Materials change, old wive's tales not so much

Richard

Richard

Final Approach
Joined
Feb 27, 2005
Messages
9,076
Location
West Coast Resistance
Display Name
Display name:
Ack...city life
Let's hear your opinion of this as applied to "shock cooling" of present day horizontally opposed piston engines on 'spam cans', whether it be a O-200 or -540.
 
or flying "oversquare" :)
 
Fearless Tower said:
Can't we just talk about treadmills or overhead breaks?

:rollercoaster:
Click to expand...



I'm in! :D


*******************


There is a jump plane at my airport that Jesse knows well. ;) It takes off full gross, flies up to 10,000' full throttle, climb prop. They pull the throttle back (or run out of gas :eek:) to full idle ( chop and drop) many times a day on weekends, all year long. Never had a problem, engine goes to TBO. Anecdotal evidence, but facts none the less. ;)
 
Last edited:
The improvements in materials technology have not changed the situation at all. The things which really wouldn't happen before still won't happen, and the things which could happen if the engine is abused still can.
 
What change? They're not making engines similar to what our fathers flew, they're making the engines our father flew.
 
steingar said:
What change? They're not making engines similar to what our fathers flew, they're making the engines our father flew.
Click to expand...
Not from a design standpoint, but from a materials technology and production quality standpoint. They may look the same, but they are better constructed and inspected, and the metals are of better quality.
 
Ron Levy said:
The improvements in materials technology have not changed the situation at all.
Click to expand...

I think that Superior, ECI would give ya an argument on that.
 
If you slip with flaps deployed in a Cessna that's certain death, even if your motor somehow survives the shock cooling.
 
JimNtexas said:
If you slip with flaps deployed in a Cessna that's certain death, even if your motor somehow survives the shock cooling.
Click to expand...

Not only is it certain death, it's automatic death. Unless you regularly fly "on the step".
 
Tom-D said:
I think that Superior, ECI would give ya an argument on that.
Click to expand...
Let 'em. Despite the improvements in quality, the thermodynamic coefficients of the metals involved have not changed significantly, so the risk of extra cylinder/ring wear due to dissimilar cooling rates is also essentially unchanged. As for the risk of quench cracking, it never existed in the first place.
 
Geico266 said:
I'm in! :D


*******************


There is a jump plane at my airport that Jesse knows well. ;) It takes off full gross, flies up to 10,000' full throttle, climb prop. They pull the throttle back (or run out of gas :eek:) to full idle ( chop and drop) many times a day on weekends, all year long. Never had a problem, engine goes to TBO. Anecdotal evidence, but facts none the less. ;)
Click to expand...

I think that is every jump operation. The 182 on our field goes to 11,000 and tries to be the jumpers to the ground and usually succeeds. I have seen him doing s-turns on final, so he wouldn't have to go around, because he was right behind someone.
 
Geico266 said:
There is a jump plane at my airport that Jesse knows well. ;) It takes off full gross, flies up to 10,000' full throttle, climb prop. They pull the throttle back (or run out of gas :eek:) to full idle ( chop and drop) many times a day on weekends, all year long. Never had a problem, engine goes to TBO. Anecdotal evidence, but facts none the less. ;)
Click to expand...
FWIW I don't generally go to idle until in the traffic pattern.

The typical jump run profile is as follows:
-Full power on takeoff, at gross weight.
-Climb at full power and full RPM for about 30 minutes with cowl flaps open
-Try to time things to where upon reaching 10,500 or 11,500 feet we're on the downwind side of the drop zone flying upwind. Pull power back to about 17" for the jump run.
-Fly straight and level for a few minutes, look around to make sure I'm not about to drop jumpers on some RV doing an overhead break, drop the jumpers
-Reduce power to 15" MP, and RPM to the bottom of the green arc, close cowl flaps
-Try to get the damn door closed
-Roll into a steep bank, peg the VSI going down
-Try to keep an eye on the traffic pattern and crazy rv drivers doing overhead breaks while making yourself dizzy and dealing with your ears wanting to explode
-Try to position yourself to where you can make an entrance into the traffic pattern that'll be safe
-At some point I pull the nose up, go to full flaps, carb heat on, and reduce the power to idle, then land.

It wouldn't surprise me if some of the jump pilots though just chop power to idle when they come down. But one can keep a little power in and still come down fast enough. So that's the SOP that people should be following.
 
Ron Levy said:
The improvements in materials technology have not changed the situation at all. The things which really wouldn't happen before still won't happen, and the things which could happen if the engine is abused still can.
Click to expand...
I would say we have seen greater improvements/impacts in the oils we use today than material technology.
 
Geico266 said:
I'm in! :D


*******************


There is a jump plane at my airport that Jesse knows well. ;) It takes off full gross, flies up to 10,000' full throttle, climb prop. They pull the throttle back (or run out of gas :eek:) to full idle ( chop and drop) many times a day on weekends, all year long. Never had a problem, engine goes to TBO. Anecdotal evidence, but facts none the less. ;)
Click to expand...

They better not be running out of gas or the pilot launched without legal VFR fuel minima. ;)

(Or maybe you never posted that online? Ha...)
 
Richard said:
Let's hear your opinion of this as applied to "shock cooling" of present day horizontally opposed piston engines on 'spam cans', whether it be a O-200 or -540.
Click to expand...

Well, I'm not going to get into the shock cooling argument, but hot piston / cold cylinder issue has been improved with newer materials.

Hypereutectic pistons have a lower rate of thermal expansion than traditional aluminum alloys. They're brittle as crap and once a crack starts, they turn into magical piston dust........ but the material is stronger and can be designed to have tighter piston to bore clearances (or larger operating temperature Deltas)

Not sure if Aviation pistons have moved to these types of alloys, but you'd be hard pressed to find a cast automotive piston that doesn't have a high Sil content.
 
John221us said:
I think that is every jump operation. The 182 on our field goes to 11,000 and tries to be the jumpers to the ground and usually succeeds. I have seen him doing s-turns on final, so he wouldn't have to go around, because he was right behind someone.
Click to expand...
And a local 182 jump operator considers a 600hour life before cracking on cylinders to be good:dunno:
 
jesse said:
FWIW I don't generally go to idle until in the traffic pattern.

The typical jump run profile is as follows:
-Full power on takeoff, at gross weight.
-Climb at full power and full RPM for about 30 minutes with cowl flaps open
-Try to time things to where upon reaching 10,500 or 11,500 feet we're on the downwind side of the drop zone flying upwind. Pull power back to about 17" for the jump run.
-Fly straight and level for a few minutes, look around to make sure I'm not about to drop jumpers on some RV doing an overhead break, drop the jumpers
-Reduce power to 15" MP, and RPM to the bottom of the green arc, close cowl flaps
-Try to get the damn door closed
-Roll into a steep bank, peg the VSI going down
-Try to keep an eye on the traffic pattern and crazy rv drivers doing overhead breaks while making yourself dizzy and dealing with your ears wanting to explode
-Try to position yourself to where you can make an entrance into the traffic pattern that'll be safe
-At some point I pull the nose up, go to full flaps, carb heat on, and reduce the power to idle, then land.

It wouldn't surprise me if some of the jump pilots though just chop power to idle when they come down. But one can keep a little power in and still come down fast enough. So that's the SOP that people should be following.
Click to expand...

You'll never see me doing overhead breaks or over flying the field when jumpers are active. Having a jumper go through the wing would not be fun. ;)
 
Geico266 said:
We don't talk about it....... much. :rofl:
Click to expand...

We have a FAA inspector who trolls facebook, fliker etc looking at skydive photos.

His goal?

Catch the jump plane in the background performing "aerobatic" manuvers
 

Attachments

  • shock-cooling.gif
    shock-cooling.gif
    944 KB · Views: 9
denverpilot said:
They better not be running out of gas or the pilot launched without legal VFR fuel minima. ;)

(Or maybe you never posted that online? Ha...)
Click to expand...

FWIW I've never ran out of gas nor have I seen another pilot there run out of gas. As far as fuel minimums you need enough to get to your destination plus 30 minutes. Your already at your destination so you could legally takeoff with 30 minutes of fuel. If your climb was delayed for one reason or another one could run out having taken off with "legal fuel".

I personally don't let myself get below 8 gallons total period.
 
Skylane81E said:
We have a FAA inspector who trolls facebook, fliker etc looking at skydive photos.

His goal?

Catch the jump plane in the background performing "aerobatic" manuvers
Click to expand...

There really are some stupid skydive pilots out there. They really don't take the fact that they're flying for hire doing something that is already dangerous and perform way too many stupid pilot tricks.
 
You must log in or register to reply here.
Back
Top