Kellym
Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ
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 Posted: Tue Nov 07, 2017 6:55 am Post subject: LycomingEngines-List Digest: 2 Msgs - 11/06/17 |
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Critical information on your engine is whether you have parallel or
angle valve cylinders, and if there are any rpm restrictions on your
prop/engine combination. Most angle valve engines have some restriction
on rpm combinations. The parallel valve in certified combinations have
less restrictions, but most props have some.
This limits your ability to run certain cruise rpm/MAP combinations,
mostly in the 2200-2300 range. These restrictions are due to harmonic
resonate vibrations in those ranges.
On 11/7/2017 6:41 AM, Paul Collins wrote:
| Quote: | Thank you all for your opinions. With the engine monitoring systems we
now often have we should be able to do a better job than just tying to
judge vibration in the cockpit.
Again, I have a Lycoming IO-360 in an RV8 with EGT and CHT real-time
monitoring. The question again is, what readings on these monitoring
systems should I use to *best protect* the engine and still
obtain/balance *optimal performance* for different altitudes/power
settings.
How about this, what settings would we look for at these “cruise” power
levels? What do you use? I know there may be some “high RPM/low MP”
folks and some “low RPM/high MP” folks – so tell us why!?
1. 45 – 50% power =
1. RPM ___
2. Manifold Pressure ___
3. CHT ___
4. EGT ___
5. Fuel Flow ___
2. 50 -55% power
1. RPM ___
2. Manifold Pressure ___
3. CHT ___
4. EGT ___
5. Fuel Flow ___
3. 55 – 60% power
1. RPM ___
2. Manifold Pressure ___
3. CHT ___
4. EGT ___
5. Fuel Flow ___
4. 60 – 65% power
1. RPM ___
2. Manifold Pressure ___
3. CHT ___
4. EGT ___
5. Fuel Flow ___
I know this is rather overloading, but to me it is what we need to aim
for. I know each airplane setup will be different, but there should be
some targets out there.
Thanks again for the help with this. In the end, there should be a
“best use” range for these settings that will keep the engine happy.
With the technology that we have now, we should be able to do better
than just throwing fuel at the engine and fouling plugs with lead.
Thanks!
Paul Collins
RV-8
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_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD |
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