Joseph .... interesting you mentioned the inboard mount for a Fox 35 ..... I did that .... the interesting thing is that the 'burp' now occurs on the hard inside maneuver.

I don't think that the phenomenon is a hard influx of richening gasses.  I think its the opposite, at the time of the acceleration, the bypass gases are pushed back into the bypass, resulting in a momentary starved condition.  (but I may be wrong)

Frank

with the overly large bypass, the gas velocity isn't strong enough the overcome the acceleration
the reduced bypass area helps create a higher velocity to help the gases get into the combustion chamber

O'Riley auto parts ..... Dupont 3608S thinner

So far, no one has mentioned being bothered by the noise. We use Cox .049 reed valve engines. The parents watched, and cheered as the kids took turns flying. The kids had a great time, and seem very excited about our upcoming building sessions for them to build their own planes.

That's all that matters. Don't listen to the naysayers who tell you the kids won't keep up with it. The point is you exposed them to it and they had fun. They now know what CL is and if they ever start modeling they may revisit it in the future. You never know when your influence will bear fruit and if it doesn't, so what, you spent a day enjoying your hobby and had some laughs with a group of eager pupils. Good job Dave.

I have seen a few Cox 049 models use simple wood screws. But after a bit if time, vibration, oily residue in the mounting screw area, etc., the screws will work themselves loose. Just check them for tightness often.

But if it were me, I would use a bolt-thru method.

Thanks guys, both great answers.