I can see where Dave gets his spelling hints...
All I can say is that this IS NOT consistent with my experience, and when we started running spigot venturis the grotesque inside/outside speed differences we had with the PA40 and 61 went away almost completely. And don't forget that we ran it stock, first, for a long time. We clued in after Billy managed to tame that with, hey, how about that, a spigot venturi, first discovered by us when David found out about it at the WC in Germany.
The "dribble hole" does indeed "dribble" and fail to atomize sometimes, Dave and I have both seen it happen on stock, out-of-the-box, "trueest of the true" Randy-blessed venturis, on the test stand. A drip forms, builds, then drops off, engine goes "blurp" for a moment. If it makes you feel any better, the original Jett venturi with the .100 diameter dribble hole did it far worse. That's why I asked for a smaller hole, which helped it considerably. The problem was cured forever with a spigot venturi, which curiously happened to fit perfectly in the hole size I requested.
I think the effect is moderated enough in the midwest and southeast (which definitely does seem to be different) that you have convinced yourself there is no issue. Although I heard several of your buddies with very similar issues, and they also had the tell-tale surging on the ground of the unsealed and leaking case/spraybar interface. All denied that it happened afterwards, of course.
Brett
HI Brett ,I don't doubt you have seen this, that is why I did so many test on my bench, and asked MANY people from all over the US and the World to check if they have it, The last person that checked this for me was Bruce Perry when he was breaking in his latest PAs, He saw nothing at any time except a white high velocity spray going toward the center of the venturie. There was never a surge or a dribble, It is very hard to even see the hole when looking at a running engine, . If you see the hole in the side, and see a dribble build below the hole, then you have a venturie that has been drilled out and has a straight section in the middle, or you have one that was made wrong, or a mistake. No less than 2 dozen people have helped me in researching this.
I do not take anything that you or David say lightly, or blow it off. Which is why I took that seriously and did so much checking/testing.
As far as the side seal, this is a problem with ANY engine, and most every time I see or hear this is when the spraybar has been removed, put back in with debris between the flat hex of the bar, and the side of the case,This happens when they compress the venturie, force the bar thru, nick off some al. or delrin debris with the threads, and install the nut with the debris still in the thread, it then goes toward the case and ends up being trapped between the nut and the case. I have seen this many dozens of times with many engines, STs, OS, TTs, Aero Tigers, PAs and others.
I never claimed that does not exist, it does, and makes for inconsistent runs. However I, personally have had ZERO problems with this . I am not sure who you are saying denies that exist, it does, and I have covered that above.
I have NEVER sealed a bar with any PA engines. others... not so much. I don't think it is just "my buddies" that have had this happen, It happens to many people, and I have also seen big problems caused by the sloppy application of sealant on many types of engines, especially PA , ST and Thunder Tigers.
by the way Billy won a WC with a non spigot true venturie, I was there and looked, so has other people, plus NATs, so obviously they both work. And there have been many top 5 flyers use and test both, that are using true venturies now. This is really not an issue to fight over, use what you like, its all fine by me, I have no problems with that at all.
You should send one of the dribble holes venturies to me for testing, so I can see what went wrong.
and by the way, problems with fuel post are in play too, like not being able to tell the size, never being able to make the excat same ones, having the brass post come out and go thru the motor (is have seen that happen over a dozen times) and having to send them back to me for a new PS crank or sometimes case. There are other but you get my point.
I will give one caution here on dribble venturies I have seen, they had the fuel feedhole drilled out much larger to use a fuel post (piece of brass tube, or eyelet) then when it was removed they tried to use it as is, the larger hole (way too big) would NOT feed correctly and did dribble into the engine.
regards
Randy