New Cedar Blades

[Shadow]

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 Ready to fly

 

[Shadow]

My first attempt at Laminating, and moving up a size in blades. So far I'm very impressed! First, Cedar is sooo nice to work with, and by laminating I think you get a straighter, stronger, crack free, work piece. First two sets of blades I made were 60 inch, Spruce. These I decided to go a little longer. Started out 70 inches by 7 3/4 wide, 1 3/4 inch thick. I used 3/16 drop at the 3 inch wide tip, 3/4 inch drop at the 6 inch half way mark, then tapered drop to full thickness at root. Slotted some nothches out and used belt sander with 40 grit to smooth down to specific angles. Very fast to do it this way I found.Other side I used thickness of 3/8 at tip and 3/4 at center. Nothched out bulk,used planer to get close to thickness, then belt and hand sander. Spent lots of time on back side to get airfoil as good as I could, I think it paid off. Two coats of Linseed oil, and were ready to fly.  Haven't had much for measurable wind , but tonite I got some real promising results, first they start turning in what seems like no wind at all!, then in about 12-14 mph was showing 6-8amps going into the 48 volt battery bank, remember this is 12 feet off the ground only, so lots of turbulance. But I cant believe how much bigger blades become by adding 10 inches. I'm sold on Cedar now. These blades doing it this way cost about 40.00 CDN, for material

[rotornuts]

Congradulations, I think you've done a d*mn fine job there. I've always been impressed with your blades though.

We have another laminating convert.

Mike

[Shadow]

[ghurd]

Very nice.

G-

[richhagen]

Hi, As Mike pointed out, they look great.  Your post also serves to show that one can never have too many clamps.  I've bought some cedar to play with, but I havn't laminated it yet.  What did you use to laminate it?  I see the "pro-bond" bottle in the photo, but I can't make out the other material there.  Rich Hagen

[Shadow]

The other bottle of glue is just an Elmers Carpenters glue, I used it until I ran out, then the pro-bond, just have to watch as  some is for Interior use only. As for the clamps, Yes use lots, but if you can get two pieces of 1 inch square tubing or flat metal the length of your blades to clamp to on each side rather than little pieces like I did. I glued both halves and  left these clamped for 24 hours. I should point out too,I mentioned above I used 40 grit sandpaper to smooth them down, then 80 grit, then 120 and 180 before oiling. This part goes real fast with a belt sander. Then a few touchups by hand and their ready to go.

[farmerfrank]

Where did you get the nice cedar. I've looked around and could only find knotty stuff. Excellent job!!!

[rotornuts]

You'll have a hard time finding clear cedar without paying a premium price for it. I suggest you try looking for 2x4 or larger with clear sections in the width you desire then rip the clear out on a table saw.

Mike

[Shadow]

I got this from local Co-Op Lumber yard, Another plus for using cedar its all stored inside, so should be good and dry. There was a few knots, but by laminating you can sometimes fit your pieces together so alot of the knots get cut off when shaping the blades. They let me sort through the pile as long as I re-stack it before I leave.I tried to get few knots,but also a blend of color.

[Flux]

Nice work, I am pleased that it all worked out well.

At that wind speed 6 to 8 amps is good for a nominal 12 ft prop. When you get it up in nice clean wind it will really perform. I think you have a better match to your alternator with the bigger prop, I seem to remember you had trouble keeping the speed up with the original.

I know what you mean about the extra 10" making it seem huge, fortunately the wind sees it that way as well.

Flux

[41south]

I might have missed it in the text, but are those pieces each 2 inch x 2 inch? really nice job. Thanks for the pictures.

[Shadow]

 Not quite 2x2. I used 2x6 which is more like 1 3/4x5 3/4. Then tried to divide the 2x6 in 3 equal pieces. So by figureing in for the saw blade width,you end up with 1 3/4x 1 3/4 or slightly larger. Then I turned them on their sides with end grains running different directions and glued and clamped. We are building a set of 60 inch ones for a freind, he used 2x4's but seems to waste a little more.I would go with 2x6 and cut into 3. Hope this helps.  

                     Thanks Everyone, For the nice comments.

[libra]

Couldn't see the last two pictures but what I saw was good. I found old  rough 2*4 cedar that was very dry and light. I had one piece of wood with a few knots and it made it tough to plane. The clear cedar was a bit more but well worth it.

Again congrats and i hope to have mine up in another month. They are 7.5 feet each and are 5" wide at tip and 12" wide at root.  Hope they work well.

Libra

[Shadow]

Wow! Those are big blades! You'll have to post pictures. They should really pump out the power. I've often wondered How big a person could go with Wooden blades? 8 feet?..or maybe ten?

[TomW]

Shadow;

I've often wondered How big a person could go with Wooden blades? 8 feet?..or maybe ten?

Well, I know DanB is flying a set of 17 footers. This would require each blade to be 8.5 feet in length.

Cheers.

TomW

[wdyasq]

Gougeon Brothers built some in the 50 Meter range of laminated Dougals Fir IIRC.

Ron