Genesis wants to twist and roll

[petej]

Hi,

I bought a new Genesis 37" cat from HK with stock rudder hardware. The rudder is in-line with the prop.
I installed a Leopard 4082 1600kv motor. I've been using an Octura m645 prop and a pair of 5S batteries, in parallel, mounted in the sponsons about as forward as possible.
The boat is very difficult to run as it constantly wants to roll (right), so it flips often (VERY).
I've tried adjusting the prop height (up/down) but no difference. Any ideas are welcome?

[Fluid]

How far ahead of the transoms (not the end of the hull) is the CG? Is there more weight on the right side (ESC, receiver, etc.)?



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[tiqueman]

We, meaning club members as well as folks Ive assembled hulls for, found that hull doesn't particularly like the larger higher pitched props. Its a common hull to lean a bit, especially under acceleration and will be upside down more often than not when exceeding speeds greater than 45. Try propping down and see what it does. When I had the genesis hull, I ran a 1600KV motor on 6S with a 442 or 642, cant remember, and it ran really well. My neighbor has one spinning a M445 prop, 1800KV on 4S and its got quite a bit of trq roll but straightens out once on plane for the most part.

CG as Fluid has recommended giving us a dimension is key on this hull as well. if its running too wet its impossible to get to handle. If I remember correctly mine was around 9" from the sponson transom.

[petej]

The motor, ESC, servo are all centered, between port ant starboard.
With (2) 3S 40C 3000mAh batteries I estimate the CG is about 14 inches from rear sponson transom. See the attached photo.Genesis motor, ESC, bats, servo mount.jpg

[jetnfast]

From what I can tell you have your batteries very far forward, which will affect your CG. If I remember correctly, the CG is 9.5'' from the second step. I have my batteries mainly centered under the hatch if that works for a point of reference.

[petej]

I'll try moving that batteries aft to get closer to a CG of 9 inches.
Would you explain how the CG between bow and stern affects or impacts the hull wanting to roll?

[lenny]

It helps with the added weight to the transom to keep it down and help with torque roll,
I think this hull likes the added weight of bigger packs in it and rides a lot better to.


Do you have any video's of it running in a straight line to see how it is riding ?
I have my strut level with the sponsons bottoms,
And running 4s2p with the cells 6"from the back hatch lip to the bow.
I am running a neu 1515 1y 2200 with a x442 and and a offset rudder,
Best speed so far was 57mph with 5800mah packs at the time.
I have pictures and video if you think they may help you.

[kwiktsi]

Same hull (Daytona), same motor running both 6 and 8s with a 642 prop and other than having to ease into it on 8s, I don't find torque rolling to be a big issue. I have to measure my CG for you tomorrow, the boat is packed away from my move. I do have the prop a little over 1/16 or so above the bottom of the sponsors, I found it did roll worse with the prop down lower and/or a bigger prop. My biggest issue was it would get rocking like crazy at speed (like a vee chine walking), especially on 8s, if I tried to run the prop lower and that got much better the higher I went with it.

[jetnfast]

Kwiktsi, what motor are you running to use both 6s and 8s? I am using an octura M445 with a FC3730 outrunner on 6s. I am thinking about cutting an X642 to try, the M445 seems slow to me....how are your temps?

[petej]

Yes, pictures of the inside of your Genesis, component layout would help.
I'll reset the strut to rest on the table-top, try a smaller prop (42mm, less pitch, ...), move weight aft and offset the rudder.

Thanks.

[petej]

Leopard 4082 1600kv motor, Seaking 180 ESC. I've tried 4S in parallel, 5S 4000 mAh, 30C, 40C batteries, in parallel, but it's a bit tight to get those big 5S packs in/out. Especially if the packs swell at all. The last attempt was a pair of 3S 40C 3000 mAh packs in series (6S). While the lightest packs I've tried, the wobbling, wanting to roll was worse.
Motor and ESC temps are cool, but the 4S and 5S batteries were working.

[kwiktsi]

Kwiktsi, what motor are you running to use both 6s and 8s? I am using an octura M445 with a FC3730 outrunner on 6s. I am thinking about cutting an X642 to try, the M445 seems slow to me....how are your temps?

Leopard 4082 1600 with detongued 642. Never had a temp issue on 8s, but I don't run it balls out the whole time either. I'll even run the same setup on 4s2p for longer run times at more controllable speeds. Run my pursuit with the exact same stuff and same way as well.

[lenny]

Hear the setup and strut and rudder combo,
I have not ran it for a year and need to shoot some new video's of it.

FC Daytona 017.jpgFC Daytona 019.jpgFC Daytona 022.jpgP1010322.jpgP1010312.jpg