Plane engines Vs. Car engines. "Alarms"

[Guest Andys@coffs]

magnetically charged hydrocarbon ... :ah_oh:

Magnetically charged hydrocarbons.....the sort of thing I expect to see advertised as part of womans make up, high in hype and zero to none on any backing science. Given hydrocarbons are sort of lacking in Fe (and thats a good thing Im thinking) and much of the engine where the oil is needed is also lacking in Fe then that kills off the magnetism element. Charge relates to electricity so those 2 words probably shouldnt be side by side except where the magnetism is related to the flow of electricity...

 

But you do have a get out of gaol card in the bracketed words following that magnificent piece of technobabble.

 

Not having a go at you Tomo, just commenting on how engineering and science which should underly all these things seems to get displaced when non technical people write press releases and marketing blurb. The worst thing is that many of them dont even understand what the fuss is about. That is, they didnt actually intend to deceive. Stupidity/ Ignorance rather than deception.

 

Andy

 

 

[JG3]

Many years ago at a country show, a fund raising effort by a local service club was to drain the oil from an old Valiant sedan, and run it around the dirt track until it seized. Bets were taken as to how long it would run. Totally fouled up the scheduling for the events for the evening, cause they thought it would only go a few laps. Even worse cause they'd pulled the exhaust off for more dramatic effect, so it drowned out following events and kept raising a cloud of dust. Off course it wasn't at full power for that big engine, but going as fast as the track would handle. No 'magic' additives, just the remaining film of old oil. Three hours later, getting to the end of the evening, it was still going strong..... Finally they drained the coolant, and then it didn't last long.......

 

 

[facthunter]

No Oil.

 

Very worn engines can run for quite a while without oil. I had a relative who ran his worn 36 Chev out of oil without realising it,and he asked me why it was low on power, as it had just ground to a halt without seizing. I checked the oil level and found none indicated. I filled it up and it ran for years after that.

 

"Superloose" engines, as they were termed, often put out quite a lot of power as they were low on friction, in their worn out condition..

 

This sort of philosophy does not translate well to aircraft applications as any sort of internal deficiency seems to lead to failure within a short time. Example. leaking exhaust valves result in a rapid deterioration and often the head breaking off the valve as a consequence.

 

When I was doing inverted and negative "G" flight in Gypsy engines where the oil system does not function properly, when inverted, I was always taught to close the throttle and then wait till the oil pressure recovered before re-opening tne throttle upon resuming upright flight.

 

Any air entering the oil system of a racing car engine is considered deadly to the bearings in a matter of seconds, not even minutes, so some engines are very critical in this area. Nev....

 

 

[stanzahero]

Any air entering the oil system of a racing car engine is considered deadly to the bearings in a matter of seconds' date=' not even minutes, so some engines are very critical in this area[/quote']A good example of this is the Holden Starfire 4 cylinder engine. Some people used to put the six cylinder big end bearing from a Holden 202 in to save money (the Starfire being a cut-down 202).

 

They always failed like this because the 202 bearings had an oil grove in only one side of each pair and the Starfire could not handle it.

[bilby54]

OK, sticking my neck out here.....Anyway, I was on a long trip of about 400+Kms. After dropping someone off about 130K's into the trip, I was getting back on track and was going down a hill. Suddenly and only quickly I saw a flash of the OIL PRESSURE light. :confused:

 

Hmmmm.... So when I pulled in to refuel, I looked at the dipstick and sure enough I (or more so the car) needed oil.

 

So it got me thinking:

 

Usually cars only have a light which goes out once the pressure is above the "required ammount", where as planes have actual pressure gauges.

 

Hey FD,

 

Interesting how these threads get off topic but make really intersting reading.

 

History and training in history, plays a big part in what we have today. The early years of flying and motoring were all based around mechanical devices and when Mr Bourdon invented the pressure gauge, everyone wanted one fitted to their car. Indicator lamps were just not practical as they were big, required a big battery, big switches and mostly powered by acetylene!! Tradition dictates why a lot of things happen.

 

If you were a struggling post war car maker then the new indicator lights were the in thing and car instrumentation took off from there. Aircraft on the other hand, had a lot of ex military jocks who needed the cockpit to look like a B17 or Lancaster and nothing elase would do so that had abig influence on how systems developed - pass the cucumber sandwiches please......

 

Modern aircraft systems were initially designed to meet the needs of the buyer and the purse string holders reckoned that the more gauges, the better the value for money they were getting. In reality, the less complicated systems work better and the modern electronic EFIS are just a breeze for construction, reliability and operation.

 

With the low oil pressure discussion that I raised, I think that you may have inadvertently answered that for me - see quote. Most vehicle oil pressure switches are set around 5 - 7 PSI falling to allow for various engine conditions so that even when the light comes on, the engine is not going to suffer much harm - (at 5 -7 psi, it is pretty well stuffed anyway!). I think that aircraft systems are set at much higher pressures for safety reasons but as always, lights tend to cause some degree of panic when they come on.

 

The reason that aircraft engines are certified to run without oil is so as they will not cause a fire, even if they can 'stick legs out of bed' or blow pots. Aero engines, unlike car engines, are designed to operate at high loads for long periods of time at high altitudes so it is highly desirable to avoid fires or catostrophic failures. Sudden loss of oil pressure is usually due to a major failure with oil all over the place and no gauge or light is going to help.

 

It might also come down to a bit of ego?? How many times have you been in a discussion and someone says "I've got the Flybit 235 with the digital cloud recogniser that answers the phone and makes coffee" but someone else has the shot blaster 2150 with more lights than you can poke a stick at!!

 

In the end it is up to either you or the manufacturer as to what system that you want for monitoring of your aircraft.

 

 

[flying dog]

Wow.

 

Thanks folks. I'd nearly forgotten about this post.

 

Yeah, I guess it is "much of a muchness" to which you chose/get.

 

Anyway, more questions coming up when my brain works out how to ask them.

 

Stay tuned.

 

 

[Guest check-in]

Even better for detecting problems is to keep an engine trend log. Once the engine is thoroughly warmed up and settled down in cruise, note the engine temps and pressures. For a consistent result always try to do it at the same PRESSURE altitude and same RPM. Of course there will still be variations according to ambient temperature, but unless you are operating at extremes between successive trend logs you will get a fair idea of how it is going as it takes a while for upper temperatures to change with the seasons to the point where there will be a noticeable effect. For that reason I try to do my trend log at 5000 feet pressure altitude, i.e. with the altimeter set to 1013 and indicating 5000 feet. Just remember to reset QNH when you are done!

 

 

[irishjab]

I have both gauge and warning light in the Jabiru J160 for oil pressure and low fuel. with gauges especially in a car , i would say something else made you aware you had a problem before you looked at the gauge, but i would also agree that you would scan the gauges in a plane more than you would in a car, but if the warning light comes on in the plane, i bet it get's your immediate attention. !!!!!!!!