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Speed,Combat,Scale,Racing => Combat => Topic started by: dave siegler on February 14, 2011, 03:12:47 PM
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I would like to put together some foamies for 1/2a general screwing around. I don't want a $200 0.49. I would like to use a few Norvel big mig .061 The needle looks like it would not work with a bladder, even on suction it is coarse. I have heard that some guys allow plane bearing 061's in 1/2 a high performance combat. I was wondering what needle valve you would use to fit a Norvel or VA?
Dave
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I tried a Norvel on a Yvenko, it was nuts tail heavy!! n~
I can agree with what you are describing.
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Dave, if you are just "screwing around" with the Norvel big mig you should be able to get a decent run with the needle provided on bladder pressure. "Even on suction it is coarse"? I fly them all the time with suction , no problem with the coarse needle. On a flying platter with a Big Mig and a balloon tank set fairly rich for launch i can get a pretty good 2 4 break and do some taildraggin. I have two ame's and two big migs on combat planes with bladder pressure, they can be a litttle touchy, but quite useable! I find that if from time to time i blow out the spraybar with compressed air they will work fine. Might try different types of bladder material to get the right setup, some can create more pressure than others.
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Dave, I have used with good success the needle spraybar assembly from the Cox production backplates. I've pressed the spraybar out of the plastic and soldered a piece of 3/32 tubing over the hole in the spraybar. Some of the older ones and a lot of the cars used these backplates. They had what I believe was the 125 thread per inch needles. I found a lot of these to be the red style backplates. Those needles are similar to the Kustom Kraftmanship needles used on the Tee Dee engines. I just file a little fish mouth on the tubing prior to soldering and be careful not to get solder in the hole. A little creativity is needed to attach to the plane but its effective and cheap. Dale Kirn used something like this on his 1/2 A speed planes that were running on bladder. I saw this idea used in 1980's Model Builder mag. I have even made a nylon insert that fits into the bathtub venturi hole of the Norvel case. Its drilled and tapped for a Tee Dee venturi which uses a fine threaded needle. The engine runs very well and starts with ease. Ken