Pilot September 2017

62 | Pilot September 2017 http://www.pilotweb.aero

probably get toasty too, and seeing the oil
and CHTs creeping towards their respective
red lines is just going to worry you.
Curiously the cockpit placard promulgates a
maximum oil temperature of 90 ̊C, while
modern thinking is that over 100 is good as
it gets the water out (oil being hygroscopic).
Anyway, at a safe height reduce power
to below METO, re-trim for 55kt and
explore the general handling. Of course,
those big wings do mean that plenty of
rudder is required when turning, due to the
adverse yaw, and the roll rate is certainly
far from sprightly. Typically, a stopwatch is
used to measure the roll rate−but with the
Venture a calendar will suffice. The ailerons
are heavy, and response slow. In fact, this
is not a machine for the ‘high gain’ pilot, as
sometimes you need to make a control
input, and then see what it does. In test
pilot speak, it could be described as an
‘open-loop’ system. Try the spoilers.
There’s quite a big nose-down pitch
trim change with full spoiler extension,
and although they don’t feel very
effective a good exercise is to try landing
without them. You’ll need a surprisingly
long runway.
Examining the stick-free stability shows
it’s positively stable in pitch and yaw, and
neutral in roll, while an exploration of its
slow flight and stall characteristics reveals
they’re very benign. Even if you get the
nose way up and really abuse the controls
it’ll just fall off on one wing into a spiral
dive. In fact, the centre of gravity is so far
forward I think it may well be impossible to
spin it (and I have tried!) The Venture is
possibly unique in that even with the
cockpit completely empty the centre of

gravity is still within limits. The minimum

cockpit load with up to 22 litres of fuel is

22kg, and remember that the tank is behind

the seats. A sensible cruising speed is

around 60-65kt IAS, and as the engine is

barely sipping ten litres an hour this

equates to an endurance of around three

hours and a still-air range (no reserve) of

about 180nm.

Shall we turn off the engine now? I

always ask, as for pilots who’ve only ever

flown power the sight of a stationary prop

can be a little perturbing. The first step is to

reduce power to 1,500rpm for one minute

to allow temperatures and pressures to

stabilise, then throttle to flight idle, ignition

off. As soon as the engine stops pitch up

slightly to stop the prop windmilling and

then use the starter motor to drive it to the

horizontal. This not only improves the view

but also slightly reduces the drag−and let’s

face it, we need all the help we can get.

The book claims a best glide of 22:1 and a

Although Slingsby Sailplanes built many

magnificent gliders, the Venture was not

an indigenous product. It was a licence-

built version of the Scheibe Falke SF 25

(Falcon) which was in turn derived from

the Bergfalke sailplane, but with the

forward fuselage redesigned with

side-by-side seats and a Hirth engine in

the nose. Called the SF 25A Motor Falke,

it first flew in May 1963, and was

subsequently built in Germany, Italy,

France and the UK, powered by a variety

of different engines including Franklin,

Hirth, Limbach and Stark-Stamo. It is still

in production today, powered by either an

80, 100 or 115hp Rotax.

Slingsby began building SF 25Bs under

licence in 1970. Called the T61A, it was

powered by a 45hp Starck Stamo MS1500

engine fitted with a recoil starter, and the

first one flew in early 1971. That May it

was evaluated by the Royal Air Force to

determine whether it would be suitable

for basic air cadet training with the

Volunteer Gliding Schools. Initially, fifteen

were ordered as Venture T1s, and Slingsby

eventually built some 77, with the most

numerous variant being the T61F Venture

T2. The first T2 (XZ550) made its maiden

flight from Slingsby’s Wombleton,

Yorkshire airfield on 3 July 1977. Along

with the 25 Fs, all the fifteen Es were also

modified to F standard and gave sterling

service until they were disposed of by the

MoD in 1990 and replaced by Grob

Vigilant T1s. Ironically, many — if not

most — of the Ventures are still airworthy,

while almost all the Vigilants are not!

Originally a German Falcon

Dave sweats holding the Venture in

formation: manoeuvrable it ain’t