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What 3 Blade Prop to Use ?

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What 3 Blade Prop to Use ?

Old 04-30-2004, 12:50 AM
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nearmissbt
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Default What 3 Blade Prop to Use ?

Wondering what size 3 blade Prop to use on an Enya 29 ? Is there a chart or a hint to sizing?
Thank you for your time !
Old 04-30-2004, 01:12 AM
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Default RE: What 3 Blade Prop to Use ?

The general "rule of thub" for going from 2-blade to 3-blade near a .35 size engine is to trade 1 inch dia for the extra blade.

So if you tend to use a 9X6 on the .29... try a 8X6 3-blade.

You are going to notice a substantial loss of static thrust with the change. Its debateable if top speed will change, that depends a lot on the model.

Going back up to 9 inch dia and reducing the pitch may or may not work... You can TRY a 9X5 3-blade in the above case, but the load of the 3rd blade is sometimes too much to allow you to do that. You would regain part of the static thrust lost, but not all of it due to an effect of the blades "flying" in each other's wake.

3-blade props are great for appearance... but if you don't have abundant exces power they are usually dissappointing on a model.
Old 04-30-2004, 08:43 AM
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dr_wogz
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Default RE: What 3 Blade Prop to Use ?

chart below..
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Old 04-30-2004, 02:58 PM
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Default RE: What 3 Blade Prop to Use ?

Unfortunately... I think that chart is for 2-blade.[&:]
Old 04-30-2004, 03:39 PM
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Default RE: What 3 Blade Prop to Use ?

Yeah, it's for 2 blades, but the typical rule still applies, 3 blades, remove 1" from teh dia. Also, some say reduce teh pitch by 1 as well..

But as we all know, it is a bit of experimentation!
Old 04-30-2004, 04:02 PM
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Default RE: What 3 Blade Prop to Use ?

Yes... as the engines get about .60 size you take off 1 inch pitcha and 1 inch dia to keep about the same load factor.

A scale effect of the larger props. The trade-off of pitch for dia also is right at 1 inch pitch for 1 inch dia at appx .30 to .46 size engines. The rule of thumb is off when you have a bigger or smaller engine.

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