Wednesday, 13 July 2011 15h00 – Moving on
The all-nighters have started as D-day for Sling 4 ATW approaches at the speed of light. Although the prototype ATW Sling 4 won’t be making an appearance at Virginia, the Sling 4 launch at 10h00 on Tuesday 19 July is a fixed date and she’ll leave for Oshkosh the next day or as soon thereafter as she’s ready. (There will, nevertheless, be a number of other standard Slings on show at Virginia).
Meanwhile, work at The Airplane Factory is reaching a crescendo. Yesterday Jean and Ruan put in a marathon session, each working for 31 continuous hours. The fuselage team worked until after midnight last night, but had the satisfaction of seeing the fuselage from firewall to tail in one continuous piece. They’re back on the job today with the objective of getting her on her undercarriage with the engine on by tomorrow morning. Ryall’s working non-stop on the Perspex for the canopy and the wing team is just surveying its work before beginning to polish them up for final fitment.
Probably the most eloquent expression of where we are right now is some photographs all, save for the shot of Jean and Ruan at the commencement of a 15 hour non-stop laminating session which was taken at about 22h00 last night all of the shots below were taken an hour ago at 13h00 today, Wednesday 13 July 2011.
Meanwhile, on the side, ZU-FNM, our Cape Town agent, Mark Bunning’s Sling, will fly later today under a proving flight authority and ZU-FNN, David Jang’s Sling has an authority to fly and is ready for delivery.
Til next time – The Airplane Factory Team
Sunday, 10 July 2011 Work continues late into each night
It’s been a long and late weekend, especially for Jean and the composites team. But first things first – Thanks to Chalkie for volunteering the use of his and Peter Hengst’s immersion suits from their 2003 Oshkosh centenary flight for our trip. It hadn’t been hours since a friend had sent through a record of water temperatures in the Bering straits and only minutes since we’d discussed taping up our sleeves and trouser legs in the absence of a better solution, when Chalkie’s email arrived. So we’ve taken up the offer and the suits will get a second chance to do some ocean crossings, hopefully once again without getting to see any water!
Meanwhile things are moving along slowly at the factory. For me, more the paperwork man, the pace on the construction of the plane seems painfully slow. The wings still need the standard leading edge tanks installed, work on the centre fuselage was only commenced this morning (Sunday 10 July) and the panel still looks mostly like a bird’s nest of wires! But Jean, Ryall, Ruan, Joseph, Brends and Florence in composites have been working serious hours. The blanks for pulling the canopy perspex over are dry and merely need to be annealed before use and the two main door frames are laid up and ready for finishing. Tomorrow a marathon session on the main canopy frame in which the doors will be housed. Mike assures me that tomorrow, with the full factory workforce available, things will suddenly begin to move more quickly. I promise to report further on that tomorrow.
Our objective remains to fly the ATW plane on Thursday or Friday this week and depart Wednesday or Thursday next week. That will always, however, be subject to safety considerations.
Meanwhile, the Airplane Factory features on Carte Blanche tonight, so if you have a TV (I don’t) get before it to watch the action.
Monday, 4 July 2011 Work on the canopy progresses, Director of Civil Aviation to launch Sling 4 on Tuesday 19 July and around the world departure delayed to 20 July 2011
Since last Friday the canopy blank has been fully prepared, two female canopy moulds cast, two foam canopy door frame cores routed, numerous centre fuselage components drawn, punched out and bent and re-assembly of the wings has commenced following tank seal testing.
While good progress is being made across the board, all substantial projects require both blind faith (to get them started and keep them moving) and also application of dispassionate decision making (to ensure they succeed rather than ending in catastrophe). While it was out plan to depart for the US from the Virginia Airshow in Durban on 16 July, we now believe that it’s too soon and we’ve decided to delay until Wednesday 20 July. With only 5 legs all the way to Oshkosh Mike and Jean still plan to arrive there on 27 July, but of course it is going to mean quite serious hours of flying. And notwithstanding that, if all goes according to plan the Sling 4 will still appear at the Virginia show en route one of its proving flights.
The route to the US is now as follows – Tedderfield to Pilanesberg to clear customs and then direct to Pointe Noire. That’s a 15.5 hour flight. Then the flight to Dakar is a long one, 4 200km around the coast (to avoid politics) which, due to a massive fuel load, will take 24 hours flying. The three remaining legs, to the Azores, New Foundland and Oshkosh come in at only 15 hours each, so that shouldn’t prove too much of a problem. A substantial benefit of the route is that it has only 4 stops en route. Our previous travels in the Sling have demonstrated again and again that the flying is easy and relaxing, it’s the stopping that’s time consuming, stressful and frustrating. So few, long legs really is the way to go. It also costs less because one doesn’t have to pay landing and approach fees as often, one sleeps in the plane, not in a hotel room and so on. Hhhmmm, anyhow, that’s still quite far away yet!
Meanwhile, the launch of the Sling 4 by the Director of Civil Aviation has also been delayed until 10h00 on Tuesday 19 July, the day before we leave. Please any interested parties feel free to attend. Finally, see below the most recent rendering of what the Sling 4 will look like when completed.
Saturday, 2 July 2011 The fuel tanks are sealed and the focus shifts to the canopy and centre fuselage.
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.
Monday, 27 June 2011 Construction continues on the prototype Sling 4 while plans develop
During the last two weeks there have been a number of changes around The Airplane Factory. While construction of Slings and Sling kits continues apace, a slightly different beast is taking shape in the northern quarter of hangar 7, directly under the watchful eyes of the company directors. Good progress is at last being made on the Sling 4. As appears from the photographs below, the lower half of the rear fuselage has already been riveted and the slight change from the standard Sling in the shape of the upper half is in evidence. The main and rear spars of each wing are loosely in place, and all 6 of the fuel tanks, which will give the aircraft an endurance of 24 hours when filled, have been sealed and are busy drying. Last night Jean and Chris Pietersen worked until 11pm in the cold hangar in order to achieve that.
Meanwhile, Gareth Bosch is working hard on planning the wiring system for the aircraft, which this time around will use a Vertical Power VP-X Sport electronic circuit breaker mechanism which is reputed to be highly reliable, easily configurable and provide excellent electrical system reporting. This will be the first Sling with the VP-X system. More generally the instrument panel layout has been settled and will be panel itself will be laser cut within the next few days. It contains two very sexy G2 MGL Odyssey EFIS instruments, a Garmin SL30 navcom radio, a Trig mode S transponder and the controller for the Airmaster AP320 constant speed propeller. Not much else is required. This time there will be no stormscope, although a Zaon PCAS traffic collision avoidance system will be plugged into and display on the MGL Odysseys. See the computer generated panel below.
Finally, time constraints have led to late night discussion on the most appropriate routing for the trip. Although the plan has, until yesterday, been to travel east to Oshkosh, and head back still going east, that requires 10 legs of which at least 3 are of more than 18 hours flying time and another 3 more than 14. Plus, travelling east the days are effectively shorter and, when tired, “tomorrow morning” comes quicker!
The flight from Johannesburg to Oshkosh going west, by comparison, has only 6 legs, all of which are less than 15 hours, and of course the days are effectively longer. So, right now it looks like it would be wise to reverse the planned direction so as to guarantee an arrival in Oshkosh before the show ends. Of course there’ll still be a great deal pressure on Mike and Jean to get there around 26 July, but at least it’s more likely to prove theoretically possible at first take off, without exceeding the speed of light. More about that later. See the map of the route below or work out the distances for yourself on Google Earth using the file in the link.
Tuesday, 21 June 2011 Construction commences on the prototype Sling 4
When the production prototype Sling , ZU-TAF was flown around the world during 2009 at take-off and landing she was loaded to 965kg, some 365kg above the maximum all up weight applicable to the light sport aircraft category for which she was designed. Yet she proved herself again and again, performing consistently well at that weight with only a 100hp Rotax 912 ULS engine.
The Sling 4, a light 4 seater variation of the standard Sling, will have an empty weight approximately 50kg heavier than the standard 2 seater Sling. With a maximum all up weight of 850kg it will have a useful load in the vicinity of 400kg, making it a respectable light 4 seater aircraft. With a 115hp turbo charged Rotax 914 UL engine, a constant speed propeller, a fuselage lengthened by some 550mm and standard Sling wings extended by 400mm each at the root, she should perform as well as the standard Sling.
In fact, so confident are we that we intend to fly our prototype Sling 4 to EAA Airventure Oshkosh, leaving within a week of her first flight, and return to Johannesburg by again circumnavigating the globe. Construction of the prototype Sling 4 commenced today and we intend to keep the public updated as the build progresses, particularly towards the end. Although the initial plan was for all 3 shareholders in the business (Mike, James and Jean) to complete the circumnavigation, production and management commitments at the factory are such that it’s impractical to take all 3 directors out of circulation for the full 4 week period of the flight. Instead Mike and Jean will be flying to Oshkosh, going west this time, and James and Jean will be returning. From Oshkosh back to SA there will also be a third pilot in the aircraft, the identity of whom is yet to be finalized, although at present if looks like our weather expert from the 2009 trip, Tim Parsonson, also a qualified pilot.
For a taste of what the Sling 4 will look like take a look at the computer generated renderings below created by our head draftsman, Ruan Coetzee. For the precise planned routing for the circumnavigation download the Google Earth file called “Sling 4 ATW” and take a look.
More next Monday!