General discussions - FAST RC boat

[King blitz]

I'm curious when your boat is just sitting in the water ..how many inches is your prop in the water.? What is your pitch at? .on my v hulls they are almost 2 " my catamarans are about a inch . basically skimming the surface almost..I moved my lipos towards the rear on my v hulls and it was a bad mistake..my nose lifted so high it flipped .I now keep them a little past the middle. For v hulls and my catamarans I keep them slightly further up.i need the weight up front for balance

 

[LibertyMKiii]

I'm curious when your boat is just sitting in the water ..how many inches is your prop in the water.? What is your pitch at? .on my v hulls they are almost 2 " my catamarans are about a inch . basically skimming the surface almost..I moved my lipos towards the rear on my v hulls and it was a bad mistake..my nose lifted so high it flipped .I now keep them a little past the middle. For v hulls and my catamarans I keep them slightly further up.i need the weight up front for balance

This is the Seaducer setup sheet I followed and matches about how I setup my 42" mono that hit 90mph.
This setup has a flooded stuffing tube setup so I can adjust the strut up and down like you do on a hydro. This will be helpful when/if I try larger props to lift the strut up higher.

 

[King blitz]

This is the Seaducer setup sheet I followed and matches about how I setup my 42" mono that hit 90mph.
This setup has a flooded stuffing tube setup so I can adjust the strut up and down like you do on a hydro. This will be helpful when/if I try larger props to lift the strut up higher.

View attachment 359665

Oh ok perfect then ..so you have a good amount of adjustments sweet...I was thinking yours was locked

 

[Big Kid]

If there is any wisdom to share with you guys it would be this ...

Higher pitch ratio props will have greater radial spill of water off the blades and thus a Higher LIFT
Higher pitch ratios as well greater diameter also have greater sideways PROP WALK
In all my years racing R/C boats and lets stay here for a moment on "MONO'S" .... the more diameter you use WORSE will be the side to side oscillation induced by prop torque. All my REALLY FAST monos generally ran fairing small props with motors tuned to be at really high RPM levels ... The FE boats should act similar & run best with smaller props on higher KV motors !!! ... RPM them up up up !!!

Another trick we used to gain better strut trim effectiveness was running on strut blades or purpose built surface deive housing was get the prop further back away from transom. This equates too the props lift characteristics having more leverage on the hulls ride attitude. Cats & 3 point hydros too

 

[LibertyMKiii]

If there is any wisdom to share with you guys it would be this ...

Higher pitch ratio props will have greater radial spill of water off the blades and thus a Higher LIFT
Higher pitch ratios as well greater diameter also have greater sideways PROP WALK
In all my years racing R/C boats and lets stay here for a moment on "MONO'S" .... the more diameter you use WORSE will be the side to side oscillation induced by prop torque. All my REALLY FAST monos generally ran fairing small props with motors tuned to be at really high RPM levels ... The FE boats should act similar & run best with smaller props on higher KV motors !!! ... RPM them up up up !!!

Agreed or move the strut up so only part of the prop is contacting the water.

My 80 mph run was 44,774 rpm
my 90 mph run last year was 48,844 rpm.

 

[Big Kid]

Agreed or move the strut up so only part of the prop is contacting the water.

My 80 mph run was 44,774 rpm
my 90 mph run last year was 48,844 rpm.

Up ... having less blade swatting at the water allows bigger props to be run .. but at a cost of increased prop walk and side/side "Chine walk" tendencies.

Yea all my experience was Nitro & Gas stuff. I would spool up the .21 nitro motors 31 to 33,000 rpm on 60% nitro & the Gasser stuff 16-18,000 rpm was pretty typical.
* Went out into the trailer and took a few pics ...
Left my FAST .21 Mono .. semi surface drive having strut JUST UNDER Kiel .. Octura X637/2 Cupped & low lift.
Mid the Gas Mono ... Custom Arnison surface drive exiting transom. Adjustable trim up down and side to side. Cupped prop as well.
Right a Gas Outrigger where rudder forward and Prop back placing rudder in clean water away from prop wash. Backcut & cupped prop.

Yea lots of ways to set up, prop tweaks one can make with each having cause & effect on handling etc ...

 

[LibertyMKiii]

Up ... having less blade swatting at the water allows bigger props to be run .. but at a cost of increased prop walk and side/side "Chine walk" tendencies.

Yea all my experience was Nitro & Gas stuff. I would spool up the .21 nitro motors 31 to 33,000 rpm on 60% nitro & the Gasser stuff 16-18,000 rpm was pretty typical.

That is good to know... If I start seeing chine walk I'll know its the bigger prop.

 

[Tex Koder]

If you have poor old man eyes I have 20/20 as long as I don't look at eclipse today while driving home I have eagle vision ... But yes Fpv would be badd ass

I'm SO jealous of folks who have such Sharp Eagle Vision!!

I have the vision of a ground mole..

 

[King blitz]

Agreed or move the strut up so only part of the prop is contacting the water.

My 80 mph run was 44,774 rpm
my 90 mph run last year was 48,844 rpm.

That's exactly how I have it on my 46" catamaran.my prop is just skimming the surface..but on my v hulls they are emerged .and I use small props .not sure why but the aluminum props I had sucked.i changed them over to copper burilium and my boats run great. Never had brass props though..do you guys use brass props?

 

[LibertyMKiii]

That's exactly how I have it on my 46" catamaran.my prop is just skimming the surface..but on my v hulls they are emerged .and I use small props .not sure why but the aluminum props I had sucked.i changed them over to copper burilium and my boats run great. Never had brass props though..do you guys use brass props?

I have one brass prop. Seems ok.
I have seen the CNC aluminum ones are no good for high power use. They tend to have one of the blades snap off.
Also found despite being CNC cut they are not always balanced perfectly.

 

[King blitz]

I have one brass prop. Seems ok.
I have seen the CNC aluminum ones are no good for high power use. They tend to have one of the blades snap off.
Also found despite being CNC cut they are not always balanced perfectly.

I could never balance a aluminum prop right.I even took them to my uncle that's been running boats since he was a kid and he him self tryed and said throw these junks away .

 

[Big Kid]

That's exactly how I have it on my 46" catamaran.my prop is just skimming the surface..but on my v hulls they are emerged .and I use small props .not sure why but the aluminum props I had sucked.i changed them over to copper burilium and my boats run great. Never had brass props though..do you guys use brass props?

Beryllium copper ( Hardenable )
Or Stainless steel
Is all i would run & SS especially at very high RPM.
Throw a blade at high RPM and stuff gets ruined in the running gear very quickly !!!

 

[LibertyMKiii]

I could never balance a aluminum prop right.I even took them to my uncle that's been running boats since he was a kid and he him self tryed and said throw these junks away .

For mine I had to remove some material closer to the hub to get it to balance. I think that area is called the "root".

 

[King blitz]

Beryllium copper ( Hardenable )
Or Stainless steel
Is all i would run & SS especially at very high RPM.
Throw a blade at high RPM and stuff gets ruined in the running gear very quickly !!!

Don't have any stainless I'ma have to check them out.

For mine I had to remove some material closer to the hub to get it to balance. I think that area is called the "root".

I think your talking about the boss

I still think the aluminum props I bought were from china and they were junk

 

[LibertyMKiii]

Don't have any stainless I'ma have to check them out.


I think your talking about the boss

I still think the aluminum props I bought were from china and they were junk

VooDoo, Pranther, and Prop shop UK are some of the big names in Stainless props.

 

[King blitz]

So here is a quick question you guys can help me with. What kind of prop would be best if I wanted to use one of my boats in salt water? I know aluminum and salt don't mix well at all so what about the others? Only asking because Im a 4 minute walk from the beach / bay and I allways wanted to run them in it.i do know all about the maintenance I'd have to do before and after id I ran in salt water.

VooDoo, Pranther, and Prop shop UK are some of the big names in Stainless props.

Thank you

 

[Big Kid]

Years back when Lets say more folks were truly 'Hobbyists" There were some of us who left no stone unturned, pushed and pushed the prop tech in similar ways as the link I posted #821
Beyond that we had Texas cut mods, Removing leade length, Progressive tip leade or flat, Star cut or dog ear on trailing edge tips and then changing Camber on working face, Trailing edge ramping / cupping as well tip cupping & more.
All these tricks were in ones tool box and applied as found needed.
Many times you would have a prop that did everything well yet lacked a bit of some attribute ? .... Switching to other props was not the anwser, but subtle prop tweaks could make all the difference !!! We had custom cupping pliers, cupping blocks & Dial indicator fixtures where measuring each and every blade at differing places could be done.
In all my years racing and doing my own motor as well prop work was able to set @ 10 NAMBA national 6 lap oval heat racing records and this outside some decent driving skill was largely in part due to PROP ALTERATION & prep. Stock props and profiles are like Vanilla and there is many more flavors one can create once learning "How-Too"

Great hobby and a HUGE rabbit hole of stuff one can learn if the desire is there.

So here is a quick question you guys can help me with. What kind of prop would be best if I wanted to use one of my boats in salt water? I know aluminum and salt don't mix well at all so what about the others? Only asking because Im a 4 minute walk from the beach / bay and I allways wanted to run them in it.i do know all about the maintenance I'd have to do before and after id I ran in salt water.


Thank you

Salt water ... Props STAINLESS !!! Flush water jackets after EVERY use, Pull drive cables and desalinate & lube soon as able after use.
Wash off entire boat and pay attention to aluminum and dis-similar metals having Galvanic Corrosion happening. salt water running requires much more stringent maintenance being done. DON'T put it away wet & forget about it

 

[King blitz]

Years back when Lets say more folks were truly 'Hobbyists" There were some of us who left no stone unturned, pushed and pushed the prop tech in similar ways as the link I posted #821
Beyond that we had Texas cut mods, Removing leade length, Progressive tip leade or flat, Star cut or dog ear on trailing edge tips and then changing Camber on working face, Trailing edge ramping / cupping as well tip cupping & more.
All these tricks were in ones tool box and applied as found needed.
Many times you would have a prop that did everything well yet lacked a bit of some attribute ? .... Switching to other props was not the anwser, but subtle prop tweaks could make all the difference !!! We had custom cupping pliers, cupping blocks & Dial indicator fixtures where measuring each and every blade at differing places could be done.
In all my years racing and doing my own motor as well prop work was able to set @ 10 NAMBA national 6 lap oval heat racing records and this outside some decent driving skill was largely in part due to PROP ALTERATION & prep. Stock props and profiles are like Vanilla and there is many more flavors one can create once learning "How-Too"

Great hobby and a HUGE rabbit hole of stuff one can learn if the desire is there.


Salt water ... Props STAINLESS !!! Flush water jackets after EVERY use, Pull drive cables and desalinate & lube soon as able after use.
Wash off entire boat and pay attention to aluminum and dis-similar metals having Galvanic Corrosion happening. salt water running requires much more stringent maintenance being done. DON'T put it away wet & forget about it

So stainless it is .. but I would need to at least change also all the hardware outside the boat to then ,like rudder ,turn fins ,,push rods,trim tabs because it's all aluminum on all my boats.if I plan to run one boat I'll have to get stainless on all of that also.ill think about it .I know about the maintenance.it takes a bit of time to get it all done and it's not something that gets done in a few minutes.im particular on how i maintain my boats and Rcs.alot easier on fresh water.something I have to think about

 

[LibertyMKiii]

So stainless it is .. but I would need to at least change also all the hardware outside the boat to then ,like rudder ,turn fins ,,push rods,trim tabs because it's all aluminum on all my boats.if I plan to run one boat I'll have to get stainless on all of that also.ill think about it .I know about the maintenance.it takes a bit of time to get it all done and it's not something that gets done in a few minutes.im particular on how i maintain my boats and Rcs.alot easier on fresh water.something I have to think about

I'd think you could rinse if after, maybe even go as far as some soap and water with a soft brush and it would be just fine.

It really wouldn't take long...

I have a regular disposable water bottle with a hole in the bottle cap I setup some silicon tube on so I can rinse my cooling system out after a run. Works great!

 

[NitroK]

Never owned an rc boat. Just curious to know how you recover a boat stuck in the lake/river/pond. Do you prepared for such contingencies?