It was a great afternoon with Jeff, Derek, Michael, Angel, and Niharika.
I started out the day working on getting the kill switches mounted. I had two proper power boat deadman switches that clip to you to shutdown the engines in case of you falling overboard. However they needed a good mounting housing.
Jeff started out working on attaching the cleats at the corners. We used the 1/4" poplar boards as a backing and the toggle bolts for securing into the plywood. The toggle bolts would go all the way up through the cleat and the board would also be stapled down to distribute the load to the plywood.
As I believe I've mentioned the lift handles were wiggling loose. So Jeff and Derek unscrewed them and pried them from their epoxy. We screwed the handles back in with lock-tite this time. And scuffed them up to try to get the epoxy to secure better.
Meanwhile Michael figured out how to wire in the kill switch for the thrust engine and ran the cable forward to the box I mounted earlier.
After preparing both the new handles and cleats we broke out the epoxy. There were a few complications. Unfortunately the stackup of the spacer board + cleat was too think such that the bolt couldn't reach the toggle bolt. We had to drill out the cleats to get the head of the screws slightly lower.
To test whether the cleat was secured well I pulled upward. Unfortunately this revealed that the port bow plywood was not secure down well at all. And the cleat had been secured down well, but the plywood gave, bending/partially breaking. So we had to mix up an additional batch of epoxy, and both secure the cleat, as well as glue the plywood down. This reinforces the urgency of running reinforcing fiberglass around the perimeter of the body to transfer the loads between the plywood on the surfaces and sides.
Unfortunately that's about when the batteries ran out in the GoPro. After securing everything we added my standard weights of barrels of water. In the beginning of the next clip you can see the buckets have appeared suddenly. The 3 parts of the video are from the 3 batteries used for filming. I'd love to have longer battery life. But at least in the Hero 4 the batteries can be changed quickly, and I have several to swap out.
In the final session we moved onto focusing on the throttle mechanism. Jeff and Michael discovered that they could loosten a nut and make the throttle move much more freely. And Jeff created a throttle mechanism out of an angle brace, 18" of aluminum tube. And most cleverly discovered that 1/4" post electric crimpable connectors can work well to crimp onto throttle cable housing. Experimenting with a few different ratios we successfully made a handle which can easily be moved, gives full range of throttle.
The one problem is that it is mounted at the aft end of the cockpit. We knew this would be a problem before we mounted it, but we wanted to test the mechanism anyway. I just need to find a longer throttle cable with housing. The current one is only 4-5 feet.
The end of the day concluded with testing the throttle and kill switch for the thrust engine. We held off on the lift engine due to all the epoxy around the perimeter. And the buckets balanced on the corner...
We started with testing the kill switches and when we tried the first kill switch it didn't do anything. So I turned it off at the engine and that killed it. After a little puzzling we remembered that the engines required an active connection to kill it instead of interrupting the signal. So it needs both the engine switch and the kill switch in the off position to successfully disable it since they are wired in series. We'll change it in the future to be in parallel such that if either are in off, it will be disabled, and it will require both to be in the on position to run.
The throttle mechanism testing was great. It worked just liked we planned. Which was a surprise due to it being made of ~ $5 in parts, an angle bracket, a bolt, several washers, and a hammered aluminum tube.
Here are a few more detailed pictures.
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| The very sophisticated throttle mechanism. |
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| The whole run of the throttle mechanism, from handle to engine. |
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| The backside of the kill switch box with the full front wiring routing visible. |
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| A new cleat and the reattached lift handles waiting for the epoxy to harden. |
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| The front port cleat attached and weighted down to help resecure the plywood to the foam underneath. |
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| The front side of the kill switch box. One kill switch for the lift engine(forward) and the other for the thrust engine. |
