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

[NotarPilot]

I sometimes use my plane to commute to work and I have my flow down so that I can get the plane started and taxied to the nearby run up area in about 3 minutes (yes, I'm very close to the run up area). I generally wait until CHTs are at least 200F before advancing the throttle and performing the run up. This usually gets the CHTs up to 230F-250F-ish range by the time I'm done. After the run up I taxi a very short distance to the end of the runway and usually get cleared for take off right away. I have a IO-360 200 hp engine.

Does anyone think that's insufficient time to warm up the engine before taking off? I've never heard of shock heating an engine but I don't want to be abusive to my engine, at the same time.

[Guest]

What's's the rush?

Clarence

[Jerry 5TJ]

I wait to take off until the oil reaches the minimum operating temperature.  You could use electric pre-heat operated via remote control to shorten that time.

[jwilcoxon78]

I go with minimum oil temp prior to starting the runup.  In the winter, it can take some time.  I'd say I'm usually idle on the ramp for a good 3-5 minutes prior to taxi for runup and then may have to wait another minute or so for the oil temp to get there.

 

[Bob_Belville]

I wait until I see 140 Oil Temperature.

[Oscar Avalle]

I wait until the oil temp is at 110 to do the run up. From start until take off it takes about 8 to 10 min

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[bradp]

I go based on oil temp at the min.  My CHTs never come up to the normal operating range on the OEM gauge but I get ~280 when ready for takeoff.   

It takes about 7 min from start to oil min temp for me in the summer.  I can be sitting for 10-12 min in the winter despite a preheat.  

[Mooneymite]

Intereting.....

Based on these responses, I reviewed my 74 POH (O-360).  I could find no limitation on minimum temps for takeoff.  On page 3-9, the POH suggests that as long as takeoff RPM can be achieved without backfiring, skipping, or reduction in oil pressure, you're  good to go.  Generally taxi-time (whatever that is?) Is sufficient for adequate warm up.  No mention of cold wx ops whatsoever.

So?  When did Mooney change the operating guidelines?

Edited June 24, 2016 by Mooneymite
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[Danb]

I'm of the opinion that heat destroys our engines,*

**taking off without preheating-or the oil temps are not in the green

 

**running to high tit temp--to high cht

 

**abusing your engine when descending at 1500fpm with no throttle

ON AN ON         HEAT KILLS OUR ENGINES --BOTH TOO COLD OR TO HOT

 

*

[MB65E]

200° cylinders, 100° On oil. I need to see both before I advance over 1000 rpm for a run up. It's treated me well. 

 

It it amazes me the Tempature cycles on the turbin Equiptment! 

-Matt

[Hank]

My 1970 Owners Manual is the same as Gus'. My typical takeoff is probably 3-5 minutes from engine crank.

In WV winters, I would preheat overnight, with roughly the same takeoff delay. I only remember timing it once, or at least noticing the time:  I flew my wife to Valentine's dinner at Arnold Palmer Intl, there's a great chop house in the old terminal. Preflighted, unplugged the heater, pulled out of the hangar, cranked up, turned everything on and taxied 1/4 mile to the hold short. Set everything, set GPS, did runup, back taxied 1000', turned around and took off on 26. Full throttle operation was nice and smooth, and it was cold out so had lots of power. Made a climbing downwind departure heading east. Climbed through a rapid sunset from field elevation of 567 msl to 7500 msl, leveled out, accelerated, set power and trimmed everything nicely. Shortly afterwards, I noticed the yoke clock, engine start had been 15 minutes prior.

The Cessnas I trained in, the POHs said specifically to wait for a certain engine temp. Mine says nothing of the sort; the page is attached below, but I've not figured out how to highlight it in the iPad like I can on my desktop--just look right under the bold heading in the middle of the page. This is what I do, and it works very well. What does your POH say? (We all know what is said about opinions . . . )

[mooniac15u]

The M20J doesn't have a minimum oil temperature listed as a limitation. It has a normal operating range (150-240 F) and a redline maximum (245 F).

The Normal Procedures section of the POH contains this statement:

"CAUTION Do not operate the engine at run-up speed unless the oil temperature is 75 Degrees F minimum (needle moves off White dot).  Operation of the engine at too high a speed before reaching minimum oil temperature may cause loss of oil pressure."

[cnoe]

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!

[Oldguy]

Like most of the comments here, I go by oil temperature rather than time. I will typically taxi down to the run-up area at my home drome when I get to 90 degrees F or better. Between start up, taxi and run up, I am usually at 125+ before launching - even in winter (in AL).

[Mooneymite]

1 hour ago, mooniac15u said:

The M20J doesn't have a minimum oil temperature listed as a limitation. It has a normal operating range (150-240 F) and a redline maximum (245 F).

The Normal Procedures section of the POH contains this statement:

"CAUTION Do not operate the engine at run-up speed unless the oil temperature is 75 Degrees F minimum (needle moves off White dot).  Operation of the engine at too high a speed before reaching minimum oil temperature may cause loss of oil pressure."

Interesting.  

What year is your Mooney?  There's nothing like that in my POH, so at some point, thinking at Mooney changed.  However, I will say, even when I do the runup with fairly cold oil temps (I live in Georgia, so anything below 80 F is frigid cold!), I have never seen any fluctuation, or loss of oil pressure except when cycling the prop which is normal at any oil temp/1700 rpm.

I'm not sure our POH's aren't in general agreement since steady oil pressure seems to be a major criterion.

[jrwilson]

My old 63C had a similar warning...needle off the white dot prior to runup 

[mooniac15u]

12 minutes ago, Mooneymite said:

Interesting.  

What year is your Mooney?  There's nothing like that in my POH, so at some point, thinking at Mooney changed.  However, I will say, even when I do the runup with fairly cold oil temps (I live in Georgia, so anything below 80 F is frigid cold!), I have never seen any fluctuation, or loss of oil pressure except when cycling the prop which is normal at any oil temp/1700 rpm.

I'm not sure our POH's aren't in general agreement since steady oil pressure seems to be a major criterion.

I have a 1981 M20J but the info I shared above is from a 1989 POH that I have in PDF.  I don't have access to my plane's POH at work.  I will double check later but I'm pretty sure mine has the same statement.

 

[rbridges]

my CFII said 107F. I have no idea where he got that number.  Anyway, I still use it.  By the time I get to the runway, it's right around there except on cold mornings.

[jetdriven]

The 77 J model has the white dot and the statement about no runup until it's off the white dot. Later models don't have that. I think it was a hold over from single weight oil and oil pump cavitation on takeoff.  With multi grade oil that's not really a risk.  Our oil temp won't move until 5 minutes after takeoff.  But I do wait until I see 250f cht before doing a runup, and ~300f for takeoff. 

Edited June 24, 2016 by jetdriven

[carusoam]

You have to be really quick to get to the runway without getting the oil warm enough...

When your hangar is near the end of the runway and you have your checklists memorized, and well practiced, it could be a problem...

I use the analog OilT gauge...  The other day it wasn't getting into the yellow zone...  Tap, tap, good to go...

Me and my O are showing some signs of age....

Best regards,

-a-

 

[mooniac15u]

5 minutes ago, carusoam said:

You have to be really quick to get to the runway without getting the oil warm enough...

When your hangar is near the end of the runway and you have your checklists memorized, and well practiced, it could be a problem...

I use the analog OilT gauge...  The other day it wasn't getting into the yellow zone...  Tap, tap, good to go...

Me and my O are showing some signs of age....

Best regards,

-a-

 

Don't tell the fuel sensor guy that you are tapping on your gauges. 

[carusoam]

I am now planning my instrument upgrade strategy.  

Is it possible to tap on a JPI 930 to fix it's problems? 

I should update my checklists to include tapping the faces of all my dials.

Best regards,

-a-

[ArtVandelay]

I have a 1981 M20J but the info I shared above is from a 1989 POH that I have in PDF.  I don't have access to my plane's POH at work.  I will double check later but I'm pretty sure mine has the same statement.

 

I have a 81 version and it doesn't have it (or at least not in same spot), 86 version does.

[Hank]

Question for the waiters:  some wait for oil temperatures, some wait for CHTs. Not everyone waits for the same number.

Where did the recommendation to wait for Reading X to equal Value Y before running up come from? Why is this more important than whatever is written in your Owners Manual / POH? I just don't understand . . . Or is this an over abundance of caution and "being nice to the engine," like reducing power after takeoff and climbing long, slow and hit due to reduced throttle?

Is this real science or Old Wives Tales? If it's real, should we wait for Oil Temp, CHT, both, or something else? And what is warm enough--off the low-end rest, bottom of the green arc, or some certain number? I'm confused . . .

[M20F]

9 hours ago, MB65E said:

200° cylinders, 100° On oil. I need to see both before I advance over 1000 rpm for a run up. It's treated me well. 

 

It it amazes me the Tempature cycles on the turbin Equiptment! 

-Matt

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.