Update on my 20 footer

[marv]

I just picked up the stator from the dipping shop.

It was dipped and baked 4 times but before that I had it

tested for shorts. Since it's a high voltage unit (50-500v)

they test at 2000v  but only milli amps.

She passed the test!

Here's a pic of the stator before dipping.





And here's one all dipped and baked.

There is also some progress on the blades.

The airfoils were cut to shape using sheet metal

NACA 4412 with the program Profili 1.2

 



I welded the spars together using tube sections from 1 1/2" OD at the root to 1/2"

at the tip.

Then I drilled the airfoil pcs. 30% from the leading edge.

In this picture the airfoil pcs. have been placed on the spars to be welded

at the appropriate angles.





The next job after welding these will be foaming between the foils with

polyurethane foam insulation.

Then glassing them with epoxy.

It has an active pitch rotor, thats what the weight is for in the spar picture.

Thats about it for now.

Marv.

[willib]

Marv that stator looks real nice!

refresh my memory , that was for a single rotor ?

and what dia was it?

what size wire did you end up using?

on my blades i use ten stations

[Nando]

BEAUTIFUL JOB !!

JOB WELL DONE !!

Nando

[marv]

Willib,  It's 21" dia. and I ended up using #16 wire.

I used 18 stations so the distance between stations would be less,

to cut down the span for the foam.

Marv.

[paradigmdesign]

Quick question, are you building this blade (plug?) for mold making purposes, or are you using that for the actual blade?  I've seen it done like this before, (warlock.com.au) and it seemed to work, but I don't know if I would necessarily recommend it (I don't think I would even recommend it for making the plug, I have tried it once).  I can only imagine there would be balancing issues with trying to get precisely the same amount of glass and resin to make the same shape without molds.  I would also be afraid of delamination issues on the trailing edge, having those pieces of steel in the final blade.  Plus if you make molds for the shell, you can add the expanding foam last, and vary it slightly between each blade to help the final balancing.

What kind glasses, and how many layers (mils total)  were you planning on using for the skin, and for the spar caps?  What kind of root buildup/reenforcement were you planning?  What is the max/min chord and twist for this blade?  And this is for a 10' blade?

P.S. I am very impressed with your stator and hub assembly, not to mention that fantastic tower you built!  Keep posting, I look forward to hearing more from you.

[willib]

25cm is only about 9.75 inches.

on my 1.875 foot radius blades (3.75 feet dia ), my root is 13 inches..

[marv]

willib,  the root is 25 inches, not 25cm.

don't let that big timber it's sitting on fool ya.

here is a pic of one spar welded up. I got all three done today.