Srm99
The problem I am trying to avoid is a DA 50 (any gas engine) running poorly at less than ¾ throttle to idle. I have seen a DR 50 dead stick in an inverted harrier, low throttle and not many “G” at that point at my home field. I still don’t believe what I saw. I am also trying to achieve no RPM changes at any attitude. My other gas planes have a tube running into the fuselage to prevent this from happening but the fuselage is sealed. This trick goes back to when gas chain saw engines were used in RC. Nothing new here at all. The balsa box is a cool idea and I wish I came up with it first. I do not have problems with G’s on any on my planes. Gas engines should not stop in the air and are the most forgiving engine you could install in a RC plane. If you are hearing a slight change in RPM during upright to inverted you need to install this tube. If you are always messing with the HI and LOW needel setting like it's a glow engine then you need to try this. Set you engine up with out a cowl and then install the cowl and it runs different...you need this tube. Some pilots do not here or care about this. Maybe only 5% care? It is worse when most of the flight is a reduced throttle. The cost of a diaphragm is cheap compared to the cost of dead sticking a plane off the field. The diaphragm moves with every stroke and if I am running at less than ½ throttle I should have longer life.

srm99, what is with the ALL CAPS and I watched you video of your WH Extra on a DA 50 dead sticking in level flight what’s with that??? OH ya you might want to edit out kicking little kids on the flight line from your videos. We need pilots to keep this sport going.
http://media.putfile.com/Extras-Lucky-Escape