Mixed Success

The morning was warm, the wind less than ten knots though varying in direction, the strip awash with people and aeroplanes and cars looking for space.

Strip

Best of all I finally had an instructor lined up – said instructor in fact being the chap whose name and squiggle appears on the cover page of the POH for the X’Air!

The sheep were out again and I joined the effort to relocate them – they’d gone both under and over the allegedly-electric fence this time!

Never mind giving me the eyeballs you - just get off the blooming runway!

Never mind giving me the eyeballs you – just get off the blooming runway!

What could possibly go wrong…

It was interesting to do the walkaround of the aircraft with someone who knew the type so well and I learned a few extra details and things to check (vent on the back of the fuel pump, and the fact the tyre pressure is actually part of the mechanics of the suspension).

It was also interesting to hear some of the changes made to the X’Air to satisfy the BMAA once they started being imported (and that just after the introduction of Section S).

The jury strut horizontally between the two main struts is a British addition to increase the tolerance to negative G, but it then interfered with the natural twist of the wing in flight (which used to cause a sort of natural washout), which made it somewhat unstable in pitch.  That was compensated for by adding a bit of reflex to the ailerons which as a side effect added 5 knots to the cruise airspeed…  Fascinating display of engineering knock-on effects!

The flaps meanwhile, are almost a paperwork exercise – there to bring the nominal stall speed down by a princely 6 knots from 38 to 32 thus nipping in under the 35 knot limit for a microlight!  (Though both stages really does steepen the approach – a lot)

After watching the flurry of departures and over a cuppa we sat down to discus what we wanted out of the day and, for my benefit, went through a sort of “microlights for group-A pilots” brief as well as the discussion of “I know it’s not loggable but how many hours have you really flown it?”

I went first, with Guy flying the first 20 minutes or so to discover any particular foibles of Rhubarb as opposed to any other X’Air.  (She does have a few we discovered – dropping the left wing consistently in when stalled in certain configurations of flap and power).  Then we started on the training proper.

Steep turns I’m fairly comfortable with in the X’Air now and I bounced us through our own wake on the first demo, leading Guy later to comment that I seemed to have used by time “productively” in the aircraft…

Stalls I hadn’t really done but are so startlingly undramatic that they weren’t too challenging – she really will just sit there with full back stick wallowing about and sinking but not really doing much of anything else at all.

Back at the strip my main offence was not getting setup and trimmed early enough to have a stable approach.  This usually (and yes I’m acutely aware it’s an repeat offence!) ended with me being high and fast and/or well off the centreline.

Neither landing we did was as neat as my attempt the previous week annoyingly.

I was also picked up on an non-aircraft-specific issue of lookout – a useful reminder of why it’s a good idea to have an instructor along occasionally regardless of specific training needs.  When concentrating on something else lookout is one of the things that does tend to go by the by.

More practice on that was lined up for after lunch (picnic outside the hut!) while Clive took his turn and I chased a rogue sheep off the runway. (The third of the day!)

Clive and Guy returned – Clive with broadly the same issues, of ending up too high.  Perhaps those cables are radiating anti-grav not just carrying electric… 😉

It was after another cuppa we hit the snag of the day.

I’d started up, on second attempt – after a bit of experimenting with choke and throttle for the warm-to-hot-ish state of the engine, and was doing the checks when on the left mag cough splutter I gave Guy a startled glance.

“That’s not normal!”

I repeated the checks on both leaving it a bit longer with on off (I have been guilty in the past of just flicking them rather than waiting to see what the drop actually is) and this time on the left it was cough splutter dead.

Fantastic.

Actually the word I used was a different one…

“That needs a look then.”  I switched everything off and clambered out.

Nick headed to the car for the toolbox and we talked through the problem.

Spark plugs came out and, though looked visually fine, were swapped over.  Same issue.

All right – check cheapest possibilities first…

A multimeter was borrowed from Andy and, being the littlest, I went in behind the panel head first to test the switches.  Not dignified – laid half across both seats with my feet hanging out over the strut and my head and shoulders laying on the cockpit floor (I needed both hands so couldn’t support myself!)

Not that.

More discussion and I learned that what I’ve been thinking of, and calling, “left mag / right mag” are actually part of an electronic ignition system known as DCDI (Dual Capacitor Discharge Ignition).  Two CDI units   fire two spark plugs each, one in each of the two cylinders.

They’re positioned front and back and no one knew which left/right switch was front and back so the next step was pulling leads of and trying it with the upshot that the final diagnosis was either the frontmost CDI had popped it’s clogs or that the associated wiring had.

Wiring is cheaper – that first!

But tracing cables is slow so with regret we said goodbye to the instructor, cursed our luck to have a tech problem on the best flying day of the year so far and pushed the aircraft back to her spot to investigate further.

And there perhaps we’ve found the problem – some distinctly underspec crimping in the connectors from the engine to the airframe / instruments was in evidence.  At least one cable was finger loose and pulled from its connector.  Two more actively fell from their connectors as we pulled at cables to move things to a workable position.

Can it be that cheap a fix?  Here’s hoping…

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