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[Peppyy]

I have been cleaning out my shed, (Since I have a dumpster in my yard for a few days) and I found an old trolling motor with a broken prop. I forgot to take photos before I started tearing it apart but you will get the idea.



This is the mess I had on my front lawn after spending an hour to remove a little cotter pin that used to hold the prop on. I ran the motor with my cordless drill and got a reading of 3 volts. I am hoping the prop will turn it faster than the drill.

I had to run to town for an emergency today and by the time I got home it was pretty dark.

I bought 2 - 3" blank electrical covers with a 7/8" KO in the center and used a 1/2" to 1/4" plumping bushing to use as a mount to the motor. Here is a close-up. The shaft has a flat on the other side which I hope to match with a spot of weld, (if I can find a welder) or try it first with just the 1/8" pin.

More to come soon.

[drdongle]

You could drill and tap the bushing for a set screw.

Carpe Vigor

Dr.D

[Peppyy]

Eeek Had a huge post ready and closed my browser by accident.

Thought about that but there is no room on the bushing for a setscrew.

Here is the hub

Here is what it looks like on the motor side

And this is the front. No room for a setscrew.

[LEXX]

I'm not too sure that oct. blank cover will give you much strength, it is made out of the same stuff as EMT, which is considered "non-ridgid"

LEXX

[Peppyy]

LEXX, The prop is 21 inches in diameter and the motor shaft is only 3/8" so I think it will be as strong or stronger than the shaft. Have a look at the first project I did. it was only a 9" prop but it surprized me at how quickly it started producing power.

http://www.fieldlines.com/story/2004/11/15/191526/10

Today out of curiosity I decided to power the motor with my 12v jumper pack and see how fast it turned. Needless to say I forgot just how powerfull a 12 pound thrust trolling motor was and it sheared the temporary #12 copper pin instantly. That little motor has an awefull lot of instant torque. I decided to wait until I have the adapter finished and the prop done.

I am debating weather to go with the 8 blades like I did on the small prop or go to 6 blades. The cover I am using has evenly spaced molding marks at 120 degrees. I am thinking that the larger diameter would have more speed with only 6 and I don't exactly know how fast I will have to turn the motor to get to 12v. I would be happy wuth 6v out of this one since I have several 6 v batts from emergency lights that I could charge.

[ghurd]

I think I remember an odd number of blades is better (vibration?).

Just got a used 24" 3- fan blade with heavy duty hub for $5 at the local junk store. Lots of points to fix the blades, set screws, etc.

Looks like mine would be easier. I hope! 'Cause thats where I'm headed.

What I've done shows that motor won't really work for 12v. Get the beer. I hope I'm wrong.

You are making faster progress than me.

G-

[Peppyy]

I too have 12volt motor, hoping to charge 6volts with that one.

I worked on the prop today and decided to go with 6 blades. The

plastic was much tougher than I had thought it would be. I laid out my

6 slices of pie first and then offset to the left 1-1/2", marked my perimeter

and drilled a 3/8" hole in each corner. As soon as my first two cuts were

complete I knew that I would need to support the blades somehow so I bought

99 cents worth of 1/4" threaded rod and cut it into 6-6" pieces. The results

made the prop incredibly strong.

This is what it looks like from the face.

Notice the change in pitch when viewed from an angle. It looks like

it will produce a lot of lift and the rods allow for a pitch changing adjustment

if I can figure out what is most efficient without a wind tunnel..

I am starting to think I may want to use a larger genny for this one.

There is another problem I hadn't considered. Once I installed the rods,

the center of the hub was offset toward the blades. although it remained

parallel to the rim, or outer ring it now hits the motor mount shaft. The

only solution I can think of is to remove the pipe mount and create a suitable

motor mount that can use a furling tail system.

The blades have not yet been detailed and sanded but the hub is removable. It is

currently mounted only by the 7/8" center hole.

[drdongle]

You might find a rolled or split pin that would do the job.

Carpe Vigor

Dr.D