As petrol engines have a pumped carb, the space immediately behind F1 can be utliised for an additional silencer, with the tank located on the CG. I have a Z38 / Hannibal which uses a Camping Gaz cylinder as a silencer. Its all home made with copper pipe fittings, silver soldered. Cost nothing. The engine noise from this model is drowned out completely if anything else is flying! For me, the principle advantage is the clean running / non destructive fuel residue on paint and wood. You won't be disappointed with the Z26 Stu k