Finding the COL / COG.

  • Put the Elevons on last night and was so pumped about how it turned out that I wanted to test fly it straight away to find the COL (Centre of Lift) I had a fair idea of where  the COL was and so just threw about 250g of lead on to make the blade balance around the estimated point.

We ended up at the Pat Moreton lookout around 20:30. there was about 7-8kts on the water ,so I guess it was about 12-14kts on the hill. Actually quite flyable. It was pretty black as there was no moon, but Roger shone the torch in the general direction.

All I needed was about 5-7 meters of flight distance so I could tell if I estimated the COL correctly. The first throw I only started about 1m off the ground. I had the Elevons on too much of a banking turn, so it made only about 3m distance banking before touchdown. Not  enough for the foil to grab. I had put a bank in the elevons so it would fly in circles as I was a tad concerned about it flying out to sea. There was a little too much on, so I straightened them up again and thought, “oh well, it’ll bank any way as no hand shaped foils fly that straight”.

The second throw was about 1.5m off the ground with almost zero forward effort in the throw. It flew perfectly….. a little too perfectly. It made about 10m distance then lifted about 5m leveled out and then lifted to at least 7-8 metres and was heading for the ocean in a dead straight line. I freaked a little at the same time as being stoked. It looked higher than the trees and I thought it was going to fly over the top of them into clean air. Luckily the turbulence from the tree made it bank right and touch down in behind them. Lucky!!

Either way a successful flight. The COL was guessed right. Next step, installing the spoilers, flaps and control gear.

The current state of Gemot.

Roger took the tape off the plane yesterday. The tape had really been doing a good job holding the whole thing together. 170g of tape all up. I thought I might get a minute or 2 of flying out of it, but as the video shows it did a lot better than that.

From here we’ll probably Araldite epoxy it and use the paper laminate system. then we should have a pretty solid wing.

The glue used for paper laminating.

Laminating the Zawlade proto.

Add a bit of water to the glue. About a 1:8 ratio of water:glue.

Paint the glue mix  on the raw foam with the paintbrush. Lay the paper on and smooth it out with the paint brush and squeegee.