It took quite a bit of fiddling to get the bottom of the sponson sides to line up, whilst ensuring that the sides were vertical. Once I was happy with the templates, the sides aere cut out and triangular balsa strips fitted around the forward edges. These served to reinforce the load bearing lower joints and also allow the top edges of the sponsons to be rounded off later.
A few more dry-fit sessions and then the sides were finally glued in place.
I did consider fibreglassing the undersides of the sponsons but covering film doesn't look very good over epoxy and I didn't want to get involved with painting so settled for 0.4mm ply 'sole plates'. No other sealing was applied, so it will be important to pay close attention to the seams in the covering to keep the water out.
I had hoped to be able to fit the motor through the cowl ring but, as you can see in the first picture, the spinner diameter is less than that of the cross mount so even with a really thin cowl ring, I wasn't confident that I would be able to get the mounting bolts in place. The idea occurred to me to try fitting the motor through from the rear of the firewall. As the second picture shows, this does bring the mounting bolt holes very close to the large circular cutout.
The firewall is 3mm ply and I cut out mounting blocks of 3mm ply, partly for reinforcement but mainly to accommodate the spikes on the T nuts. As you can see, the T nuts themselves also had to be butchered somewhat to let the motor through.
With the motor mounting sorted, the firewall position was finalised and it was glued in place. To avoid filling the motor with balsa dust, I made a 'dummy motor' to hold the spinner in place while sorting out the contours of the nose.
I hoped to cover the hatch in six sections of 3/32in balsa but after fitting the first two, the stress on the framework was such that I reverted to the slow but sure method of planking it.
The last construction detail was the tailskid - a simple balsa/ply sandwich. Owing to lack of forethought on my part, it is only fitted to the balsa underside so won't take much abuse. Hopefully though it will keep the load off the rudder hinges when the model is sitting on the grass.
So, after a few rounds of filling and sanding, the month ended with a final photocall for the uncovered model.