Real world costs

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crashxpert
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Joined: 25 Jan 2017, 22:51

Real world costs

Post by crashxpert »

The Comanche has been a faithful companion since I bought it when it was released. Through hiatuses and new aircraft releases I always come back to my Comanche. Since she was the first aircraft that I treated like a true study level aircraft, she and the bo are the only aircraft that I have never crashed in the sim from accident or design. Since install I set aircraft and engine to new with zero hours and since I have it up to 883.7 hours. Haven’t had to do anything other than change oil until now. Shop tells me both main tires are shot, left brakes worn, started worn(been yellow for about 500 hours now) and cylinder 3 compression is getting low. I’m assuming shop labor for aircraft is similar to auto shops but does anyone know what parts roughly cost? Also is 100ll still around 8 bucks a hollow or ya it gone up. I know I’ll never own one in person so I just try to simulate it the best I can. Thanks in advance for any info.
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AKar
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Joined: 26 May 2013, 05:03

Re: Real world costs

Post by AKar »

Tires somewhere around $100 each, standard Cleveland brake disks a bit above $200 each, linings not much, starters starting from 'bout $500, and for a cylinder kit today's price is $1357.00 each.

Of course, parts may only make some fraction of your total maintenance costs.

-Esa

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AKar
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Re: Real world costs

Post by AKar »

On this topic, BTW, some time back I intended to make a quick guide on how to find up all the necessary items using sources you can nowadays look up by googling. In essence, you can find a PA-24-250 parts catalogue from the internet (but not the guaranteed latest copy!), and you have some well-known suppliers of aircraft spares with good search engines. The fun begins when cross-reffing all the stuff you find from the catalogues against all the OEMs, replacing ones, PMAs, STCs and other stuff readily found, while remembering what could or could not be legal in your particular case. And of course, with no explicit aircraft s/n at your hand in the sim. :)

-Esa

JRBarrett
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Joined: 11 Sep 2009, 22:45

Re: Real world costs

Post by JRBarrett »

A Part 135 jet operator I used to work for had a turbocharged P-Baron as a company utility airplane. (Continental TSIO-520-LB engines). The owner of the company, who flew it most, insisted on running it too far lean of peak, and every time we did a 100-hour or annual, we would inevitably find at least one cylinder low on compression due to burned exhaust valves.

Fortunately, Penn Yan Aero, which is a first class engine rebuilder, Is located only 45 minutes away, so every time this would happen, we would end up pulling the bad jug (or jugs), and drive it up to PYA to have the valve replaced and the seat re-ground. (However, you can only do this so many times before the cylinder will need to be replaced). They could usually turn it in 2 or 3 days, depending on how busy they were.

As I recall, getting the valve replaced would run around $600, and total labor time to pull and then reinstall the cylinder would range from 8 to 16 hours, depending on which one it was. Since this was a company airplane, using in-house mechanics, the labor was essentially free, but a job like this, at prevailing shop rates would probably run between $1200 to $2000 dollars (having the existing cylinder repaired), and quite a bit more if a new cylinder and/or piston was required.

The normally aspirated IO-540 on a Comanche would probably be a little less prone to damage from misuse - in general, turbocharged engines rarely make TBO without requiring some kind of major maintenance unless they are operated strictly by the book at all times.

In the sim, it’s quick and easy to overhaul the engine with the click of a button. In the real Comanche, an overhaul is going to run about $25,000 on average.

Right now, with the worldwide drop in oil prices, 100LL is relatively cheap compared to prices a couple of years ago. Here in the northeastern US, I’ve seen it as low as $3.50 per gallon recently, but average is probably closer to $5.00

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AKar
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Re: Real world costs

Post by AKar »

Depending on when that was, if the engine was operated far enough lean of peak and in otherwise sensible manner (not to be taken for granted!), I'd guess the main reason for premature pulling of the jugs being abysmal quality of certain Continental replacement valves at least during one time period, say, somewhere around 2010. I don't know if the issues were resolved as I quit working in GA field before, but at some point in time, we had several instances of even inlet valve damage like never seen before in big-bore Continentals. The reason for these was poor metallurgy of these valves which was, in fact, so bad that it could be demonstrated by very tactile means when having a proper valve and a BS one. (Using a fairly blunt tool, such as a flat screwdriver, one could cut away the material with relative ease from the BS one.)

Edit: I must pull back the above. After sharing some recollections, most likely none of the referred experience was related with the exhaust valves, all were the intake. Hence, this issue had almost certainly nothing to do with a specific exhaust valve problem.

Many turbocharged aircraft engines are problematic in part because running them relatively hard but by the book ends up putting them in fairly critical operating condition, with very little 'tolerances' towards either the parts and assembly, or the operator. When premature engine wear/damage is discovered, telling that it has been operated only by the book (or worse - operated only very rich) acts as a Get Out of Jail free card, and operating practices are almost never considered contributory. The opposite is true if the engine happens to be operated with very lean settings, even occasionally: it nearly always goes beyond being a contributory factor to be the direct cause. As it turns out, very seldom are either of these example engines properly instrumented. So, any evidence of the actual operating conditions is almost never available.

Above excludes known instances of truly ill-advised deviations from the book procedures, which, unfortunately, do happen.

-Esa

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