Prop mod Questions.

[rcboatlover]

I just bought some new props and have a few questions about doing mods to them.

First question is about taking some of the tongue off. Should this be done to almost every prop? Or only if more RPM is needed? Seems like every prop I see has it done.

The second is the bar cut. Most guys cut a notch in the trailing edge by the hub, but can I taper the trailing edge from the end of the prop all the way to the hub? It would start as the stock edge and slowly get deeper untill it reaches the hub.

Hope this all makes sence!

 

[AndyBrown]

Cutting the tongue can benefit some props on some boats. This is not a straight across the board benefit for everything.

Same thing for the Barr cut. I used to do that cut many years ago on some props but prefer the tapered back cut. But again, not most of the time.

If you are seeing these things done to MOST of the props you see it is mainly because it is IN STYLE in your area and not because it is the best thing to do for every situation.

Now if you see the fastest boat at your pond that is just lke your boat, then I would definately do the prop the same.

 

[nitrotoys]

You didnt even say what boat, or power plant your going to use.

Give that info, and maybe there is a stock prop with little or no tweeking will work.

I have a few stock props that work just fine for me.

Others are modded, Most all tongues been cut off.

bar cut basically unloads the prop some for more RPMs, But again, its for what your using it on.

Tom

 

[rcboatlover]

Thanks for the help guys!

I diden't mention a prop, boat or engine because I wanted to know more about modding props, not what mod to do, but how to do it. But since you asked... the prop I'm working on is a X470/3 for a Twincraft with a Hanson G23. I tried a friends stock prop and liked it, but I lost some speed. That's why I want to cut the tongue down and then back cut it if that's not enough.

Andy I see there are two different names and methods for cutting the trailing edge. So the bar cut is a notch by the hub, and back cutting is tapering the cut to the end of the prop. Thanks, that really clears things up! My next question is if there is a difference between the two?

 

[nitrotoys]

Just remember the fastest boat dont always win the race.

 

[AndyBrown]

For props with large trailing edge cup, the tapered cut will reduce the load the most. This is because you will remove a little blade area near the tip which is the part of the prop that works the engine the most.

Always nice to have speed on reserve when you need it.

 

[nitrotoys]

Andy, Speaking of props, Have you started to carry propshop props?

I heard you were to start, and didnt know if you have or not yet.

Also if you are carring them, are you modding them also?

Tom

 

[Chris Wood]

Has anyone played with cupping pitching what ever you want to call it the leading edge of blades??

is there a trick to it and does it work

and do you then have to go back and pitch the trailing edge to equal them out??

thanks

 

[nitrotoys]

I have spooned the tips on a few props, give you some gains, on some boats.

Mono worked great, On a cat, Bogged down. same engine.

I think before you start modding props, you need to see what your boat does, and then tweek here and there, and retest it, need to use gps or something to clock speeds, and if its a gas engine a tach.

For a gas engine you want to mod your prop for the power peak of the rpm range, and what your top speed does as well.

 

[AndyBrown]

Tom,

We will have a Stock of Prop Shops soon.

Yes I have some experience modifying those props for the Gas boats.

We will also carry some of the smaller sizes to cover a range of Nitro boats.

Get your orders in before the spring rush hits.

Andy

 

[Don Ferrette]

"Get your orders in before the spring rush hits."

Andy ain't kiddin' about the spring rush thing. I'm surprised he has any fingertips left by mid season............

 

[Mark Anderson]

I did 470x3 for a local gas guy that runs pretty good. It is back cut .100" and then cupped till the motor liked it. We did not try the prop stock as we had good data from others that indicated the back cut helped.

Mark

 

[Don Ferrette]

I did 470x3 for a local gas guy that runs pretty good. It is back cut .100" and then cupped till the motor liked it. We did not try the prop stock as we had good data from others that indicated the back cut helped.
Mark

I remember doing about the same thing as Mark to a 470/3 for a guy running a gas mono, worked real well. I'd give Mark's recommendation a try.

 

[rcboatlover]

Sounds good! I know the stock prop is going to be too much for my engine, so I will back cut it alittle and thin it out. After that I will just have to wait till the ice clears so I can give it a try!

Hey what is a Texas cut?

 

[[email protected]]

Dremel used to sell these flat black rubber pads that you stuck sand paper discs to to help B/S props. Similar to what a body man would use. Did they disco' them?? Are there any other producers for these?

What Dremel bits are you guy's using?? Any part numbers or photo's of all the stuff you guys use would be sweet![/b]

 

[Doubledog]

I took a stock X470/3 and ran it on my G230RC. It loaded up very bad and seemed to never quite get out of it. Even at different strut heights.

Then did the tounge mod and it helped noticeably. Its still slower than others in my box, I feel that it needs a little more removed and possibly a back cut.

The biggest pain for a newby trying to mod props was/is getting the blades the exact same. I've worked out a template from another prop thats pretty close to where I want it.... that and using my calipers.

Email me and I'll send you some photos of it.

 

[Randy Rapedius]

Andy.

Are you personally doing ALL your prop work? I was told that you hired someone to do props for you.

Randy

 

[user 115]

What tools and devices are people using to sharpen and balance your props?

Thanks,

Charley

 

[shoboat]

Prop Tools,

Many of them. Start with a 6" grinder and special wheels from 3M. Add a

jewelry high speed buffer/polisher. Prop pliers,Grimracers pitch gauge,

mandrels,dremel with 100 bits or more,jeweler rouge,cotton buffs,the list

goes on and on, but this will get you started. Oh yeah, I forgot the toxic

dust mask and face shield also. :unsure:

Happy Holidays Everyone,

Mark Sholund

PROPS-4-U

[email protected]

 

[user 115]

Hi Mark,

That should keep me busy for awhile..

Thanks.

Charley