# Auto conversion ideas

In my lifetime, I have known 5 pilot/builders that had auto engine powered experimentals. All spent far more time and money engineering, tinkering, and repairing their one of a kind setup. All experienced multiple small, and sometimes large, failures. All of these aircraft have either been re-engined with Lycomings or have been scrapped out.

I'm not saying it can't be done, but I just can't figure out why it should. It just seems like a square peg, round hole type of solution.

Speaking of small n, the engine that tried to put me in the dirt was a certified Lycoming, not a Viking. What to do... don't answer that I'm being rhetorical....
"Rhetorical." Then again, rhetorically speaking, how many hours have you flown in aircraft powered by certified Lycomings, vs. hours in Honda-powered aircraft? This is where the statistics get fun....

This plot, to me, shows the fundamental issue with auto-engine conversions. Of the homebuilt powered by traditional engines that suffer an accident due to a mechanical failure of the engine, about 18% of the accidents occur during the initial test period (40 hours). If an auto conversion DOES fail, there's a 30% chance it'll be in that test period.... and about 20% of the accidents occur in the first ten hours!

During that initial 40-hour test period, the builder of the airplane is supposed to be paying attention to the condition of the airplane...and the engine. Auto engine converters aren't catching incipient problems.

Ron Wanttaja

In my lifetime, I have known 5 pilot/builders that had auto engine powered experimentals. All spent far more time and money engineering, tinkering, and repairing their one of a kind setup. All experienced multiple small, and sometimes large, failures. All of these aircraft have either been re-engined with Lycomings or have been scrapped out.

I'm not saying it can't be done, but I just can't figure out why it should. It just seems like a square peg, round hole type of solution.
Cost is the major one. A new O-200 costs something like \$35,000, a Rotax 912 about the same, but a typical auto engine conversion may go for a third of that. If the C85 in my Fly Baby goes Tango Uniform, it will probably cost me a ton of money. And the engine has been out of production for ~50 years.....

Ron Wanttaja

Yeah but it has also weeded out engineers and pilots like myself who are actively working on new experimental aircraft and auto conversions.
Engineers and pilots actively working on builds don't generally spend much time on HBA or anything else. They're in the shop, or at work. I'm retired and not building or restoring anything aviation-related at the moment, so I'm here and at HBA. Too much, usually.

Cost is the major one. A new O-200 costs something like \$35,000, a Rotax 912 about the same, but a typical auto engine conversion may go for a third of that. If the C85 in my Fly Baby goes Tango Uniform, it will probably cost me a ton of money. And the engine has been out of production for ~50 years.....

Ron Wanttaja
Amen. I’m looking at most options for my current build. C-85 or O-200 are candidates, but so are the Rotax 912 series, Aeromomentum, D-motor, Verner, and so on. Maybe, possibly even Corvair, but I dunno. Trying to get a straight answer to a simple question from that cult seems to be an exercise in futility.

There are some pretty interesting options out there.

I just tested, you can still register and join for free. Select the basic plan. Note: I used an incognito window to do the testing.

Tim
Go back in after a few days and you will get a message on every thread you click that says you need to upgrade your account to read replies even after logging in with a basic account.

Go back in after a few days and you will get a message on every thread you click that says you need to upgrade your account to read replies even after logging in with a basic account.
I'm a moderator over there, I will look into this. The new forum owner has not been transparent about all the changes.

I'm not saying it can't be done, but I just can't figure out why it should.
This seems to be where all of the data points.