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Old May 5th 10, 04:25 PM posted to rec.aviation.soaring
Mark Jardini
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Posts: 48
Default Apis motorglider

OK- I have a few minutes so I will give you my impressions of the
aircraft.

First, the aircraft is built very well with a lots of attention to
detail.
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?

Mark