Wren 44 Gold Helicopter Owners Manual
Page 2
Wren 44 Helicopter Turbine
This unit is a unique miniature gas turbine engine driving through a small gearbox suitable
for driving the rotors on pod and boom sport helicopters 0.90cu in (15cc) size upwards and
with suitable additional gearing provides adequate power to fly scale helicopters and camera
platforms in excess of 50 lbs (23 kg) AUW.
New for 2014 includes new internal kerosene start system as standard, which eliminates all
the extra components required for propane start in a neat and tidy package.
The engine is usually supplied as part of a complete airframe package but it is not difficult for
the experienced builder to convert most large airframes to turbine power, or scratch-build
their own models. There are several interesting models featured on the Wren website at
www.wrenturbines.co.uk
Whatever you are building, there are technical considerations and
aspects of safety specific to turbine models and we would like to offer some advice based on
our seven years experience designing two-stage turbine helicopters.
SAFETY
This section is intended to cover aspects of safety specific to turbine helicopters. The
manual does not cover the flying of the helicopter as it is assumed that the owner has prior
flying experience and that this would not be a first model. Turbines are NOT toys and
anyone building or operating a turbine helicopter must have suitable skills and experience.
FIRE
There is a small but real risk of fire when operating turbine powered models. Hot kerosene
ignites readily and it is almost impossible to put out the fire without a fire extinguisher. Only
carbon dioxide (C02) extinguishers are suitable as powder types will ruin the engine but in
an emergency use what you can. Do not operate your engine unless you have an
extinguisher at hand. If there is a fire inside the engine, try to direct the extinguisher into the
air inlet, otherwise attack the seat of the fire.
HOT PARTS
Turbines generate large quantities of hot gases and have parts that stay hot for a long time
after the engine has stopped. Both the exhaust gases and these parts are sufficiently hot to
cause serious burns. Make sure that anyone not familiar with turbine operation is aware of
this.
Critical components adjacent to hot parts may need protection or spacing away from heat
damage by distance or physical protection. An aluminium foil faced insulation material is
suitable for wrapping around hot parts of the engine and is available from Wren Turbines if
required.
Even in a small airframe like the
Mark Symons Bergen Magnum
(left) the engine tucks in neat and
tidy and enables all the originally
supplied transmission and fan
components to be used.
The free flow of cooling air negated
the need for any further heat
resisting processes and proved a
trouble free install.
