Larry,
Looking forward to your venturi tests!
I've looked at Eric's web site, but only see the larger Super Tiger needle valves. Which one are you using?
Ran one of my new AP Wasps on the bench today.
None of the shops around here stock the all Castor fuel the AP instructions recommend, so I had to compromise. Used a pint of my thirteen year old Dukes fuel, with added Castor to bring it up from the original twenty percent pure Castor, to twentyeight percent Castor. Added enough Norvel 35 percent nitro fuel, to bring the total nitro closer to fifteen percent. I calculate the blend to be twentyfour percent pure Castor, plus a little synthetic from the Norvel fuel.
The first run (3/4 oz tank), using a 5.7 X 3 APC prop, with the carb wired wide open, gave me a steady 15,300 rpm. The second run showed 16,400 rpm! Both runs were just off peak rpm, so the the engine leaned out normally at the end of both tanks.
Had to use my starter for all starts, because the piston to cylinder fit is very tight. Hand flipping never got it past the first compression stroke.
One thing I noticed while adjusting the needle valve, is that it's very sensitive to touch, and pushing down very lightly on the needle seemed to richen the mixture, and dropped the rpm a noticeable amount. I suspect the R/C carb tolerances are a bit loose, but a fixed venturi should cure that.
Bill