Converting from 2 blades to 3 info

[hack73]

A general rule for converting from 2 blades to 3: Decrease diameter by 1" and increase pitch by 1".

[crashedagain]

Hello Hack,
Why is it that the length and prop are changed? i don't see a reason to shorten the length, but I am sure you experienced guys can give a good reason based on the laws of Physics as to why this should be done.

Colin.

[mrmugen]

Well you engine will be turning 1.5 times the normal weight by adding another blade so I believe that has something to do with it. I chatted with the owner of our lhs about this very question some time ago. It was when I was building my P-51. I know that on the larger scale planes they work great for torque apps like 3D and such. My friend Bob ran a 3 blade prop on his cub with floats and it did very well. I will ask him what prop it was. Kevin

[hack73]

More info:

www.mh-aerotools.de/airfoils/propuls2.htm

www.zingerpropeller.com/_2_blade_.htm

[higbe33]

hack - nice chart on that second link, but has anyone tried a 3-blade yet? Think I'll give a 9x6 a try if they have one that will fit over our nut and not have to be modified to fit.

With the 2-blade prop testing Joe did here; www.ampaviators.com/index.php?option=com_content&task=blogcategory&id=17&Itemid=28 the GWS HD 10x6 was a nice replacement for the stock prop and using that chart makes me think the 9x6 3-blade would be a place to start. I'll let you know if I find one, but in the meantime I'd sure like to hear if any others have tried a 3-blade.

Hig

[5280ducs]

I just bought 3 props here: www.gwsprops.com/gws_props_main_page.htm I bought a couple of 9x5x3s and an 8x4x3. If you scroll to the bottom of the props page he also carries 3 blade spinners. I also bought a spinner. The prices are very good and the shipping was super fast. I actually screwed up and had to place 2 orders (forgot the spinner on the first one). He refunded my shipping on the second order and shipped it all in one package without my even asking. I thought that was pretty cool! I`m going to get some data with my watts up meter. When I do, I`ll post it here.

Jeff

[subed]

I bought a few gws 3-blade props as well, but you can you tell me what I need to adapt them to fit the SC?
Thanks!
Ed

[5280ducs]

My props came with a set of adapters like the ones shown here www.gwsprops.com/9x5x3.JPG

[subed]

GWS sent me the adapters after the props. Glad they did, but which one fits? Does it slide over the prop shaft to properly fit the prop? Thanks!