Slingsby T61 Motor Glider Project Diary by Trevor Hewson
The Astrohog build went somewhat more quickly than expected so, after a few months break, I found myself in November 2009 staring at an empty building board. I put off the difficult question of what to build next by embarking on long overdue refurbishment of a couple of faithful old models (the Lazy Bee and P38) and was given an Autogyro kit for Christmas (see Rotorshape). So that got me through to the beginning of February but the UK 2010 Winter was one of those that seemed like it would never end so, even at that late stage, I found myself looking around for the next major build. Eventually, I settled on the idea of a motor glider and before long found myself looking through Cliff Charlesworth's plans. The T61 seemed the right sort of size and so the plan, canopy and cowl were ordered and by the beginning of March I was in possession of a large pile of wood. I was somewhat alarmed to find that the wood weighed about 21lb which did make me question my 10 - 11lb all up weight target but then, I had over-ordered somewhat on the ply so, brushing aside such doubts, I set about clearing enough space on the bench to start. |
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March 2010 (More on March) The spar itself was the obvious place to start. Before fitting the second facing to the inner section of the spars, the brass joiner boxes had to be fitted. I did this with two pairs of balsa wedges to set the forward sweep and dihedral angles.
By the end of the month I had begun construction of the right hand wing by gluing the leading edge portions of the ribs in place, followed by a balsa false leading edge. |
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April 2010 (More on April)
The underside sheeting was applied in similar fashion then of course the process repeated for the other wing. The resulting D boxes are incredibly strong.
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May 2010 (More on May)
The fixed portion was tackled first with the result you see here. This was actually a departure from the arrangement shown on the plan - see detailed May diary entry for more details. The aileron ribs were notched for the top and bottom spars (allowing for the subsequent facing) and the trailing edge was given the same treatment as the fixed section, with a selection of packing pieces used to set the washout.
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June 2010 (More on June)
July 2010 (more on July)
The formers were then joined using basswood for the lower longerons. The root ribs and top spine are just dry fitted in this picture.
Next came the upper longerons (basswood again) and the upper stringers. Spruce is specified for all longerons and stringers but I opted for balsa for the stringers, again in a quest to save a bit of weight at the tail end.
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September 2010 (more on September)
I also made the basic seat bench at this point so that the pilot could be properly positioned. |
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