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![]() "Michael" wrote in message ups.com... Jim Macklin wrote: Get a better and more qualified instructor. 100 hours is very little time in a particular model, but this guy is either ignorant or you didn't understand him. Actually, you're displaying the ignorance here. The syncrophaser is used to get both props turning at the same speed and with the blades in phase to reduce noise. Correct, that is the primary purpose. However, its range of command is limited - generally 25-50 RPM. Many also have an indicator (the needle the instructor is talking about) which tells you which way to make the adjustment to bring the props within the range of command of the synchrophaser. Since the prop governors used in piston airplanes are proportional-only controllers (no integral component) the RPM on the failed engine WILL drop - and it will drop by enough to take it out of the range of command, though not enough to be obvious (or even noticeable) on the average GA tach. In that case, the needle will become an effective indicator not only than an engine has failed, but which one. In any multiengine aircraft, you identify a failed engine in positive steps. The problem with the in-line airplanes is that only reduced take-off performance (reduced climb) alerts the pilot to an engine failure. Only if he ingores the information provided by the synchrophaser. Michael Hi Michael, I've got some Skymaster time, and I'd have to go with Jim. I've used the tach to determine the failed engine, but have never used the synchrophaser as you describe, nor have I heard of anyone who does. If that little wheel in there is spinning to the left(at high rpm), does that tell you it is the front, or the rear engine? Also in the event of an engine failure, the manual tells you to turn off the synchrophaser so that it doesn't limit, even slightly, the rpm of the operating powerplant. It may even be on the "before takeoff" checklist. In my case we only blew off one cylinder head on the rear engine. There was no indication on the panel, just a "BAM" as reported by a rear seat passenger just after rotation, and a report from the tower of "heavy black smoke, from the rear engine". We climbed to pattern altitude, shut down the rear engine(smoke turned white), and landed normally. Al p.s. This was on a trip to Seattle with 6 pilots in the airplane. My flight instructor was in the right seat, and I was flying. Immediately after landing, I turned off the active at the first intersection, and as I was braking to a complete halt, went through my "Mixture/Master/Mags" shutdown, and turned to the right to tell the flight instructor to evacuate. He wasn't there. He was about 75 feet away, lighting a cigarrette. He had bailed out just after we left the active. No way you'd catch him in no crashed airplane. |
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I agree.
-- James H. Macklin ATP,CFI,A&P -- The people think the Constitution protects their rights; But government sees it as an obstacle to be overcome. some support http://www.usdoj.gov/olc/secondamendment2.htm See http://www.fija.org/ more about your rights and duties. "Al" wrote in message ... | | "Michael" wrote in message | ups.com... | Jim Macklin wrote: | Get a better and more qualified instructor. 100 hours is | very little time in a particular model, but this guy is | either ignorant or you didn't understand him. | | Actually, you're displaying the ignorance here. | | The syncrophaser is used to get both props turning at the | same speed and with the blades in phase to reduce noise. | | Correct, that is the primary purpose. However, its range of command is | limited - generally 25-50 RPM. Many also have an indicator (the needle | the instructor is talking about) which tells you which way to make the | adjustment to bring the props within the range of command of the | synchrophaser. Since the prop governors used in piston airplanes are | proportional-only controllers (no integral component) the RPM on the | failed engine WILL drop - and it will drop by enough to take it out of | the range of command, though not enough to be obvious (or even | noticeable) on the average GA tach. In that case, the needle will | become an effective indicator not only than an engine has failed, but | which one. | | In | any multiengine aircraft, you identify a failed engine in | positive steps. The problem with the in-line airplanes is | that only reduced take-off performance (reduced climb) | alerts the pilot to an engine failure. | | Only if he ingores the information provided by the synchrophaser. | | Michael | | | Hi Michael, | | I've got some Skymaster time, and I'd have to go with Jim. I've used the | tach to determine the failed engine, but have never used the synchrophaser | as you describe, nor have I heard of anyone who does. If that little wheel | in there is spinning to the left(at high rpm), does that tell you it is the | front, or the rear engine? Also in the event of an engine failure, the | manual tells you to turn off the synchrophaser so that it doesn't limit, | even slightly, the rpm of the operating powerplant. It may even be on the | "before takeoff" checklist. In my case we only blew off one cylinder head on | the rear engine. There was no indication on the panel, just a "BAM" as | reported by a rear seat passenger just after rotation, and a report from the | tower of "heavy black smoke, from the rear engine". We climbed to pattern | altitude, shut down the rear engine(smoke turned white), and landed | normally. | | Al | | p.s. This was on a trip to Seattle with 6 pilots in the airplane. My flight | instructor was in the right seat, and I was flying. Immediately after | landing, I turned off the active at the first intersection, and as I was | braking to a complete halt, went through my "Mixture/Master/Mags" shutdown, | and turned to the right to tell the flight instructor to evacuate. He wasn't | there. He was about 75 feet away, lighting a cigarrette. He had bailed out | just after we left the active. No way you'd catch him in no crashed | airplane. | | |
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