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Working out CG

I had another attempt at putting the motor in tonight. This time i found the centre of the craft which is 4.2 meters / 2 = 2.1 meters and then made a mark on the craft that was 2 inches (50mm) behind that centre line. Its at this 50mm point that i placed my pole under the craft to use as a balance point. The skill saw you see on the back of the motor is adding weight that the oil and water will weigh just in case you were wondering 🙂

I added the blue bin you see there which is full of 20kg worth of concrete sand which is simulating my fuel tank, i then sat up the front of the craft and got my wife to sit directly behind me as the passengers weight and then moved the motor around until the craft was slightly tail heavy. If i shift my weight forward a fraction then the craft is wanting to start to drop in the front, indicating to me that its not over tail heavy and is probably about right going by my new understanding of how it should all work out .

The EA82 motor is now sitting alot further back than it was on my first attempt last night and looks more realistic. The distance from the front of the duct to the middle of the motor is approximately around 900 mm. I just have to check now with people that have been there done that and know what they are talking about if i am in fact on the right track with the procedure .

Here you can see if you look close enough the mark i made on the top deck that shows where the pole is sitting for the balance point. The make shift fuel tank (blue lid bin) is sitting directly over the balance point and the length of wood i have laying width ways across the craft to the left of the bin is where the intended mid bulk head will be, which is where the radiator will mount to. So therefore the tank and radiator will be sitting the closest to the balance point

Basically in a nut shell this is the procedure i am currently doing:

Found the center of the crafts length and made a mark that was 50mm behind this line towards the duct end I then placed a pole under the craft at the 50mm mark i made and then placed the motor in the rear of the craft. My wife and I sat in the drivers and passengers seating position and then shifted the motor back and forth until the craft become more tail heavy than anything else. Kept shifting the motor until it got to the point where if i (the driver) was to lean forward a little you could just feel the back of the craft wanting to lift. I made it tail heavy so that when thrust is applied it wont try to plough in everywhere i go.

I’m thinking that having it adjusted to suit myself and my wife’s weight is going to be more appropriate seeing as that’s who most commonly will be in it, and if i am in it on my own then i will add some weight under the seat to act as the weight she would otherwise be providing.

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