ORIGINAL: gcb
ORIGINAL: zachery
... what are the advantages and disadvantages of backplate pressure and using bladders?.
I will have to defer that question to folks who use it. I use suction or muffler pressure.
As a SWAG, I would try a bladder before going to the trouble of modifying a backplate for pressure. See if it runs well at all on pressure. There should be info on the net for making and using bladders.
What vintage AME do you have? Before the REVLITE versions, the AME and Big Mig came with a brass needle (early) and steel/aluminum (later). The earlier version seems to have a finer thread than the later ones. This may be important when running pressure. The Zeus was made to run on pressure and has a fine thread.
Again, perhaps someone who has run pressure will respond.
George
Edit: Afterthought...you might want to check out some of the NORVEL info (15 pages), or ask the same question on the "1/2A & 1/8A Airplanes" forum. Good folks, very knowledgeable.
My first examples were Zeus type and to pressurize them I took 1/32 brass tubing and drilled the backplate for this. One advantage was that i was able to bring the tube out and up to the base of the cylinder, making it so much more accessable. The final thing is to get a piece of .006 wire and blacken it with a match and insert it into the tube and solder the tip. withdraw the wire and you have a nice .006 thou hole which is just about perfect for pressure.
Oh and if your going to do that use a 4/2 prop and ear protection when you fire it up.
Dennis