propjobbill

GWS motor performance question

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Has anyone ever checked out the performance on GWS 280 or 400 gear driven systems? I have several 280 and one 400 with gears. Their Charts says I should get a given amount of thrust with 8.4 volts for example. When I use them as direct drive the charts come close. When I use the charts for the gears my engine really lags behind.

Example 280 motor with a GWS prop 10x 7 should produce about 8 oz of thrust at about 4,000 rpm with 8.4 volts with a 3.75 gear box. When I try I get about 2700 rpm with about 4 oz of thrust.

I’ve tried different batteries with the same results. Why am I getting less power about 30% less than they say.

Can anyone help?

Thanks

Matt Kirsch

My Feedback: (21)

Laboratory conditions vs. real-world, probably. In lab conditions, they can provide the motor with the voltage from a fully charged 8.4 Volt battery (approximately 10 Volts). Real world, your battery will suffer voltage depression; it'll be lucky to provide 1 Volt per cell under load.