This last weekend was productive and the major portions of the frame are now complete.
After attaching the engine mounting plate to the frame, the next step was assembling the lower frame. The lower frame is similar to the lower ring of the upper frame, so it was possible to reuse the jig for the upper frame with some minor modifications. This was simply making new wood rotor shaft mounts for the lower frame and swapping them out in place of the old ones. Then all of the lower frame elements were cut and placed in the jig.
With all of the elements in place, the same process for riveting the gussets was followed.
Next the lower rotor shaft mounts were machined out of metal. There was a couple of hiccups due to the double sided tape not holding and bit breaking.
Once the mounts were completed, the shaft mounts were attached with bolts to the lower frame in the same manner of the upper frame.
In the future the gussets would be attached to the top side of the lower frame. However, at this stage the method of attaching the idler pulleys and tensioners hadn't been finalized. Therefore the upper gussets were left off at this point.
With the two halves completed, it was time to start attaching them together. Both halves of the frame were attached to the rotor axles to hold the two halves relative to each other. It was easiest to work with the frame flipped over since most of the riveting was on the bottom.
Four lengths of tubing were initially cut and attached on the sides of the frame along with the gussets for the lower frame. Clecos were used to hold the parts together prior to riveting.
Next the lower cross members were added to the lower frame
With all of the new elements attached, it was time to riveting the parts and finalized the attachment between the frames. At that point the frame was flipped back over to see the progress.
At this point about 80% of the frame is complete. the frame members at the front of back need to be added and some smaller cross members need to be added to stiffen the frame. However, before completing the frame elements, the attachment hardware needs to be completed to make sure there aren't any issues with the remaining structure. Once the attachment hardware has been finalized, then the frame can be finalized.