After four other projects now on the bench my plans include a Balsa USA Bristol M1c. 59" span and 5/6# weight. I have ben doing some research on making it fully electric, including the price of power. The brushless motor and ESC will be about $200. How much would be the cost of a four stroke of any quality? About the same. Li-ion batteries will fly the thing about 20 minutes at a time. I seldom fly more than 10 minutes per flight, ergo two flights before recharge unless I want to invest in another battery setup. I've flown the old fashioned can motor/nicad setup for over 25 years. A five minute flight with all those heavy nicads and the can motors were alright in their day, which is past. Just remember to keep your fingers away electric powered props. they start immediately when turned on.