Turning into the wind for runup

To keep the cylinders as cool as possible.
 
I didn’t say I thought it would make much difference, but 100 mph from the prop + 5 from the wind is 105 vs 95 if you do it the other way.
 
It also keeps you from blasting the plane following you on the taxiway
 
Fair enough. I ask this because the F33 has a bigger turning radius than the 172 I used to fly, so there have been times I have gotten to the end of the taxiway, and felt there wasn't enough room to turn 180* into the wind.

I'm comfortable enough doing the runup while taxiing to the runway, so this may be a moot point, but thought the peanut gallery would appreciate some fodder while our wives are out shopping on Black Friday.
 
My mooney gets real hot in summer on the ground. I try to keep her into the wind as much as possible. The light sport I fly doesn’t get that hot on the ground so I don’t worry so much about it.
 
I'm not an engineer, but why is a few degrees of cooling the cylinders so important during that phase? Aren't they about to be a lot hotter after takeoff anyway? And most of the time around run-up I'm trying to bring up the oil temperature, which of course is heated via cylinder temperature.
 
This is mostly an OWT that has been handed down for generations. In the case of strong winds and a light tailwheel airplane, there could be operational reasons to turn into the wind, but keeping the engine cool isn't one of them. A few extra knots of wind isn't going to make any difference.

In my opinion, first consideration should be who you're blasting behind you. Second, whether or not you have a clear view of the final approach.
 
Ryan F. said:
This is mostly an OWT that has been handed down for generations. In the case of strong winds and a light tailwheel airplane, there could be operational reasons to turn into the wind, but keeping the engine cool isn't one of them. A few extra knots of wind isn't going to make any difference.

In my opinion, first consideration should be who you're blasting behind you. Second, whether or not you have a clear view of the final approach.
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Not exactly an OWT, but it is based on older airplanes.

In tailwheels (light or heavy), if there is any appreciable wind, you may find the airplane starting to drift while running up with a crosswind.

As far as temp, in my experience, I have found oil temp to be a bigger factor than CHT.

If it is hot out and there is a crosswind, for example, my downwind engine on the Beech 18 can experience significantly higher oil temp even though the oil cooler inlet is behind the prop.
 
To cool the engine. Don't know about you guys, but my engine is idling most of the time until take off. Also the airflow from the propeller is minimal near the crankshaft.
 
dbahn said:
I'm not an engineer, but why is a few degrees of cooling the cylinders so important during that phase? Aren't they about to be a lot hotter after takeoff anyway?
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They get hotter, but on takeoff, there is significantly more forced air, so it keeps the CHTs under control.

Not all airplanes are equal here. Some (like the Continental W-670 in my Waco) take forever to get warm. Others can be pushing 400F just coming up to run up power while parked and any increase in airflow helps.
 
Fearless Tower said:
Not exactly an OWT, but it is based on older airplanes.
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Sorry to be contrary, but it really is "mostly" an OWT. As with all things in aviation, there are few absolutes, but for the purpose of this thread -- "cooling" the engine with the "extra wind" -- it is certainly an OWT, again, mostly.

John Deakin has covered this a few times.

https://www.advancedpilot.com/articles.php?action=article&articleid=1844

As long as you're not blasting people or property behind you, you're fine from a cooling standpoint.
 
Groundpounder said:
Wouldn't the air flow from the prop overpower any kind of tailwind there might be?
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In my experience, it is more a factor of cooling after the actual run up. In other words, if my CHTs get high during the run up and then I’m stopped pointed away from the wind while waiting for takeoff clearance at a busy airport, my CHTs May stay uncomfortably high and I have learned to give myself room to turn wide and point into the wind while holding short.
 
Ryan F. said:
Sorry to be contrary, but it really is "mostly" an OWT. As with all things in aviation, there are few absolutes, but for the purpose of this thread -- "cooling" the engine with the "extra wind" -- it is certainly an OWT, again, mostly.

John Deakin has covered this a few times.

https://www.advancedpilot.com/articles.php?action=article&articleid=1844

As long as you're not blasting people or property behind you, you're fine from a cooling standpoint.
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Did you read my post?

I speak with experience. An OWT is a myth. This is not a myth, it just may not apply to most modern GA airplanes.

The danger with calling things OWTs is that you fail to understand the reason behind its existence. Then if you ever find yourself in a airplane where the guidance still applies, you can find yourself in trouble.

That doesn’t mean that every airplane should be pointed into the wind, but there are some that need to be.
 
Fearless Tower said:
That doesn’t mean that every airplane should be pointed into the wind, but there are some that need to be.
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Fair enough. Like I said, there are always exceptions. The original poster is flying an F33... there are no special operational considerations for engine cooling w/r/t aligning into the wind in that aircraft. Or most piston airplanes for that matter... (not all.) There's a reason I keep using the word "mostly."
 
First let’s set the wind speed at 30, gusty and position the plane so the wind is nearly a 90 degree crosswind for run up.

1. We risk upset in a especially in high wing airplane.
2. We will get a poor run up check especially in an aircraft with a large diameter propeller.
3. The control wheel will be flopping around in the gusts.
4. Yes, you are missing superior engine cooling.
5. Everyone watching you will know you are a rookie.
 
I have not turned "into the wind" in 30 years. I turn about 90 degrees to the active runway so that:

1. I won't blast anyone behind me.
2. I have a clear view of the taxiway behind me.
3. I have a clear view of any airplane on final on the active runway.
 
When I flew 135 freight we did our runups taxiing to the runway for takeoff. It was a waste of time to sit at the end of the runway running up engines. And time was money.
 
Clip4 said:
First let’s set the wind speed at 30, gusty and position the plane so the wind is nearly a 90 degree crosswind for run up.

1. We risk upset in a especially in high wing airplane.
2. We will get a poor run up check especially in an aircraft with a large diameter propeller.
3. The control wheel will be flopping around in the gusts.
4. Yes, you are missing superior engine cooling.
5. Everyone watching you will know you are a rookie.
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Typically the puppy mill schools don't fly when the wind is 30. Also, the puppy mill schools teach a 15 minute runup procedure. Got to run that multi page checklist they developed. :rolleyes:
 
Doc Holliday said:
Typically the puppy mill schools don't fly when the wind is 30. Also, the puppy mill schools teach a 15 minute runup procedure. Got to run that multi page checklist they developed. :rolleyes:
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Yeah no kidding. There’s a 141 school nearby that I’ve observed on several occasions. It’s amazing how long and drawn out their run up and pre-takeoff procedures are, not to mention their post landing debrief. I’ve concluded their mission is to keep the Hobbs running as long as humanly possible.
 
Groundpounder said:
Wouldn't the air flow from the prop overpower any kind of tailwind there might be?
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You'd think so, but it can and does make a difference.
Fearless Tower said:
Not exactly an OWT, but it is based on older airplanes.
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Mine is not an "older" airplane; it s a relatively new design, and built in 2011. In winter, I warm up pointed out of the wind or it can take forever to get the oil up to temp -- sometimes it simply can't. The runup is so short it's not really a big deal, but on a really hot day you'll see a definite difference in temps between into the wind and away from the wind. So, I'd say not an OWT, and like most things in aviation -- it just depends on the airplane.
 
I sat on the taxiway in a Bonanza at Minneapolis for almost an hour one morning...the wind had gotten strong enough that they had to change to the single runway instead of the parallels. When our temps started increasing, we turned more into the wind every time we stopped. There were several airplanes that decided to pull out of line and shut down due to temperature.

As others have said, it’s mostly a waste of time, but conditions can exist that make it necessary, and the habit pattern might help you remember when the time comes.
 
I read a study once that said the prop produces almost 0, nil, nothing, in regards to cooling air at run-up. And, the best cooling is obtained by pointing either directly at the wind, or directly away.
 
Weekend Warrior said:
I read a study once that said the prop produces almost 0, nil, nothing, in regards to cooling air at run-up. And, the best cooling is obtained by pointing either directly at the wind, or directly away.
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If you can find that study, I'd really like to see it. When doing ground runs with the cowling off, temps go up really fast. With the cowling on (and prop blast therefore being circulated over the engine), temps stay manageable. I infer from this that the prop is responsible for most of the cooling.
 
I've long been a skeptic of the "face into the wind" thing. I strongly suspect that the prop is supplying the air movement for cooling. Unless you're in a hurricane, I doubt that the ambient wind is doing much of anything (relative to the prop blast).
 
Hot start Cirrus, hot day, you point it into the wind during run up or when sitting waiting for clearance or the engine is getting uncomfortably hot quickly. 172, not as much. Now if it isn't easy to point into the wind, I don't do it, but it's what I've been trained to do and I've watched that CHT gauge rising in hot weather. On a 5 degree day after the initial start up? I don't point into the wind.
 
write-stuff said:
I've long been a skeptic of the "face into the wind" thing. I strongly suspect that the prop is supplying the air movement for cooling. Unless you're in a hurricane, I doubt that the ambient wind is doing much of anything (relative to the prop blast).
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The problem with these internet discussions is that people want to make it an all or nothing argument. Like it's all about the wind or al about the prop. It's not. They both create an effect. Whether or not it matters is dependent largely on the amount of wind and the design of the airplane.

But if you really want to see how much of an effect the wind has, try holding short on a hot day in a multi-engine airplane for a prolonged period of time with the wind off to the side. You will see a difference. Depending on the airplane it may or may not be a problem.

I've seen it in the Baron and Beech 18. While the difference was noticeable in the Baron, it wasn't an issue. In the Beech 18, it is definitely a concern.
 
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write-stuff said:
When doing ground runs with the cowling off, temps go up really fast. With the cowling on (and prop blast therefore being circulated over the engine), temps stay manageable. I infer from this that the prop is responsible for most of the cooling.
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That is because the cowling keeps the airflow around the engine. You will see a difference between cowling on or off regardless of where the wind is.
 
Good airmanship occurs on the ground, too. Take great care of your airplane and it will take great care of you. This board goes ape over the costs of maintenance and overhauls, but overwhelmingly argues against keeping engines and oil cool on the ground? Do what you want, but I treat my airplane like it’s the only one I have, and the only one I can afford. ;)

(The reason they’re called “old wives’ tales” is because those husbands who did those things lived to be very old. Those who did not died young, leaving behind young widows. Go read the “old widows’ tales” for the crap that doesn’t matter.)
 
To help keep FOD from getting into the prop.?? :rolleyes:

I mostly do runups while taxying to the runway, depending on which plane I am in. I prefer to do runups before boarding passengers.


Except in Alaska, I only did runups on paved ramps. Gravel tends to get into the prop(s) which pees off the mechanics. Also the prop(s) would spray everyone and everything on the ramp with gravel, and then no one will invite you over for Thanksgiving moose....:lol:
 
In nearly twenty years of flight instructing in nearly every reasonably common piston single imaginable (and a fair number of light twins as well) I have never been able to detect any difference in engine or oil temperature during the runup based on the position of the aircraft relative to the prevailing wind. The majority of that instruction occurred during the scorching Florida summers. To me it strains credibility to suggest even big bore, tightly cowled engines will experience any detectable cooling benefits for the duration of the runup.

A Beech 18 could be a logical "exception" and it's a worthwhile footnote to the conversation. But that is hardly the typical GA airplane these days.

I'd much rather see consideration given to where the tail is pointed, and if possible, a clear view of the final approach is maintained. The risk of a runway incursion carries a far more substantial potential penalty.

I do agree that on a high wind, gusty day, you may want to turn some airplanes into the wind, particularly tail wheel airplanes. That's a different operational consideration. Engine cooling is a non-factor in "most" conceivable scenarios.

If there is data to the contrary, I'd love to see it. Deakin suggests they have data suggesting downwind may be preferable to upwind (!) but to my knowledge he hasn't published that or written about it specifically.
 
Clip4 said:
wind speed at 30
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How many people are flying their single engine piston with a sustained wind speed of 30 knots?

I highly doubt the more typical 3 to 5 knot that most people see does anyting...

Doc Holliday said:
15 minute runup procedure
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At least.. but compared to a 45-minute preflight the 15 minutes for the run-up is not bad


...I do notice that in gusty winds I get funky RPM readings, but that's true also facing into the wind I have found as the relative wind speed for the propeller changes by the same factor
 
PaulS said:
Hot start Cirrus, hot day, you point it into the wind during run up or when sitting waiting for clearance or the engine is getting uncomfortably hot quickly. 172, not as much. Now if it isn't easy to point into the wind, I don't do it, but it's what I've been trained to do and I've watched that CHT gauge rising in hot weather. On a 5 degree day after the initial start up? I don't point into the wind.
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Oh man, that is the worst, especially as you see the oil temp approaching 200..
 
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