Are you aware of Jerry Booker's work with his plane the RedTailHawk? He has a Yahoo group that is basically a blog of his build. Electric power self launch ultralight glider. It has flown successfully. Lots of good info on his blog re. batteries, motors, chargers, controllers, prop brake, etc.
groups.yahoo.com/group/RedTailHawkUltralightSailplane/
Also as I previously mentioned, Dale Kramer's work with the electric Lazair is very exciting:
blog.cafefoundation.org/?p=6259
and here:
www.airventure.org/news/2011/110727_lazair.html
Michael
On Dec 27, 2012, at 6:13 AM, ekolbs wrote:
I may have a slightly different view on the CD than many in this group. I love the CD, but wish to modify it for my particular wants and needs. I have no desire to foot launch the CD. I intend on attaching a small, light RC type of engine. That allows me to increase the empty weight up to 254 pounds, an additional 110 pounds! I saw a hang glider at the Oshkosh fly-in that launched with two RC engines that were about 13 hp each. There was another article in the EAA or Kit Plane magazine where a man had a power pod with two RC engines for self launch. His total power package weighed about 30 lbs. My point is, add 30 lbs of engine and you still have up to 80 lbs of weight allowance that you can put into structure. You can even elect to continue to operate the CD as a pure sailplane (tow to altitude or rolling hill launch). Not saying that you have to use the full 80 lbs, but it gives you options. I doubt that many CD's will actually meet the 144 lb US limit. I will take the weight penalty, besides extra wing loading should provide smoother ride and better penetration than an extreamly light wing loading. Yes, this is a compromise from the original CD. It would not be a CD anymore, but a new design. At least it's based on a proven design as compared to starting from a clean sheet of paper. As with any new design or modification, beware. It will take proper engineering, construction and testing. Just some thoughts to keep my brain working.
