vs Rotaxes
(Sept 18th, 2006)
Inspector was here! (Sept 20th, 2006)
Mr. Kerkhoff was here inspecting the still-open wings. He counted some bolt and rivet rows here, had a close view there, everything O.K. so far, wings can be closed -Yehoo-.
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Lyncosaurs vs Rotaxes
(Sept 18th, 2006)
I have extended my PPL by a German Ultralight license the last week (3-axis, 475 KG MTOW)
after a couple of hours on a FK-9 (highwing with struts, 3-gear, composite,
Rotax 912UL 80HP engine)
here's now my very subjective comparison between the C-150 and the FK-9.
1. handling
-----------
by pushing the FK-9 up at the prop root and thus unloding the front wheel
the aircraft can be turned on the spot by an average person (not possible
with a C-150).
2. preflight-check
------------------
the FK-9's checklist is not so well structured than the C-150's, maybe just
a matter of the different maturity of the two models.
no gyro instruments, no radio navgation instruments in the FK-9, but a Garmin Pro Pilot III instead.
The cowling of the FK-9 can be taken off by removing a couple of Dzus fasteners (not possible to have a full view on the Cessna's Lycoming).
Oil consumption of the Rotax is neglible - not so with the Lycoming.
standard procedure for the Rotax is to turn a few prop blades through - I've never done this with the Lyco(don't know why, too dangerous?)
not to forget to remove the safety pin from the parachute rescue system (which is mandatory for all German ULs)
3. re-fueling
-------------
my club's FK-9 consumes auto super fuel which is not available on our home
airfield. 100LL should only be used in an emergency because the lead content
is no good for the Rotaxe's health. This means packing a few fuel cans into
the car and driving to the nearest gas station before going flying. In the
FK-9 fuel level is can easily be inspected through the two transparent fuel
tanks which are located just behind the seats (this is not so with the C-150
which requires a ladder to fill up and the unreliability of the fuel indicators
are legendary)
4. seating
----------
FK-9's seats are made of composite and are as filligran as the rudder pedals.
for me seating is comfortable on the non-adjustable seats. There are very
nice 'Schroth' 4-point harnesses in the FK-9.
5. starting the engine
----------------------
there is no primer in the FK-9 but a joke (which is actually the lever of
a bicycle gear-shifter). Engine start in the FK-9 is not as shaky than in
the C-150. Throttle in the FK-9 is quite crude and needs a lot of force
and travel, this is someting which could be easily improved on this aircraft.
6. taxiing
----------
nothing special here
7. take-off
-----------
takeoff is usually done with first flap setting. climbout is done with 100km/h
(I'm used to knots but you can't have everything). The FK-9's climbing attitude
is ~very~ steep compared to the C-150 but climb rate is only a bit better.
8. cruising
-----------
what I felt at first is the quick response to power change of the FK-9.
I you push the throttle lever forward you suddenly gain speed/altitude.
Stability of the FK-9 seems a bit more flimsy than the C-150. In the beginning
I permanently chased the ball of the slip indicator.
9. engine control
-----------------
every fool can handle a Rotax. No mixture to take care of, no shock-cooling
problems (because of the 912's water-cooled heads), just watch the water
temp stays below 115 deg.C. The FK-9 still stays afloat with about 3500
engine RPM which may be well less than 40 HP.
10. airwork
-----------
ULs are not required to go through the complete FAR-23 certification process.
Therefore you may read in the operating handbook that full stalls are prohibited
as well as lazy-eights, chandelles, high-speed steep turns etc. You will
NOT read about how to recover from a spin. This is a reason to drive a C-150
(Aerobat) from time to time.
11. approach
------------
the FK-9 likes to glide! If I don't reduce to almost idle on base and final
the bird will glide all along the runway. Flaps are not very effective,
even on second position. However slipping is allowed even on full flaps
(not so with the C-150)
12. landing
-----------
just the usual flare
13. shutting off the engine
---------------------------
just switch off the ignition. The Rotax will die very suddenly with a last
shaking.
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Aileron Balancing (Sept 17th, 2006)
The Sonex ailerons are statically balanced. This is done by two quite massive lead counterweights. The ailerons are either over-balanced or under-balanced. They should not be indifferent.
this is the balancing instructions from Sonex Ltd...
... and this is the way I actually did it. The trailing
edge is about
10mm down from the horizonal, a little bit of lead had to be drilled
out.
On Wednesday inspector comes to have a thorough look on/in the wings. If everything is according to his desires then the wings can be finally closed.
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Finished the Right Wing this Weekend (Sept 9th, 2006)
...because the right wink looks like the left wing mirror-inverted there are no pics this time.
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