run for a full 4 minutes and only used 4400 mAh your average amp draw is only 66 amps, hard to believe. How were you running, all WOT, half WOT, no WOT? It sounds like your prop is running 'way too low, forcing the bow down. Set the boat on a table with a dead flat surface. Raise the strut so that the bottom is 10mm above the table and parallel to the table top. With the CG at 30% (that's ~33 cm ahead of the transom) you should be flying the boat off the water. You may need to raise the strut further but try 10mm first. And put the x462 back on, you'll get in the 100s when the boat is trimmed correctly. No point in just heating things up with too much prop.



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[GRAEME LOUW]

Hi Fluid
Nice to chat to you again !.No I did not do a full 4 min. I would do a run turn around come back at about half throttle and burn it again into wind,so I would guess it ran about 2 min at full 100% power. Yes if thats the way you set it up then I am far to low down. My strut is just above sponson level.
Tell me ,I have terrible torque steering and need about 60% left rudder to keep it stright but then the speed goes for a ball of ........
I cant run it that way ,do I offset the strut a bit or weigh the left side of the hull down to correct this.
I eagerly await your reply !
We have a long weekend here so I will do some playing and let you know. Do I really need to use a oil cooler for the drive shaft. I have teflon running in brass tubing as the oil is messy and stinks when hot
Thanking you
Graeme

[Fluid]

Graeme, I have never used an oiler on my flex cables, never needed it. I run all my boats without teflon liners and use a 70W synthetic gear oil which has an EP additive in it. Never had a heat issue, broken cable due to heat, etc. It doesn't stink after a run either. What lube are you using?

Raising the strut will likely reduce your torque steering, as will the smaller x462 prop. This will raise the bows out of the water and should help a lot. All the big cats I've built have had the strut offset 5 to 7 mm to the right of the center of the tunnel. Let us know how it goes this weekend.


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[RaceMechaniX]

Graeme,

Good to hear you got the cat built and running. It does sound like the nose is too wet and as Fluid pointed out raising the strut will help. The centerline of my strut on the conquest us up 13mm from the bottom of the ride pads. This seems odd, but this is common with the AM cats. Another point: did you sand and blueprint the bottom of the running surfaces? I found the ride surfaces are not great on the bottom of the conquest and did a lot of wet sanding to straighten the ride surfaces and make sure all the corners are sharp. This helps considerably.

Your battery placement looks good it the photos so I suspect its something else. If you have a larger prop you can try that as well, you are barely working this motor. Try a X467.

Also make sure you have at least 3/16" clearance between the end of the strut and the drive dog. I also noticed you do not have the skeg strut, this hurts and may be why you are having to give so much left rudder.

If you need further detail on the bottom let me know.

Tyler

[danielplace1962]

Your problem is most certainly the lack of a skeged strut. Good to have it 1/4" offset to the right also. Get a skegged strut and you won't believe the difference it will make. Tbe skeg will make it track straight so you cvan take out all the rudder trim and your speeds and handling will both improve. The Conquest hull needs the skeg.

[GRAEME LOUW]

Hi Guys
Thank you. I did run the boat twice over the weekend but same results so after reading your advise yesterday I have been hard at work rebuilding the conquest as you have recommended. The torque steer is making it impossible to get any speed as I need so much rudder to keep it straight and when I release the throttle if I dont let go the rudder the boat 360s to the left. This shows how much rudder I need. I have taken off the strut and will move it over to the right by 5 mm. The rudder was not dead centre when I removed it - It was about 2mm to the left so that also did not help. I am going to remove the drive shaft with the teflon liner and refit a smaller brass tube that fits the 1/4 shaft. The only reason I have not got a skeged strut is that when I ordered the goodies from Steve he had no stock so I ordered the non skeged one. I COULD NOT WAIT !!!!
We have a public holiday today so while the wife is out shopping I can get some work done
Will let you know how it all goes
Tyler please can you tell me how to sort the bottom of the hull out as after checking it the corners edges are not all that sharp,and could use some work. Do you paint the bottom of your hulls,or leave as from factory gelcoated
Enjoy your days
Cheers
Graeme

[Fluid]

Use some wet-or-dry 100 grip paper on a sanding block to flatten the bottoms of the steps. Wash off the paper often with soapy water and sand wet. You will likely sand through the gel coat - as long as you don't go through the glass you will be alright. You want the step bottoms flat and smooth, the edges will come out okay. Once they are flat, switch to 320 or 400 grit and smooth them. You don't want the steps to be polished, the finer paper will leave a good surface.

I am not certain what you mean by "the rudder was about 2mm to the left". Move the strut 5mm to the right of the center of the tunnel - measure the centerline. You can put an "S" bend in the stuffing tube after it exits the bottom of the hull to line up with the strut.

The skegged strut may be part of the problem, but I have run the hull without a skeg and it did not exhibit the dramatic left turning that yours does. But the skeg should help, as will offsetting the strut.



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[GRAEME LOUW]

I offset the strut 5 mm off to the right and picked the strut up 10 mm from bottom of strut to sponson bottoms. I also put the batteries right at the back of the hull but the nose still is too wet and the boat still pulls badly right. I have ordered a skegged strut that will be here in a day or two but that wont help with the nose down situation.I really dont know what to do. CG is right back and strut up. Speed today 80 km/h. Any other suggestions !Is the holding rudder to the left the whole time pushing the nose down !
NB I do have two water pickups ONE ON EACH bottom OF THE SPONSON about 12mm from transom They stand out 6mm proud of sponson. Could this be a problem ? I will flat out the sponsons later this week as recommended by Tyler and Race Machanix
I am really confused as to why the boat is screwing me around like this. Whats next as I am determined to show the gas boaters that electric is fastest !!!e
Cheers
Graeme

[Fluid]

Those water pickups certainly could be driving the nose down, as is holding hard left rudder. Your rudder has two pickups, use them and remove the sponson-mounted ones. Fill the holes and sand the sponson bottoms. Next try some positive trim in the strut by raising the prop end of the strut a couple degrees, that will also help to raise the bows.

Where exactly is the CG in cm from the transom?


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[GRAEME LOUW]

Hi Fluid
The CG is at 31 cm from transom right now,.The pickups are so small I dont think it would make any difference but I dont really know
I did try the rudder pickups but got so little water through I was concerned. Also the pickups are are the right side of rudder so I was concerned that when I turned one direction I would have no water circulation. Is this a problem ? What I was thinking is moving the motor slightly back when I change the drive shaft from the teflon system to brass tube only as recommended by Race Mechanix. By doing this I have more space to play with the battery allocation I dont have to place them right at the back of the boat.This same hull with the Leopard 5698 ran perfectly but the Leo was lighter hense the CG I got 100km/h with the Leo so I am sure the hull can do it.
I really do appreciate all the help from you guys as I am really new into the boating and want to get my setup correct and fast.
I have also got a rcmk hydolift 1100 and I have two TP 4092 that I want to build BUT FIRST NEED TO SORT MY CONQUEST OUT
Cheers
Graeme

[Rumdog]

A rudder with a longer standoff will help a lot in keeping the boat running straight. What servo are you using, and what linkage?

[RaceMechaniX]

Graeme,

If you have water pickups on the bottom of the transom and they are not flush with the riding surface you will experience all kinds of headaches as you described. I would switch to the water pick-ups in the rudder and fill in the sponson ones and sand them smooth. if you think you have low flow from the rudder use a small drill bit as a pipe cleaner and spin by hand to flush out any build-up in the rudder. Typically rudder pick-ups flow very good. Don't worry about the pick-ups on one side, unless you see very little flow coming out.

It looks like you are using a copy of a Speedmaster rudder. It will also be worth you while to buy a real speedmaster rudder with a straight blade and dual water pick-ups. The tapered blade you have adds lift to the rear pushing the nose down. I also prefer to short offset rudders for the AM hulls, I have tested longer offsets with poor results. The rudders close to the transom handle the best in my experience. This is how mine is set-up.

Also please post a picture of the bottom when you have a chance.

Tyler

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