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What's the difference between the cnc machined props and say an octura??? Are they heavier? What would be the equivalent of an m445 if it was cnc out? Y is everyone using the other brands and not cnc Thanks in advance!
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Octura are heavier, MUCH heavier, it really took me aback the first time I held a CNC prop, I've not weighed either but I wouldn't be surprised if the CNCs were less than half the weight of an Octura ready to go, and a third of the weight fresh out of the pack.
An M445 equivalent would probably be a 447 as the blades are thinner than the thick M series, and they have less blade area which comes from having even less tongue and a slight backcut which all contribute to less load, however I would start with the same size and work up keeping an eye on heat as ever.
In the FE race scene over here there are more CNC alloy props in use than there are carbon, BeCu and stainless combined, both ETTI and Tenshock are way more popular than Octura here and R2 are probably about the same, Tenshock seem to be the best of them and I know several people that have switched from ETTI to Tenshock and noticed a difference, R2 come at a different price point so I haven't seen that crossover for direct comparison yet.
I use Octura because I have a box full of them, and over the years I have learned to shape and bend them to my and my boat's liking so I don't think it gives me any disadvantage, if I was starting out now, I would buy a bunch of Graupner carbons (right now, while they are still available, as Graupner are teetering on the edge) and when I found the right size I would buy a Tenshock CNC the same size as the blade shapes are very similar. It is a quick and easy way of getting to a prop that performs very well, can be cheaper too as we know Octura's put more load on than Graupner's if you get how much smaller you have to go wrong and buy another than an R2 CNC would have been cheaper and a Tenshock about the same.
I would guess what puts most people off CNC is the price being around double what an Octura is over here, it makes them a pretty expensive proposition if like me you don't factor your labour into the equation, if you do however they are amazing value, I spend a full day on preparing 2x £15 Octura props normally, if I had spent that day at work doing overtime I would probably had a better time, (I hate doing props and my hands start aching after a couple of hours, and I always cut myself) and would have earned £120 which is enough to pay for 4x Tenshock CNC props at £30 each, but I would have a lot less job satisfaction.
There are some for whom CNC props will not be good enough, I hear the 7075 alloy they are made of does not take kindly to bending and can crack or snap if tried to bend much, so super tweakers like the Snowman won't like them, they are weaker than stainless or heat treated BeCu too so I doubt they will be any good for those running SAWs.
We run much higher KV setups here than you do in the states, with correspondingly much smaller props to keep the amp draws reasonable, the idea of 1500kv in a 4s boat seems completely alien to me.
I haven't seen a prop bigger than 45mm on a raceboat for years, so I cant say how well the larger sizes hold up.Paul Upton-Taylor, Greased Weasel Racing. -
Funny you say that, I'm one of the odd balls who is running high rpm with small prop.Comment
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Wow thank u for the detailed response! Will have to read it a couple times to understand it fully!!!Comment
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R2 hobbies props a a mild grade aluminum compared to some other like the ones OSE sells. I bought a pair and I'm not thrilled with the quality.
Never tried Etti or Tenshock props.
BerCu Octura props and other such as ABC and Propshop props are generally stronger material than poor aluminum or even the better ones OSE sells.
If you ding an Aluminum prop most times it's done, Octura, ABC, Grimm racer etc.. are re-workable more than aluminum.
Nortavlag Bulc Comment
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Isnt CNC technically just anything made on a lathe by a computer? or somthing? to me sounds like a car manufacturer called... CARComment
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Close, I would guess they are made on a (Computer Numerically Controlled) milling machine not a lathe, but you are right that CNC just describes the manufacture process rather than the company name, hence us discussing CNC props from several different companies, ie ETTI, R2 and Tenshock.Last edited by NativePaul; 09-19-2013, 04:22 AM.Paul Upton-Taylor, Greased Weasel Racing.Comment
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Aluminum Props
...If you ding an Aluminum prop most times it's done...
VERY true statement, see attached pix. T6061 CNC'ed x442, I got a little too close to the shore last summer, kiss $22 + ship goodbye.
But, I'll buy replacements in time for summe, I don't have the time nor inclination to spend all day prepping props. I spend a good couple / three hours prepping the CNC props as it is to get the machine marks out + add a satin finish per these instructions... http://www.aquacraftmodels.com/acces...op-tuning.html
BTW: they are very light weight as Paul statedComment
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It's always good to have a wide selection of props Alum. or any material. ...and yes the CNC ones do save alot of time. It's also nice for those that have aging hands and sore knuckles from arthritis. Nortavlag Bulc Comment
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So I wouldn't have to do anything to a cnc prop to run it? Example-sharpen or balance it or anything, just throw it on and run it!?Comment
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Yes, that's what they're designed for... http://www.offshoreelectrics.com/pro...+2+Blade+PropsComment
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I disagree. I haven't bought a cnc'ed prop from OSE but, I've bought them from elsewhere and although you don't have to sharpen them, it makes a world of difference.
Finishing them doesn't do much but, blade sharpness is important. Nortavlag Bulc Comment
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