RocketBoy
Aircraft Products
Parts and accessories for your F1 Rocket or Homebuilt aircraft.
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Parts and accessories for your F1 Rocket or Homebuilt aircraft. |
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Regular Rocket stuff
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What's
New!
Flight test 1 Flight
Test 2
Flight Test 3 - Flowing the Nozzles Flight
Test 4 - Instrument Calibration Flight
Test 5 - Cruise Performance |
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Dynamic Balance
Dynamic balancing is a process where a rotating mass is balanced for smooth operation while it is spinning. This is different from static balancing where the object is balance using a pivot. Generally the object being statically balanced is not moving. After an object is statically balanced, it can and probably will vibrate when spun. This is due to different weight densities at asymmetrical arm locations from the center of rotation. Dynamic balancing measures the actual spinning vibration, then guides the user to place balance weight where needed to result in a smooth running object.
Below is a picture of the
ACES ProBalancer. It comes in an nice black case with many accessories.
The case is free because the rest of the stuff in the case costs around
$8,000. Borrow one if you can. I did. The camera flash liked the roll of
reflective tap in the box. See the bright spot?
Procedurally, one vibration transducer, and an optical RPM pickup were attached to the engine. The optical pickup shines a beam of light forward to detect a piece of reflective tape attached to the back side of the propeller. The vibration transducer is mounted as far forward as possible to detect the prop vibrations. Inside the ACES box, a couple of setup menus are completed and the engine is read to run. The ACES box reads the detected vibration and displays that information as IPS (inches per second) and degrees from the tape. After the first engine run, the ACES guesses where to add a weight to balance the prop. This guess is really not that important, as the vibration information that will come from the second run will contain all the answers. Again the engine is run. This time the ACES knows the first set of vibration data, the recommended weight and it's location, and the resultant vibration data. NOW, the ACES does it mathematical magic. It generates a REAL balance weight and location. The user removes the old weight and installs the new. This next engine run should show a significant reduction in overall vibration. IT DOES! This process is repeated as many times as needed to achieve the desired result. I've found, after balancing several engines, it take two additional engine runs to fine tune the balance weight. The goal is generally .05 IPS or less. My F1 started at .36 IPS and finished at .04 after the second run. Done.
The vibration sender and optical pickup are visible here.
A close-up up of the vibration transducer.
View from the flight deck. I tied the tail down securely for these high power engine runs. The target RPM was 2300. This left my hands free to operate the ACES. It's best to have two people to do this job.
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"Sadly,
artificial intelligence will probably never be a match for natural
stupidity." |
