Dartmoor Gliding News - Wednesday 10 December 2025

I wasn't going to blog today as we didn't fly, but the Duty Instructor sent me photos for the blog, so here goes.

The forecast for once was dry, sometimes sunny, with a south westerly wind. The Dos Amigos (Mike and Peter) conducted a pitch inspection. The Duty Instructor was up for flying, launching from the track at the west end.  But prudence arrived on site, and we decided on ground school, glider and vehicle maintenance, rather than churning up the pitch even with the proposed conservative operating measures.

Scratch had a breakthrough with the retrieve vehicle.  For years, we have suffered from drained batteries when the ground radio is left switched on.  Separate switches, key switches, even the idea of timers haven't solved the average pilot's inability to switch off the radio at the end of the day.  As I am sure our readers know, car batteries are expensive.  So now the vehicle key has a kill cord attached.  Just like a jet ski.  Take the key out of the ignition and the kill cord comes off, and the radio is switched off.  Genius.  Why didn't we think of that before?

With the decision made not to fly, Scratch could start on some private vehicle maintenance.  A gnarly problem; how does a VW Polo lose all its engine oil when there isn't a leak?  Whether the issue was solved is undetermined, but members are pleased that our oldest trainee is back on the road, and she can continue to come to the club and fly.  However, we need another member to solve the problem of non-stop rain.

Mike Jardine had already prepared the club laptop for the morning brief.  But now it wasn't required.  So it would be ground school instead.  Following a few questions from new member Michael Malic-Smith, I offered to deliver my lecture on glider instrumentation to our trainees and others.

Gavin in full lecture mode

Before the lecture, a few hands withdrew the fuselage of the Twin Astir Trainer from its trailer.  The first Wednesday Waver to look at the fuselage was John Osment, who required a few more measurements and questions answered before he finalises, and makes, the new instrument panels.

While the lecture was underway, there was some simulator work going on behind the blackout curtains.  A local task had been set; Brentor, Roadford reservoir, Lydford, and Brentor.

Mike Bennett tries his hand in the revamped simulator.  Note the rear seat instruments under test on the right-hand side.

After the lecture, others had a go and I too tried my hand in the simulator.  On my initial attempt I landed out at Launceston as there is a bug that prevents you from looking up to get some pointers of where the thermal activity might be.  On my second attempt, I got round in 25 minutes.  I am not sure is that is good or bad, but it felt slow.  As the updated simulator gets more use, we will be able to iron out the bugs and get Viktor's 3D-printed instruments properly mounted and commissioned.

Outside, DB was beavering away recommissioning the hydraulic brake system on G-CHBK.  What should have been a simple job turned out to be a difficult one.  After struggling with the brake bleeding kit, DB removed the brake flexible (pipe) and checked it.  Very little movement of air.   The rubber had swelled with age and caused a blockage.  Time to start sleuthing and find some spare parts.

The hydraulic brake calliper

No part numbers, no manufacturer's name.

It would be good to know who makes this so we can get some new brake pads

Who built this? Where is used elsewhere?  Can any readers identify it?

A search of T'interweb didn't reveal any answers.  I then turned to the “saviour”.  However, AI is not really very helpful in practice.  Lots of noise and bluster, but not much in the way of hard facts.  Copilot told me what I already knew; this is probably a motorcycle rear brake system.  Clean off the dirt and look for part numbers and manufacturers names.  Ask enthusiast forums for help.  Talk about stating the ***** obvious.  I installed and tried using reverse image lookup software on my pc. Again without success, and they say that AI is going to revolutionise the way we operate.....perhaps not, a bit of normal intelligence seems to be able to do much more.  So here is a challenge, can any of our readers use AI successfully to identify who makes this brake calliper and its part number?  The reward won't be a chocolate bar, but one of those items we keep cool in the kitchen for when the hangar doors are closed after flying.

Nice new DOT 3 brake fluid, but can DB commission the system?

The master brake cylinder and reservoir lives under the rear seat

The brake flexible and the banjo fittings were measured; 10 mm ID with straight and 28 degree fittings were identified.  A replacement was ordered and should arrive ready for our next attempt on Saturday.  Meanwhile, I will contact the UK GROB agent, Oxford Soaring, and GROB and LTB Linder in Germany to find out more about our hydraulic brake system.

The suspect brake flexible

Phil and a team of helpers checked the paint on the cockpit surround of the rear canopy.  The verdict, not good enough. So Phil, Ian, and David Moorley set about rubbing it back. It proved to be a messy job, but they cleaned up after themselves. Meanwhile, I researched a better paint to apply the fibreglass.

In the sunshine a few trailers were opened up to air the glider and some fettling was underway.  Care was needed as the rigging area was muddy and care was needed when moving vehicles around.

The Wednesday Wavers departed earlier than normal but were looking forward to Saturday when the field should be drier and aviation might commence.

When I got home, there was a delivery from Oxford Soaring waiting for me; the next piece in the Twin Astir Trainer puzzle.

The new stick grip for the rear control column in G-CHBK, complete with EASA Form One

Here's looking forward to a flyable Saturday. 

Gavin Short