Prop Selection....

[OffShore_RC]

I will be purchasing a formula 1 tunnel hull boat (Hobbyking H2O style Formula 1 Tunnel (https://hobbyking.com/en_us/hobbykingr-h2o-style-650ep-formula-1-tunnel-620mm-arr.html?___store=en_us)) and the very first thing I would like to do is to upgrade the plastic prop. but having been out of the RC boating scene for a while, I am not sure what to look for when selecting a prop for a particular boat.

If it helps, the length of the above mentioned boat is 24 inches (2ft), same length as my proboat Apache.

Any advice would be greatly appreciated so I can learn :smile:

[MadProps]

that motor comes with a nylon 28mm 1.4 p 3 bladed prop.
if you cant choose a prop from that..... one of us can recommend an Octura and you will need a 4mm to 3/16 bushing from OSE

[OffShore_RC]

Please correct me if I am wrong, but nylon props are essentially plastic right? They will break eventually? I am not going to be racing it off the bat, just going to turn down the throttle on my transmitter and then just run it slow and easy until I get used to the handling.

[NativePaul]

Yes nylon is a plastic a rather floppy plastic that makes for pretty inefficient props, and it will eventually break. Much better are the Graupner 2318 series props, they are still plastic and will break eventually, but they are carbon reinforced plastic which is much stiffer and makes for some of the most efficient props available.

If it is of decent efficiency a motor that size and KV should be able to spin an Octura X435, X632, or Graupner 2318 36 for sprint type durations. If you want longer runtimes an Octura x430 or Graupner 2318 31 should give you about 5 minutes on 3s 2000.

You would need a new driveshaft not an adapter to run Octura props as all the suitably sized ones are 1/8" bore, and cutting down an x438 (the lowest load Octura 3/16" prop) doesn't reduce amp draw to 1/8" level until the blades are tiny and all the low end thrust has gone. Whereas the Graupners are 4mm threaded, as are many CNC Props.

[MadProps]

sorry about that ..... no bushing needed with these props

http://www.ebay.com/itm/4mm-VXP-FAST-Upgraded-X-Series-32-40mm-1-4p-CNC-Prop-EP-Electric-Boat-Octura-M-/171932968902?var=&hash=item280800e7c6:m:malgyJL-DpHSbknK8UibWLQ

http://www.ebay.com/itm/4mm-VXP-FAST-M432-32mm-1-4p-De-Tongued-X432-CNC-Prop-EP-Electric-Propeller-/311454459735?hash=item488421e757:g:oWoAAMXQ9MVRf49 U


https://www.offshoreelectrics.com/proddetail.php?prod=tfl-5b11x35

I will take mine apart and see if a shaft upgrade is easily doable

[OffShore_RC]

Does Pitch matter in a prop?

[MadProps]

Does Pitch matter in a prop?

Pitch is defined as "the distance a propeller would move in one revolution For example, a 21-pitch propeller would move forward 21 inches in one revolution

lower pitch will give you a better hole shot where as a higher pitch will deliver greater top speeds, but slower acceleration but you will need the power to push the higher pitch props

[rol243]

an easy way to answer about Pitch is ; if it hasn,t got any it won,t move. a good example is a helicopter as when there sitting on the ground with the rotor blades spinning there is no pitch but as soon as pitch is added the heli can lift off. i would buy a nice metal prop the same size as the recommended one on boat now as the boat will go better than the plastic / nylon prop.

[ray schrauwen]

You can use graupner threaded carbon props on a standard 1/8" threaded stub shaft if you drill through the brass and plastic with a 7/64" drill bit and use the plastic like it's a nylock nut. I've done this long ago. Use a fresh drill bit.

[Nevs]

1,4-1,6 pitch is safe. Past that..It becomes "sensible". Meaning that if you got just a little to much drag. You will loose any speed.

[OffShore_RC]

an easy way to answer about Pitch is ; if it hasn,t got any it won,t move. a good example is a helicopter as when there sitting on the ground with the rotor blades spinning there is no pitch but as soon as pitch is added the heli can lift off. i would buy a nice metal prop the same size as the recommended one on boat now as the boat will go better than the plastic / nylon prop.
That's a good way of putting it. One of my step sister's husband is a helicopter pilot IRL and I am an aviation nerd :biggrin:

[OffShore_RC]

When choosing a prop size, should you get the same size prop as it comes with? In other words, how do I choose the right size prop?

[Nevs]

Just to "keep the picture"..if you have a heli with maximum pitch (90 degrees)..You will have no lift of..

[zooma]

Just to "keep the picture"..if you have a heli with maximum pitch (90 degrees)..You will have no lift of..

No, but lots of torque.