Wing tip smoke
Hi Mike.
How about poring gas or somthing over them, and then put a long fuse in and the you can take a glowplug and hook it up to a 1,2 volt battery in the fuselage and put a microswitch between the battery and the glowplug and the connect a servo to the switch and the you can tun on the glowplug in the air and the the glowplug lite the fuse.