The behind the spar and both leading edge fuel tanks in each wing of the Sling 4 have been pressure tested and there are no leaks. They will therefore be finally assembled into the wings over the next few days.
Meanwhile, the greatest single challenge facing the team is the development of the canopy in the tight time constraints facing the project. Far more complex than the standard 2 seater sliding canopy, the 4 seater canopy comprises 5 sections with mid-located gullwing doors which are visible, opened, in the undercarriage-less photograph some entries down. This design will give additional rigidity to the entire airframe structure. The canopy frame, however, which is to be constructed from carbon fibre and glass fibre with epoxy resin, is a complex structure will take some time to prepare. Luckily for The Airplane Factory Manfred Springer, who lives on the airfield, has a 6 by 3 m 3D routing machine and has prepared a blank of the canopy from which a female can be cast. Jean is working on the problem day and night and will be doing everything necessary to ensure that by the end of this coming week a fully functional (and knowing Jean, probably also beautiful), canopy arrangement is available).
Simultaneously Terry is on the final straight with the small brackets and other finishing elements of the centre fuselage on Solid Works. Most of the remaining centre fuselage parts will be punched out tomorrow (Saturday) and construction on the centre fuselage will commence in earnest on Sunday/Monday. Although the control arrangements are slightly different in the Sling 4 and the additional seats and changed wing placements require some changes, conceptually the Sling 4 centre fuselage arrangements are materially the same as on the Sling 4. Three months ago 10 people, 5 of whom had absolutely no mechanical experience, built a Sling in 7 days. (For a teaser on that see http://www.youtube.com/watch?v=yShaGeKPGyo). Now, with an entire factory full of experienced aircraft assemblers, the Sling 4 (sans canopy anyhow) should be a cinch to complete in 6 days. Of course unlike with the 7 days aircraft, the rear fuselage and wings are already almost complete!
More news will follow after the weekend. For those doubters, however, The Airplane Factory’s confidence that the aircraft will be completed by next weekend is demonstrated by the fact that the Director for Civil Aviation in South Africa, Mr Thwala, has agreed to launch the prototype at 10h00 on Monday morning, 11 July, 9 days hence. We are honoured to host Mr Thwala and we also invite those who are interested in seeing ZU-TAF completed to attend the gathering. We promise a full tour of the factory to those who are interested.
Until next week, sala kahle.