"Speed is not everything, but..."

Speed is not everything, but it is worthy to mention that we have recorded 193 mph with the EVF powered Electra Jet.

The power was provided with our new "Super 12S" 5012 EVF. Powered by a 1521 Neu motor; the battery compliment was (2) 6S, 5000 mAH 25c T.P. Saddle CellsTM . Static power consumption of the "Super 12S" is 4968 Watts.
The weather was near perfect, about 85°F, mildly humid and calm - unusual for Florida in August.

Flight Techniques? Yes, some precision flying is required to place the model straight and level at least 500ft prior to the recording device and 500ft past it in low "G" Flight. This is difficult to do at an event when concerns for other model aircraft and safety are present.

The Electra Jet was not designed solely for speed. It is primarily an aerobatic sport model that also flys and lands very slow. It has wash-out in its "Vess" designed airfoil to ensure positive stability. So, when it goes this fast; it is a measure of its efficient design. This is what BVM Jets and the EVF are known for and what BVM customers expect from us.

Measuring speed using Doppler

The Doppler Effect is the change in frequency and wavelength of a wave as perceived by an observer moving relative to the source of the waves. (From Wikipedia)
What is good Doppler data? Good data will be displayed on the WaveOscope Doppler software as multiple "S" shaped curves. A good "S" curve is formed by analyzing the sound waves of a moving object as it travels past a recording device. While the model approaches the camera, high frequency patterns created by the fan blades passing the stators are recorded; as the model passes the camera, these high frequency tones turn to low frequency. From the difference in frequency, model speed can be determined.

Can Doppler be fooled? Yes! One common error occurs when the motor is cut while the aircraft is flying away. It is very important to center the pass in front of the recording device with no change to the throttle position.

For the technically curious, the Doppler recording showing the 193 mph and 190 mph back-up passes are shown below.

193 mph
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190 mph
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NOTE: Accuracy is greatest when data is analyzed at the upper end of the sound spectrum.

Faster yet?

You can count on it as we introduce more power down the road. However, this combination allows 5-1/2 minute flights with proper throttle and energy management.
With 56 test flights on this particular motor and ESC (and no issues) we feel that BVM EVF customers will be happy with the reliability of the 5012.

The EVF design runs cool and does not need a cool down period after flight. You can log back to back flights as quick as you can change batteries. The EVF comes to you factory assembled and test run, just bolt it in and turn on the juice!

More info on the EVF 5012 power system will be posted soon.

Note: The EVF 4010 recorded speeds in the 167-174 mph range in the same Electra under similar conditions.

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