Savin' the Prop

[shimmydampner]

Go poor a cold bucket of water on your hot car engine and see what happens.

Surely you're not suggesting that the effect of heat loss by air cooling is the same as by "a bucket of cold water"?

Jake, from now on don't put your room temperature beers in the fridge. Instead put them in a cooler of ice water. You can thank me later for this life changing advice. Throw in some salt and you'll think I'm your god!

[PilotDAR]

Go poor a cold bucket of water on your hot car engine and see what happens.

So now we're discussing what happens when you pour water on a liquid cooled engine?

[Old Dog Flying]

The same situation occurred while demonstrating a Rockwell 112TCA. Tower confirmed nose wheel only partially down, rescue equipment called out. Shut down the engine on short final, held the nose off and as speed decayed I felt a thump and waited for the bottom cowling to scrape the runway.

Surprize, the nose gear had secured and no damage to a beautiful aircraft. The nose gear springs were stretched too far to lock the gear down and when air pressure decreased we rolled out safely.

The springs were replaced and the customer came back a week later and bought the plane.

Do what is necessary to reuse the plane another day...there is no one answer to every situation

Barney

[FADEC]

So far as not being able to go around; that is the situation in a four engine airplane with two out, or a three engine with two out.
The commit point is 500 feet; after that, no go around.

How many have ever shut down an engine in flight and stopped the prop? In a 172 with either a Continental or Lycoming, you have to slow pretty close to stall.

On a long runway, one would have plenty of time to do it IF one can fly with either hand, which any real pilot should be able to do.

Any Airline Captain will have flown both seats; either hand. An Airline F/O likely flew left seat previously. Any Instructor should have both hands experience.

As for the Lake taxiing into the hangar; all Lakes have metal props, unless they have the MT Reversible STC prop.

[lownslow]

Go poor a cold bucket of water on your hot car engine and see what happens.

Nothing.

I drive through puddles all the time (the bigger the better - I'm basically a giant kid) and have yet to have any shock cooling issues. Even if I did it likely wouldn't be catastrophic, I assume the worst I could do would be a slow leak from a crack in a cooling jacket. Annoying, yes, but not a deal breaker.

Someone smarter than me could chime in on what 'shock cooling' actually does to an air cooled airplane engine, but I suspect it's more an issue of accelerated wear than the catastrophic explosion your instructor taught you to fear.

[jakeandelwood]

Go poor a cold bucket of water on your hot car engine and see what happens.

Nothing.

I drive through puddles all the time (the bigger the better - I'm basically a giant kid) and have yet to have any shock cooling issues. Even if I did it likely wouldn't be catastrophic, I assume the worst I could do would be a slow leak from a crack in a cooling jacket. Annoying, yes, but not a deal breaker.

Someone smarter than me could chime in on what 'shock cooling' actually does to an air cooled airplane engine, but I suspect it's more an issue of accelerated wear than the catastrophic explosion your instructor taught you to fear.

Yes, a cracked "cooling jacket" no big deal, those are easily replaced on a liquid cooled engine.

[cncpc]

How many have ever shut down an engine in flight and stopped the prop? In a 172 with either a Continental or Lycoming, you have to slow pretty close to stall.

I have. Several dozen times, one of them unintentionally on a sharp pull up from a forced approach in which a truck drove onto the intended landing area, crash zone. You don't have to stall, but yes, it is a low speed. Once you have it stopped, then you can increase speed a bit without it windmilling. A fair bit, actually. If you do a restart as part of the demo, it windmills very quickly once the starter gets it moving, and from there fires right up.

I think it bears saying that for a single with a nose gear problem, you can actually plant the mains and then shut down. So you have a pretty good indication then that a go round isn't necessary. Main gear bad, nose gear good, on a single its kind of your choice. If you think you can hold it straight, and the nose gear will hold up, maybe keep it running. But I'd shut it down once the nose wheel was planted anyway. You don't need it anymore, and you're ready for the worst case scenario.

All of this is pretty easy peasy if you think it through.

[C.W.E.]

Someone smarter than me could chime in on what 'shock cooling' actually does to an air cooled airplane engine, but I suspect it's more an issue of accelerated wear than the catastrophic explosion your instructor taught you to fear.

I have no idea if I am smarter than you but a lot depends on the airplane and engine you are flying.

Somewhere in my " stuff " I still have the engine handling manual for the R4D-8 with the Wright R1820 engines, the warnings about thermal shocking is quite interesting.

Bottom line it can get really expensive and unsafe if you do not control thermal shocking the engine.

[goingnowherefast]

Shock cooling is a real thing, if you knew how most cylinders were made and you'd understand why. However shutting an engine off at low airspeed after a gentle descent isn't going to do anything. Even a cracked cylinder isn't going to kill you. Just won't run quite right afterwards and the owner won't be happy if he finds you've abused it.

Run the engine hard, a bit too lean at Vx for a while, get it good and toasty, then do an idle Vne dive. That'll be real tough on it. Every engine and installation is different too. Mooney vs 172, might be the same engine, but cowled differently. Put turbos on to push up engine temperature and it's a different animal again. Radials with the huge frontal area, different again.

If my gear won't go down on a piston, I'm not too concerned with shock cooling on the rollout (slide-out?) if the engine is off. More concerned with aircraft control, potential gear collapse, fuel leaks, fire, etc.

[jakeandelwood]

I just talked to my insurance company about this. They don't care what you do really, they are just hoping no one gets hurt in the end and you don't compound the emergency. Ff you need a prop or engine teardown or whatever damage is done in the accident they will pay, your rates may go up if you start having numerous at fault claims. Insurance rates are mainly based on pilot experience and type of aircraft. I can see with the ridiculous parts prices how damage costs can easily exceed hull value, best be saving that 2 blade prop then.

[PilotDAR]

I can see with the ridiculous parts prices how damage costs can easily exceed hull value, best be saving that 2 blade prop then.

Have you priced out a prop, crankshaft and bulk overhaul lately? Yeah, nothing is low cost for aircraft, and that situation is only going to get worse. Insurance companies know this too. If you'd like to keep the cost of insurance jut a little bit lower, apply your flying skills the best you can to mitigate damage for them (or yourself, if you're self insured). If you can prevent something being damaged with minimal risk, do that! Why not be thought of well by your peers for an act of airmanship with good intent, and a better than normal outcome (like the pilot who inspired this discussion), instead of making the insurance adjuster, agent, repair shop(s), and some peers roll their eyes while they think about how they'd have done it differently. Fly better to inspire other pilots to also fly better, rather than saying "that's all I have to do, so it's all I will do".

You'd be amazed how long planes last if you treat them gently, while flying them with skill. (Spoken as the owner of one of my planes for 31 years, and another for 10 years now). I'm proud of how I have returned every plane I was flying to where it was supposed to be, with no pilot induced damage of any consequence. Some of those safe returns have been with some pretty significant failures, including four engine failures, three significant control system failures, and two events (sadly on the same set of floats on two different planes) where a mainwheel would not extend.

Demonstrate that super pilot skill every now and then to keep flying more economical for all of us!

[jakeandelwood]

I can see with the ridiculous parts prices how damage costs can easily exceed hull value, best be saving that 2 blade prop then.

Have you priced out a prop, crankshaft and bulk overhaul lately? Yeah, nothing is low cost for aircraft, and that situation is only going to get worse. Insurance companies know this too. If you'd like to keep the cost of insurance jut a little bit lower, apply your flying skills the best you can to mitigate damage for them (or yourself, if you're self insured). If you can prevent something being damaged with minimal risk, do that! Why not be thought of well by your peers for an act of airmanship with good intent, and a better than normal outcome (like the pilot who inspired this discussion), instead of making the insurance adjuster, agent, repair shop(s), and some peers roll their eyes while they think about how they'd have done it differently. Fly better to inspire other pilots to also fly better, rather than saying "that's all I have to do, so it's all I will do".

You'd be amazed how long planes last if you treat them gently, while flying them with skill. (Spoken as the owner of one of my planes for 31 years, and another for 10 years now). I'm proud of how I have returned every plane I was flying to where it was supposed to be, with no pilot induced damage of any consequence. Some of those safe returns have been with some pretty significant failures, including four engine failures, three significant control system failures, and two events (sadly on the same set of floats on two different planes) where a mainwheel would not extend.

Demonstrate that super pilot skill every now and then to keep flying more economical for all of us!

Perhaps I'm wrong then. I found an old invoice for a gear up landing from my plane from 20 years ago, it was $25'000 back then, prop, engine inspection, skin, gear door and cowl flap repair, probably double that now.

[youhavecontrol]

We had a crash of one of our training aircraft on landing about 4 months ago. The nosewheel broke off, cowling smashed-in, wing tips damaged, tail damaged, prop broken in pieces and the engine mount was bent and damaged. The insurance company is still debating a repair pay-out or a write-off. It's been sitting under a tarp in the hangar for a long, long time. If a plane can go through all that and sill be possibly repaired, I can't imagine a gear-up landing is necessarily worthy of a write-off... especially if you save the prop with your fully-capable piloting skills.