10-8-04
Today, I test flew the first Jabiru powered Skyranger in the UK.
It has the latest Jabiru engine. There have been many changes in
the last couple of years to increase horspower and cure valve/cylinder
head problems.
The latest Jabiru mount for the Skyranger that moves the engine
forwards some more to allow fo a conical filter to fit without interference
with the firewall ) althought this one has opted for a remote airbox).
The cowlings are 4" further forwards when compared to the 912
installation. The whole cowling set moves forwards taking the windscreen
line with it. This gives the Skyranger a more raked screen and sleeker
lines which is nice.
The engine sounds very sweet on idle and is quite low reving, redlined
at 3300. Power was better than I expected, there are a lot of stories
about Jabiru horepower being a little exaggerated (probably the
case with the early engines) and direct drive engines are not at
their most efficient for airframes, optimised to be most efficient
for climbing at modest airspeeds. The 912 still has the edge on
climb but by 100 fpm or so. I recorded a good solid 700 to 800 fpm
climb rate at max takeoff weight from sea level and a 20c climbing
at 55 knots. Max straight and level was in the order of 80 - 85
knots CAS. Cruise was nice at 2500 rpm and 70 knots. Faster was
possible but the engine airframe combinaison has a sweet spot there.
Engine likes to idle fast a 1000 rpm (sound low but this means prop
speed is way higher than a 912 idling at 1500). This flatters the
glide at low speeds and makes it float down the runway if the approach
speed is little hight and works against the brakes a bit. No real
problem, but practice the odd dead stick landing ( on a quiet and
big field !) so you don't get caught out if you have to glide for
real!.
Rest
of the handling was pure Skyranger, nice and easy with no vices,
stable and yet manoeuvrable. I was concerned that the longer nose
might result in reduced directional stability but it didn't feel
noticeably changed from the 912 with fin.
So all in all I was pleasantry surprised. The Jabiru does make a
nice combination with the Skyranger, look good, sounds nie and performs
well. Time will tell wether all the reliabiliyy issues have been
ironed out with this latest engine model, but I reckon it shouldn't
be much of a headche.
Maintenance is slightly higher than with a 912, lots of head retorques
and valve clearance checks, but on the plus side it is slightly
lighter and fair bit less costly to buy.
