Static RPM

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YCCA
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Static RPM

Post by YCCA »

Question for you guys. I have a 2001 DA-20 C-1 with the I0-240. Went flying today and the engine would not make more than 2100 RPM on takeoff roll. After leveloff, the RPM got to 2500RPM but no more.. Seemed a little more sluggish than normal. Has anyone ever experienced this?
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Rich
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Re: Static RPM

Post by Rich »

I don't have a DA20, but given a fixed-pitch prop, this indicates a fairly significant restraint on full power. As to what, in turn, to look at, it depends on any other observable factors (fuel flow reduction, mag check -pretakeoff and inflight, any untoward vibration, etc.) Absent anything obvious I'd have the throttle linkage checked. Also be sure there are no obstructions to the air intake like bird or hornets nests, dead bat, or whatever,
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Pascal
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Re: Static RPM

Post by Pascal »

Was your indicated airspeed lower than usual?

When I purchased my 1999 DA20-C1 in April of 2017 I discovered that the tach was more than 10% off so I had that instrument replaced. Might be worth it to check with a digital RPM reader.
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RMarkSampson
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Re: Static RPM

Post by RMarkSampson »

I had cylinder 4 exhaust valve go sour on me a year ago - failed compression check at annual, but I never really saw a decrease in RPM or HP. However, I could see the issue in the cyclic nature of the EGT. After tackling Rich's obvious items, maybe check for a fouled spark plug. Do you have temp probes for each cylinder, EGT and CHT? Looking for a cold cylinder and or exhaust gas would identify an issue. There are three in-flight tests that Mike Busch recommends - not sure if they are relevant based on your symptoms. The "Ignition Stress Test" the "Mixture Distribution Test" and the "Induction Leak Test."

You asked about the MT prop on another post - that "cruise prop" once installed will likely reduce RPMs during static full power run ups and takeoff roll - as opposed to the two other "climb props" (relatively speaking...)
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Re: Static RPM

Post by Spinner »

Has anyone ever found/installed a digital tach in the C1? Would like to know if there are any kits out there that people have used. Diamond is telling me that the 4 tachs that I ordered may be on hand by mid July from Superior. I won't hold my breath.
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Re: Static RPM

Post by Kesk »

I've seen them get as low as 2100 in the summer, depends on the weather. As a precaution it's always good to perform a fuel setup and verify your throttle body and injector pump are adjusted properly. That often fixes the problem.
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Re: Static RPM

Post by Spinner »

After my digital question I think that we have installed at least 8 digital tachs in our DA20-C1's. Students and instructors as well as maintenance love them.
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Re: Static RPM

Post by Nacium »

I had the same situation couple of times in my flight school last year and for my instructor it was something normal 2100 RMP at the beginning of takoff roll. OAT +20 C, ca. Q1020, Continental.
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