Frank Volker
05-13-2014, 03:26 PM
Some time back (about 100 Internet years ago), I posted some info on the comparison of various <a href="http://www.boatracingfacts.com/forums/showthread.php?195-A-Brief-History-of-QW-Loop-Engine-Pipes">QW Flathead Exhaust Systems</a>. That analysis was part of my MS Thesis at University of Missouri. While fumbling through some old docs, I found some copies of photos that I snapped of the setup I used while conducting that work. The quality is typical early 70's Polaroid, but I thought it might be interesting since it's these are the only photos I've ever seen of an engine mounted on the QW dyno.
57548
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<p><b>Photo 1 - Engine Mounted - Magnetic Pickup</b>
Engine shown mounted on dyno table. A small pin screwed into the hub of the flywheel hub is sensed by the magnetic pickup and is used to trigger the oscilloscope. Small indentations drilled in the hub correspond to EO, IO, and BDC. These "blips" are fed into Channel 2 of the oscilloscope and sync the scope sweep with the exhaust pressure pulses for a complete cycle. </p>
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57545
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<p><b>Photo 2 - Engine Mounted - Pressure Transducers</b>
Transducer #1 (#1 XDUCER) is mounted about 2" from the exhaust port. Transducer #2 is mounted about 7" downstream. Most of the data taken was from #1. In one test, the wave propagation velocity was measured by observing the time required for the wave to travel from #1 to #2. </p>
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57546
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<p><b>Photo 3 - Oscilloscope and General Setup</b>
Shown are the two-channel oscilloscope, camera, cabling, and box above scope containing the Kistler charge amplifier and temperature readout box. The temp readout was digital and used Nixie tubes which are gas filled. Unfortunately, the RF energy from the CD ignition was sufficiently strong that it would light up all the segments of the tubes, rendering the device unreadable. The small box to the left of the temperature readout is the Kistler charge amplifier for the pressure transducers.
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57547
<div style="border:1px solid black; width: 70%; padding: 8px;">
<p><b>Photo 4 - Dyno Console</b>
I probably have about 3000 hours of brain film recorded of this image. The center knob controls the water flow to the Stuska water brake dyno. The big dial is the torque gauge. If I recall, the dyno torque arm length was chosen such that the pressure recorded by this gauge allowed a simple RPM times Gauge Reading = HP. I seem to recall the dyno limit being somewhere around 100 HP.
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Overall, it was a fun project. As I mentioned in the original postings, coming up with the Gen 3 flares was a real treat. Most MS work involves just that--a ton of work and then a long string of apologies on why Plan A didn't work out and why Plan B sucked even worse than Plan A and how it would have been perfect If There Was More Time. I was happy not to have to dip into that sort of back peddling. The biggest disappointment was the problem with the temp readout. As it turns out in 2014, the average temperature doesn't mean that much anyway. In gas dynamics, the key word is "instantaneous". After all, when the exhaust first opens, things are sonic+ and temps are ridiculous. And then along comes a big suction wave and you have air/fuel vapor where fire used to be. Average? Just pick a number.
Frank
57548
<div style="border:1px solid black; width: 70%; padding: 8px;">
<p><b>Photo 1 - Engine Mounted - Magnetic Pickup</b>
Engine shown mounted on dyno table. A small pin screwed into the hub of the flywheel hub is sensed by the magnetic pickup and is used to trigger the oscilloscope. Small indentations drilled in the hub correspond to EO, IO, and BDC. These "blips" are fed into Channel 2 of the oscilloscope and sync the scope sweep with the exhaust pressure pulses for a complete cycle. </p>
</div>
57545
<div style="border:1px solid black; width: 70%; padding: 8px;">
<p><b>Photo 2 - Engine Mounted - Pressure Transducers</b>
Transducer #1 (#1 XDUCER) is mounted about 2" from the exhaust port. Transducer #2 is mounted about 7" downstream. Most of the data taken was from #1. In one test, the wave propagation velocity was measured by observing the time required for the wave to travel from #1 to #2. </p>
</div>
57546
<div style="border:1px solid black; width: 70%; padding: 8px;">
<p><b>Photo 3 - Oscilloscope and General Setup</b>
Shown are the two-channel oscilloscope, camera, cabling, and box above scope containing the Kistler charge amplifier and temperature readout box. The temp readout was digital and used Nixie tubes which are gas filled. Unfortunately, the RF energy from the CD ignition was sufficiently strong that it would light up all the segments of the tubes, rendering the device unreadable. The small box to the left of the temperature readout is the Kistler charge amplifier for the pressure transducers.
</p>
</div>
57547
<div style="border:1px solid black; width: 70%; padding: 8px;">
<p><b>Photo 4 - Dyno Console</b>
I probably have about 3000 hours of brain film recorded of this image. The center knob controls the water flow to the Stuska water brake dyno. The big dial is the torque gauge. If I recall, the dyno torque arm length was chosen such that the pressure recorded by this gauge allowed a simple RPM times Gauge Reading = HP. I seem to recall the dyno limit being somewhere around 100 HP.
</p>
</div>
Overall, it was a fun project. As I mentioned in the original postings, coming up with the Gen 3 flares was a real treat. Most MS work involves just that--a ton of work and then a long string of apologies on why Plan A didn't work out and why Plan B sucked even worse than Plan A and how it would have been perfect If There Was More Time. I was happy not to have to dip into that sort of back peddling. The biggest disappointment was the problem with the temp readout. As it turns out in 2014, the average temperature doesn't mean that much anyway. In gas dynamics, the key word is "instantaneous". After all, when the exhaust first opens, things are sonic+ and temps are ridiculous. And then along comes a big suction wave and you have air/fuel vapor where fire used to be. Average? Just pick a number.
Frank