So That Was What It Was!

The story? I was flying the Extra with the new GP38 engine. I had given it a bit more lean on the low jet to reduce the burbling at low throttle. After couple of flights it seemed like the exhaust note was a real bark now - a bit too noisy I thought. Checked exhaust, nope still nice and secure. Spoke to Jon Jacobs later and said I think I need an OS33GT exhaust, better baffled but expensive. Jon says there is one on BMFA for £60 incl P&P. Went home and secured it. Great! Today I did the change over but had to remove 20mm of downpipe to allow the cowl to slide back on. Sorted but will probably need to use 19mm ID silicon tube extension to keep the carbon off the fuselage underside.

Has anyone got a spare 22mm clip by the way?

Anyway, tidying up and putting the original exhaust into a bag for storage noticed that the "smoke blanking plug" was missing. :ohmy: Aha! That's why it was noisy! I feel really stupid now. £60 for nothing. No not really, the OS is far superior compared to the Heinz bean tin supplied by GP.

Should this be in Stories of Stupidity?

ive got the spring clips Phil - give me a call

Kevin Ross wrote: ive got the spring clips Phil - give me a call

Thanks Kevin, will do. Should only need one. Not desperate though due to weather. When are you next up the field?

hoping to go this week but awaiting a rendering contractor to start work.

Well tuned it up today with new exhaust. Running nice. Installed cowl, came back a few hours a later to give it a whirl. Doh! Take-off distance extended, top throttle does not leap forward like it used to, sounds rich now. Same issue that Jon Jacobs had. So, add a tube to the carb cover into the fuselage and make some form of access from the top of cowl to the carb jets. A large fuel dot would look the part and not out of place.

If it sounds rich, it almost certainly is rich, why not try tuning it again before trying to fix a problem that doesn't exist??