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bob27s -> Needling Jett Q500 Motors (8/14/2003 2:10:04 AM)
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Hi John...
I use basically the same proceedure Dub does.
Assuming a Q-500 installation with a bubble-jett tank..... and your initial set up....
Open the needle 4 turns
Start the engine, turn the needle in slowly, watch the tach, and listen. Over about 20 seconds or so the muffler and engine will warm up.
Find the peak RPM for the prop you are using on that day. RPM will vary with conditions. It should be well above 19K.
As you find the RPM rise stopping.....note the RPM and quickly back the needle out a half turn. Shut the engine down, and let it cool for at least 15 min.
Subsequent starts for racing:
Back the needle out about 1/2 turn from that shut down.
Start the engine... let it run about 10 second. This is usually the time it takes me to remove the glow driver and put it in the box.
Turn the needle in so the RPM is about 400 down from your initial peak reading. This should be about 1/2 turn back in.. maybe a little more.
Fly the plane.
Thats about it.
Of late, I've simply started the engine... then tuned up to 19,300. Seems to work fairly consistantly... sometimes ends up a tad rich, but thats ok. Unloads nicely in the air.
Bob
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