tomfiorentino

Hi guys,

I know we all know about the tank height issue in the Phoenix 7; I recently changed to the Dubro 16oz tank which fits in the ARF fuse like it was made for it, and the center of the tank is about 1/2 inch lower...that has helped mitigate issues all the way around.

I have the OS 55ax, red Jett muffler, 15% Omega fuel, 11X7 APC prop and I'm getting 13,440 rpm on the ground, no flights with this set-up yet. I ordered a few 12X8's at my LHS as I read that is a great prop combo with this engine and exhaust; I'm interested to see what that does too.

My question relates to the effects of the tank height (and fuel level) as it relates to idle and transition in addition to HS needle sensitivity. If you can, please confirm what you think is normal vs. something I should keep working at:

1. I'm finding 3 clicks to be the difference between screaming RPM and blubbering rich. This seems to be more sensitive than any OS I've had before so I can't be so sure if this is coming from the performance exhaust or not. Thoughts?

2. At less than half tank, idle gets better and transition gets even a little better yet. Does the lower tank volume have a mitigating effect on the tank height issue or is the muffler pressure alone enough to keep the whole system stable regardless of fuel level? I am hesitant to mess with the low speed needle because the issue with idle seems to change with fuel level (see #3), so I don't want to start chasing my tail.

3. Above half tank, it loads up on an extended idle and when I move to WOT it needs two very quick pinches of the fuel line to break open to 13,000+. I'm thinking it will unload in the air quicker...anyone take a guess on that?

I'm good enough to fly and will probably do that on Thursday. That should give me information about what is going on in the air, but in the meantime, who has some thoughts?

Thanks,
Tom