Foam blade pix.

[Jerry]

I these pictures load?



Blade on bench with twist supports while quering.



Another angle while blade sets up.



Yet 1 more angle.



Blade cleaned up. Showing twist from root to tip 20 degrees diferance.



Shows aluminum sheet metal root support for root stringth. root support is cupped.



Comming along but much finish work to be done.

                      JK TAS Jerry

[Jerry]

The fan blade hub and the wooden blocks creat the amount of twist along the lingth of the blade.

The 2 thin pices of 3/32" plywood panneling are glued directly together on the trailing edge and at the tip.

The leading edge is 3/4" wide at the root and tappers to no gap at the tip. This is hard to see in the pix.

This bade is 48" long, 8" wide at the root, 2.5" wide at the rounded off tip. There is a 20 degree diferance between the root and the tip. This twist stayed after removing the blade from the supports over night. It seems fairly strong. For a lager version one might double up on the skin wood?

Some type of weather coating will be next along with small diameter wood dowls cut in half and glued to form the rounded leading edge.

The cup was achived by spacers on the aluminum root support. The trailing edge was bolted together, a 1/2" spacer in the midle and a 3/4" spacer on the leading adge.

spacers of demishing lingth were plced on the leading edge from the root to the last one 1/4" at 8" away from the tip.

This gave a 3/16" thin full lingth trailing edge and a leading edge tappering from about 1" to about 3/16" at the tip.

Next I'll cut the small dowls and glue them to the leading edge. After this glue sets sanding will smooth to clean the leading edge lines.

After weatherization the leading edge will get some aluminum tape for abrasion protection.

Rite now the blade weighs 3 LBs. It will get a littel heaveyer.

Any + or neg thoughts are welcome.

                                JK TAS Jerry

                               

[hiker]

hey looks just like an oreo...i jokes..

whats the plan? light blades easy start up--less wear and tear on the bearings?

hmm--fiberglass over the blades for extra stringth..

had my minnie mill up and running with a furling tail-dual rotor-then we finally

got some snow up here[wet snow]..froze up like a rock..guess i need some kind of

shroud over the rotors...anyone have any problems with the big mills?

well thats one thing you don"t have to worry about with the motor to alt conversions!

sorry jerry didn"t mean to crowd your space.....

[RobC]

Looks good Jerry. Most people don't realize it but that spray foam is good for all kinds of things besides filling cracks. I think your blade will work great.RobC

[hvirtane]

Hi,

it looks to be good.

The guy Pentti Kontkanen, from

Finland is using aluminum coatings

for his foam blades. I think

that his construction method

is to make the hollow aluminum

blade first ready outside and

then fill it with the polyurethane

foam. (I've posted a translation

of his web page on the other

discussion.)

I think that a very

similar method would work with

wood laminations. Maybe a wooden

board inside in the middle

from the root to the tip

would help for making it strong?

- Hannu

[Jerry]

Hiker you can crowd my space any time. I injoy all the stuff you do.

I figure the more we share the more we learn. As I posted the other day this is one awsome think tank.

                          JK TAS Jerry

[Jerry]

Thanks Rob C.

And all the parts are at Lowes. Fairly cheap to.

I'm eager to see how your laminated door skin blades turn out.

Hiker is right, fiberglass or something as a coating for stringth?

I have some fiberglass shower wall sheeting that might work laminated to these blades as a water bairier and stringthener?

Just keep trying stuff, might find something that works good?

                     JK TAS Jerry

[Jerry]

Thanks Hannu

You were my insperation to try this. Keep up the good work.

                   JK TAS Jerry

[Ungrounded Lightning Rod]

Next I'll cut the small dowls and glue them to the leading edge. After this glue sets sanding will smooth to clean the leading edge lines.

Why not cut some foam-compatable garden hose in half, stick that on, and fill it with more foam?

[Ungrounded Lightning Rod]

Or maybe use half-round molding rather than cutting dowels yourself.

[Jerry]

Thanks underground.

Thats good info. I'll check it out.

                          JK TAS Jerry

[troy]

Looking good Jerry,

Can't wait to see how they perform compared to your other cool blades.

Best,

troy

[Jerry]

Hi Troy.

I've decided to do a 3 blade. Originaly I was going to do a 4 blade at 27 degrees but after looking at the blade and how it rests I've decided on 23 degrees at the root and 3 blades.

This prop is going on the F&P to see if it will concore the F&Ps cogging isues.

                               JK TAS Jerry