Wet-N-Wild

Can someone tell me why there is cupping of the prop? I work on and build full size boats running in the area between 75-97mph depending on the combo, so I know about real props and cupping and pitch and all the effects, but is it the same on these small props as well. A prop with no cupping and you will run a higher rpm then with cupping. Running no cupping and more pitch to bring down the rpm in more speed affective on real boats. Is this true with the RC gas props? I'm starting to get into balancing a sharpining and would like to know if the values are the same as real props before I start so I can experament.

lildude2599

You asked a question that you no the answer to. Ask yourself this is this a real prop? Yes but the power is alot less.

Scott Schneider

In layman's terms, the VISCOSITY of water is fixed, but it is all Large or small boats have for prop traction. Too LARGE heavy boats water is fairly thin, and getting an effective hook up too it is more difficult. Smaller lighter boats find that relative too there size & weight water is thicker and offers better bite.
Tricks in getting better efficiency out of a prop really cater too the smaller size boats .... this is why altering a props pitch & cup is so much more effective with the models.

Prop RPM also effects greatly the changes we can do for greater efficiency.

Here is an ideal tool to explore this realm: .... http://www.modelgasboats.com/Magazin...ping_Tool.html

Wet-N-Wild

In real boats you do not want any cupping so there is less turblance in the water for the next blade, you want the prop to slice the water so you give more pitch to increase the speed and drop or increase the rpm to spec. Is this true in these boats?

Dan S

yes, it is pretty much like the real boats.

you can play with more pitch, less pitch, more diameter, less diameter all this to try to gain the best performance.
just like the real boats the HP available will also help in the selection of a prop, including prop material.

you can also add cup or remove some cup.
you can also play with the props tongue and ears, removing the ears will unload the prop therefore making it possible to spin a prop to which in its original form the engine would not have been able to spin, for example an Octura X440, removing the ears will now be an M440 and so on.

so like you said in your first post, its the same thing but on a smaller scale.

Dan.

Wet-N-Wild

I guess is what it comes down to is cupping a big deal or not? is there advantages? what are they? what are the dis advantage of no cupping on a prop?