Engine mounting fixed

Dad finished the inserts for the engine; for where the threads were stripped. I glued them in, with thread-lock, a couple of days ago. We still need a new drive shaft.

wrinkles, but not so many

The October 12th blade has started to show some small wrinkles, but not so bad as before.
Maybe the foam was not well enough mixed? I mix it with a pencil in a cup for 20 seconds.
Maybe there was not enough foam, therefore not enough pressure.

I will mix more foam next time and release from mould after 3 days.
I want to see the weight lift a little, so I know there was enough pressure.

Chiselling

I have made a start at cutting the profiles in my wooden propeller plug.

paper printouts

I have printed out the paper printouts to help me cut the wooden plug for the left-handed prop

Two weeks

I removed the latest propeller blade from the moulds, after two weeks curing.
I trimmed the foam flashing off it. There is no noticeable smell from it. I hope this one doesn't get wrinkles like the last one.

Left handed prop

I have built the old "DanCAM" software I wrote to design my prop blade.
I was hoping to cut a plug for the other blade direction, the left-handed one. The piece of wood I bought has twisted a bit, after being left against the wall, so I will need to measure the twist to take it into account before printing the paper profiles for it. It would be nice to rewrite the propeller part of the software as part of my HeeksArt software http://code.google.com/p/heeksart/

Another blade

I've got another blade in the mould, with foam in. I'll leave it for two weeks before touching it again. That will be September 12th.

Shrinking foam

The propeller blade, which came out of the mould two days ago, has started shrivelling on the top surface. The foam sometimes does this. I think it is because of forces when trying to get it out of the mould. I will try leaving the next one in the mould for a lot longer, I suggest a week, so the foam is more set when I get it out.

Stripped threads

I tried tightening up one of the bolts that holds the engine to the frame and found that the threads were stripped. It had come loose on yesterday's engine run. I took the side of the engine off and washed it in warm soapy water. Dad is going to make some steel inserts for all four bolts.

Engine driving blades

I fitted the blades to the hub. I set them both to the same angle using a pole pushed against the 750mm radius part of the underside of the blade.
I ran the engine and gave it some revs, but it seemed out of balance. The drive came disconnected from the reduction parts. This bent the drive shaft which hit my hand. My hand seems to work ok for typing. I need to work out some good ways to balance the blades. Also I need to fix the drive shaft more securely, next time.
The blades were going at 4.1 revs per second when it broke ( I looked at the video frame by frame to measure the speed ).

Engine run test

Dad spent the last few days making bits to fit the existing reduction drive and test frame to the generator engine. The next thing is to mark the zero angle of the blades, so I can insert the blades at the right angle.

1m blades

I have moved on to a compromise design with 2 2m diameter propellers, contrarotating. Today I am making another one of these 950mm blades, from my mold. It is made from 25g per square metre glass cloth and polyester resin, with polyurethane foam core.

Big Propeller

In 1999, I started making a 4m diameter propeller to push me along on my paraglider. I can't find any pictures of me flying on it, but here is one from June 2005, testing it out of the window in the workshop. I didn't fly the one in this picture, but I did a flight with an earlier design and just about maintained altitude. It was awkward to carry up the hill and I couldn't launch from the flat, so I had some occasions where I drove all the way to a hill, carried it up in two loads, lauched, which was tricky, and then found that engine wasn't working properly. My dad did all the clever metalworking and engineering.