The following is a verbatim copy of the article as published
in Australian Gliding magazine, june 1965. Thanks to David Goldsmith, editor
of "Vintage Times", newsletter of Vintage Gliders of Australia. Original
copy available here.
The First Sagitta Arrives
By Jan Coolhaas
(As published in "Australian Gliding" June 1965)
After a lot of wharf hold ups, one Sagitta arrived at last at Camden on the
6th April, no less than 2 weeks late.
Syndicate members John Blackwell, George Detto, Trevor Kyle and myself were,
of course, out in full force to unpack the Sagitta. The first impression one
gets is the magnificent canopy, with the result that everybody had to try
out the cockpit the moment the fuse was lifted out of the crate.
One syndicate decided to take the Sagitta to Forbes for the Easter and Anzac
holidays for its first flight. To make this possible, the framework of the
trailer was built on the weekend prior to Easter, a temporary measure to get
the Sagitta to Forbes. The trailer will be enclosed at a later date after
the Forbes camp.
On Easter Saturday the Sagitta was rigged at Forbes for the first time. A
look at the very solid spar and large fittings make one realize right away,
why the Sagitta has the reputation of one of the strongest gliders in the
world.
Rigging is simple, the wing connection being very similar to the Ka-6. All
controls connect automatically when the wings and tail planes (2 pieces) are
fitted.
Although the Sagitta is a midwing glider, the dihedral gives sufficient
clearance at the wing tips. The fuse is extremely thin behind the cockpit,
which gives this glider a glorious sleek appearance.
The construction is completely orthodox. This is a great advantage in
regards to club use, because of its easy of repair, but it does show very
slight waves on the wing where the ribs are (a disadvantage all gliders have
with orthodox construction).
The impressive instrument panel would probably make our Sagitta the best
equipped glider in Australia. It is fitted with oxygen, 2 vario meters,
A.S.I., altimeter, compass, G-meter, artificial horizon and electric turn
and bank indicator. Trevor Kyle's radio out of the Foka will be fitted in
the near future.
George Detto had the honour of the first flight. He was particularly
delighted with the visibility. John Blackwell was also in the clouds in
regard to the visibility. He also was greatly impressed by the handling
characteristics. According to him it was "as if the wings are attached to
your back - you become part of the aircraft."
The next day, George, Trevor, John and I all had soaring flights which gave
us the chance to put the Sagitta through some thorough tests. Although
conditions were rough it was wonderful to fly between thermals safely at
speeds of 200 km/hr (125 mph). The Sagitta is a wonderful aircraft to throw
about in loops, chandelles, stall-turns, barrel rolls and spins.
John and I did a number of tests and these are the results:
Rudder Effectiveness:
For 30 degree rolls, about 100% rudder is required and 50% aileron to keep
the nose at one point on the horizon. This means that the rudder is
sufficient effective, but not very effective.
45 Degree change in turns:
Only 3 to 3.5 secs. were required, which shows that the ailerons are
excellent. The aileron stick load is about 5 lbs., which is somewhat too
heavy. This may be newness (the Sagitta I flew in Europe had much lighter
ailerons)
Side slip:
With 100% rudder, the side slip is effective.
Dive brakes:
The dive brakes were found to be speed limiting, but for landings are
somewhat weak. However they are sufficient for good spot landings.
Landing:
The approach is somewhat flatter because of the dive brakes, yet very easy
to handle. The wheel brake on the stick is excellent.
Visibility:
Excellent, probably the best of any glider.
Ventilation:
The glider can be flown with the canopy approx. 1 inch moved back, this
gives reasonable ventilation.
Take-off:
On aero-tow as well as on the winch very easy to handle, particularly once
one get used to the very sensitive aileron. The Sagitta becomes airborne at
65 km/hr.
Straight and level:
With hands off very stable.
Trim and range:
The range is OK, but does not give a very clear cut speed (spring seems
somewhat weak). The position of the trim is on the right of the stick; on
the left side would be a better position.
Directional stability:
Excellent with a speed of 90 km/hr. and gives no tendency to oscillate or
spiral dive.
Dynamic longitudinal stability:
Excellent, only very slow dampening oscillations occurred between the
minimum and maximum speeds of 70 and 140 km/hr respectively - the aircraft
was trimmed at 90 km/hr.
Stalls:
a) In straight flight - warning at 70 km/hr, stall 60 km/hr
b) Side slip - warning at 75 km/hr, stall 58 km/hr
c) 30 Degree turns - warning at 75 km/hr, stall 62 km/hr
d) With dive brakes - warning at 80 km/hr, stall 65 km/hr
The stall warning (buffeting) is very clear and occurs considerably above
the actual stalling speed. The stall is very gentle and in each case occurs
after a period of "mushing".
Placard speeds:
Max speed 270 km/hr
Max rough air speed 200 km/hr
Max speed aero tow 160 km/hr
Max winch speed 110 km/hr
Best L/D speed 85 km/hr
Best min sink speed 76 km/hr
L/D ratio 1:34
Conclusion:
In performance the Sagitta would be very similar to the Foka. Because of its
strength this glider is particular popular in New Zealand and California,
where conditions can be exceptionally rough.
Its good points are:
1) Excellent visibility.
2) High rough air speed and strength.
3) Orthodox construction.
The poor points are:
1) Spring type trim.
2) Rather weak dive brakes.
For the price of £2295 (without instruments) the Sagitta seems an excellent
glider, particularly for the rougher inland conditions.
