Propeller talk post

[dasboata]

OK guys I will add stuff to this post as we go along, I'm ignoring any questions of what prop do I need on my set up,, For argument sake All model boat props were 2 blades in the 80's so when you wanted a 2 blade prop you asked for a 440-450-460-470- ect,,, now when the 3 blades came out or got discovered back then they became 440/3-450/3-460/3-470/3 ect,lets all get on the same page

[fweasel]

What's your preferred method to describe an ABC prop (1715 for example) in terms of the rake angle and blade area, 1715 17-45?

[Fluid]

Why not use the manufacturer’s designation: 1715-17-45(2) CLL?

[dasboata]

What's your preferred method to describe an ABC prop (1715 for example) in terms of the rake angle and blade area, 1715 17-45?

1715 I'm assuming 2 blade 17* unless told 1715/3 but now with all the new ABC props I need to be careful

[photohoward1]

17 is the diameter 15 is the pitch angle. if you multiply 17 times 15 it equals 2.55” of total pitch. For every turn the boat travels 2.55”. There is slip. Can’t be much simpler.


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[Fluid]

The problem is how to ask for the exact ABC prop you want.

diameter - pitch ratio - rake - blade area - number of blades - chopper/cleaver - left or right hand

Use the maker’s prop designation. Can’t be any simpler - if you want to identify a specific ABC prop.



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[dasboata]

2017 ABC prop chart

[T.S.Davis]

I had trouble where I asked for props he hasn't even designed yet. Like I wanted something in particular that doesn't exist. That'll learn' me! Check the danged chart.

[Alfa Spirit]

Very easy

[dasboata]

good Visual the 10* is a lifter it lifts the transom and as it does that it lowers the bow as the rakes get higher there is less transom lift

[fweasel]

good Visual the 10* is a lifter it lifts the transom and as it does that it lowers the bow as the rakes get higher there is less transom lift

Cool, I didn't know the relationship between rake and lift. Does the rake angle change the thrust cone too?

[dasboata]

Cool, I didn't know the relationship between rake and lift. Does the rake angle change the thrust cone too?

yes Ryan you can visualize the thrust will be tighter on the higher rake props

[fweasel]

yes Ryan you can visualize the thrust will be tighter on the higher rake props

Ok, makes sense. Does a narrower thrust cone mean less forward propulsion? Does a narrow vs. wide cone matter when considering a boat that turns vs. SAW?

[dasboata]

Ok, makes sense. Does a narrower thrust cone mean less forward propulsion? Does a narrow vs. wide cone matter when considering a boat that turns vs. SAW?

common sense says yes,, tighter thrust cone more thrust , I don't think the turns matter if your using a strong enough servo

[dasboata]

[QUOTE=Alfa Spirit;735707]Hummm ...


[IMG]ht


this is not show and tell please remove your post this is a informative contributions subject

[Alfa Spirit]

This is an informative contribution picture

[NativePaul]

How big would the hub have to be to be able to balance a 45mm single bladed prop?

Do you think it would be an advantage, or would the extra size and weight of the bigger hub more than counteract the extra efficiency of the bigger blade running in cleaner water?

[dasboata]

How big would the hub have to be to be able to balance a 45mm single bladed prop?

Do you think it would be an advantage, or would the extra size and weight of the bigger hub more than counteract the extra efficiency of the bigger blade running in cleaner water?

never thought about it as it a waste of time for me as someone would of done it already

[raptor347]

How big would the hub have to be to be able to balance a 45mm single bladed prop?

Do you think it would be an advantage, or would the extra size and weight of the bigger hub more than counteract the extra efficiency of the bigger blade running in cleaner water?

Fairly large. Probably need to use small tungsten slugs. We did it with pylon racing props, but they were compression molded carbon fiber.

[H&YRACING]

How big would the hub have to be to be able to balance a 45mm single bladed prop?

Do you think it would be an advantage, or would the extra size and weight of the bigger hub more than counteract the extra efficiency of the bigger blade running in cleaner water?

I've made a few. The hubs are not round, but when rotating the net Hub area is around 1/2" or slightly bigger. They do work, but I didn't see any huge revelation.
Obviously balance is the key and difficult to achieve. A novelty for sure.