Genesis w/Turnigy 180A, Leopard 3270kv, 4s - only 50kph.. Low RPMS.. What is wrong?

[Fluid]

...I've seen multiple videos of people with my configuration doing 85mph+. ...

That is a large part of the problem, believing what you see on YouTube. Believe me, it is not easy to get 85 mph out of any 4S cat, period. I have held several catamaran records over the years, and the current official record for a 4S cat is 85 mph on a surveyed course, not made up by someone trying to fool you. The motor you have is not going to do it, sorry. If you copied a YouTube setup, too bad.

We need to know some basics like was the boat running freely on the back half of the sponsons or plowing, how hot does everything get after two minutes, etc. It is often difficult to diagnose problems from hundreds of miles away. The folks on this forum are FAR FAR more honest and knowledgeable than the producers of those phony videos on YouTube. They have been there, you have not. Don't dismiss them, or you may never get the help you need (rather than the help you think you want).

That said you should be getting better than 40 mph. Some potential causes:
Incorrectly labeled or faulty motor
ESC not giving full throttle
Bad cells in packs
4S1P packs sagging heavily under load
Running too wet




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[LarrysDrifter]

Sounds to me like youre lacking torque from the smaller motor and youre running props that IMO are too small for the boat, which are spinning to fast to get traction. I think its just a bad combo with the 37" hull, 36mm motor, and 38 & 42mm props and 4s voltage. I would change the motor to a 40mm and a larger diameter, higher pitch prop. I personally would run 6s depending on kv of course, but since you run 4s, use a 2000-2200kv motor as said above.

[jamie]

I had the same motor and a swordfish 200 running on 4S for speed runs only in my UL1. The amp draw is massive & no more than 2/3 runs max. or you will burn up something... Chances are the esc is way overloaded and not coping with the voltage drop or i guarantee you the answer is in one or more of the things that Fluid suggested... I only used it to get over 70 MPH with my boat and then retired it & the idea to focus on having more fun sport running. Build a 6S setup with 1600KV you will have a lot more fun trust me

[Rocstar]

Just for a comparison, here is mine running 57mph on 6S with 3730 FC 1580KV, T180 ESC, m445. Temps are cool and it's a blast to run.

http://www.youtube.com/watch?v=UbiLR_JiBY8

[Nosbig]

a 42mm prop on a 3674 is pretty big, even if you were running that setup on 2S or 3S (3S would be the highest I would run that motor for a hot setup).
Is there alot of bubbly sound? It could be the prop isn't biting.

[Fluid]

He said that the rpm was low: "Motor just not getting the RPM up...." If that is an accurate statement then propeller cavitation is not the problem......



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[lomdel]

I'm no FE expert, but I use the rule of thumb : Low Kv + High Volts = Cool, fast runnings. Aim for around the theoretical 30k rpm range, not 40k... Just my 2c

[oyvstok]

I found the problem. It was the ESC going into protect mode because of the voltage dropping in the beginning. When i got it going it went like crazy. Not much heat either. Was good with the 38x55mm prop and went crazy fast with the 42x66. Uncontrollable speeds at 42x66 prop and a bit more heat but still ran it a lot without problems. Read more about strut height and angle now and will try it with 38x66 tonight. Moving to brass tube pickup for cooling with bigger tubes and offset rudder later. This motor is crazy. Motor is not hot at all and it's a blast to run.

[RcMr1999]

What timing do you have and what was the best prop on that settup?

[gsbuickman]

newbies .....

[flraptor07]

You guys do realize this thread is 2yrs old?

[RcMr1999]

You guys do realize this thread is 2yrs old?

But I would like an answer anyway?

[gsbuickman]

But I would like an answer anyway?

This thread is dead, dude is still listed as a junior member, ie: not an active member.
Start a new thread. Let us know, what kind of boat your working on, how big is it, how fast are you looking to go & will it be a sport or race setup ?. Pics and/or videos will be helpful.....

[RcMr1999]

Ok, Thanks