Hi everyone
I am back on the mail group after a long lay-off! My name is Nick Norman
and I fly the Europa G-EIKY owned by Jonathon Milbank which was
mentioned by Rowland last week.
Having re-set all the trigger coils (we had to take a couple of them off
to bend the metal brackets) and dressed the one that had been contacting
the trigger AND sawn off a mil or so from the mounting pillars of the
outer pickups so that they now line up with the target as per the engine
manual's specification, we ground-ran the engine the other day and found
it transformed! Instant starting from cold in near-zero temperatures,
idles sweetly as low as 800, no mag drop difference or roughness.
Moral - check the trigger coil clearances (before installation - we had
to take out the engine to adjust!) if you can as the manufacturer
obviously has a quality control problem - they should be 12 - 16 thou,
and the axial misalignment between target and pickup should be less than
0.3mm. Unfortunately we were unable to test fly BECAUSE....
On rigging, the inner tailplane sleeve TP6, of which there has been some
chat recently, was found to be unbonded. At first this was put down to
bad building, but after a little more attention I realised that it was
because there was a tiny amount of play between the TP4 torque tube and
the TP12 lever arm. The play was so slight it could only be felt and not
really seen, but with the tailplane on minus the pip pin, the trailing
edge could be moved up and down by around 10mm before the torque tube
started to rotate. This means that effectively, the elevator drive was
being transferred by the TP6 sleeve, and IMHO, this is why the sleeve
unbonded - it has far too small a diameter to carry that sort of load.
The culprit is obviously slight enlargement of the hole through which
the (supposedly interference fit) pins TP14B pass, but ultimately I
think the design is bad - the drive from the stick comes onto the torque
tube, then is transferred to the lever arms, meanwhile the torque tube
is rigidly attached to the tailplane outer sleeve.
The implications could be quite serious if the aircraft is flown with
the tailplane sleeve unbonded (or if it unbonds in flight) - it is
possible that the tailplane could slide out far enough for the lever arm
pins to come out (depending on the size of your recess for the
pip-pins), thus losing control of one of the tailplanes. Even if this
does not happen, the slop in the linkaged between the tailplane and the
mass-balance could result in the tailplane fluttering, an effect which
can be disasterous.
Of course we have been in touch with the factory and they are thinking
about it, but in the mean time we will not be flying the aircraft! May I
suggest that readers condsider doing the same, or at least check very
carefully for any play between the torque tubes and lever arms (try
fitting the tailplanes without the pip-pins and trying to rotate them
whilst watching the alignment of the pip-pin holes) and also ensure that
the TP6 sleeves are still firmly bonded.
I know this sounds a little dramatic but we are talking about a primary
flying control surface here.
BTW, my credentials are that I am a professional helicopter pilot,
glider (sailplane) pilot and degree-qualified electronic engineer. I
hold a British Gliding Association inspector's rating for airframes and
engines which allows me to work on, repair and renew certificates of
airworthiness on sailplanes and motorgiders.
Sorry to be the bearer of bad news,
ps I don't know if the XS uses the same tailplane drive, but I suspect
it does.
Nick Norman
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