High Level Testing

Another trip to test out various bits of the new aircraft. Here we are at 6000ft with the autopilot engaged, holding the altitude and maintaining course. The route took us northwest from Perth over the mountains to Fort William, then south to Oban and east back to Perth. There was about 20kt of wind at 6000ft and quite a bit of mountain wave activity. The altitude hold managed to cope, but several times the ALT light flashed as it was nearing the limits of its capability in the up and downdraughts.

The sunshade was deployed to test its capabilities. All satisfactory apart from when I leaned too far to my left to inspect something on the ground and the internal rib of the shade snagged on my headset and I was stuck. Taking the headset off and untangling it fixed the dilemma. Lesson learned.

At one point in an updraught, with the autopilot lowering the nose to try and maintain altitude, we got a nice healthy groundspeed:

The route on Skydemon:

…and as seen on Flightradar24. The autopilot does a good job of flying in a straight line. The slight wiggles are where it got a bit bumpy and I hand flew as the autopilot was struggling a bit in the turbulence.

After landing we taxied to the pumps and filled up to full again. The amount uplifted and the flight time since the tanks were last full calculates at just under 29 litres/hr fuel consumption. About 10 lt/hr more than the Sting, but the autopilot, baggage compartment and extra fuel capacity makes it worth it. And also the extra speed!

Talking of extra fuel capacity, the next test is to fill to full fuel including the tip tanks and depart with 210 litres on a long trip. The plan is to route down the east coast towards Newcastle, then across to Stranraer, over Arran to the Lochgilphead area and back to Perth via Loch Lomond. This is long enough to verify the fuel feed from the auxiliary tanks and the associated low fuel warning lights. Also we are not too far from a diversion airfield should the tip tanks fail to flow. All being well, each tip tank should give about an hour, thus extending range by (ballpark) 280 miles.

I’ve been reading (again) The Flight of the Mew Gull by Alex Henshaw, all about the record breaking Cape Town and back flight in the late 1930’s, and filled with inspiration have been planning some long range flights on Skydemon. Our RV itself has been to Cape Town.

Perth to the Faroe Islands is well within range, as is Perth straight across the North Sea to Stavanger. But both involve a lot of cold water, and we don’t yet have a liferaft. That is on the shopping list, but until then, we’ll be going the long way round to Sweden, remaining within gliding range of dry land at all times.

Talking of Sweden, our trip last summer earned us the highly coveted, world famous and prestigious Scottish Aero Club Longest Distance Flown 2018 award. We’re going to have to go further next year to defend the title!

p.s. updraft or updraught? Answers on a postcard…