Touch & goes or stop & go?

Joe_B1

Joe_B1

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Joe_B
Been wondering about this for a while but since I own one now, I need advice.

Back when I was taking my flight training in 83, and flying Cessna 150's with continental engines, we did many touch and goes and it was OK with the flight school. As a matter of fact, they preferred it as it was a busy class D.

Since then, I have been told several different things about it. One flight school said no T&G with anything with a continental engine. One place said no T&G period. My A&P told me that the engine cools on final and when you give it full power after the landing, the thermal shock can damage a cylinder and he has seen cracks, etc.

So I fly a 1979 Archer with a lycoming O-360 engine, am I killing it doing T&G's or is this just a myth?
 
Ive heard a lot of arguments over the years on why not to do touch and goes, but I can honestly say that cylinder cracking is one Ive never heard before today.

If that were true, no flight school in the country would allow touch and goes - they'd be losing too much money with cylinder changes.

You're not going to kill your engine in an Archer doing touch and goes.
 
Joe_B1 said:
since I own one now, I need advice.
...
So I fly a 1979 Archer with a lycoming O-360 engine, am I killing it doing T&G's or is this just a myth?
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Beyond whether or not it's good for the engine, what's the point of T&G's if you are done with training and own the airplane? You're not paying Hobbs time and you're not trying to drill a sight picture into your brain. The additional time is also useful for padding your logbook hours (your insurance company will enjoy seeing that).
 
I'm not sure how your engine is going to tell the difference. Maybe stop-and-taxi-back is different than touch and go, but a stop and go isn't going to change the temps much.

The big problem with the Stop-and-go is that some mutherloving deer might bite you in the back of your goshdarn neck.
 
What is the guidance for the time period (stopped in the middle of the active runway) for re-warming up the engine?
A possible technique would be to never reduce power to less than 50% while braking to a stop.
 
I don’t believe there is evidence that TGs cause cylinder damage.
 
If cracked cylinders were a concern, there would be thousands of cylinder replacements every year, hundreds monthly.
 
Random slightly off-topic question: Is practicing a power-off stall any different from a T&G from the engine's perspective?
 
The school I went to was a 6000’ delta airport. Stop and goes could get dangerous and terribly disruptive to the traffic flow. The school planes did close to a hundred a day T&Gs.

I still do them in my 172 just about every day. What else is there to do in a 172?

I did 5 landings this morning and 4 were T&G on grass. My buddy seems to think I use less fuel flying the pattern?
 
Schools will have different rules about touch & goes. Usually it's based on a history of mishaps but there might be other reasons. There are advantages and disadvantages to touch & goes as opposed to full stops from both a training and currency perspective. Personally, so long as we define a touch & go as "a landing of your choice followed by leisurely reconfiguring the airplane for takeoff on the roll, followed by the takeoff of your choice," I'm pretty neutral on the subject, unless it involves a retract. While people to retract touch & goes quite successfully, I think the risk of an accidental gear up is significant enough to outweigh any of the benefits (at least insurance rates for retracts seem to suggest that).
 
This is an example of something someone dreams up and starts telling everyone and it just takes off running with nobody bothering to ask "where's the data?" Show me the Continental SB that says no T&G's.
 
The thermal shock thing is hogwash. If it were true you'd see even more issues from balked landings. I highly doubt they're really that much different on the engine.

https://www.avweb.com/ownership/shock-cooling-time-to-kill-the-myth/

But there could be other valid reasons for a club or school not allowing touch and goes. The recent fatal at KMWC would be exhibit A.
 
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Racerx said:
The thermal shock thing is hogwash. If it were true you'd see even more issues from balked landings. I highly doubt they're really that much different on the engine.

https://www.avweb.com/ownership/shock-cooling-time-to-kill-the-myth/

But there could be other valid reasons for a club or school not allowing touch and goes. The recent fatal at KMWC would be exhibit A.
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The article touches on a subject I've heard debated quite a bit:

Thomas also pointed out that flying through rain reduces CHTs by nearly as much as a 50 percent power reduction. There’s no history of airplanes regularly flown through rain having to constantly replace cylinders.
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... and there it is. :)
 
This is what happens when the FBO puts up a suggestion box for employees.
 
asicer said:
Random slightly off-topic question: Is practicing a power-off stall any different from a T&G from the engine's perspective?
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If anything it would be slightly harder than a TnG. Generally it's a little colder up there where you're doing stalls, and when the nose falls down for that second or so until it powers up it's putting alot more of that colder air over the cylinders than being stopped/slowed on the pavement.

But it's still all basically negligible.
 
The A&P that told me all of this said it is not from shock cooling but rather than going from a closed throttle and subsequent landing roll (cooling) to full throttle for the "go" part. I tend to fall on the side of it does no harm as I have done hundreds of T&G's in my day without a problem. The reason for the post was a recent conversation with him where he reiterated the statement.
 
Joe_B1 said:
The A&P that told me all of this said it is not from shock cooling but rather than going from a closed throttle and subsequent landing roll (cooling) to full throttle for the "go" part. I tend to fall on the side of it does no harm as I have done hundreds of T&G's in my day without a problem. The reason for the post was a recent conversation with him where he reiterated the statement.
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So normal takeoffs are destroying engines also? I would hazard a guess that over-leaning in general causes more damage to cylinders than T&Gs ever will.
 
woodchucker said:
So normal takeoffs are destroying engines also? I would hazard a guess that over-leaning in general causes more damage to cylinders than T&Gs ever will.
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I guess you have never read about LOP operations.

No such thing as over leaning.
 
OK, the vast majority say engine damage from T&G's is BS and I tend to agree. I have never bought into that story myself but I guess some people do. What was posted here makes total sense to me.
 
Pinecone said:
I guess you have never read about LOP operations.

No such thing as over leaning.
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Well there is the point when you get too lean and the motor stops doing it’s thing.
 
flyingron said:
I'm not sure how your engine is going to tell the difference. Maybe stop-and-taxi-back is different than touch and go, but a stop and go isn't going to change the temps much.

The big problem with the Stop-and-go is that some mutherloving deer might bite you in the back of your goshdarn neck.
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Just call a bambalance.
 
I'm a bit militant about repeated T&Gs in a complex aircraft, I think it a bad idea. Easy to think you puttee gear down and you didn't. That, and with the Johnson bar it gets really hard on my arm. I can't imagine a reason not to do them in an aircraft with the gear welded down.
 
EdFred said:
Just call a bambalance.
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ugh.gif
 
Gary Ward said:
...My buddy seems to think I use less fuel flying the pattern?
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It's true. Less than in cruise. I have the numbers to prove it in my Warrior. I track fuel usage for every flight. Pattern work uses about 1 gph less than a 65-75% power cruise.

I've never like T&Gs, and it's not because of engine stress. First, I'm not sure of what they teach over a stop and go, and they seem more dangerous considering the reconfiguration that must happen in a very short time period. You want to practice a go-around, then practice a go-around.
 
Let's start a war.
Shock cooling is a myth.

Don't quote a friend of a friend who knows a guy.
Show me scientific proof to prove me wrong.
:devil:
 
Shepherd said:
Let's start a war.
Shock cooling is a myth.

Don't quote a friend of a friend who knows a guy.
Show me scientific proof to prove me wrong.
:devil:
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I checked all the courthouses in the U.S. and there ith no record of myth Shock Cooling becoming mythus shock cooling.
 
I support the notion that shock cooling is a myth. The jump operation at SDM (San Diego) repeatedly gets TBO out of their engines. But, often, the jump pilot beats the humans to the ground.
 
Rgbeard said:
I support the notion that shock cooling is a myth. The jump operation at SDM (San Diego) repeatedly gets TBO out of their engines. But, often, the jump pilot beats the humans to the ground.
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Maybe it’s the species they use for jump pilots more so than the engines…
 
I think that I'm on to something. All this talk about shock cooling got me thinking back to the days that I worked out of KBFM in Mobile. TCM had its engine test cell in the vicinity of our company "hovel". As we all know, engine makers must run an engine at 100% straight for 100 certification hours. The test cell seemed not to contain the racket all that well. 100 hours is four days. Plus. The sound seemed to go deep into your body. Prayed for a flight to escape.

Come to think, I never heard any sound of idling, revving, stop, start. Just full tilt boogie for 100 hrs. Could it be that any deviation from wide open is harmful?
 
If shock cooling were really an issue in a descent followed by full power application, there would be a lot of engines coming from together in aerobatic planes.
 
Shock cooling in normally aspirated airplanes is pretty much a myth. In turbo charged engines however, heat management of the turbos is critical. I think that is what started the myth, people reading about one and carrying that information to the other.
 
Maxnr said:
Come to think, I never heard any sound of idling, revving, stop, start. Just full tilt boogie for 100 hrs.
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What did they do to keep the sump filled with oil?
 
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