What prop to ust on A Tucano Turbo Prop Powerd by the big Wren T. P.
07-06-2008, 11:22 AM
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What prop to ust on A Tucano Turbo Prop Powerd by the big Wren T. P.
Guys I was wondering what size prop to use on the wren turbo prop motor installed on my Comp Arf Tucano. I am having overheating issues I have been running a 2 blade 26 x 12.5. I only seem to be able to get the prop up to 5100 RPM before the heat levels on the motor start to get in the danger Zone. I am open for any suggestions.
Ronald R Long
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07-07-2008, 12:00 AM
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RE: What prop to ust on A Tucano Turbo Prop Powerd by the big Wren T. P.
If it is the 54 TP, the size range is in the manual (can't remember off the top of my head) But if the EGT is getting too high, then the prop is too big..
07-07-2008, 03:54 AM
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RE: What prop to ust on A Tucano Turbo Prop Powerd by the big Wren T. P.
From the manual:
Propeller selection.
The engine produces power equivalent to an 80-100cc petrol engine and propeller choice needs to be made carefully as the drive system works like a constant torque, variable speed device. Wooden propellers are probably best though carbon fibre is a good 2nd choice. Wood is ideal as if you are unfortunate to have a nose-over it will simply break the blades. A carbon prop will not usually break but will place a large force on the prop-shaft which may bend it.
A propeller size of 450x305 (18â€x12â€) 2-blade is about the smallest diameter and pitch which can be used on the engine and max engine rpm should be reduced to 130,000rpm for safety.
A 750 x 250 (30†x 10â€) is the largest we have run though we needed to reduce max rpm to 140,000 to keep exhaust temperature down. Two, three and four blade propellers have all been used successfully and generally for each extra blade you need to drop 25mm (1â€) diameter or 25mm (1â€) of pitch.
The guide for maximum propeller size loading is the engine running temperature – you should stay under 650’C at max rpm set, and this is reached with a 550x300 (22â€x12â€) or 660 x 250 (26â€x10â€) 2-blade at an engine speed of 150,000rpm. Larger diameters can be used but the max’ engine speed must be reduced to limit temperature rise.
If the maximum engine speed is reduced to 140,000rpm it is permissible to increase propeller size up to 750mm (30â€) and 250mm (10â€) pitch. This size has been tested by us. Remember: the guideline to loading with larger propellers is engine temperature (650’C).
Please note that prop rpm can increase up to 20% in the air therefore users should take care to ensure propeller rpm is no more than 7500rpm static on whatever size is used.
In tests at the max rpm of 160,000 ( core engine) the propeller rpms were:
6900, 23 x 12, 3-blade, METZ Carbon.
7800, 22 x 10, 3-blade, Menz Wood.
6100, 28 x 10 2-blade, METZ Carbon
7600, 26 x 8, 2-blade, Menz Wood.
Sara Parish
Wren Turbines
Propeller selection.
The engine produces power equivalent to an 80-100cc petrol engine and propeller choice needs to be made carefully as the drive system works like a constant torque, variable speed device. Wooden propellers are probably best though carbon fibre is a good 2nd choice. Wood is ideal as if you are unfortunate to have a nose-over it will simply break the blades. A carbon prop will not usually break but will place a large force on the prop-shaft which may bend it.
A propeller size of 450x305 (18â€x12â€) 2-blade is about the smallest diameter and pitch which can be used on the engine and max engine rpm should be reduced to 130,000rpm for safety.
A 750 x 250 (30†x 10â€) is the largest we have run though we needed to reduce max rpm to 140,000 to keep exhaust temperature down. Two, three and four blade propellers have all been used successfully and generally for each extra blade you need to drop 25mm (1â€) diameter or 25mm (1â€) of pitch.
The guide for maximum propeller size loading is the engine running temperature – you should stay under 650’C at max rpm set, and this is reached with a 550x300 (22â€x12â€) or 660 x 250 (26â€x10â€) 2-blade at an engine speed of 150,000rpm. Larger diameters can be used but the max’ engine speed must be reduced to limit temperature rise.
If the maximum engine speed is reduced to 140,000rpm it is permissible to increase propeller size up to 750mm (30â€) and 250mm (10â€) pitch. This size has been tested by us. Remember: the guideline to loading with larger propellers is engine temperature (650’C).
Please note that prop rpm can increase up to 20% in the air therefore users should take care to ensure propeller rpm is no more than 7500rpm static on whatever size is used.
In tests at the max rpm of 160,000 ( core engine) the propeller rpms were:
6900, 23 x 12, 3-blade, METZ Carbon.
7800, 22 x 10, 3-blade, Menz Wood.
6100, 28 x 10 2-blade, METZ Carbon
7600, 26 x 8, 2-blade, Menz Wood.
Sara Parish
Wren Turbines
07-07-2008, 08:39 AM
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RE: What prop to ust on A Tucano Turbo Prop Powerd by the big Wren T. P.
Great info thanks Sara and Ron I will be able to get the proper prop and get the temp down.
Ron
Ron
