headhunter23

Hello, just as the subject is posted, I'm looking for a single bladed prop for high rpm boat.

Thanks to those that post.

Ivan.

DUSTINNEWTON

Single bladed?

crazy maxx

no. the smallest blade #is 2 the highest i think is 6

topfuel4430

hmmm.... single bladed propellor. Interesting.

~James

Justaddwata

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Heard of them (and not just on April 1st) but not for RC. Not sure where you would start to be honest.
For what kind of power were you looking? That would be a start I guess.

headhunter23

Bugger, 2 blades eh? I was reading some prop guru's website here and he was saying with a single blade you would have less resistance and be able to run at higher rpm perhaps even at an increase efficiency. Since my new motor has 3200 rpm/volt, I figured that would be the way to go.

Any of you guys see a calculator or some sort of equation that spits out pitch of blades?

Ivan.

DUSTINNEWTON

Well, curiosity got the better of me and I Googled it to see what a single blade prop was. It's a helical blade that spirals around the prop shaft, like a screw. Interesting. Theoretically, it sounds good. More blade area to push more water without multiple leading and trailing edges that would be on a multi-blade prop.

impalaman63

DUSTINNEWTON

Is that "The Minnow" from Gilligan's Island? The line "...a three hour toour, a three hour tour..." comes to mind! :-))

jdoug

That thing looks to be way out of balance...

topfuel4430

Thats kind of what I had in mind when I saw "single bladed prop", which just wouldnt work. The props pictured, are obviously in need of repair/replacement.

I wasnt thinking about the impeller type of "prop". I guess that would work to an extent, but for all intents and purposes, why re-invent the wheel? If there were such a thing as "single bladed" props, dont you think the SAW guys would be using them to set records with?

If you need to free up RPM, there are many ways to do this with the conventional props we have now days.

~James

Flabum

A single bladed prop would be way out of balance and would take out your whole running gear. The pictures above, the sailboat has a fold away prop with one blade missing and the second picture was of a prop someone cut the other blades off of it. I am sure both props produced enough vibration in the boats to mix drinks well.

LtDoc

Balance is the problem. Are single bladed props possible, either the 'screw' type or a real-live single blade as most people would think of it? Sure. For the one that looks like a blade is missing, just add enough weight to the right place to counterbalance the existing prop. Efficiency of either type? I sort of think it would be a negative number - LOL. 'Course, if you shaped that counter weight properly, dang!... it'd look just like another blade! At the rpm you motor will be capable of I just don't think I'd wanna try that counterbalanced single bladed prop.
- 'Doc


TAKE PICTURES!

mfr02

I made one when I found an underwater obstruction of the solid kind with my two bladed prop. Made it to the shore, but nearly shook the hull to pieces.
The very first screw propellors were as described, but were almost immediately dropped for the bladed type.
I am told that the screw was invented by Archimedes. Good old Archimedes say we all.

zubee1

In control line speed events they used use single bladed props I don't know of any used for RC boats but it could work if the correct counter balance were used.

headhunter23

Wouldn't a single blade be more like one continous blade up to where it starts... not just the other one or 2 blades taken off. Just to even balance it, would look more like an impeller.

truckerzero

in control line speed they custom make a 1 bladed prop by cutting off one blade and add a conter weight and balace it on a prop balancer so in thery you could do this with a boat propeller a 1 bladded prop has the least resistance and is the most effiecient they get a small plane to 175 to 195 mph on just 2.5 horse power i seen this at alocal park it was quiet interesting

ryan_t888

I've also seen 1 bladed props for plane's. Balance is the number one issue along with drag from the balancing counter weight. In theory single blade props will work better.

What has been missed within this post is we do represent our props as single bladed. We run surface drive's which only allows for 1 blade in the water at one time which unloads the motor.
If it was a single bladed prop we would only be able to run submerged drives so the single blade would stay in the water at all times. When dooing this the entire drive would be in the water increasing drag, yet again.

Ryan

DUSTINNEWTON

VERY good point Ryan. The air is far less drag-inducing than water (which is why fast boats get up and out of the water to increase speed), so on a surface drive prop, that blade that's out of the water creates far less drag. I would bet that the surface drive would work far better than a single blade, harkening back to the saying that if it was better, everyone would be doing it!

Umi_Ryuzuki

That is what I am imagining...

ryan_t888

I'm seeing like an auger or something similar to that in your photo. That to me is just one continuous, long fold of material. One blade means just that to me. One offset single prop blade.

Ryan