Aerovee engine concern

[joepowel70]

I'm concerned about using the Aerovee engine on my airplane. I recently heard of the accident involving an Aerovee and a Sonex crashing in WI because of the propeller.

Are there alternative engines? Is this a design flaw, builder error, part defect? Have there been previous failures? Opinions?

http://www.faa.gov/data_research/accident_incident/preliminary_data/media/M_0805_N.txt
AIRCRAFT LANDING, PROPELLER SEPARATED WHILE IN-FLIGHT, MADE OFF AIRPORT FORCED LANDING, FLIPPED UPON TOUCH DOWN, PORTAGE COUNTY (STOCKTON AREA), WI

And this article http://www.wisconsinrapidstribune.com/article/20110805/WRT0101/308050050/Injuries-minor-small-plane-crashes-near-Stockton

And this http://wiwgcap.org/wing/content/view/407/1/

Any landing you can walk away from is a good landing.
Anyone who has flown with Captain John Thompson has probably heard him say that. Saying that however, just took on a whole new meaning after he made a successful forced landing near Stevens Point yesterday.
The plane was a Sonex, a light sport aircraft owned by student pilot Bret Taplin.
Shortly after take off from the Stevens Point airport, Thompson noticed an unusual vibration. Just as he was reaching to pull the throttle back, the propeller separated from the rest of the aircraft. He noticed smoke started coming up around the cowling.
What can only be described as instinct took over for Thompson. He briefly considered landing on a road, but traffic and the possibility of power lines seemed to make that option too risky.
From an altitude of about 1200-1500 feet above ground, Thompson made a mayday call and decided to land the plane in a potato field south of Highway 10 and east of Stockton Road.
As the plane neared touch down, however, the main wheels got caught in the vegetation. The nose wheel hit the dirt and flipped the plane over onto its canopy.
"When I saw the blur of the prop go away, and Brett says

[radfordc]

Yes, some Aerovee engines have had prop hub failures. Mine failed after at least two prop strikes. One failed after the builder used the wrong procedure to pull the hub. Others for reasons not understood.

Sonex LLC says if done correctly the hub is strong enough.

Waiting to hear more details about this latest one.

[NWade]

Joe - No engine has a perfect history. Many Sonex folks love their Jabirus, but if you do some research on the early Jabiru models and reviews, you'll find some serious concerns / problems. The trick is separating fact from fiction, and what failures result from improper use or improper assembly (versus inadequate engine parts or engineering).

--Noel

[Andy Walker]

I don't think there is a documented case of the hub failing on a properly assembled engine that never had a prop strike. If you're worried, get the preassembled crank/hub assembly for an extra few dollars and sleep like a baby at night. :)

[Dan]

Definitely the way to go IMO. If you buy the preassembled crank/hub does Sonex assume the liability? Hmmm......

[joepowel70]

I don't think there is a documented case of the hub failing on a properly assembled engine that never had a prop strike. If you're worried, get the preassembled crank/hub assembly for an extra few dollars and sleep like a baby at night. :)

Since posting my concern, I've spoken to a few previous Aerovee owners who had crankshaft/hub failures. According to them, they did not have prop strikes and their engines were assembled correctly.

I might try and contact Sonex to see if they have any history data.

[radfordc]

If the Aerovee prop hub is a major concern then check out the Great Planes Force One hub. Steve Bennett says there has never been a failure of their hub. You can buy a GPAS engine with the Force One hub and install it in a Sonex/Onex with no issues. If you currently own an Aerovee you can retrofit the Force One hub by buying a new crank/hub/bearing assembly and having your current engine case machined.

[radfordc]

If you buy the preassembled crank/hub does Sonex assume the liability? Hmmm......

No, they don't "assume" the liability. In fact, you have to sign a liability release to buy parts from them.

[Sonex1517]

I am not concerned and intend to fly an Aero-Vee. In fact, it was one of the reasons I chose Sonex.

Great thing about America - we all have our own opinion....

[Sonex1517]

Definitely the way to go IMO. If you buy the preassembled crank/hub does Sonex assume the liability? Hmmm......

I would ask why in the world Sonex would assume liability? It's a freaking homebuilt! Lawyers are for Cessna, which is why I got out of owning a certified aircraft.