How long from start up to take off? (Normally aspirated)

[carusoam]

Hank,

Primary training gave me....  yellow zone was good while on the ground, green zone while flying...

my check lists only mention to check engine instruments after engine start.

 

my POH gives the following specifics...

~~~~~~
~ CAUTION ~ 

Do not operate engine above 1000 RPM unless oil temperature is 75 F (24 C) minimum. Operation of engine above 1000 RPM at temperatures below 75o F (24oC) may damage engine. 

 

Best regards,

-a-

[N201MKTurbo]

15 hours ago, cnoe said:

Warm up? When I started up yesterday the JPI showed my oil temp to be 92 before I turned the key! The guys out in Phoenix probably have to COOL DOWN their engines before start up!

I was practicing commercial maneuvers last night. OAT at 9:00 was 101.

 

[jetdriven]

8 hours ago, M20F said:

Same and if I am in a bit of a hurry I will close cowl flaps to warm it up.  I don't depart or even do run up till 200/100.  In the winter I might wait even a tad longer to allow the cowling and all in it to get a little toastier.  

Ive read enough that states don't close the cowl flaps to warm the engine on the ground.  Even though the gauge comes up faster, the restricted airflow causes hot spots on the engine.  

 

[Hank]

7 hours ago, carusoam said:

Hank,

Primary training gave me....  yellow zone was good while on the ground, green zone while flying...

my check lists only mention to check engine instruments after engine start.

 

my POH gives the following specifics...

~~~~~~
~ CAUTION ~ 

Do not operate engine above 1000 RPM unless oil temperature is 75 F (24 C) minimum. Operation of engine above 1000 RPM at temperatures below 75o F (24oC) may damage engine. 

 

Best regards,

-a-

Thanks! But some people wait for 100 or 107 Oil temp, some wait for 200 or 250 CHT. Why different things (oil or heads), why the different temps?

[M20F]

5 hours ago, jetdriven said:

Ive read enough that states don't close the cowl flaps to warm the engine on the ground.  Even though the gauge comes up faster, the restricted airflow causes hot spots on the engine.  

 

I would agree if done for long periods similar to ground running without the cowling on.  My opinion and what I do YMMV. 

[StevenL757]

To the original question posted, I second Jerry and Daver's notes.  The AFM is your guide here.  It's there for a reason.  You need a minimum oil temp before sufficient takeoff power can be applied...It isn't based solely on CHT.  Maybe I'm reading the question wrong (and if so, forgive my tone), but if you need to ask about a "fastest time" to get a runup done and get airborne, your time management (as well as ADM skills) need reviewing.

Begs the question as to what other corners you'd be tempted to cut during the flight.  I sincerely hope the answer is "none".  Fly safe.

Steve

[Mooneymite]

33 minutes ago, StevenL757 said:

To the original question posted, I second Jerry and Daver's notes.  The AFM is your guide here.  It's there for a reason.  You need a minimum oil temp before sufficient takeoff power can be applied...It isn't based solely on CHT.  Maybe I'm reading the question wrong (and if so, forgive my tone), but if you need to ask about a "fastest time" to get a runup done and get airborne, your time management (as well as ADM skills) need reviewing.

Begs the question as to what other corners you'd be tempted to cut during the flight.  I sincerely hope the answer is "none".  Fly safe.

Steve

Steve, the interesting part of this discussion is not so much the differing opinions, but the significantly different guidance in the POH/AFM.  Contrary to your statement that a minimum oil temp is required, my POH uses steady oil PRESSURE as one of the criterion, but no minimum temp is mentioned at all.

I was unaware of the changes and differences.

Mooneyspace is a great resource.

[StevenL757]

49 minutes ago, Mooneymite said:

Steve, the interesting part of this discussion is not so much the differing opinions, but the significantly different guidance in the POH/AFM.  Contrary to your statement that a minimum oil temp is required, my POH uses steady oil PRESSURE as one of the criterion, but no minimum temp is mentioned at all.

I was unaware of the changes and differences.

Mooneyspace is a great resource.

Good points.  Although I was referring to my specific model's AFM (and that each model's procedures may differ), I was keying in to the note of urgency in the original post, and emphasizing the fact that we should be mitigating risk by managing to our respective AFM numbers.

[carusoam]

There are two important things that I am aware of going with warming the engine....

1) getting oil flowing through all parts of it.  Which may require getting the oil warmed up depending on how cold it was before starting.  Slinging the oil to splash it to internal parts may take a few minutes.  I have heard the valve train get quiet a minute or two after start up of various engines I have owned.  A subtle hint of how long it takes to get oil to that part of the engine.  Cold oil takes longer to get there.

2) cylinder choke, tightness of fit to the piston rings, oil flow.  The dimensions of the engines parts are selected based on their operating temperatures.  The cylinder head can be run near 400°.  The metal's expansion is temperature related.

Engineers call this a 'time study' reviewing what happens in a process in relation to time expiring...

 

From a pilot's point of view....  (What I used to try to do while when flying often)

1) Use the flow method of following the POH's procedures. (High efficiency, No steps left out)

2) Use the check list to verify all the steps.

3) Taxi to the far end of a 4,000' runway.  (Most often the primary runway direction based on wind direction)

4) Perform the run-up.

5) Depart.

 

I saw the challenge of trying to be ready to fly as quickly as the airplane was.  (Engineer inside)

The taxi time to the far end of the runway is a comforting time.  When you get there, everything is warm and ready for the run-up.  Several minutes of mental review of what is going to happen next.  Then consistent going through all the steps and meeting expectations.  Too slow taxi speed, the alternator can't keep up.  Too quick, opens up other risks...

A brief taxi directly to the run-up area at the close end of the runway would lead to ground running and waiting for temps to rise.  In this case, I used to taxi out the long way towards the midpoint of the runway to taxi back to the run-up area. (Uncontrolled field)

Early on, I thought performing the pre-take-off checklist while taxiing was a way to save a few minutes.  (This is more like texting while driving).  Back in the day my multi-tasking skills were much stronger.  But the brain can only pay attention to one thing at a time....

My usual flight is about 1:15.  I had get ready goals and tie down goals.  Heat of the sun, closeness of the beach, family in the back seat....

None of this was to 'short cut' any steps or lower the quality of the steps.

I also applied this technique to automotive maintenance: oil changes and brake pad changes.  (Deep engineer inside)  I would lay out all the tools and supplies before starting the timer! 

It turns out to be a real cognitive challenge of following all the procedures at the requisite quality.  Cut out most of the wasted time.

How long does it take...

1) Drive to the airport.

2) Preflight the plane.

3) taxi and run-up.

4) fly to destination.

5) park, shut-down, tie-down, and cover plane...

 

Picture me smiling while I think about this stuff.  

my hour flight probably took an hour to get started.

Download and Review your JPI data to see how long it takes for CHTs to come up to temperature.  Take a look at the consistency of your run-up information.  Single mag EGT rise and returns.

How methodical can YOU be?

As usual, let me know what I left out....

These are PP thoughts with an engineering flavor.  I am not a CFI...

Best regards,

-a-

[M20F]

5 hours ago, Mooneymite said:

 Contrary to your statement that a minimum oil temp is required, my POH uses steady oil PRESSURE as one of the criterion, but no minimum temp is mentioned at all.

No minimum temp is written but you will not get a steady oil pressure with power changes when the oil is cold.  Thus in order to achieve steady oil pressure you need to heat the oil sufficiently.  

[Mooneymite]

Just now, M20F said:

No minimum temp is written but you will not get a steady oil pressure with power changes when the oil is cold.  Thus in order to achieve steady oil pressure you need to heat the oil sufficiently.  

Exactly.  I think this was the thrust of my earlier comment.  There is no temperature number in my POH associated with this criterion.

Edited June 25, 2016 by Mooneymite

[M20F]

Just now, Mooneymite said:

Exactly.  I think this was the thrust of my earlier comment.  There is no temperature number in my POH associated with this criterion.

There is no temp directly associated but it is implied by the oil pressure requirement. It is just semantics but either scenario be it 100F or steady oil pressure will give the same result.  The two though are directly related even if the POH doesn't specifically outline it.  Some things just come down to common sense.  

[Mooneymite]

Just now, M20F said:

There is no temp directly associated but it is implied by the oil pressure requirement. It is just semantics but either scenario be it 100F or steady oil pressure will give the same result.  The two though are directly related even if the POH doesn't specifically outline it.  Some things just come down to common sense.  

Where did you come up with 100F?  Would 99, 98, 101, 102 work as well?  How about when the oil pressure is steady?

[carusoam]

Go to the limitations section of the POH... 

Engine limitations is a section that contains these key details.

The O's POH states clearly that when using the appropriate oil, Take-Off should only occur after OilT reaches 75°F.  Engine limitations section....

somewhere in there there should be a description of the yellow and green zones of the oil T gauge....

Not that 74 or 76°F wouldn't work the same.  But they are reporting what they tested and found most reliable...

Instrument markings section...

OilT 

- Yellow zone 100 - 170°F

- Green zone 170 - 240°F

- Red line 240°F

anyone see a mismatch between engine limitations and OilT gauge markings?

Reporting what I THINK I am reading...

'Minimum oil temperature, Take-off...75°F'

Best regard,

-a-

[M20F]

2 hours ago, Mooneymite said:

Where did you come up with 100F?  Would 99, 98, 101, 102 work as well?  How about when the oil pressure is steady?

It is a rough thumb of where I can shove in full power and be guaranteed not to shoot my oil pressure over red line.  There is no need to be obtuse, you have no way of telling that oil pressure is at steady state short of shoving in the power.  Based on experience a temperature of 100F means that pressure will stay steady/in the green when I apply take off power. 

[NotarPilot]

Ok, I think we've established oil temp and pressure should be at a value prescribed in our respective POH's. I'm based in sunny Southern California so it doesn't take long for oil temp to reach 100F. When I asked my question I was thinking more about engine longevity and metallurgy. I think we can all agree that practices stipulated in the POH are not always written with engine longevity in mind. But what about warming up the cylinders so that the temp uniform prior to take off? I don't think anyone has ever talked about shock heating an engine but is it something to consider when going from a cold engine to TO power in a short amount of time? 

Even if you take a hot day for example where it might be 105F and your oil is immediately over 100F on start up (assuming a cold start). I don't know if I would be comfortable with just taking off right away. Of course this is hypothetical since you would need time to do your checks before take off which allows the cylinders to warm up too. So my question being, besides oil temps, does anyone have a theory on what temps the CHTs should be at before taking off?

[Zwaustin]

Roughly 10-15 minutes in my K model at a class Delta.... In summer around here temps are well within tolerance in 10 minutes. 

[Hank]

My takeoff this morning was just over three minutes from engine start. Temps were 88° outside; Oil Temp was just coming off the peg and CHT was near the middle of the green (well above 200°). The joys of small, uncontrolled fields! If only we had fuel . . .

[carusoam]

O cylinders from POH...  250°F to 460°F green zone on the ship's CHT gauge.  Redline at 460°F...

I'm sure there are too cold limitations, but they are more common in Canada in the winter.  Where oil really gels and and negative OATs really make changes to the dimensions of metal parts.

Most of our guidance is preheat when temperature goes below 40°F.  Mostly because 100LL doesn't evaporate well below that temp.

Hank has demonstrated 3 minutes from start to being in the green.

I'm sure there may be concerns that parts of the engine are not heated.  Again, another challenge related to being in Canada in the winter, is when moisture is frozen in a vent line.  Take extra precautions to make sure you have no ice in your vent lines.

Warm oil circulating everywhere, all Cylinder temps up in the green, no ice blocking vent lines.  Can it get any better than this?

Shock cooling is a problem when the exterior of an object is cooling faster than the interior of the object or some parts are cooling faster than others.  This builds a lot of internal stresses.  This can be exacerbated when the cylinders are really hot >450° and the heat is turned off and airflow stays on generating maximum cooling of very hot objects.

Shock heating has not been a problem.  Excessive heat is. As in high CHTs and TITs.  But the rate of heating is not mentioned anywhere that I can find...  There isn't much stress when an engine is heated from 100-200°F  compared to excess cooling from 400° With negative OATs...

sorry, that's the best I can describe my minimum understanding of the situation...

I'm no expert, just a PP...

Best regards,

-a-

[Guest]

Inadequate warming prior to take off is a problem.  Here's what RAM Aircraft say as about it.

http://www.ramaircraft.com/Maintenance-Tips/Engine-Shock-Heating-During-Takeoff.htm

Clarence

[N201MKTurbo]

For the twenty years I used the Mooney to commute, if I had to wait ten minuets for the engine to warm up it would have tipped the time scales in favor of driving.

Do you wait for your car engine to warm up for ten minuets before driving down the road? Well, maybe sometimes in the winter.

[Hank]

2 hours ago, M20Doc said:

Inadequate warming prior to take off is a problem.  Here's what RAM Aircraft say as about it.

http://www.ramaircraft.com/Maintenance-Tips/Engine-Shock-Heating-During-Takeoff.htm

Clarence

Interesting article. But if I "smoothly advance the throttle to 27-30" MP," I dint need to wait before releasing the brakes and advancing the throttle to takeoff power, because I'm already there . . . My Performance Tables only give 28" with 2700 RPM at sea level; as RPM decreases, so does MP. So this article apparently doesn't apply to most Mooneys.

[ArtVandelay]

For the twenty years I used the Mooney to commute, if I had to wait ten minuets for the engine to warm up it would have tipped the time scales in favor of driving.

Do you wait for your car engine to warm up for ten minuets before driving down the road? Well, maybe sometimes in the winter.

Obviously if the car engine dies it doesn't put your life or vehicle at risk. For those with large boats, also warm up their engines, because boats don't have brakes, they use reverse, if a boat engine quits you have lost control, around marinas and bridges and jetties this can cause a lot of damage.

[Guest]

10 hours ago, Hank said:

Interesting article. But if I "smoothly advance the throttle to 27-30" MP," I dint need to wait before releasing the brakes and advancing the throttle to takeoff power, because I'm already there . . . My Performance Tables only give 28" with 2700 RPM at sea level; as RPM decreases, so does MP. So this article apparently doesn't apply to most Mooneys.

While it doesn't state Mooney specifically, the concept still applies.  Warming the engine and applying power smoothly is beneficial.  Ask any engine shop about scuffed piston skirts from inadequate warm up prior to application of power.

Clarence

[Mooneymite]

Just now, M20Doc said:

While it doesn't state Mooney specifically, the concept still applies.  Warming the engine and applying power smoothly is beneficial.  Ask any engine shop about scuffed piston skirts from inadequate warm up prior to application of power.

Clarence

Scuffed skirts, eh?

That's  easy for you to say.