RE: apc 15x4
Several years ago I ran a Super Tigre S91K (cowled/inverted) on a 8.2 lbs (dry) tail dragger MT Joss Stik (mid wing mod) with an older Zinger 14~8 and a Magic Muffler that flew about 75 mph straight and level, vertical out of sight and straight down. Plan on building another like it.
Terry in LP