It’s the final weekend of the month and that traditionally means that the entire Airplane Factory staff complement gets off early on Friday and that no-one works overtime on the weekend. Mike, Jean, Gareth and James, however, are here putting some of the last minute touches (what Jean refers to as “tweaks”) on ZU-TAF before we really pile on the proving hours from tomorrow afternoon onwards.
With 8 hours flown we already know that she flies beautifully, but we’re required to fly 40 hours before we obtain an authority to fly from the CAA. Also, we still need to test her at MAUW, quite apart from the testing on a myriad of other systems and configurations. Some thoughts that have been taking some mind-space over the last few days include –
Checking and rechecking the fuel system – The Rotax 914 UL engine is turbocharged and requires high fuel pressure to operate. There are two high pressure electrically powered fuel pumps and no mechanical backup. That does mean that electrical failure also results in engine failure. We were always going with 2 fuel pumps (which is standard with the engine). As of yesterday we’re also putting in another 26 Ah backup battery to increase redundancy in the event of an over ocean failure.We’re going east again and our routing sees various small changes as we think up new ideas. Right now it looks like Tedderfield, Durban, St Denis (Reunion), Male (Maldives), Phuket (Thailand), Taipei (Taiwan), Sapporo (Japan), Adak Island (Bering Straits, Alaska, USA), Torrance Los Angeles (California, USA), Green Bay (Wisconsin, USA), St John’s (New Foundland, Canada), Santa Maria (Azores), Dakar (Senegal), Pointe Noire (Republic of Congo), Pilanesburg (South Africa). The longest leg is Dakar – Pointe Noire at 4 200km.If you read Wikipedia on Adak Island, Bering Straits, it includes the lines – “Gales occur in all months of the year at Adak”, “Adak has an average of 341 days per year with measurable precipitation” and “The foggiest months are July and August when an average of 26 of the 31 days each month have fog” (we plan to arrive on about 18 August). Sadly the airstrip does not have an ILS approach, only an NDB DME, for which we don’t in any event have the instruments. We ought to be able to do a GLS using our MGL Odysseys, however. It does sound interesting with sea temperatures close to 0 degrees!We’ve put in two “transfer fuel pumps” to transfer fuel from the B and C “accessory” tanks to the standard “A” tanks, from which fuel is drawn for the engine. Again, there are two for redundancy, only one is needed. The standard Sling 4 tanks take 75 liters each. The B tanks take 65 liters each and the C tanks take 87 liters each. That gives a total fuel capacity of 454 liters. At 20 liters per hour, that’s an endurance of 22.5 hours. And cruising at 100 knots (185 kph) that’s roughly 4 150 km. It does mean that for the Dakar to Pointe Noire leg a little extra fuel will also need to be carried on the back seats.The entire trip will involve about 230 hours of flying. At an average engine RPM of 5 200, that means that the pistons will each move up and down more than 71 million times during the circumnavigation!With final preparations underway, we’re now even beginning to plan last minute luxury items like the iPod playlist, a small stash of good whiskey in case we have to spend a day or two at sea and so on.As appears from the photographs, our satellite tracking device is installed. That means we can be seen by the world even while we’re totally isolated. We have only a VHF radio, which means we have no communications with land except in the first and last hour of each oversea flight. One difference this time is that the satellite tracker does enable us to send out a series of 23 character standard messages, plus 9 characters of our own. And we can receive text messages of up to 23 characters!We’ve had an argument about whether to take an analogue compass – there’s an electrical compass in each MGL Voyager and, providing we’re moving, our handheld Garmin 495 GPS operates as a compass. All require electrical power, however. Finally, we’ve an old black and white LED Garmin Pilot III which uses penlight batteries. Do we bother to take a standard magnetic compass on a circumnavigation at all? What views?
In response to the suggestion that we pass through East London on the way out and visit the annual South African EAA convention – we’d love to do that, but it just doesn’t seem practical given that we need to leave from an international airport. It does look like Mike, Jean and James will fly down together in the Sling 4 to King Shaka, Durban, from where James and Jean will depart for Reunion, on Saturday 6 August 2011. If all goes according to plan Mike will then fly the Airplane Factory demo Sling to East London to participate in the EAA Convention. We promise to make up for the absence of the Sling 4 by attending many shows after we return!
Hold thumbs , thanks for the support and please come and see us off from Tedderfield at 09h30 next Saturday if you live in the JHB area. Fly-alongs toward Durban are welcome.
The Team