ORIGINAL: Speedy-Gonzales
When flying 30cc and under I would recommend the IBEC. Especially in the much smaller 15-20cc gas/ignition engines. The weight savings is substantial. There is a fear of IBEC's due to their original reputation of being unreliable but so were the smaller gassers themselves. I would not hesitate using an IBEC. Especially the TechAero or WIKE units. I have been using them for 2 years with only one failure on 50-60cc gas.
For those of you that don't know......IBEC = Igniton Battery Eliminator Circuit
SPEEDY
I use the Syssa IBEC not only on my DLE-20/Velox, but on several other planes like a DLE-30/Ultra Stick, DA-60/MX2, and what I like the best, (87 flights since August), a DA-120 powered 104 inch AJSlick. There is no reason to carry a separate ignition battery, just another thing to charge and/or fail. For me, if it is smaller than a DLE-20, I use electrons. None of the sub DLE-20's make much sense, since they weigh about the same and make less power. I have about 250 flights on the Velox, and the joke around here is how little gas it uses. I fill it up at home (16oz) and fly it 5-6 times in a day. Even if the fuels were the same price, I just can't handle all the slime, and a glow motor uses about 3x more fuel, so the flight times will be less or I would need a bigger tank. On my smaller planes, I just bring 4-6 battery packs and fly. The big DA-120 has now flown in 85F and now in 28F and has run perfectly. I just put the wings on it, install the 2, 3000Mah LiPo's, fill it up and fly. No starters, just turn on the ignition, flip it and go. It uses about 20oz of gas in 9-10 minutes. If DA made a smaller engine, I would buy it in a heartbeat.