I’ll admit it, this is pretty esoteric for a general-public blog, but, what the hay! Following is one fellows strategy for dealing with the short life of the typical ultralight 2-stroke engine. He looked at the problem from a purely economic point-of-view, and although the idea of doing this has occurred to me before, I’ve never seen it articulated as well.
First, though, what is the problem with ultralight engines?
Well, most of the 2-stroke Rotax engines have a TBO (time between overhauls) of about 300 hours. Most active UL-ers will fly about 100 hours a year, but the average might be more like 50 hours/year. That means that every 3-to-6 years, you need to do a complete overhaul of the engine in order for it to be considered reliable.
As a comparison, the 4-stroke Rotax engines, the 912 and 912S, have a TBO of about 1200-1600 hours… or, 12-32 years of service before an overhaul, given the average UL pilots flight time. So, they cost a lot more up-front, but being able to fly around for 12 years without worrying about reliability: priceless!
I was presented with this philosophy about Rotax overhauls at the repairman maintenance class I took this summer. It opened my eyes to a new way of looking at the subject. The A & P who offered it has been in ultralights for over 20 years, is a Quicksilver dealer, and used to have a clean room for doing Rotax overhauls.
He no longer does them and advises his clientele to do the following:
Set your engine up per Rotax, warm it properly before flying, use good oil, perform the normal maintenance per Rotax, and keep good engine logs. Fly it for 400 hours, then put it up for sale — while you are still flying it — for half the price of a new engine. There will always be somebody looking for a bargain engine and you should have no problem selling it at that price (that’s the complete engine, gearbox, carbs, exhaust, i.e. the works).
Take that money and the cost of an overhaul (including new crank, as per Rotax) and buy a new engine.
Brian used the example of a Rotax 582. New engine (check falling dollar value to be correct) $7,000 USD. Cost to overhaul, with new crank, $3500, or half the cost of a new engine. Voila’, you just bought a NEW engine for the cost of an overhaul.
And the guy who bought your old engine? If he treats it the same way you did, it goes at least another 400 hours. The average guy flies 50 hours a year, so he gets eight years of service from the engine at $450 a year (approx) or $9 an hour. AND the engine still has value at the end of that time.
One of the fellows in the class runs a towing operation in Florida. When presented with this idea, he ran the numbers for his business that night and told me the next day he had just done his last engine overhaul, too.
Now there are some important considerations to this philosophy. Number one is, you can’t scrimp or cheat. You have to embrace the philosophy in its totality. It’s also advantageous to sell it while the engine is still on your aircraft. The potential buyer gets to see it run, it’s not under a bench covered by a blanket. It’s a living, breathing, honest-to-goodness aircraft engine, not a bench weight of unknown condition. Number two, keep good logs. If you are familiar with genearl aviation aircraft you know that the logs themselves have value, even without an engine attached. Their value to you is that it shows you are an above average owner in the ultralight universe, and this impression is passed on to your prospective buyer.
As I said, I didn’t invent this philosophy, I only present it for your consideration.
I’d say that’s a pretty good strategy.