Well finally got the 106 / extra into the air last weekend.

After testing on the bench and some short ground runs I was very happy with the performace of the motor.
On the ground...........engine runs great (is this starting to sound familiar?)
In the air.................it does the same old and OFTEN documented, "goes so rich when you roll or knife edge it almost dies"............!!!!!

Now the engine is a QS series WITH the carb trumpet. If you examine one of these you can see that the trumpet has a large lip on the inside. What I think happens is NOT an airflow problem as a lot of people seem to think. (before I get flamed Im talking engines with the trumpet only here). What Im thinking is that any excess fuel blown from the carb gets caught in the trumpet (because of the large lip) , pools in there........and then temporarily floods the engine when you roll or invert. The fuel may also block the carb diaphram air feed to but Im not certain.

Now..........of course.......if the engine is leaned to the degree that there is no fuel blowing from the carb (and therefore pooling in the trumpet) then the problem goes away..............and so does your lovely new plane when it deadsticks into the ground because you new engines low end is way too lean.

What Im thinking of doing is running the low end slightly leaner and then perhaps drilling a series of small holes around the widest part of the trumpet to try to eliminate any fuel build up....................or just take the trumpet off and resetting the needles to that!!!

ANYWAY THIS IS JUST A THOUGHT.............JUST AN IDEA AS TO WHAT IS HAPPENING..........ANYWHO MOVE ALONG PEOPLE, NOTHING TO SEE HERE!!

kindest regards, IanB

PS KEEP A LOOKOUT FOR THE NEW MTV SHOW........"PIMP MY PLANE"