Prop Q.

[chirotray]

This may be a dumb question, but could somebody explain "detounging" to me. I know which part the toungue is, but dont understand the benefit of cutting it off. (which is what i assume detounging is, but dont know)

[Raydee]

http://rcboat.com/prop.htm

Read Area'a to cut.

[chirotray]

Thank you very much.

[egneg]

The reasons behind this are a give and take situation. You will get a better top speed but sacrifice low end acceleration. There are various degrees of detongueing depending on the variables for your hull and what you most want from it. The stock props that are offered have many variations available without modifications being needed - unless you know exactly what you want and why.

[chirotray]

Ok, im starting to form some ideas here....thank you for the education guys. One more question......hi-lift props, do they just lift the ass of the boat up? And do they have any place on a cat, or just on hydros?

[SweetAccord]

A high lift ia a prop which tends to lift the transom when the boat is running. Lift is great for a hydroplane but is usually unwelcome in a mono. Cupping is a curvature added at the props trailing edge, normally very slight, towards the blade center, shaped like a spoon. It reduces cavitation and maximize thrust, increasing the effective prop pitch. Additionally, it lifts the bow and narrows the thrust cone. Cupping has to be equal in all blades, or you will have an imbalanced prop, that may load up the motor. Maybe the question could be, "Why would you want to do this in the first place?"

Prop mods are usually done because of the intended use or to improve perforance. However - not all series props require modifications for good general use. For example - the X Series props with the tongue removed perform much better when used in surface applications. With the higher power of todays BL motors and inproved cells - this mod can increase boat speed.

At slow speeds - the tongue bites the water quickly, which is a good thing. But at high speed, the tongue causes drag and disrupts water flow. Removing the tongue, if done correctly, will increase the prop rake and consequently increase overal pitch. This mod for racing props because of the effects of reduced blade area is ideal. It's been recommend staying away from lifting props unless modified by a professional. The props recommend for consideration are as follows:

• Octura X-440,
• Octura X440/3,
• Octura X640,
• Octura M440;
• ABC 40X53,
• ABC 40/52/3,
• Prather 215, 220

Secret: If you are going to get into modifying a prop this will help. Spray machinist die on the props. Run the boat several laps and bring it in. Look at the color of the die on the props. The areas that have the die removed are doing the most work. The dark areas are areas that improvement can be made and/or material can be removed. The ideal prop would have a nice even area of die removed. This would indicate that the entire blade surface is working together to move the water. Also will show if one blade is working harder than the other.

Hope that helps.

[chirotray]

Where do cats fit in there?

[tth]

If You Use Octura "m" Series Props They Have A " Less Exaggerated Tongue". Like The M440 The Only Reason That Your Boat Would Need A Detongued Prop Is If Your Motor Wasn't Revving Up Like It Needed.

[chirotray]

Wow, you ask and you shall receive......you guys are better than an instruction manual! The reason i ask all this, is I have a blackjack, and im not seriously racing, just me and a buddy with an sv trying to one up each other every week. It seems the popular prop is a detoungued x642. And theyre currently hard to come by. I do however have a mistakenly ordered grim 38x63 lifter. Im trying to figure out if its worth the twenty bucks to give it a try. Any opinions on that scenario???

[SweetAccord]

I'm not familiar with Cats too much, but can say three bladed props are more often used on cats and hydros, because they produce more lift. Basically any changes mentioned would have more of a dramatic effect on a Cat than a V design.

[chirotray]

I'm not familiar with Cats too much, but can say three bladed props are more often used on cats and hydros, because they produce more lift. Basically any changes mentioned would have more of a dramatic effect on a Cat than a V design.

Thank you man, youve been most helpful!