Dartmoor Gliding Society Club News: Dartmoor Gliding News - 5 June 2024

After John Allan made his first 300km flight from Brentor on 5 June I invited him to tell us how he did it. This is his tale.

Gavin Short

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300km Gold Distance flight

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This year started badly for gliding, the weather from January all the way through to the end of April was pretty poor, including several weeks of no flying at all, in February, due to the state of the airfield.

At last the weather started to improve, and I had started to get some good soaring flights to push out beyond gliding range of the airfield - the 5NM limits having been wiped away when I passed my Bronze Cross Country Navigation and Field Landing assessment in the Autumn of last year. I was getting used to my Mini Nimbus (KPV) again, and really starting to feel at home in it after the long winter. The opportunity of good weather saw me complete a Silver distance (50km), which completed my BGA Silver Badge.

The next week we had a club trip to Aston Down, and with a keen eye on the forecasts for cross-country flights, I took the opportunity to start pushing further, with cross-country flights most of that week, including flying the Aston Down Club 100km task with enough time to make two extra legs taking it to over 200km. The point of all of this, is that it starts to build up experience and knowledge of the sky, your glider, how the instruments work for navigation, and how your own mind and body cope with long, 5 hour plus flights. Diet and hydration and comfort matter. I don't think it's safe to fly for longer than around 2-3hrs for without being able to drink at least 2 or more litres of water and have the means of easily getting rid of it!!! I think to start flying further you need to really know it's all going to work as planned, so that you can focus on lookout, the task and what's happening to the weather and the surrounding sky. Time in the air, improves thermaling skills, and brings knowledge and confidence to know when a cloud looks good and roughly what to expect in terms of a climb, and how to quickly make use of a thermal when you find it.

A week after I got back from Aston Down, RASP was showing signs of an excellent Wednesday at Dartmoor Gliding, and the WhatsApp group was full of enthusiastic chatter. From the Monday onwards, I kept an eagle eye on the various gliding forecasts. RASP continued to show a 4-5 star prediction across most of Devon. I felt that as I'd done a 216km flight in a 5 hour 16 minute flight at 46km/h, in theoretically poorer conditions with time wasted flying about aimlessly for some of it, that if I really pushed then 300km would be achievable in the 5-6 hour thermic window, that was forecast.

For a 300km task, you have to declare what you are going to do. I'd been working out various ways of getting a 300km flight. An out and return flight seemed less likely to be achievable as RASP showed that the good soaring area would create a gap from Exeter up the M5 in the late afternoon, and that would possibly mean a landing at North Hill - perfectly safe, but with logistics to sort out the retrieve, or a proper land out a long way from Brentor.

I played with various options alongside the RASP charts during the week (SkyDemon Lite is great for quickly working out task distances), and then a few messages back and forth with Richard Roberts. The night before, I settled on a three turn point, "cats cradle" task of Brentor (BRT), Chard (CHA), Roadford (ROA), Dulverton (DUL), Brentor (BRT), giving 309km. I thought I'd get the bit past Exeter out of the way first, then I could always bail if I didn't fancy going back up to Exmoor later, but conditions over North Devon were forecast to remain good late into the afternoon, so it all seemed to work - in theory!!!

Wednesday came, and the forecast still looked good. I made my declaration on paper to Gavin, our Official Observer, as I don't seem to be able to electronically declare a task to my IGC Flarm, and I also wanted to use the BGA dongle logger as a backup, so the paper method seemed very easy and safer. At the briefing in the morning, I was put on the spot by duty instructor Mike Jardine, who asked what task I had set, so no backing out now!!!

Several gliders had launched from 1100hrs but weren't managing to stay up yet, it was fairly blue around the airfield, not exactly as forecast. At 1200hrs, I felt there was a reasonable chance of getting away, and I needed the time to complete the task before the thermal window closes. A small wisp of a cloud was building and passing over the winch, it looked as if it had turbulent air moving up into it. I took the winch launch to 1,200ft, into the 10Kt North Westerly wind, turned and went straight back to my thermal which was now halfway down the airfield, tricky at first but once I reached a decent height of around 2,500ft, I could push out further to much better lift and climbed to cloud base near Tavistock. I started my task at around 4,000ft AGL, with plenty of height to reach some better looking sky towards Okehampton.

Annoyingly, I could hear that one of the undercarriage doors hadn't closed properly, and was a little like having the back windows of a car open, when you get a kind of thrumming noise. I put the wheel down, less noise, wheel up, more noise, normally it's much quieter. I briefly thought to land and sort it, but the day would have been wasted, and if it started to bother me, I could fly with the wheel down anyway, so I just lived with it and soon forgot about it.

The day was building and conditions improved rapidly, and I was able to make good progress round the active Willsworthy danger area, to Okehampton Camp and turned east towards Exeter. The altimeter subscale now set to QNH, now I'm out of gliding range of Brentor.

Progress was good, and I had been warned that there would be lots of other glider traffic about, and there was. I've not seen it so busy in the South West before, more like being at Aston Down in that respect. I was able to keep moving on fairly fast between good thermals. I then passed Exeter airport, keeping clear to the north. Soon I was looking down on North Hill and Dunkeswell a few miles to the north, then I passed Honiton and saw Chard ahead. I enjoyed great views down the south coast to Weymouth, and to the North coast as well.

Passing North Hill airfield (middle) with Dunkeswell airfield, far right

I joined another glider in a thermal at Chard, and then a third joined us as we climbed, each leaving quickly as we got up towards cloud base. I later worked out one of them was doing a 750km task out of Lasham including a leg down to Liskeard - no wonder they were gone and off into the distance as soon as they left the thermal!!

Now for the longest leg into wind all the way to Roadford. North of Exeter airport was a little blue, but making a detour along cloud streets lined up from North Hill towards Exmoor seemed a long way out of the way, so I pushed on just north of Exeter, thankfully finding better thermals when I did get to the clouds, due to the sunshine on the ground. Along the northern edge of Dartmoor things went very well, and I sped along under cloud streets, and was at Roadford in no time, often with other gliders nearby again.

Change of cloud base height, North of Exeter Airport. It seemed like may be a convergence, but wasn't, and there wasn't really any lift up the side of the clouds, as you expect from a sea breeze front.

Now to Dulverton. With some knowledge of the Macready speed to fly theory, I knew I needed to add a few knots above my best glide of 51Kt, for the good thermals, so 60Kts between thermals. Dulverton appeared ahead. However, things were looking rather more blue than it had been, now at around 1630hrs as I turned Dulverton, I was looking at a rather large area of blue sky with only a few small clouds. Thermals were there, but really rough and broken, and I started to think I may end up landing out.

But after I got the measure of this change, in the way they worked, I managed a decent climb to near cloud base, enough to just push on for the better sky towards Okehampton, I'd been blown a bit to the east and looking down at Crediton to my left wasn't really what I needed, but a few thermals later I was in great thermals along the North of Dartmoor and a few miles east of Okehampton. As I climbed, my navigation computer pinged to say I was above final glide. I had more good climbs ahead, but I climbed to cloud base anyway - let's not mess this up now!!! Past Okehampton Camp, turning south towards Meldon, making very sure I was staying clear of the active danger area again. I set the altimeter back to QFE.

Home run from Okehampton looking down on Meldon Reservoir. Now being careful to stay outside the Firing Range beyond Meldon which was active.

I took a totally unnecessary climb over Lydford, but I really enjoyed myself in a lovely thermal. I flew through the finish line at Brentor at about 2,500ft, looking about for what was launching and what was happening, pre circuit checks, radio call, circuit and landed.

John's Mini-Nimbus "peanut", (KPV), joins the rest of the gliders ready for derigging at the end of a great day

309km, total flight 5 hours 14 minutes. As I type I'm hoping this will qualify for a 300km Gold distance flight, plus both legs of the 100km diploma as my handicapped speed was 65.8Km/h which will hopefully scrape in the 65Km/h requirement, but this is all subject to verification by the BGA. It's also my furthest ever flight so far, and fastest task.