Running at High RPM

[secretapproach]

[ QUOTE ]

Ahh but Confucious asks: if we're out here buzzing around trying to build hours what's the hurry in getting there faster? Who here didn't wish they had 20% more time in their logbooks?

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Thanks for pointing this out, pilot602! You beat me to it.

 

[ready2fly]

Well, I put this post to the test last night in the Mighty One-Fiddy (C150) on my x/c.

I had the thing running consitantly at around 2600+ rmp - JUST above the red line. I got extra speed, but the Mighty One-Fiddy guzzled the fuel.

A 1.5 hour flight used up ALMOST half the tank.

BUT - the engine instruments stayed WELL within the green the entire flight.

 

[IrishSheepdog]

[ QUOTE ]
Ahh but Confucious asks: if we're out here buzzing around trying to build hours what's the hurry in getting there faster? Who here didn't wish they had 20% more time in their logbooks?

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I dunno... I just kinda want 20% more cash in my wallet I guess.

Hehe!

 

[DrBenny]

[ QUOTE ]
I met a guy while i was stuck in an airport last October. He had a Cessna 140 and was flying it across the country. I couldnt help but think how much that would suck and get old. (I guess this happens after you have CFIed for awhile). I always assumed everybody loved to go faster rather then slower. I have always liked and gotten my thrills from flying faster equipment. This guy blew me away b/c he really liked going slower, so he could enjoy the scenery better. More power to him, but i aint going with him!
Different strokes for different folks,
KA

[/ QUOTE ]
That's true. I really should revise my comment. I do occasionally like going fast--to a point. For me, that means about 150 kts, which I will never get in a C-172. Eventually I think my plane of choice will be a Sary-Toga or a Staion-Aire. But then, you must realize that my choice is also based on comfort.

It is interesting. I really don't enjoy flying the airlines (but would probably love it if I could sit in the front seats). It is boring, and over much too soon.

No, I wouldn't be the "Cross-country Cessna 140 Guy," but I might go for the much more modest title of "Baltimore-Dallas Cessna Skylane Guy." Yeah, I'd like that.

 

[E_Dawg]

[ QUOTE ]
Well, I put this post to the test last night in the Mighty One-Fiddy (C150) on my x/c.

I had the thing running consitantly at around 2600+ rmp - JUST above the red line. I got extra speed, but the Mighty One-Fiddy guzzled the fuel.

A 1.5 hour flight used up ALMOST half the tank.

BUT - the engine instruments stayed WELL within the green the entire flight.

[/ QUOTE ]

What TAS and what altitude if you don't mind? That's suprising that you used half the tank (or almost). As I said I once flew for 2.2 and used amost exactly half = 4.4 total!

 

[ready2fly]

Ed, I it varied between 100 MPH (it's an OLD 150) to 115 MPH.

I found it strange that it would use that much fuel too. Perhaps the guages are off.... WAY off.

 

[pilot602]

REAl dumb question but,

was it leaned out properly?

 

[IrishSheepdog]

[ QUOTE ]
REAl dumb question but,

was it leaned out properly?

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I was going to ask the same thing. Different leaning procedures between pilots could yield very different results in fuel usage. Just simply the different between best economy and best power.

 

[ananoman]

Some engines have an enrichment feature where full throttle will add more fuel than normal for cooling. This could lead to significantly higher fuel burn if you run wide open.

If you are running full throttle below about 6-8k feet you really don't want to lean. You only want to lean at 75% and below in most engines.

 

[E_Dawg]

Why?

 

[DrBenny]

you have to watch the EGTs and CHTs.

 

[pilot602]

Leaning out at power settings above 75% can do serious damage to the engine - mainly burning up valves, etc.

Each engine is different and 75% is ageneral rule but I like it better than the "above 3k or 5k lean."

Wasn't even thinking when I asked about if it was leaned because if it as being run full out it wouldn't have been leaned. But, that itself may be the answer. If, R2F, you had been accustomed to fuel burns with a leaned engine a full power, no leaned engine will guzzle far more fuel.

Sometimes .... ok most of the time ... I'm kinda dumb!

 

[ready2fly]

I'm gonna have to go with the answer of "Probably not leaned out properly" IF, that is, the fuel guages were accurate - which I have no reason to believe they were faulty.

I was at 2500 ft. the entire time, so I didn't lean.... probably the thing right there, huh?

 

[E_Dawg]

I always lean above 3k; if it's a hot day I lean it out even lower. The mighty 152's poh even has a section on the use of leaning for takeoff and cruising below 3000' (it's ok per the poh).

I don't do that though, I like to have all the power possible on takeoff; it's such a rush in a full power climb in a 152, especially when the mixture is full rich. One time I almost got 500fpm!!!!! It was REALLY cold that day; or maybe the VSI was just inop. I also taxi with it really lean to warm it up and keep the plugs from fouling.

 

[ready2fly]

Yeah, that's why I didn't lean it. Too low. I have the POH out in my flight bag. I'll re-read that section (skimmed it before, but was taught to lean after 3000).

Ed - I tried to respond to your PM. Did you get it?

 

[Alchemy]

If you notice in the Cessna POH's, it's always reccomended that you do a full throttle static runup, then lean the mixture for best power prior to takeoff when departing airports higher than 3000 MSL.

It's really easy to forget about this if you don't fly in high altitude areas much, but usually you'll only forget to do this one time in your life.

I'll never forget my 2500 ft takeoff roll in a 172, then struggling to maintain a 150 fpm climb with mountains looming 10 NM from the threshold at E38......

 

[E_Dawg]

Ouch; what is the altitude at the airport?

 

[ready2fly]

Maybe I should add that I fly out of TPF in Tampa... which is right on the Bay and has a WHOPPING altitude of 8.... feet.

Soooo, leanin' for takeoff REALLY shouldn't be an issue.

 

[Alchemy]

4515 MSL, pretty hot that day too. Full tanks and 3 SOB, with some baggage. Left the mixture full rich for takeoff, but the climb performance improved considerably once I hit the "Mixture-Lean above 3000" step on the climb checklist.

 

[averyrm]

[ QUOTE ]
it's such a rush in a full power climb in a 152, especially when the mixture is full rich. One time I almost got 500fpm!!!!! It was REALLY cold that day; or maybe the VSI was just inop.

[/ QUOTE ]

Last summer I flew a 150 with a STOL kit, climb prop and a 180hp (yes, that's not a typo) conversion. I'd get about 1800fpm with just me in it and a take-off run of about 200'-300'. My first time flying a regular 150 afterwards made me think the engine was breaking and not producing power