{"id":6259,"date":"2012-07-16T17:26:33","date_gmt":"2012-07-17T00:26:33","guid":{"rendered":"http:\/\/cafe.foundation\/blog\/?p=6259"},"modified":"2012-07-16T17:26:51","modified_gmt":"2012-07-17T00:26:51","slug":"electric-lazair-progress","status":"publish","type":"post","link":"http:\/\/cafe.foundation\/blog\/electric-lazair-progress\/","title":{"rendered":"Electric Lazair Progress"},"content":{"rendered":"

During a visit to the International Vintage Sailplane Meet at Harris Hill, New York, your editor was fortunate to be a guest of Dale and Carmen Kramer, who graciously showed their home, once that of Glenn Curtis, \u201cThe Father of Naval Aviation.\u201d<\/p>\n

\"\"<\/a>

Dale and Carmen Kramer in the front room of their home. The picture on the wall behind them shows Dale flying over NASA's 747 and Space Shuttle at the Paris Air Show<\/p><\/div>\n

Now the Hammondsport cottage (as in Glenn Hammond Curtis), which overlooks the lake where Curtis flew his early amphibians, is home to a high-tech cottage industry, with Dale creating battery monitoring systems, \u201cbrain boxes\u201d, and other elements of his electrical power system for ultralight aircraft.\u00a0 He designs the schematic and printed circuit boards for the system, sends them off to a PCB manufacturer and hand mounts very small components on the finished circuit boards, a process that would normally use expensive \u201cpick and place\u201d machinery and wave soldering.\u00a0 His low-tech version of wave soldering takes place in a toaster oven.<\/p>\n

\"\"<\/a>

One of four battery packs that will be fitting in wings behind motors. Note BMS board on top and neatly done, Kramer-designed battery box surrounding cells<\/p><\/div>\n

A table on the covered and shaded front porch overlooks the lake and holds stacks of water-jet cut pieces awaiting assembly into the battery boxes that Dale creates and rotates in the AutoCAD\u00ae images on his computer screen.\u00a0 He also programs the operation of the BMS and other electronics that comprise his complete power system.<\/p>\n

He has been working with Joe Ben Bevirt of Joby Motors to improve the motors.\u00a0 One step removes the bonding agent between the motor\u2019s stator and its external housing; simply shrink fitting the parts together, thus obtaining better heat transfer and cooler running.\u00a0 The roughly six pound units produce 15 to16 kilowatts, or about 20 to 21.5 horsepower.\u00a0 Joe Ben is also providing motors with double sets of leads, six per motor instead of the usual three.\u00a0 This increases power significantly, with two motors in one, and two throttle signals going to each motor.\u00a0 Power is not doubled, but increased.<\/p>\n

Dale is also redesigning the battery packs.\u00a0 Originally, he fitted a 50-pound pack within the wings behind each motor.\u00a0 Now two 25-pound packs will replace that single battery pack, each having a BMS and charging circuit, allowing more discrete monitoring of the batteries.\u00a0 It also allows management of battery health at the individual cell level.\u00a0 As Dale said, \u201cIf you want to take care of your very expensive batteries, you have to do it right.\u201d\u00a0 He compares batteries to having a pre-paid fuel tank, and you can\u2019t afford leaks.<\/p>\n

The video provides Dale\u2019s explanation of the tidy way in which he\u2019s coordinated a great many things into a simple operating system, centralized in his brain board, which provides output to the LED displays that Dale has programmed.<\/p>\n