Hi Kristin,

I would have been a real thrill to get it into the air.  I thought ours was
the last but not so. (ex Thai Dimona's)   so well done.

We have now about 170 airframe hrs now since the first flight in June 2014.
It has exceeded my expectations by 150%.  There are a few negatives  but the
positives more than outweigh them. I guess we were lucky because it came
with a zero timed engine. . it had a forced landing about a year before they
were retired from the RTAF which broke the U/C  . they blamed it on a "Flat
Battery.  The engine was sent back to  Limbach for a rebuild which was
carried out but they forgot to restamp the serial plate with a -2
indicating a rebuild.  Caused a bit of confusion

Of interest, ours has the older aileron system.. Because of the wing design
the"up" loads on the ailerons when cruising is quite high and Wolf Hoffman
designed it so the aileron push rods were in compression when the up loads
were there.  (notice the position of the ailerons above 100Kts)  TO overcome
the bending moment, they included 5 linear bearing (3 bearing)  sets per
wing.  Unfortunatly, they also used  weird bearings .. ie each bearing set
had 3 bearings pointing inwards.  For some reason they used nylon for the
complete bearing outer .. including the ball race.  With the humidity in
Thailand and nylon absorbing moisture, these "outers" expanded a little .
enough to seize all 30 bearings which combined with the push rod being in
compression, stiffened up the aileron control.   So we purchased a new set
of bearing sets from Diamond . they are the same as used on the DA-40,
except were "proper bearings" with just a nylon "tyre" on the outer surface.
It was a mission to replace them  but now works well with no sticking. I
think with the later design (in tension)  they also changed the ratios so
you didn't have such a high load rolling into a turn.

I do like your canopy . looks like new and the side vents with the pop out
ventilators really great.  I find the front NACA duct not as effective as it
should be 

Of interest, I have installed a Westach dual CHT system on the rear 2
cylinders and use that as a guide to engine management  

Also..

*An MGL FF-1 fuel computer

* Intercom using the amplifier in the radio..  FSG-90 it think

* USB sockets for 5 V  (not so good as a standard 12V outlet better using
the car type chargers)

Plus some other tricky bits . but basically tried to keep it all as simple
as possible.  There was a lot of extra wiring in the Thai Dimonas which was
removed.

 

The biggest issue we have at the moment with another Limbach powered Grob
109 is the fuel..  100LL avgas is not actually low lead and seems to be
causing big problems with lead build up on the valves (in fact everywhere)
.. eventually burning thru. But also it seems the lead layer is causing a big
reduction in the heat transfer from the valve thru the seat into the head.
Resulting in what appears to be heat damage ie valve seats becoming loose
etc etc.   Nigel Baker (Limbach Australia) is the one to talk to there.. But
my take is to use 98 LL auto fuel only.   So far the L2000 in the Dimona is
running really sweetly and has about 150 hrs TT.  The oil when using avgas
gets black real quick while the 98 Auto fuel .. the oil stays a slight gold
colour.

 

But you should  really enjoy the H36. It is not a speed machine but is VERY
stable at the bottom end (slow speed) much better than the Grob 109 which
was designed around the same time.

 

 

Best regards

 

Ian Williams

ZK-GCB

Auckland

New Zealand

 

 

 

From: [email protected] [mailto:[email protected]] On
Behalf Of Kristin Nowell
Sent: Sunday, 1 May 2016 5:07 a.m.
To: [email protected]
Subject: [DOG mailing list] Tom's American xThai Dimona

 

 

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