SonexBuilders.net

Hello Everyone,

I have put together a cost calculation to own and operate a Sonex. The spreadsheet doesn't include the cost of the Sonex itself but only the recurrent costs. I would like your help/feedback to validate my numbers. I'm a Sports Pilot student and my wife and I mission is to commute once or twice a month for about 2 hrs each way. The fuel/hr is 8Gal because I will eventually consider a Turbo AV.

Thanks for the help!
Tex

Description, AVG Year, Monthly cost
Insurance $1,200.00 $100.00
Hangarage $1,500.00 $125.00
Maintenance $200.00 $16.67
Annual $450.00 $37.50
Total $3,350.00 $279.17

Description, Total cost, Cost per hour
Overhaul (250hrs) $1,500.00 $6.00
Fuel (100LL 8g/hr) $49.64
Oil (quart/hr) $2.88
Total per hour $58.52

I think you are low on the insurance cost. The quotes I'm getting are in the $2200-$2500 range for a taildragger sonex. The annual cost is also a little high. It shouldn't cost $450 unless you are doing an upgrade. Hanger costs are variable and specific to the region they are in

Keith
#554

Howdy,

I see you are a fastidious fellow who wants to quantify all possible expenses, so I will offer my humble thoughts.

I think a factor which would impact the maintenance expense is the amount of hours you think you will fly per month/year. When you first get it you will probably fly it quite a bit (its a blast!). I just spent $120 on new main tires, aviation oil $ 9 per quart, oil filter $ 9, K&N air filter cleaning and oiling kit $ 20. Occasional spark plugs, dist cap & rotor, etc. I also have personal consumables like current maps, and GPS software subscriptions. There will also be the random accouterments that you just have to buy (should you be impulsive like me), like my recent purchase of the 6" tailwheel assembly, terrain following radar, or RATO assemblies for the occasional short field take off.

Kevin K.

The insurance costs seem highly variable: I am a low-time pilot and my costs with a trigear are less than $1200. (I think my hull and liability coverage is probably close to what mos people buy.)

I'm not following the oil expenses shown in the OP: There's no way to burn a quart an hour unless you are flying without rings or have a smoke kit. Maybe a quart every ten to twenty hours?

Maintenance costs shown are probably on the low side, even if you do everything yourself (e.g. if you have a transponder, that has to be tested every 2 years, tires wear out, brakes need new pucks, even modern electronics fail sometimes, etc).

As you can see, a lot of the costs are fixed ones (hangar, insurance, annual inspection). Accordingly, the most effective (and fun!) way to reduce your hourly costs is to fly more hours per year. Or, partner up with someone.

-----

For the most part you have the costs about right. Do you have to pay property tax on the plane?

Figure 5 gal/hr for gas and an oil change every 25 hr. I don't burn a quart between oil changes.

Annual should be around $300 or so. You might do a valve job every 250 hr that should cost less than $150. Major overhaul "should" be after 500 hours I would hope.

Thanks Guys.

I have been tuning some of my calculations based on your feedback. I will share in a few days.

About the AeroVee engine...as radfordc said the overhaul should be every 500 hours. Do you all have experience with this? Does the AeroVee last that long? And...how many "overhauls" can we put on it before we need to buy a new engine?

Texfly wrote:Thanks Guys.

I have been tuning some of my calculations based on your feedback. I will share in a few days.

About the AeroVee engine...as radfordc said the overhaul should be every 500 hours. Do you all have experience with this? Does the AeroVee last that long? And...how many "overhauls" can we put on it before we need to buy a new engine?

A major overhaul is pretty much a new engine. Replace crankshaft, pistons, cylinders, bearings, valves, pushrods, lifters, and maybe cam shaft. The only thing left is the case, heads, and the accessory parts.

Is it 500 hours for the AV engine?

I have read about the Corvair (about $11k) with 100hp, TBO 1500 hrs (cost ~$1100)...it sounds more convenient even of the new AV Turbo...

Hi Texfly,

I'm building a Waiex, so I can't give you an exact run-down on cost to operate yet, but I have owned several planes in the past.

First, the best advice in here by far is fly it a lot, that spreads out the fixed costs. More importantly, it will make you feel confident with your plane and positive about what it does cost. There's no free lunch out there, but the sonex is small and efficient and really about as inexpensive as your going to get short of hanging the lawnmower off the back of your beach chair.

You should have a good idea of the fixed costs before you get in. These really won't go away and if you're in over your head on these you'll never enjoy it. Then figure out what you can set aside for flying, which is basically gas and (everything else). Decide what you're going to set aside per hour for the everything else, then make it work. I know, not very scientific and a little tricky to graph in 3D, but your plane isn't a statistic, it's a thing that breaks when it feels like it and generally runs fine for a really long time in between.

Corvair Power. Go to FlyCorvair.net and FlyCorvair.com, same guy, two complementary sites full of a ton of info. I'm building (with assistance) my own Corvair engine and I have become very impressed. It's a great choice, but it will require you to get more involved with your motor than the other choices. In the end, the plane pretty much comes down to the motor anyway.

Contact me anytime, good luck. Gordon