This new development from the highly popular Wren 44 Gold thrust engine stable, has been long awaited. It has built on the success of the Wren 54 Turboprop which has now been on sale in various forms since 2002. The engine has been the outcome of a long R&D programme primarily concerned with maximising the performance and minimising the aggravation of installing and operating, allowing the flier to get on with the business of flying.
We have been careful to keep the weight of the unit down but have not compromised stiffness which has shown itself to be a major concern for turbo-props. The engine is not modified for use in this application apart from a small hole drilled in the case to add a lubrication port, enabling the full perfomance to be used in driving the propeller, producing performance usually described as 'awesome' by all those witnessing it.
The gearbox assembly is strongly built to withstand many hours of operation and is designed to be lubricated with a small fuel take-off from the engine. All this is automatic and the user need do no more than put fuel into the tank, charge batteries and go fly!
We have tried hard to produce a compact high power to weight engine capable of filling the gap left by the noisy medium to large I/C engine, and the existing range of turbo-prop engines now becoming available. Most of these are really only suited to large aircraft around 2.5 to 3m (8’ to 10’) wingspan, which has implications for cost, transport and suitability of flying field. There are a large number of airframes already available in the 2m (6’) size that are attractive for conversion to turbo-prop for the reasons outlined above and are suited for the average club flier. The low installed weight around 2kg compares well with equivelent 2-cycle engines and helps to keep the wing loading sensible.
Noise is becoming a major concern and the 44 turbo-prop enjoys a remarkably low noise figure, rivalling electric models in many cases. The noise is predominantly propeller noise and with the smooth application of torque and total absence of power pulses enables a very low perceived noise level to be achieved.
The Wren 44 Turboprop enjoys the same highly responsive engine as the Wren 44 Gold thrust version so the absolute minimum throttle lag can be appreciated by those keen on prop hanging and the usual aerobatics. The small engine size enables the fuel consumption to be described as 'stingy' so no need for lugging a big fuel bottle around.
Importantly, the engine is already well established so you are not buying an unproven design. Parts and service is readily available and the hundreds of Wren 44 Gold customers across the world will testify to the longevity and ease of use of this world-beating engine.
WARNING - it is most important that there must always be some load on the output shaft as otherwise the 2nd stage turbine will be running unrestrained and may easily speed up beyond it's safe running speed, even when the gas generator is running at only a modest rpm. This means the unit should never be run without a suitable propeller fitted.
|Max. Power Output||7.5HP / 5.6Kw @ 195,000 rpm|
|Weight||1680g / 3lbs 11oz|
|Overall size centre section||326mm x 86mm / 12.8" x 3.4"|
|Ancillaries weight (inc battery)||280g / 10oz|
|Mounting||Hole dia 85mm / 3.4", 6 x M3 screws|
|Propeller rpm range||1,100 to 9,000 rpm|
|Propeller size range||17" x 12" - 28" x 10" (2 or 3 blade)|
|Fuel Consumption @ max thrust||176ml per minute / 5.8oz per minute|
|Recommended Set-up||6.400 rpm on Metz 22" x 13" 3-blade prop|