Flaps on touch and go

[Cyril Gibb]

I always open my cowl flaps before landing.  It's one less thing to do on a go-around (or touch and go).

The concept of shock cooling using air as a coolant never made sense to me.  Why doesn't flying WOT at cruise speed with high cylinder temperatures into pouring rain at 40F have a damaging effect?

I'd imagine throwing bucket loads of cold water onto the cylinders at high speed would be several orders of magnitude more potent than just opening cowl flaps.

 

[jetdriven]

Take a look at the log of the CHT when opening the cowl flaps before landing and leaving them closed. You'll be firewalling a 150 degree engine instead of a 230 degree one  

On a J model at least, locking the cowl flaps full open in flight damages the hinges, and eventually tears out the rivets that hold the cowl flap frames in the cowl and eventually will tear the cowl flaps frames too. I replaced all that but it's probably a 2k job for the work. There's really no need for anything more that trailed open for takeoff. 

[Mooneymite]

Back to the subject of T&G's:

Don't do them if you're not comfortable with them, but why haven't you become comfortable?

T&G's do allow more landings in a shorter amount of time.  Prior to the advanced simulators, we did T&G's in single and multi-pilot Navy aircraft.  The airline did them for years with new pilots in big and small airplanes.  I do them in all the airplanes I've owned, or rented. 

 To me, a T&G is simply a maneuver.  Practice and learn until proficient...or not.

[David Medders]

2 hours ago, Cyril Gibb said:

The concept of shock cooling using air as a coolant never made sense to me.  Why doesn't flying WOT at cruise speed with high cylinder temperatures into pouring rain at 40F have a damaging effect?

I'd imagine throwing bucket loads of cold water onto the cylinders at high speed would be several orders of magnitude more potent than just opening cowl flaps.

 

In cruise, combustion is making sufficient heat to counter the thermal effects of 40F rain -- as seen in JPI data.

Reducing power while landing significantly reduces combustion heat available to counter the cooling effects of ambient air -- again, as seen in JPI data.

[David Medders]

16 hours ago, jaylw314 said:

...but unless your CHT's are in the 400's right when I pop open the cowl flaps and reduce power, I just can't see it being faster than -60 degF/min.

As I said in my initial post, THIS IS FROM ACTUAL JPI DATA. The behavior is consistent. Final approach CHTs are in the low 300Fs. Lycoming's recommendation is -50F/minute.

[David Medders]

15 hours ago, gsxrpilot said:

I'll say it. shock cooling is not a problem at all in fact it's just one of those Old Wives Tales that seem to hang around forever. A lot of it probably has to do with Lycoming's lawyers not letting them change their documentation for liability reasons. It has nothing to do with what's in the documents, but any change invites liability.

I think you'd find that most owner pilots that are very involved, studied, and keeping up with information and research, have let this myth die long ago.

 

gsxrpilot -- How do choose the manufacturer's recommendations to follow versus those you ignore?

I think you'll find that being condescending is rarely a good approach to civilized discussion.

[gsxrpilot]

I follow the manufacturer's recommendations that have not been disproven with more modern testing and recent data. Full disclosure, I've attended the APS class at GAMI and have seen their test facility and watched as tests have been run. I've also studied their data and the conclusions they've drawn from it. It was very convincing. But even before attending the class, I'd learned that the consensus from this forum and the BeechTalk forum, that pilots who get involved and study the data, consider shock cooling to be a myth. Whereas the defense for the issue of shock cooling comes from a simple, "it's the manufacturer's recommendation". 

I'm sorry, I shouldn't have been condescending about it. But its difficult not to see this as silly, when it has been so thoroughly debunked as a myth by the data.

[Cyril Gibb]

8 hours ago, jetdriven said:

Take a look at the log of the CHT when opening the cowl flaps before landing and leaving them closed. You'll be firewalling a 150 degree engine instead of a 230 degree one  

As a retired geek, I check my downloaded engine data at night after my flights.  Perhaps my F with the stock cowl and the guppy mouth closure has different cooling characteristics than a J.  My cowl flap open approaches never have come close to that cool.  It's always 220-230.  I run LOP, so cruise CHTs are typically 300-350 depending on OAT.  I choose to run my engine in a narrow temperature band.  Most days my cyl temp from takeoff roll to taxi back to my hangar is within a 120df range.

I do have to play with throttle, mixture and rpm to maintain that.  It's fun to be able to make the engine do what you want.

[jetdriven]

J cowl flaps are a lot more effective than previous versions.  Locked open you can feel the buffeting in the floor of the plane. 

[steingar]

On 6/26/2017 at 0:16 PM, Mooneymite said:

Back to the subject of T&G's:

Don't do them if you're not comfortable with them, but why haven't you become comfortable?

A reasonable point, and I should get more comfortable in my aircraft doing them, just because I should.  I feel I should be able to operate my aircraft throughout its flight envelope.  But I think a relevant question is, what am I practicing them for?

If I am becoming more proficient so I can do that many more landings in less time, the reasoning is bogus.  I can do perhaps four landings before my arm gives out from pumping the Johnson bar.  I am a tiny little pipsqueak of a guy, and my days of weightlifting are far, far behind me.

If it is to avoid hazards on the runway, I have to wonder.  What hazards are going to appear just as you're touching down that you didn't see on short final?  Can't you avoid them by braking?  Is it really that much better to put in the power?  After all, if the hazard is in such proximity that you can't avoid by braking, you might wind up hitting it at higher speed as you put in the power.

I suspect many do them because its what they did in training.  I would point out that trainer aircraft are far simpler and more forgiving than our Mooneys, and do have a bit more room between the prop tip and the asphalt.

[Mooneymite]

13 minutes ago, steingar said:

I suspect many do them because its what they did in training.  I would point out that trainer aircraft are far simpler and more forgiving than our Mooneys.....

We did them on fairly complex aircraft where there wasa lot more going on than a Mooney. 

Max training...min time. 

T&G is a maneuver, but usually not a required maneuver. 

If they don't suit one, he can avoid the maneuver. 

[David Medders]

On 6/26/2017 at 0:37 PM, gsxrpilot said:

I follow the manufacturer's recommendations that have not been disproven with more modern testing and recent data. Full disclosure, I've attended the APS class at GAMI and have seen their test facility and watched as tests have been run. I've also studied their data and the conclusions they've drawn from it. It was very convincing. But even before attending the class, I'd learned that the consensus from this forum and the BeechTalk forum, that pilots who get involved and study the data, consider shock cooling to be a myth. Whereas the defense for the issue of shock cooling comes from a simple, "it's the manufacturer's recommendation". 

I'm sorry, I shouldn't have been condescending about it. But its difficult not to see this as silly, when it has been so thoroughly debunked as a myth by the data.

Paul, I am not arguing the existence or impact of shock cooling. I have an academic interest, but the answer will not change the way I fly. My initial post referred to remaining within Lycoming's recommended temperature limits. Flying within those limits costs me nothing and is well within my capabilities. Flying beyond those limits gains me little if anything.

In other words, "It is the manufacturer's recommendation" is not a defense of shock cooling. It is my approach to flying -- reinforced as I progressed beyond piston aircraft.

You are, of course, free to fly your aircraft and manage your engine as you wish. However, picking and choosing which limitations and recommendations to honor can be a risky game.

Cheers

[Yetti]

Doing transition with a mooney CFI.  We would both check the floor indicator about the same time. Almost wacked heads.

[N201MKTurbo]

I think it is funny seeing people who seem more concerned about how other people operate there stuff then their own. I guess they are just trying to validate their own decisions.

The great thing about owning your own plane is that you can run it any way you like.

These planes are so robust that they will soldier on just fine no matter what you do to them. There are engines out there that were treated with kid gloves and still went south and some that were ham fisted from day one and made it past TBO with little maintenance.

[steingar]

19 hours ago, Mooneymite said:

We did them on fairly complex aircraft where there wasa lot more going on than a Mooney. 

Max training...min time. 

T&G is a maneuver, but usually not a required maneuver. 

If they don't suit one, he can avoid the maneuver. 

Most pilots don't do primary training in complex aircraft.  Pretty spendy.  And I doubt many of us really need to "max training...min time".  Like I said, what is the T&G really for?

[N201MKTurbo]

1 hour ago, steingar said:

Most pilots don't do primary training in complex aircraft.  Pretty spendy.  And I doubt many of us really need to "max training...min time".  Like I said, what is the T&G really for?

There are a lot of maneuvers that are done for training and check rides that have no bearing on your everyday flying. They are meant to improve or demonstrate your flying skills. I think the touch and go fits into that. It does have some practical benefit. There could be a situation when you had to abort a landing after touching down. It has a lot of crossover skills for a missed approach or a go around. The bottom line is it should be something any pilot can do without much thought. If it isn't than perhaps more practice is in order.

[Hank]

1 hour ago, steingar said:

Most pilots don't do primary training in complex aircraft.  Pretty spendy.  And I doubt many of us really need to "max training...min time".  Like I said, what is the T&G really for?

What turbo said!

What's the reason to learn turns around a point? Lazy eights? Constant speed descents? I never do any of those outside of training . . .

But they teach aircraft control, and you learn to make the plane do what YOU want it to do.

[Skates97]

Going on a long cross country this weekend so took my son out to the airport last night to look the plane over and take a short flight so that if anything looked amiss I would have a few days to take care of it. We have a VFR planning chart on the wall at home where I have blue pins for every airport I have landed at. If my son has been with me they are red pins. I asked if he wanted to change out one of the blue for red so on we made it a short flight from Corona (KAJO) to Riverside (KRAL) because he hasn't been there yet. I asked if he wanted to do a touch-n-go at Riverside and he was excited to see what it would be like. Two pumps of flaps for the landing (15° take off flap setting), once on the ground, eased the throttle back in and was in the air quickly, gear up, rolling the trim forward, flaps up, not a big deal. The 5,400' runway was probably about 2,000' more than I needed. I realize that it is different in the long bodies and the electric gear and flaps probably play a part of it. However in a short body with a Johnson Bar and manual flaps it really isn't difficult or complicated.

As others have said, I think it is something that people should be able to do. I don't do them on a regular basis but it is in the tool box. There isn't anyone keeping track of Hobbs time to charge me for time in my plane, but last night it shaved some time off the flight and when we got home my son pulled a blue pin off the map and replaced it with a red one.

And although I didn't do my primary training in a complex plane, I am constantly trying to do "some kind of training" in my Mooney. Even if it is just flying around for fun I am trying to become more precise in my control of heading/altitude, and every landing is a challenge to make it better than the last. Constantly trying to get a better feel for the plane and the way to control it and make it do what I want it to keeps it interesting and fun.

[steingar]

3 hours ago, Hank said:

What turbo said!

What's the reason to learn turns around a point? Lazy eights? Constant speed descents? I never do any of those outside of training . . .

But they teach aircraft control, and you learn to make the plane do what YOU want it to do.

Turns around a point are simply landing patterns sans airport, since airports tend to be full of landing airplanes.  Admittedly I haven't done lazy eights or constant speed descents, so I don't know what they're there for.

Being able to control the airplane through all the phases of its flight envelope is indeed a praiseworthy goal.  But how many of us can do that?  How many do steep turns at 60 degrees, like another thread was asking?  How many do chandelles, or even land according to PTS standards (1500 feet if memory serves, although I would be happily corrected if mistaken).  

I tend to think of T&G's as a maneuver to avoid ground hazards that appear late in the landing (like a deer on the runway).  But I've started thinking that aggressive braking might be the better strategy.  If you can't miss whatever's in front of you by breaking and perhaps maneuvering on the ground, how likely are you to get off the runway before hitting it?  I'd rather hit at low speed than high speed.  There is also the issue of lots to do and lots to get wrong.            

I'll likely start doing them in controlled situations myself in the near future, lots of big runways where I live.  Another fun thing to do with an airplane.  But I think I'll always have this issue in the back of my head.  When push comes to shove, what is the best strategy?  I've seen accident reports where the nut took off, something was wrong and the nut died.  had the nut stayed on the runway metal would have been bent, but the nut would have walked away.

[David Medders]

2 minutes ago, steingar said:

...land according to PTS standards (1500 feet if memory serves, although I would be happily corrected if mistaken).  

ATP PTS standard at my last recurrent was between 250 feet before and 500 feet after the aiming point.

I see significant benefits in staying consistently within that box. Of course, I have seen lots of pilots miss that box trying to be smooth in a checkride. 

Cheers

[Skates97]

19 minutes ago, steingar said:

 I'll likely start doing them in controlled situations myself in the near future, lots of big runways where I live.  Another fun thing to do with an airplane.  But I think I'll always have this issue in the back of my head.  When push comes to shove, what is the best strategy?  I've seen accident reports where the nut took off, something was wrong and the nut died.  had the nut stayed on the runway metal would have been bent, but the nut would have walked away.

Go someplace with a long runway, around here there are quite a few that are 100-150' wide and 7-10,000' long. Get yourself set up with take off flaps for the landing. With a strip that long you have plenty of time so after you are on the ground and lined up on the center-line just let it roll along and you can adjust your trim a little and then slowly advance the throttle. After you have done that a few times you will feel more comfortable with advancing the throttle sooner after getting on the ground and the amount of force you need on the yoke to hold it while you adjust the trim as you start your climb. Find a friend or CFI with Mooney experience to go with you and help out if needed.

When I was safety pilot for @MHemperly while he shot approaches he finished off with a touch-n-go at my home base (used to be his home base too) of Corona with its 60' x 3,200' runway. At the time he mentioned doing it I thought "That's crazy in a Mooney on such a short runway." But he was as smooth as could be and it was a complete non-event. I was impressed.

[steingar]

Good advice.  I've a 12K footer near home base, so not a bad idea.  

[Andy95W]

After 2 Touch and Goes on a 12k foot runway you'll seriously wonder why you ever thought it was a big deal in the first place. 

Ar you talking about Rickenbacker?  I still remember when it was Lockborne AFB...

[Jim Peace]

Question:  Do you have more to lose or to gain from doing a touch and go in a complex airplane single pilot or even multi crew?

I am not saying I have not done them?  I have in Cessna 150's to the 747-400.  But what do you gain?  I would say the big planes may be safer because you have the pilot not flying  resetting your trim and flaps.....but and this is a big one for even the small planes.....what if your flaps don't come up or get split on the way up....just WTF do you do when you rotate and realize you do not have an even takeoff flap setting? or you misread your trim setting......figuring all this out at 100 feet is not where I want to be.

Go ahead and keep doing touch and go's in Mooney's.  As we keep losing planes mine will only go up in value.....supply and demand......

 

 

Edited June 28, 2017 by Jim Peace

[chrisk]

For shorter runways, I use take off flaps.  For longer runways, I use full flaps, reconfigure on the ground (trim, flaps, cowl flaps), then add power.   At night, its always a full stop and taxi back, never a touch and go.  And often, my touch and go turns into a go around a few feet above the runway.