I Agree With TSM About The Severe Maintenance And Joseph About The Short/Long Trips.
This is the advice to give somebody who does a lot of short trips and using the old Owner’s Manual, too.
Aren’t you required to rebuild airplane engines after a certain number of hours? What’s the point of trying to squeeze a few more hours out of an engine if you’re just going to have to rebuild it anyways?
Just depends how the pilot treats the engine,
Things like power-idle descents can cause shock cooling which can crack the cylinder head and failure to preheat the engine on days when the temp is below 50F can also cause increased wear. But under normal, proper use circumstances the engine should go several thousand hours before requiring an over-haul.
Again, you’re not just squeezing hours out of the engine, but saving very $expensive$ avgas and also doing away with the hazard of rocks, etc being blown everywhere by the prop.
Something else I will add to this is the fact that aircraft spark plugs tend to fowl up during prolonged ground operation (due to mixture-rich, luke warm engine) unless the engine is leaned aggressively. So CSAs mechanic didn’t want to have to worry about fouled spark plugs in the near future, either.
airplane engines are and should be made as fail safe as possible, but making sure its really up to temp before using and the use of Ashless Shell Aerolube 90 or 100 wt in some cases as just a few examples that you really can’t compare to the needs of the ordinary auto.
Keep in mind that we are comparing air cooled engines and liquid cooled engines here. Auto engines are designed to run at a variety of RPMs whereas aircraft engines are designed to run at one relatively low RPM for hours on end. It’s sort of an apples and oranges thing. Aircraft engines have a recommeneded time between overhauls. Any short run times detract from that number.
I never start my airplane to just move it a short distance. In most cases it doesn’t pay to fly less than 100 miles or so. Driving is almost as fast where the interstate speedlimit is 70MPH, and there isn’t the hassle of getting where one wants to go once one gets to the destination airport. The plane is always warmed up prior to take off during taxiing, run ups, and mag checks. I fill it when I land, so a two minute run to the gas pump is unnecessary. That also keeps condensation from forming in the full fuel tanks.
OTOH several years ago it was recommended by Cessna that it was wise to “heat soak” an engine by starting it up and allowing it to warm partially, then shutting it off for a minute to allow EVERYTHING to be evenly heated, prior to take off. I don’t do that, nor do I know anyone on my airport who routinely does, but they say that’s the way to make an engine go to TBO.
What I meant is that isn’t there a rule set by the FAA that the engine has to be rebuilt after X number of hours regardless of actual wear? If that is the case I imagine, assuming all the required maintenance is done, that the engines never get close to being actually worn out and so it doesn’t make much sense to try to prolong the engine life way past the mandated rebuild point.
Good point with expensive Avgas, though and it sounds like it is safer/easier/cheaper just to push them around.
You are correct about the TBO rule. One thing to consider though is that during a major overhaul, each engine component is disassembled and measured against the factory specs for wear. If components such as crankshaft journals or cylinder bores are within spec, they are left alone, saving the very expensive cost of replacement. Thus, if properly taken care of, overhaul cost should be lessened.
Here in Wash. DC from April to November we have street cleaning each week on alternating sides of the street. Since I don’t drive to work I have to move my 2 cars from one side of the street to the other twice a week. So that’s less then 5 minutes of running and no substantial distance traveled. Besides that I drive them about 3000 miles a year. I try to use the older car ('88 Accord) for short trips, bad weather, etc. The newer car ('06 Matrix) might sit for 2 weeks before I take it on a longer drive (45 minutes or more).
I change the oil (dino) every 6 months and the filter once a year on both cars. The Accord motor is quiet and burns no oil at 218k miles. During the winter months I charge the batteries for a few hours once a month. My last battery in the Accord lasted 7 years. Mufflers (OEM) on the Accord last about 5 years.