C-208 operators.

Goreman11

Goreman11

Well-Known Member
Skimmed through the POH a little and can't seem to find an answer. I am trying to find a minimum limit on the propeller rpm for take off, if their is one. I have only found the max limit of 1900.
 
Well...doing some digging through my POH (for a 600SHP bird).

Before start, propeller lever FULL FORWARD. No mention before takeoff aside from that.
All takeoff data is listed with the propeller RPM set to 1900.

Which, in my opinion, means taking off with it set less than max/full forward makes you a test pilot.

You'd have to find someone with access to a maintenance manual to find out what the allowable variance is on prop RPM with the lever full forward. I imagine gauge accuracy would be more of an issue than anything. We had a plane one time that would only read 1850 with the lever full forward, but with a digital laser tachometer the prop was turning right around 1900.
 
1900 (100% Np) is max normal for takeoff and is the only performance RPM listed.

Anything less, as stated, you're a test pilot. Anything more, and you are using the governor(s).

As it has been said, prop lever goes full forward before start. Heck, there are operators that don't operate at any setting other than 1900 RPM.
 
Ok. Atleast I'm pretty sure I'm not missing anything in the POH. We pull it back to 1750 through 1000 ft or at pilots discretion.
 
ctab5060X said:
Heck, there are operators that don't operate at any setting other than 1900 RPM.
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That was us! Even now in the Metro it's 100%, all day every day.
ctab5060X said:
How is it pulled back to 1750?

We only go back as far as 1850 for climb and 1800 for cruise.
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The range is 1600-1900, so 1750 should be no issue at all.

I never much understood pulling the prop back on the 'van. Didn't save fuel or decrease the noise any substantial amount. Talking to the Pratt guys they didn't see any difference in wear with engines off of birds running reduced or full RPM consistently.
 
z987k said:
Nope you're a test pilot.
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Say again?

The Cessna POH checklist (rev. 29 anyway) shows cruise climb - "Propeller - 1600-1900 RPM" as well as providing cruise data for 1900, 1750, and 1600 RPM. I don't see where you'd find flying in the Cessna-approved performance window being a test pilot.
 
ctab5060X said:
How is it pulled back to 1750?

We only go back as far as 1850 for climb and 1800 for cruise.
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To be honest I have never done the climb at anything different than 1750. Usually utilize a cruise climb of about 120 kts anyway. We do it mostly to lower the noise level even though its really not to much of a difference between settings.

JeppUpdater said:
That was us! Even now in the Metro it's 100%, all day every day.

The range is 1600-1900, so 1750 should be no issue at all.

I never much understood pulling the prop back on the 'van. Didn't save fuel or decrease the noise any substantial amount. Talking to the Pratt guys they didn't see any difference in wear with engines off of birds running reduced or full RPM consistently.
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Cant dispute this much either. Haven't seen much of a difference. Just been told that it is a little more efficient
 
JeppUpdater said:
Say again?

The Cessna POH checklist (rev. 29 anyway) shows cruise climb - "Propeller - 1600-1900 RPM" as well as providing cruise data for 1900, 1750, and 1600 RPM. I don't see where you'd find flying in the Cessna-approved performance window being a test pilot.
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Sorry, I was just reading all the other OMG! test pilot stuff and figured why not this to? If you fart and fly, you're a test pilot, because, well we don't know if the test pilot farted at rotation, giving more thrust.
 
JeppUpdater said:
That was us! Even now in the Metro it's 100%, all day every day.

The range is 1600-1900, so 1750 should be no issue at all.

I never much understood pulling the prop back on the 'van. Didn't save fuel or decrease the noise any substantial amount. Talking to the Pratt guys they didn't see any difference in wear with engines off of birds running reduced or full RPM consistently.
Click to expand...

Which prop are you running?

I never noticed a difference pulling the Hartzell composite back off of 1900, but I definitely noticed a change in cabin noise with the McCauley. Then again, I'm flying with a noise cancelling headset this time around too!
 
ctab5060X said:
Which prop are you running?
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It was a mix. We had at least one of every option of factory engine and prop combinations prior to the addition of the -140.

Our company procedures permitted running down to 1600 if we liked, just no one did. Just slowed the bird down and freight doesn't care about noise.

The only time I noticed a difference was on a long repo flight in the mid-teens I pulled it back out of curiosity. With basically all the noise in the turbine suburban being wind noise off the prop, pulling it back at altitude did seem to make a difference.
 
JeppUpdater said:
Say again?

The Cessna POH checklist (rev. 29 anyway) shows cruise climb - "Propeller - 1600-1900 RPM" as well as providing cruise data for 1900, 1750, and 1600 RPM. I don't see where you'd find flying in the Cessna-approved performance window being a test pilot.
Click to expand...

If you takeoff with the prop at 1750 and some power setting that gives 675SHP you'll be generating the same SHP but I can't vouch for the thrust - thus expect a longer takeoff roll than normal. It'll fly with the prop all the way back for takeoff - but I couldn't tell you how long your takeoff roll would be
 
All my Caravan time has been prop full forward as well. Didn't see a need to bring it back.
 
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