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On May 5, 8:25*am, Mark Jardini wrote:
OK- I have a few minutes so I will give you my impressions of the
First, the aircraft is built very well with a lots of attention to
Cockpit is very comfortable but it is tight and could be longer in the
trunk area. I am 6ft and OK. Plenty of leg room. Plenty of width.
Panel is DG style and enough room for 7x 2-1/4 size instruments.
Rigging is fiddle-ish. I have not managed it without at least a
modicum of help. If you are going to fly alone, you will need a remote
control self rigger to move things about.
The trick is that the wings need to be in anhedral to fit into the
drag pins, then the tips come up to align the mains.
Derigging is quick. I timed myself from taxi to trailer through
driving away at 40 minutes.
Avionic is a very good trailer.
The engine installation is the crown jewel of the aircraft. Just
beautiful. The 447 is a tried and true powerplant. I have never had
trouble with starting or relights, and I make it a point to do one
relight a flight even if I don't need it. The only issue I see is that
the toothed belt driving the prop is sealed inside the mast. No way to
change it. I hope is lasts a long time......
I get generally 500fpm. The engine should be turning 6000+ rpm's and I
get only 5800 so I think the factory prop is too coarse in pitch, but
I am not ready to change it yet.
Also the engine temp runs very cool, rarely getting above 180C even on
hot days. Good for longevity but I think that there is a lot of power
there still not being utilized. By lb/hp it should do better. I am
Still messing with the carburetor. *I am roughly getting 1000 ft per
liter of fuel.
I have recently put turbulator zigzag as recommended at 65% MAC and
that dropped 3 kts off thermaling speed. 30 deg bank and 40kts.
I think the rudder needs turbulators as well. Rudder forces at low
speeds are initially high, then release giving more yaw than you asked
for. Feels like I am pulling a high drag bubble. It swims in yaw a bit
in cruise as well. That should be correctable. More to come.
Flaperon forces are high. You are pushing a big wing through the air.
I climb with most anything, Run is not bad up to 80kts. The trim is
unsatisfactory. It is a simple spring arrangement. (I was spoiled by
Glasflugel's push button trim). You can adjust it for enough back trim
or enough forward, but not both. The elevator has a deep recurve on
the trailing edge, so the stick forces go up with airspeed. At
redline, the forward pressure is prodigious. I don't think I will fly
in that speed range often though.
That is all that comes to mind. Questions or comments?
I've been building an Apis M from a kit purchased 4-5 years ago from
AMS-Flight. I obtained an amateur-built airworthiness certificate
last summer and flew it as a pure glider, and promptly "bent it" a
little -- I'll come back to that.
Let me address the issues I've come across over the several years of
putting the glider together, and visiting the factory (both AMS and
Pipistrel) several times.
(1) The 447 installation has been problematic, for all concerned. So
far as I know, only 3 with that configuration were delivered by the
(AMS) factory. One, a kit put together by Jack Lurowist (deceased),
did not go together at all well -- there were major vibration
problems, confirmed in a factory-built ship by Paul Yarnell. As best
I was able to determine, the issues were mostly due to the inherent
vibration of the 447 and inadequate shock mounts (at the mast/fuselage
hinge), a lack of torsional rigidity in the carbon propeller mast, and
propeller balance and/or symmetry issues. The sealed mast was one of
the factory "fixes" and apparently cured the torsional rigidity
problem. The recommended belt (which I understand to be essentially a
Harley-Davidson belt) replacement procedure is to cut, with a Dremel,
the epoxy/tape that bonds the belt cover to the carbon mast, and then
rebond/tape it when done with the belt replacement. One of the
results of the excessive vibration was that the exhaust system
developed cracks with a very few hours of operation. I've been told
that the factory fixes (replacement rubber shock mounts, bonding the
belt cover to the mast, and a redesigned propeller) essentially solved
the problems, and perhaps Mark's experience is proof of that. The
more recent fix for all the 447 problems was a complete redesign and
replacement of the propulsion subsystem; the current self-launch Apis
uses a Hirth F33 engine in a mast built up from aluminum plates,
hinged on an entirely different lamination bonded into the upper
fuselage immediately in front of the mast door opening.
(2) My experience with flaperon forces is a bit different from
Mark's. The problem in my fuselage, and apparently many others, was
misalignment of the flaperon bell cranks mounted on the engine
compartment sidewalls. Pipistrel has redesigned those bell cranks to
incorporate a self-aligning bearing to accommodate the wing dihedral.
I'm currently in the process of replacing these bell cranks and will
insure that the bearing housings attached to the sidewalls are
precisely aligned with the flaperon hinge post axis. Another flaperon
(static) force issue discovered by Robert Mudd is the misalignment of
the several flaperon hinge posts; this misalignment, if present, can
be felt when moving the flaperon from one extreme to the other with
the glider disassembled. The flight result of my particular problems
was that the flaperons were _extremely_ stiff, and controlling the
glider on tow was a two-handed operation. I expect all these static
force issues to go away with the proper installation of the new bell
cranks. Hopefully I will discover Mark's high speed control force
issues when I get the ship flying again.
(3) Finally, my "event" (it wasn't an accident or incident, so that's
what my FSDO inspector called it) last summer. To make a long story
short, I landed in a bit of a crosswind and when my steerable tail
wheel touched down, I entered a PIO (yaw axis) and left the runway.
When I tried turning to parallel the runway, the ship yawed (to the
right) but continued straight ahead in the soft dirt, putting a
substantial side load on the main wheel. The tire peeled the right
wheel half completely off the wheel assembly bolts, fortunately with
no other damage to the fuselage. I've replaced the factory wheel (and
brake) with a Tost Tria wheel and disk brake.
BTW Mark, I've been meaning to come over and see you, and your Apis
for at least a couple of years. I. and my Apis, are in northern Idaho
during the summer.
-- Bob --
Apis motorglider - drive belt replacement
Mark Jardini wrote:
The belt can be seen and inspected through it s length. The center
portion of the mast is enclosed trapping the belt within by some mid
shaft cross sectional enclosings. I can only assume this is one of
those fiberglass impregnated toothed belts they use in cars that last
My guess would be you send the mast back to be opened and reclosed or
you buy a new one.....
My Nimbus 4DM syndicate has had two engine drive belt failures over
the last 8 years, one at the launch point just before the after-C of A
test flight six weeks ago. The belt was changed within a week, but
could have been quicker had we stocked a spare.
In the case of any belt-driven MG engine, there really should be a
relatively straightforward way of replacing the belt if it fails,
without rendering the engine unit unserviceable for a considerable
time. After all, preventing lands-out is the whole reason for having,
and paying for, an engine installation.
Lasham Gliding Centre, UK
Apis motorglider - drive belt replacement
Many thanks to all for the helpful comments. Let's hope JJ isn't
I'm not sure if AMS flight builds it anymore, because I've read that Pipistrel currently builds it and is heavily refined in quality in many aspects. I'm definitely gonna get one as my first glider. That's all I can give you for now...
Em quarta-feira, 5 de maio de 2010 10:54:59 UTC-3, Mark Jardini escreveu:
I have an APIS MC. What would you like to know?
I didn't find information about Apis M and MC, what's the difference? Thanks.
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