From 49" to 61"

[Jerry]

Most of the time I build my blades to 49" on ocasion I build  at 55" with 6" extensions. This time I'm trying 8" extensions.

Also 2 additional chages. I now have a 1/4" solid steel hub and I'm trying a nesel (sp?).

Heres a picture of the 49" with the old hub.

Heres the new extended version.

I use 2 strips of aluminum 2" wide 1/8" thick and 8" long. This is acctully very strong. I've been flying the 6" version 4 years without a hitch.

Heres the back side.

This is tip end. Shows small angle at tip.

I call this the whale back veiw. This rise in the center of the trailing edge is the same on the Lakota blades.

This veiw gives a good idea of the tip to root twist and cup.

This is a good twist veiw from above.

The nesel will protect the shaft to hub adaptor. This is a 3/4".

Blade, nesel and hardeware.

I'm not sure how this blade will work yet. The 6" extension work very well, these are 8".

I'm sure the rpm will be slower than the 49" but with more touqure and more power for a larger and slower alt then I typicaly use on the 49". I'm sure the startup will be much earlyer. I'll try this on the F&P first but it will most likely end up on an 8" to 10" dual rotor alt.

I belive the cup, twist and thinness of this blade are responcable for its great preformace at 49"s. Now to find out how it works at 61 inches, Was 4FT one now 5FT one.

I don't think the nesel helps any but it looks cool and it protects the hub to shaft adaptor.

                          JK TAS Jerry

[Jerry]

Whoops, sorry about post one of the pitures twice. Also forgot to point out. The bolts sticking out the back are normaly cut of. I took these pictures outside and it was getting dark. I'll cut of the exsess off tommorow. A Dremel with the heavy duty cutoff friction wheels works best on these #10 SS screws.

                            JK TAS Jerry.

[sahlein]

Jerry,

What is the center-most part... the grey stuff... made from??

Thanks,

Joe S.

[richhagen]

Jerry, you know if you have any trouble with starting torque on a bigger genny, you can probably use wider aluminum strips for at least the upwind side of the aluminum sandwich extension as the theoretical blade would be wider there anyway, and at a similar angle.  You don't have an airfoil, but I would guess that it would not penalize you that much on the high end.  It might make for an interesting performance comparison for low wind speed - and for high as well.  Rich

[Jerry]

Hi Joe.

Its made of 1/4" steel. A freind cuts and bends these for me at his steel fabrication shop.

I've painted it gray to stop rust. They are pitched at 23 degrees, taped and threded for my plastic blades.

                        JK TAS Jerry