Genesis build failing

[Juraj]

Yes the connectors are quite large What prop would you recommend ?

[Fluid]

Lots of issues, most have been addressed above.

- Too much motor Kv for that boat.
- No gap between the drive dog and the strut. Use a 4mm gap and lose the disc.
- Poor prop choice. I'd suggest a Prather 230 to start, maybe a 235 later.
- Water pickups, lose those. Either use the rudder pickup, or drill through the sponson bottoms as suggested.
- Skeged strut - cut it off.
- Strut position, hard to see in photos. You will probably want the strut level with the table and maybe up 2mm to start.
- More battery capacity will help some.
- Motor timing should be 15* advanced.

With some work you will get the cat running better.

.

[Juraj]

Thanks for all the tips , question why a 4 mm gap ? Wouldn't that push a bunch of water into the hull?
Also the prop you suggested is pretty close to what I got what's the difference ? And yeah I'll get rid of the pickups on the bottom
Thanks

[martin]

The Prather prop suggested is similar in diameter & pitch but your prop has 3 blades, the Prather has 2 blades which makes a big difference to unloading the motor. Re the gap between the dog & strut, if you have a 1 piece flex shaft you need a gap as suggested to take up flex wind up. But if your using the square drive 2 piece shaft then you don't need a large gap as the dog is designed to run against the strut.

[Juraj]

Oh I see yeah its a one piece so I'll make a gap
Thanks

[Fluid]

Your prop is 48mm in diameter with 1.9" of pitch? (1.9" x 1.9" diameter x pitch)

Or is the pitch multiplier 1.9? (1.9" x 3.6")

Prather 230 = 1.9" x 3.0"
Prather 235 = 2.0" x 3.2"

None are the same, but the biggest change is the number of blades. That hull is big enough that it will need a thrust cone at least 1.8" to 1.9" in diameter for decent efficiency, larger would be better but the Kv is so high....



.

[Juraj]

OK looks like I was wrong it says 1.8p 48mmx 86mm pitch

[olwarbirds]

My Genesis does not like 3 blade props. 642 prop Neu 1515 2200kv 6S 65-130c 5000mah gps'd 78 mph. Since I'm running a higher KV motor 45mm is most Im going to risk, for you the suggested prather 230 or x445 would be a good choice. My CG is more like 40%, but mine is a SAW setup, I have seen others mention that the cg is further forward on the Genesis than other cats. Fluid is right on strut, set hull flat on table with rudder and strut hanging over, raise strut 2-3mm to start, o angle...Some have had goodluck with the skeg type strut, I personally found its not needed if you set it up right and it does create drag. I'm also really surprised with that big 3 blade prop and those little connectors creating a bottleneck (impedance) that things are not heating up. You have gotten some great suggestions from the guys, now correct and you will have a rather fast boat...have fun.... DJ

[Juraj]

IMG_20140725_151433.jpgYeah the only 2 blade prop I have that's even close is a 42mm but that's pretty small , I figure since this motor is 100mm long it should have plenty of torque, I have just cut off the skeg and adjusted the strut and I'm gonna go out and see if its faster without it .
I'll do a GPS speed after every modification and then I will know what made the most difference. Why doesn't this boat like a 3 blade ?
Is it just more lift?

[Juraj]

OK well I just did a run without the skeg and it is definitely faster , but I can't go full throttle , the prop walk is too serious its starts to turn pretty hard . but good news is its up to 85kph

[Chrissharp]

If this boat is not running wet wont your water intakes be above the water line attached to the tunnel hull like that.

[Juraj]

Well I can't say for sure they are in the water but I think with my sustem I should be just about maxing out the ESC and the ESC is not getting over 50degrees ever most of the time its at around 42 , so I can only assume its getting plenty of water. But I am going to be moving the intakes to the bottom of the ride pad like was recommended . hopefully then with less drag I'll be hitting the 90s

[Juraj]

Well now just for the sake of science I have a 5 blade 45mm 1.8p prop I'm gonna try it see what happens. Hopefully I don't fry the ESC .

[Juraj]

Pretty similar to 3 blade but has much harder time getting on plane once it does it rockets off . guess I'll be buying a 2 blade

[kfxguy]

I would not run a 5 blade no matter what.