Forgot to enrichen

RyanB

RyanB

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It happens, during taxi I have been trying my best to lean out, today I must not have leaned hard enough because i forgot to enrichen it before taking off. I lined up for takeoff gave full power and the engine seemed to be making full power, I didnt notice any thing unusual. As i was upwind about 1000 agl i looked down and saw the mixture still lean, pushed it full rich and only seemed to notice a slight increase in engine RPM, which tells me it was not leaned out very much but oddly enough as I recall from memory, the mixture was leaned out at least an inch or so, maybe even more. Always learning and something to learn a lesson from, before EVERY takeoff its "lights, camera, action, everything forward". Anyone else ever done this?
 
I'm sure that virtually everyone has done this or similar numerous times.

But I don't blame it on "forgetting" - checklists are there so that "forgetting" should not even be an option.

So rather than promising yourself you'll remember next time, maybe zero in on checklist use and discipline.

If you're asking for advice, that is! ;)
 
Yes. Been there, done that.

If you had an engine monitor your would see that the egts are through the roof and chts are right behind. Not a good idea to run lean on take off.

Make sure when you move the throttle forward to hit the mixture forward also. Only use full rich on take off, or go around.
 
You're right, there is absolutely no excuse to forget this, I use checklists on every flight. Liningup for takeoff I like to have memory items such as "Lights,Camera,Action" etc. Im sure EGT's and CHT's were high, but like I said, when I enrichened, I didnt hear a huge roar in power just a slight increase so whatever the setting was it must have been fairly low even though it looked well leaned. I assume the worst that could have happened was detonation and the engine running rough, but like I say lessons I try to learn from
 
Ryanb said:
It happens, during taxi I have been trying my best to lean out, today I must not have leaned hard enough because i forgot to enrichen it before taking off. I lined up for takeoff gave full power and the engine seemed to be making full power, I didnt notice any thing unusual. As i was upwind about 1000 agl i looked down and saw the mixture still lean, pushed it full rich and only seemed to notice a slight increase in engine RPM, which tells me it was not leaned out very much but oddly enough as I recall from memory, the mixture was leaned out at least an inch or so, maybe even more. Always learning and something to learn a lesson from, before EVERY takeoff its "lights, camera, action, everything forward". Anyone else ever done this?
Click to expand...

Full rich is far richer than maximum power requires.
 
Yep, I've leaned on taxi and then forgotten to go to full rich on take off. Also forgotten to retract flaps on a C-150 during a T&G. All that stuff happens to us all...I think. :redface:
 
As long as you remain 250° ROP, you will make full power and be safe from detonation. Normally you can lean a pretty good ways before you get there.
 
Ryanb said:
You're right, there is absolutely no excuse to forget this, I use checklists on every flight. Liningup for takeoff I like to have memory items such as "Lights,Camera,Action" etc. Im sure EGT's and CHT's were high, but like I said, when I enrichened, I didnt hear a huge roar in power just a slight increase so whatever the setting was it must have been fairly low even though it looked well leaned. I assume the worst that could have happened was detonation and the engine running rough, but like I say lessons I try to learn from
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You seem to expect that enriching the mixture would increase your power? You take off full rich (allowing for elevation) so that excess fuel keeps the cylinders cooler not to give you more power. You lean at higher elevations or density altitudes to get more power as a too rich mixture will rob you of power and may even cause the engine to run rough.
 
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I generally lean about 2/3 towards Idle / Cutoff. Parked in the grass once, had to give it extra power to pull back onto the asphalt and it tried to quit until I pushed the. Insure forward a little bit. Left it there for the rest of the taxi.

Don't worry, you can't over lean for low power ground operations. Lean enough that you'll notice giving it takeoff power, and you won't do this again.
 
If anyone says they haven't done it, they're lying if they've flown a lot.

If it made full power for take off, I probably wouldn't have pushed rich at a thousand feet, just pull the throttle and prop and leave it. Close the cowls later ... watch the EGT and CHT and adjust as needed.

It isn't sudden death to take off leaned out. You're going to lean it at high elevation or DA anyway. :redface:

.
 
Its just one of those things i need to correct, say it was something like forgetting to put the gear down, something to make a memory item of, its in a different checklist but anyway.. Thanks for the replies everyone!
 
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I did it once for about 10 seconds on take off. Noticed all my LED bars pegged on my monitor. Glad to know it happens to other people, too.
 
You need to lean more on the ground. Lean until it starts to stumble at idle then slightly in. If you advance it to full power like that the engine will stumble and won't make any power. Problem avoided.
 
jesse said:
You need to lean more on the ground. Lean until it starts to stumble at idle then slightly in. If you advance it to full power like that the engine will stumble and won't make any power. Problem avoided.
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Word.

I try to pull the mix right after start up. You don't need full rich to warm up and taxi.

Full rich is like full choke on these engines. :redface:
 
I did this by accident yesterday! I went through the whole run-up checklist. I was all setup and #3 ready for takeoff, when I was told there would be a delay on departure since there were multiple IFR departures. I leaned it out while I waited for 10 minutes, then about 800 feet on takeoff the engine seemed a little rough. I instantly knew it was the mixture from doing it once before. shame on me for not double checking that just before takeoff..
 
jesse said:
You need to lean more on the ground. Lean until it starts to stumble at idle then slightly in. If you advance it to full power like that the engine will stumble and won't make any power. Problem avoided.
Click to expand...

In fact, unless you've leaned it that far, you've probably not done SQUAT for leaning at the idle/near-idle settings you're using to taxi (unless you have a Navion that need more power to taxi). The mixture control doesn't do much for the idle loop until you're near cutoff.
 
Witmo said:
You seem to expect that enriching the mixture would increase your power? You take off full rich (allowing for elevation) so that excess fuel keeps the cylinders cooler not to give you more power. You lean at higher elevations or density altitudes to get more power as a too rich mixture will rob you of power and may even cause the engine to run rough.
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...or quit altogether.
 
Ryanb said:
Its just one of those things i need to correct, say it was something like forgetting to put the gear down, something to make a memory item of, its in a different checklist but anyway.. Thanks for the replies everyone!
Click to expand...
Sounds like another vote for personalized checklists. If you are leaning for taxi, your mixture setting is a definite checklist item for takeoff.

Obviously, whatever you are using didn't work, since it was missed. The question comes down to whether it's because of the format of the checklist (I notice that even the lowly 152's manufacturer's checklist has mixture as a checklist item before the takeoff) or the way you used it.

Both are correctable. :yes:
 
midlifeflyer said:
Sounds like another vote for personalized checklists.
Click to expand...

Agreed.

But use a LOT of care preparing them.

I made my own for my Sky Arrow, and somehow left "Canopy - CLOSED AND LATCHED" off.

I've told the story elsewhere, but one chilly day that omission nearly led to disaster.

If you watch any of my videos, you'll see me lift my left arm as I check one final time on the takeoff, in case I missed it on my revised checklist, and I also put a reminder right on the face of my airspeed indicator, so I can't miss it with my "Airspeed - ALIVE" call.

16751512292_38dea2767e_z.jpg


9437357014_14597c796c_o.jpg
 
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One key to a good checklist is to keep it simple and small. For most any aircraft you're talking one half of a sheet of paper, front and back. I keep mine under my leg, do everything and confirm on the checklist.

For ground ops lean the snot out of it, ain't going to hurt anything, it should be leaned to the point that full power causes the engine to flat crap out.
 
I may have missed this, but did you say what your density altitude was at take-off? If I lean for taxi and forget to enrichen on takeoff, the engine will sputter and probably die. But I am near sea level.
Ryanb said:
It happens, during taxi I have been trying my best to lean out, today I must not have leaned hard enough because i forgot to enrichen it before taking off. I lined up for takeoff gave full power and the engine seemed to be making full power, I didnt notice any thing unusual. As i was upwind about 1000 agl i looked down and saw the mixture still lean, pushed it full rich and only seemed to notice a slight increase in engine RPM, which tells me it was not leaned out very much but oddly enough as I recall from memory, the mixture was leaned out at least an inch or so, maybe even more. Always learning and something to learn a lesson from, before EVERY takeoff its "lights, camera, action, everything forward". Anyone else ever done this?
Click to expand...
 
nope....never forget, never do anything wrong..... I'm Perfect in every way:goofy::D
 
JOhnH said:
I may have missed this, but did you say what your density altitude was at take-off? If I lean for taxi and forget to enrichen on takeoff, the engine will sputter and probably die. But I am near sea level.
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DA was low around 500' if I remember correctly.
 
Ryanb said:
DA was low around 500' if I remember correctly.
Click to expand...

You probably did your engine some good, by leaning for take off, you most likely cleaned up the combustion chambers and plugs, Keep up the good work. :)

And remember that leaning does not cause detonation.
 
Henning said:
As long as you remain 250° ROP, you will make full power and be safe from detonation. Normally you can lean a pretty good ways before you get there.
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you are sooooo wrong.
 
jesse said:
You need to lean more on the ground. Lean until it starts to stumble at idle then slightly in. If you advance it to full power like that the engine will stumble and won't make any power. Problem avoided.
Click to expand...

Agreed. At my taxi mixture if I apply take off throttle the engines will just sputter. Taxi needs only enough fuel to keep it running, more does nothing good.
 
FastEddieB said:
Agreed that that sounds very wrong.

Which this should make perfectly clear:

tcm_mixture_sweep.jpg


Your waaay rich of best power 250° ROP.
Click to expand...

Ok, let me put it this way, you will still make full Take Off Power (since take off power is predicated on "Full Rich" at low altitude) or More, while staying safe. Full Power you are not really that safe at taking off.
 
FastEddieB said:
Agreed.

But use a LOT of care preparing them.

I made my own for my Sky Arrow, and somehow left "Canopy - CLOSED AND LATCHED" off.

I've told the story elsewhere, but one chilly day that omission nearly led to disaster.

If you watch any of my videos, you'll see me lift my left arm as I check one final time on the takeoff, in case I missed it on my revised checklist, and I also put a reminder right on the face of my airspeed indicator, so I can't miss it with my "Airspeed - ALIVE" call.

16751512292_38dea2767e_z.jpg


9437357014_14597c796c_o.jpg
Click to expand...
I made that same mistake in my Flybaby one day. I had just done a ton of mx involving many critical things and was very distracted checking all of those things before takeoff. I forgot to latch the canopy on my Flybaby (three different latches all were a pita). It departed after takeoff at about three hundred feet. It was...exciting.
 
FastEddieB said:
:dunno:
Click to expand...

You're operating in what is known as 'the Red Box', a mixture ratio that when exposed to elevated CHT and ICP results in a destructive form of combustion that if I call detonation some dude will explain is not possible, so we will leave it as a destructive form of combustion where peak ICP occurs BTDC creating wave fronts that deliver levels of force that will shatter the tops of forged Pistons leaving large holes in them. Ben has nice pictures of the result.

Since climb reduces cooling, climb is the most vulnerable phase of flight to enter these conditions, and since we are low on takeoff, the risk of consequences for entering engine crippling conditions are elevated.

So basically, since full rated power is predicated on full rich at Sea Level along with a couple other conditions, any leaning from that point in this conditions will result in the engine exceeding rated horsepower. So really unless the OP was LOP, the only performance difference he would have noticed was an increase in performance, and an increase in CHT. As long as the CHT doesn't exceed 370° he is in pretty much safe territory, mixture alone would not cause a destructive situation.
 
My :dunno: was not really asking for more info on the topic, which I do pretty much grok.

It was because I found "Full Power you are not really that safe at taking off." impossible to parse.
 
Henning said:
You're operating in what is known as 'the Red Box', a mixture ratio that when exposed to elevated CHT and ICP results in a destructive form of combustion that if I call detonation some dude will explain is not possible,
Click to expand...

your destructive form of combustion is simply >HEAT<.
 
FastEddieB said:
My :dunno: was not really asking for more info on the topic, which I do pretty much grok.

It was because I found "Full Power you are not really that safe at taking off." impossible to parse.
Click to expand...

Because you are beyond Rated Power (200 hp engine putting out 220 creates more heat and pressure) and at risk of the phenomenon formerly known as Detonation. Grok?
 
Henning said:
Because you are beyond Rated Power (200 hp engine putting out 220 creates more heat and pressure) and at risk of the phenomenon formerly known as Detonation. Grok?
Click to expand...


Detonation is still detonation, but an all together different than what happens in the phenomena you are talking about.

And BYW ICP's are not what causes Detonation.

When you realize what the difference is between ICP and BMEP is you'll understand the difference between destination and over heating.
 
Tom-D said:
your destructive form of combustion is simply >HEAT<.
Click to expand...

No, we used to call it "detonation" but every time that happens some dude comes along arguing that detonation can't happen for semantic reasons. What happens is you get the pressure fronts colliding over the piston before it gets to TDC and it tends to break pistons. It is heat related both in production and prognostication.
 
Tom-D said:
no you are not.
Click to expand...

Look at the above charts knowing that Rated Power is determined at a mixture far richer than any shown on that graph, and back your claim; because the graph above says otherwise.
 
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