From the first hover trials the available surface area of the lift fan was significantly limited by the large surface area of the engine mount. A rough estimate is that it was covering 70% of the surface area of the fan, leaving only some small slivers of intake areas open. You can see that all but a 6" chord at the front and back of the fan were open in this post.
For a quick comparison you can see the new mount preassembly on the left with the parts cut away on the right.
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| The parts of the new mount next to the parts of the old mount. |
Here it is on the fan, you can see the front and back has close to double the area, as well as large areas on the sides open as well. The main blocked area is basically under the engine now, and is also near the center of the blades which is not an efficient area anyway.
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| Fit testing the engine mount before gluing. |
Here's one last shot of it waiting for the epoxy to harden.
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| The new engine mount in the clamps waiting for the epoxy to dry. |
The construction technique was to cut down the boards previously used to a 10.5" square around the engine mount. Then aluminum c-channel is fitted side to side and along the sides of the board. That aluminum c-channel is then bolted to 1" steel square tube. The c-channel is epoxyed on the sides of the boards which are sanded down to a press fit.
Looking at the design I think the aluminum c-channel all the way to the edges might be overkill and just more air resistance. I may go back and trim the outside 6" off since the steel should be strong enough on its own.
In this process we had quite a bit of epoxy left over. Michael noticed it was getting hot enough to be either smoking or steaming. In the following video you can see the epoxy puck which had been created by the hardening epoxy still in the bowl. In the first second you can see a little bit of the steam/smoke right by his hand in front of the cabinet. I guess the perimeter is still not yet hardened since it's being cooled by the environment.
Here are the timelapses from today. We ran out of battery half way through so there's two parts.
