Wanted: Infos about Damage due to wrong Startup Procedure in German Planes

[hiro]

thanks for posting that, it really helps

[Continu0]

Nice, keep it comming! It would be nice to have more informations about potential damage, but this seems to be a difficult task.

I will progress all the info to the german forum asap after i wrote my exams! (3-5 days)

[Foo'bar]

Like Continu0 wrote we're asking for consequences if engines won't be treated properly. Don't post manuals, we have them all.

At the moment we only suffer consequences if RPM is too high or if temperatures water/oil are too high.

What we need is:

What should happen if you run the engine full speed before proper temperatures have been reached?

What should happen if charching pressure is too high over a long time?

etc.

[Sutts]

Guys,

I've found an excellent article explaining the reasons for and the type of damage that occurs when you fail to pre-warm an aircraft engine or go to full throttle before it warms up sufficiently.

http://www.avweb.com/news/maint/182846-1.html

It's as much about bearing and piston clearances as the viscosity of the oil - which was new to me. Essentially, on a cold engine the clearances between the moving parts are much reduced (or almost zero sometimes) which means less space for oil to penetrate and more metal to metal contact causing bearing wear, spun bearings and piston scuffing etc. While there is a danger of engine seizure on the ground, far more dangerous is the potential for failure during or after takeoff due to the hidden damage caused on startup.

Interesting quote:
"In less than a minute, a single cold start without proper preheating can produce more wear on your piston aircraft engine than 500 hours of normal cruise operation. If it's cold enough, a single cold start can cause the catastrophic destruction of an engine shortly after takeoff. This is serious stuff, folks!"


Wouldn't it be great to see guys falling out of the sky or forced to operate under reduced power because they abused their precious powerplant?

[Sutts]

Another great article discussing among other things the causes and effects of carburrettor icing and detonation and preignition.

http://www.free-online-private-pilot...owerplant.html

Scroll down to Induction Systems and Ignition Systems....

It seems that using high boost and low RPM is a real engine killer - resulting in detonation and preignition. This creates excessive heat and large forces on the piston and rods while still in the compression phase.

Some good info on turbo and superchargers too, including the damage that can be caused by turning the engine off before the turbocharger has had a chance to spin down and cool a bit. Not relevant now but I have high hopes for some US types in the near future.

[robtek]

I've just talked to Mr. E. Meier from Meier-Motors ad asked him about cold-start damage on the DB601.

( http://www.meiermotors.com/ )

He told me that he started to work as a apprentice on the DB601 and that all damage from a cold start would just reduce the time between overhauls.

Depending on the state of the engine one could experience a seizure during the take-off run or reduced power from worn bearings if the engine was mistreated this way.

The time between engine changes on a bf109 was usually 25h, but a Staffelführer could extend the lifecycle of the engines of his Staffel by careful handling of the engines up to 50h. (i.e. cruising at 300 km/h)

All pilots during that time took extensive care of their engines, using high or emergency power settings only when really, really needed.

He also told me that it takes 90s for the oil to reach the last bearing in the DB601 (about 80s in a RR Merlin)

The oil used during the war was sae100 or sae120 single viscosity and really stiff when cold.

The Jumo211 of the Ju87 had a equipment for cold start that allowed to inject 20l fuel into the engine oil for thinning it, the fuel vaporing when the oil became hot.

[Sutts]

Originally Posted by robtek

I've just talked to Mr. E. Meier from Meier-Motors ad asked him about cold-start damage on the DB601.

( http://www.meiermotors.com/ )

He told me that he started to work as a apprentice on the DB601 and that all damage from a cold start would just reduce the time between overhauls.

Depending on the state of the engine one could experience a seizure during the take-off run or reduced power from worn bearings if the engine was mistreated this way.

The time between engine changes on a bf109 was usually 25h, but a Staffelführer could extend the lifecycle of the engines of his Staffel by careful handling of the engines up to 50h. (i.e. cruising at 300 km/h)

All pilots during that time took extensive care of their engines, using high or emergency power settings only when really, really needed.

He also told me that it takes 90s for the oil to reach the last bearing in the DB601 (about 80s in a RR Merlin)

The oil used during the war was sae100 or sae120 single viscosity and really stiff when cold.

The Jumo211 of the Ju87 had a equipment for cold start that allowed to inject 20l fuel into the engine oil for thinning it, the fuel vaporing when the oil became hot.

Great info straight from the horses mouth! Thanks robtek.