5 Blade Cleavers?

[Flying Scotsman]

As has been said before I find sharpening and ballancing a 3 bladed prop a real challenge never mind the other tricks of the trade in prop mangling.

Douggie

[TINY]

[QUOTE=Fluid;378412]I think I said no record holder calculates viscosity. Viscosity is a measured value anyway, as is density, salinity, etc. Do you use an AntonParr 500, a Fann 35, or a Marsh Funnel to obtain your viscosity values? How you would use this subtile information for making a prop decision - when other factors like wind and waves have a much larger effect on speed - escapes me. You would need a large database of test results to make any practical use of viscosity measurements.

Regardless, good luck on your attempts. If I can assist in any way, just let me know. I've held a few SAW records myself....

No apparently thats a little old school, we use a brookfield DV-11+..Not that i claim to be able to operate it properly but my fellow racer has access to it at his place of work..
I suppose the saw events you have experience in are a little different to over here?? Maybe... Most of the time its glass and not in the salty choppy sea??
,
Wind and wave is an obvious factor but if you are looking for an edge then you need to up the ante.. Being a fluids engineer i imagine you would understand.. I'm a mere mechanical engineer that builds the trains we ride on.. Not the cordial we drink or the oil we put in our cars.. Cheers

Thankyou for your offer of help..

[Fluid]

Having access to the equipment and knowing what it is for are two entirely different things. I've used the Brookfield instruments for decades, and they are useless in characterizing Newtonian fluids like water. They use low and ultra-low shear rates - nothing like what a propeller sees - and are used to measure non-Newtonian fluids like paint and oil. The Anton Parr 500 is a cutting edge rheometer - but it too is useless in characterizing water. If you like doing mental gymnastics which result in no useful data, feel free.

SAW racing is what it is - smooth, rough or in between, whatever the conditions on race day. The difference between water with a very slight chop and glass smooth is at least 5 mph. Being a fluids engineer I'd rather spend time drinking a cordial than wasting time on fluid dynamics which have no practical end use in FE SAW racing.

Again good luck - really. I think you'll find that the time spent in trying to characterize tiny differences in water would be better utilized in actually testing the model and developing a database based upon performance rather than upon dubious math.



.

[TINY]

Fluid you have me all wrong, mental gymnastics is not my forte..
As for useless, guess proofs in the pudding, and by the way that machine is no dinosaur. Less than a few years old. The manufacturer is decades old.
Sometimes being wrong isn't that bad.
Have a great xmas

[antslake]

You guys are funny!

[LarrysDrifter]

Fluid may seem to be stern at times, but, more often than not we all sound (read) like as$holes. Its just the nature of reading someones typed posts. I dont know him on a personal level at all, but I can assure you he is a very smart and knowledgable man among many others here. Im no engineer of anything, Im a pipefitter building and maintaining gas stations (on the petrolium aspect). I know nothing of fluid dynamics, but I do agree with Fluid. Id stick with testing of props and messing with hull adjustments such as hardware settings and center of gravity. I am no pro at FE , but my own personal claim was an 81 mph twin cat 32" L ran on 4s per side. The more I messed with it and the more props I tried, I finally got the speed I was looking for..on GPS, of course.

[TINY]

Yes I understand. Fluid is a wordsmith and can bamboozle alot of people.. There is no doubt fluid has a depth of knowledge that many would envy, hence his respect on this forum,,

Barry sheen was brilliant but alas developments evolved as did age and technology.

I still respect Barry, but doohan and stoner would kick his ass...
Merry xmas

[LarrysDrifter]

Nevermind.

[Steve-O]

Just out of curiosity: What is the viscosity of water at 70 degrees F. and how much would it have to change to make a prop change effective?