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- เผยแพร่เมื่อ 19 ก.ย. 2024
- Dyna Vibe Propeller Balance. Cessna 177 RG prop balance. Note: when I said 160 deg. was the light spot i meant to say it is the heavy spot. As you can see I put the weight opposite that. I added about 10 grams to the weight when i moved to the flywheel bolts. The vibration level was acceptable on the last run. The Honeywell balancer is nicer because it saves the reading.
I upgraded to the new Dynavibe that gives the split calculation. Made my own mounting kit by simply tig welding a couple stainless nuts with proper size bolt end for each sensor. I purchased all the standard hardware (nuts, bolts and washers) and put them in an inexpensive Harbor Freight plastic storage box after pre-weighing them. Saves time.
I made my own dynamic balancer using an accelerometer and optical sensor from Amazon, a tablet app, and 2 channel HANTEK oscilloscope that uses a tablet or laptop's screen. It produces a sine wave from the accelerometer and a pulse from the optical sensor and when I'm at the RPM I want to measure, I do a screen freeze and shut the engine down. I measure the difference in milliseconds from the peak of the sine wave to the start of the pulse, convert to a ratio, and multiply by 360. I don't get an IPS result (I can only measure raw millivolts from the accelerometer), just a sine wave showing fewer millivolts amplitude. I ended up with about 20 grams on the ring gear of my Lyc O-290 after 3 tries which produced a sine wave with just noise, no discernible sinusoidal pattern. Significant improvement in the cockpit, and I gained about 100 RPM at the same manifold pressure with a fixed pitch prop. I think remaining vibration I still have is from the engine's torque pulse rocking couple.
If you push the other button it averages the balance and you don’t have to watch it and remember it.