Bob Wilder owns the new world record for longest-duration indoor flight with a radio-controlled electric airplane. It stayed aloft for 4 hrs, 17 min, and 57 sec.
Wilder says it is important to perform tests to find the maximum thrust using the minimum current draw from the batteries. So he analyzed many combinations of motors, gear ratios, propellers, and batteries. "The real bottom line in producing an airplane that will fly inside for several hours is thrust versus current draw," he says. "That means the size of the battery and the size and efficiency of the motor are key."
Wilder uses a permanent magnet motor from Maxon Precision Motors (Burlingame, CA). He claims that the company's coreless motors provide the low-current consumption needed for extending battery life in competition. The motor's iron-less core eliminates cogging and provides smooth rotation even at the lower speeds required for landings.
For more information about motors from Maxon Precision Motors: Enter 539
A bold, gold, open-air coupe may not be the ticket to automotive nirvana for every consumer, but Lexus’ LF-C2 concept car certainly turned heads at the recent Los Angeles Auto Show. What’s more, it may provide a glimpse of the luxury automaker’s future.
The complexity of diesel engines means optimizing their performance requires a large amount of experimentation. Computational fluid dynamics (CFD) is a very useful and intuitive tool in this, and cold flow analysis using CFD is an ideal approach to study the flow characteristics without going into the details of chemical reactions occurring during the combustion.
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