Maintenance costs-engine size

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Bede
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Maintenance costs-engine size

Post by Bede »

Are maintenance/overhaul costs typically proportional to engine size? ie an O-540 is 50% more to overhaul/maintain than an O-360.
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Heliian
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Re: Maintenance costs-engine size

Post by Heliian »

An overhaul will cost about 40%more.

Regular maintenance will only be about 20 to 30% more.

Servicing will be even less of a gap.

In my experience though, the different engines are in different types, which have different maintenance costs.

Then throw in the T's and I's and the numbers change again.

What are you looking at?
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Bede
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Re: Maintenance costs-engine size

Post by Bede »

Hi Heliian,

Thanks for the info. I presently have a C150 on wheels. I'm thinking of going up to a 4 place on floats. I was thinking of something like a 180 HP C172 or C180. My family is small, so a C172 would work, but a C180 would do everything I want. I think a C180 would be a pretty big jump in operating costs though.
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fish4life
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Re: Maintenance costs-engine size

Post by fish4life »

Unless your family is 2 people then the 172 is going to be too small, they become pretty useless when you strap floats to them. A 180 is a beautiful family airplane and by the time you factor in insurance etc I bet would be within 15% of the operating cost of a 172 on floats.
Being faster the 180 will burn more per hour but will be very close in fuel burn to the 172 per mile.
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goingnowherefast
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Re: Maintenance costs-engine size

Post by goingnowherefast »

You can pull the power back on a 180 and burn 12gph doing 120mph. A 172 is 10 gph at 90mph. Assuming both on floats
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fish4life
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Re: Maintenance costs-engine size

Post by fish4life »

goingnowherefast wrote: Sat Jun 30, 2018 8:11 pm You can pull the power back on a 180 and burn 12gph doing 120mph. A 172 is 10 gph at 90mph. Assuming both on floats
The speed difference will also most likely make the cost per mile to run the engine the same for Maint
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Bede
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Re: Maintenance costs-engine size

Post by Bede »

Great info. Thanks guys.
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Tanker299
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Re: Maintenance costs-engine size

Post by Tanker299 »

The 180 and a properly equipped 172 are not as far off as you think. 172s can have from 160-210hp and with the right floats and stc have a payload of 7-800lbs. 180s have 8-900. That said the price to buy a 180 and 172 on floats is not always that far apart. Sometimes the 172s are more. I flew one for a bit with the 210hp and constant speed prop. Flew great with 3 full grown adults in it.
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AR705
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Re: Maintenance costs-engine size

Post by AR705 »

I agree with Tanker299, the performance isn't that far off. But I disagree on cost, it is pretty different!! But depends what you want to do. I fly an 0-320D2J 160hp 172M on Aqua2200 floats (formerly CAP2000s). Very happy with it for what I want to do (which is mainly afford to own a plane and use it), but have contemplated 180 many times!! Family size isn't relevant as there is lots of room in a 172, it's family weight!! I have a useful load of 700 lbs. And can fly comfortably at this weight. I don't usually fly with full fuel but normally at least 3 hrs fuel for longer trips. Tougher conditions like hot and/or glassy require a bit bigger of a lake but I like to have lots of room when heavy regardless. Smaller lakes call for shuttling loads to keep things light. When it's just me in an empty plane on a cooler day with decent breeze, it's off the water in no time and lots of fun. A 180 hp would be great an give me aprx 200 lbs more useful. Have heard of several people with 180hp 172s with around 900 lb useful. And it would perform great!

Costs... I plan for 9 gph but burn consistently 8gph at 2400-2500 rpm. Cruise reliably at 100 mph (with no wind) and mine isn't a fast 172. As with any plane, wind is a big factor. Have seen from 78 mph to 145 mph ground speed on cross countries! I do changeovers still to wheels in the winter so that's an extra cost.

I've compared my costs for a 172 in great detail to getting a 180, because I'd love a 180!! I paid 40% less for my plane than for a similar engine time 180. My insurance (based on quotes) is less than half of a 180 (and that was keeping the 180 on floats only). I priced operating costs based on fuel burn and also considering cruise speeds. I figure I fly around 9000 miles per year, at 95mph in 172 and figure would be 120 mph in 180. Based on my these and other calcs, a 180 would cost me $8000 more per year to take me 9000 miles. And this is NOT factoring in deferred maintenance costs (engines/props). If you factor in a same timed engine, and add the deferred costs to hourly costs, a 180 would cost me $12000-$15000 more per year to operate. And it would seem more 0-320s make it to TBO than 0-470s, but not always the case... This cost is also NOT factoring in that I can burn mogas in my 172 (although apparently some 180s can burn it as well). For me sadly, at this point I can't afford this extra operating cost for the sake of a couple hundred more lbs of load capacity. Do the math and see what works for you! Either way it'll be great fun!!
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