Prop choice

[Mike53]

Steve,can you tell us a little bit more about the process ie; learning the program -how hard? Did you have use of a CNC machine or did you hand carve it?
Totally impressive results and at $80 in material and the cost of the software I am intrigued :idea: :D
Thanks
Mike

[vicdelgado9]

Steve, I second that! They look great! I am very interested in possibly making my own prop as well. I am interested in hearing more about how you made your own prop, by hand, or equipment needed, and the software.

[sonex892]

Mike and Vic. The program is fairly simple to use. Its uses excel, just need to enter data in the fields such as RPM, speeds, HP, airframe type (slippery or draggy) diameter, type of wood etc. It took a little playing around with these fields to get the prop pitch I wanted. From this it will produce performance graphs and plotted airfoil section drawings for seven stations along with a table of coordinates for each station. I then copy these coordinates over to autocad manually to draw each station and from these drawings I make a plan view template of the prop shape. This is used to mark out the blanks. These could also be drawn by hand with a ruler and French curves.

top templates

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I do all the carving by hand but with powertools mostly.

1/Bandsaw to cut out the blanks and drill a centre hole which becomes the reference for absolutely everything.
2/Reciprocating saw to cut down to the station marks in the glued blanks, carefully stopping about 1/8" proud

blanks with depth cuts

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3/Electric plane to to rip it down to these cuts.
4/ File carefully to go down to final shape at each station, a vixen file would do for this,
5/Angle grinder with a 40 grit flap disc fitted to knock down the high bits.

grinding off the high bits

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6/Belt sander to bring it down to final shape starting with 40grit progressing to finer grades
7/Sanding by hand
I do steps 3,4,5 and 6 on the rear or bottom blade first then repeat the process on the top or front of the blade. As soon as I start with the belt sander on the top of the blade I start looking at the horizontal balance.

Thats how I have done it I'm no expert. It takes me about 60 hrs to do each one and its a dirty and dusty job

Steve
Sonex 892

[Mike53]

Thanks Steve,it must an immensely satisfying feeling flying behind a prop you made yourself.Did you have any issues balancing the props?

[rizzz]

Wow this is awesome Steve.

Anybody have an idea what it would cost to have your prop machined in a shop once you've designed it with the JC Propeller software and created a 3D model in AutoCAD they can work off?

[sonex892]

Thanks Steve,it must an immensely satisfying feeling flying behind a prop you made yourself.Did you have any issues balancing the props?

The balancing can be a PITA and can take quite a bit of time. I have been using a rod through the centre hole of the prop sitting on a couple of levelled runners, with the workshop doors shut to stop the wind. Balancing it horizontally first I then paint still checking for balance. I use a one pack floor finish for the paint. I then vertical balance. Every prop so far has needed a lead slug for the vertical. Then a final balance by feathering the paint on the heavy side.

Ive seen a couple of alternative plumb bob type balancing setups on the net recently. I would like to try one out to compare it to what I've been using.

Steve
Sonex 892

[Mike53]

I'm thinking this is a great idea but wondering like Michael above if there is an easier way and I remembered this that I saved to my favorites a while back. http://buildyourcnc.com/cnckitintro.aspx For a couple hundred dollars you can build your own 3 axis CNC machine.
Cheers
Mike

[fastj22]

I just ordered a Prince from Sonex over the web. I know they are on Christmas shutdown, but at least I have the order in when they return.

For those who got a Prince, what was the turn around time from order to delivery? I've heard stories of over 3 months. I hope not, but I think the Prince is the best choice for a good climb prop.

I ordered the prop through Sonex just after Christmas. I got notification today from FedEx I have a package coming from Prince to be delivered on my birthday, Jan 16th. So that's about a 2 week lead time with a holiday thrown in. I'm very impressed in both Sonex and Prince. I feel like a kid waiting for the delivery man.

[rizzz]

I'm thinking this is a great idea but wondering like Michael above if there is an easier way and I remembered this that I saved to my favorites a while back. http://buildyourcnc.com/cnckitintro.aspx For a couple hundred dollars you can build your own 3 axis CNC machine.
Cheers
Mike

Wow, If I had seen this before I started building my Sonex, I would have built one of these first, would have made the making of the angle parts and the smaller flat parts so easy!

I might still build one looks like a great toy to have and pretty easy to build (compared to an airplaine!), the plans are only $35 so I might order those now anyway.

[Mike53]

I agree the possibilities are fantastic.Problem is the Auto Cad software .
I am familiar with and use sketchup all the time in my business but to the best of my knowledge you can't transfer anything from it to a cnc machine so what I was wondering is would a product like TurboCad http://www.cadandgraphics.com/tcpro16.html work in this respect ? Most Auto Cad software is pricey but the Turbo Cad can be had for a few hundred dollars ,albeit an older version but who cares.Does anyone know if it will work ?This would be a great way to render the Onex for paint schemes also.
Mike