Although it is an interesting concept, I think you'll find very fast that electric power rules under a .40-size plane.

The advantages of glow cost and power are lost in the 39" span [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXDUE7&P=7]Kyosho Spree[/link] plane.

A Speed 380 (aka Speed 400) motor would be comparable to a .09-size glow engine. The Speed 400 motor is about $8, the .09 [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXB443&P=7]Cox Tee Dee[/link] is $67 without any throttle control.

The light build firewall would have to be strengthened to withstand the additional vibration from the glow engine.