Prop where to start.

[wamf]

I have a new boat, it's a bby oval master 21. I will be running a 2s lipo with a 3000kv bl motor. Supposed to weigh about 2.5lbs all done. Looking for speeds in the low 20's. What size prop should I start with?. I did ask Randy but his recommendations were based on what he had on hand. I have a x431 and the purple plastic octura , whatever that is.

Thanks
MikeV

[Rex R]

the standard answer is start small and work your way up . I'd start w/ the (red?) x431, incidently all octura props(that I've seen) have been marked for size on the propnut side of the boss. I would imagine that a 432 or a 632 might work well.

[Eyekandyboats]

431 is to small.
look at a 435 and up.
i run 2s in a 3600 kv boat and i spin a 637 and a 640 which is a custom job

[D. Newland]

Please post the exactly what motor/ESC and battery MAH you are using. There's a ton of info on the BBY OM 21 out there/here! It's been a very successful FE hull for many years.

[wamf]

Please post the exactly what motor/ESC and battery MAH you are using. There's a ton of info on the BBY OM 21 out there/here! It's been a very successful FE hull for many years.

Its a feigao 540S xpower 70amp with poly rc 4900mah lipo. I didn't see much info on the boat out there. I want a long run time
MikeV

[D. Newland]

To clarify: the information "out there" is probably more in the heads of FE people, not necessarily posted on the boards.

But, I may have spoken too soon, knowing your motor selection. Not that that's a bad thing since you're looking for long run time.

Is it a 12S Feigao motor? Are you using a 1/8" prop shaft? If so, the X435 2 blade is a common prop for that hull. The fact that you're running a higher wind motor will help greatly with your runtime.

You'll need to be very aware of your runtime the first few runs out. Use a stop watch and record your runtime AND how much MAH you charge back into your LiPo's.

Start with a 1 minute run, check your motor/esc/cell temp's and if all OK (warm to the touch-not hot), go for another minute. Check temps again and put your pack on the charger. See how much MAH drain you had. That will help you figure out your amp draw and how long you can safely run your setup and not damage your equipment.

Post your results here if you need help with any amp calculations.

[wamf]

Thank's for the help. Yes it is a 12S Feigao motor with 1/8" shaft.
Mikev

[wamf]

I finished my bby oval master 21. Using the feigao 12s 2958kv motor. xpower 70amp esc. Ran with a 431 red and it would top out at about 20mph not get very hot ( hold for 30 seconds+ ) after 10 min but take 20 feet to get going. With a 634 it was closer to 30mph got hot quick and accelerated right from the start. Aluminum 432 ran well but took almost as much distance to get on a plane a little hotter than 431. The 632 jumped at the start ran in the mid 20's but got kind of hot fast,( could hold for 7 seconds) Any sizes in between That I'm missing.
MikeV