Crank Shaft Faiure

[Aldo]

Been reading a thread on the EAA forum about AeroVee reliability. Several of the contributors imply crank shaft failure is possible, but if you have retro fitted the "beefed up" crank shaft failure is less likely. My Sonex has Aerovee 2.1 engine #0310 with 150 hours on it. As I am still learning about this engine, I would appreciate any comments and info you all have.

Thanks again!

[SonexN76ET]

Aldo, a crankshaft failure has never been an issue with Aerovee 2.1's.

On earlier model engines there were maybe one or two that the NTSB found clearly linked to builder error. Unfortunately these two or three incidents have been reposted over and over again on the web making it look like a major issue when it is not.

Also some other engine builders have tried to make this an issue to try to sell their in house engineered cranks. But research shows these other firms have had their share if crankshaft and prop hub failures.

It should also be noted that Lycoming and Continental have had their share of crank issues too.

You have the same crank the turbo guys have that are pushing 110 HP. You have nothing to worry about as long as you maintain your engine.

There are plenty of uninformed opinions out there on other forums.

Thanks,

Jake

[radfordc]

I Can tell you how to have a prop hub failure. Have two prop strikes and continue to fly for another 100 hours.

[Mike53]

Aldo, a crankshaft failure has never been an issue with Aerovee 2.1's.



Also some other engine builders have tried to make this an issue to try to sell their in house engineered cranks. But research shows these other firms have had their share if crankshaft and prop hub failures………….

There are plenty of uninformed opinions out there on other forums.

Thanks,

Jake

Aerovee has never had a crankshaft /hub failure due to design .Agreed
Where did you find 'The other firms"crank failures? By other firms I assume you refer to Aerovees direct competition,Revmaster,Great Plains,Hummel.
I too spent a lot of time searching for crank failures attributed to their designs and found not a single one.There was rumblings about early rev masters but I never found any concrete facts on an actual failure due to design.

If these failures were due to owner builder errors then the other firms have had as many design attributed failures as Sonex ,zero.
Mis -information is a drag.
Truth is all four companies make a great product . :)
Mike

[SonexN76ET]

Mike, I am sorry for any misunderstanding you might have with me, but I am the last person on this forum who is going to put out bad information. If you do a search of the NTSB accident database you will find at least one Great Planes crank/prop hub failure. Furthermore, Lycoming had a large crankshaft replacement AD a few years ago.

Please keep the name calling off this forum.

Jake

[daleandee]

Please keep the name calling off this forum.

Hi Jake,

Maybe it's just me but I haven't seen any name calling as yet and, for that reason, would ask that the insinuation of such be avoided. As far as you never giving bad information ... the AeroVee Turbo is rated at 100 HP not 110.

Just sayin'

:?

Dale
N319WF

[SonexN76ET]

All I am saying is I am not putting out misinformation. Dale, the turbo is 100+ HP. I think someone said in a video it may be close to 110 HP. I consider it name calling when someone says I am putting out disinformation. I will happily leave this forum and just mind my own business if this continues. Let's be civil and respectful of each other!

As far as crankshaft/prop hub failures go, there have been very few in the VW conversion community. What I have seen, however, is that other manufacturers have tried to allude to these failures being primarily to do with the Aerovee and have done so to push their custom crankshafts.

Here is the NTSB report on a Great Planes powered Sonex that had a prop hub failure: N164JL, NTSB report LAX02LA279
It also says Great Planes had to put out a service bulletin due to this one and another one.

Relevant text:

"During a telephone conversation with a National Transportation Safety Board investigator, the pilot
stated that while in the initial climb, about 300 to 400 feet above ground level, the engine surged
and the airplane could not sustain lift. The engine was still producing power, but failed to
distribute that power to the propeller. With a lemon grove directly ahead of him, the pilot opted to
turn back to the runway to land. As he began a left turn toward the runway, the left wing impacted
the dirt and the airplane "cartwheeled." He felt a violent reaction in the cockpit as he was thrown
from the airplane.
The pilot further stated that, while doing an engine teardown, he discovered that the propeller hub
had separated from the crankshaft. The non-aircraft grade bolt that connected the hub to the
crankshaft had "backed out" leaving the propeller spinning freely. He also noted that 2 weeks prior
to the accident he had a similar propeller hub to crankshaft separation problem, at which time he
removed the propeller hub and reattached it. He thought that the bolt's threads were loaded
improperly and the bolt was not sufficient in transferring the load.
The Volkswagen Type 4 engine crankshaft end has a conically tapered end with a shoulder reduction from
the crankshaft diameter that in an automotive application contains a press fit pulley. To adapt the
engine to aircraft application, a conically tapered metal sleeve (the kit manufacturer refers to this
as a "tapered spacer"), which is seated on the shoulder to bring the diameter of the shaft end to a
constant taper for the propeller hub to fit over.
Great Plains Aircraft, a distributor of the Volkswagen Type 4 engine, released a Service Bulletin
after investigating this and a similar accident. Their examinations revealed that the bolt did not
fail; rather, the bolt loosening and backing out is a result of the tapered spacer spinning on the
shaft. They further stated that normally about 51 percent of torque is transmitted through the
tapered spacer to the tapered crankshaft. They noted that if the tapered spacer breaks loose, the
entire load is distributed to the rest of the crankshaft. The length of the tapered spacer is about
1.250 inches, with the remaining length of the crankshaft/propeller hub taper about 1.200 inches."

[rizzz]

All I am saying is I am not putting out misinformation. Dale, the turbo is 100+ HP. I think someone said in a video it may be close to 110 HP. I consider it name calling when someone says I am putting out disinformation. I will happily leave this forum and just mind my own business if this continues. Let's be civil and respectful of each other!

As far as crankshaft/prop hub failures go, there have been very few in the VW conversion community. What I have seen, however, is that other manufacturers have tried to allude to these failures being primarily to do with the Aerovee and have done so to push their custom crankshafts.

Here is the NTSB report on a Great Planes powered Sonex that had a prop hub failure: N164JL, NTSB report LAX02LA279
It also says Great Planes had to put out a service bulletin due to this one and another one.

Relevant text:

"During a telephone conversation with a National Transportation Safety Board investigator, the pilot
stated that while in the initial climb, about 300 to 400 feet above ground level, the engine surged
and the airplane could not sustain lift. The engine was still producing power, but failed to
distribute that power to the propeller. With a lemon grove directly ahead of him, the pilot opted to
turn back to the runway to land. As he began a left turn toward the runway, the left wing impacted
the dirt and the airplane "cartwheeled." He felt a violent reaction in the cockpit as he was thrown
from the airplane.
The pilot further stated that, while doing an engine teardown, he discovered that the propeller hub
had separated from the crankshaft. The non-aircraft grade bolt that connected the hub to the
crankshaft had "backed out" leaving the propeller spinning freely. He also noted that 2 weeks prior
to the accident he had a similar propeller hub to crankshaft separation problem, at which time he
removed the propeller hub and reattached it. He thought that the bolt's threads were loaded
improperly and the bolt was not sufficient in transferring the load.
The Volkswagen Type 4 engine crankshaft end has a conically tapered end with a shoulder reduction from
the crankshaft diameter that in an automotive application contains a press fit pulley. To adapt the
engine to aircraft application, a conically tapered metal sleeve (the kit manufacturer refers to this
as a "tapered spacer"), which is seated on the shoulder to bring the diameter of the shaft end to a
constant taper for the propeller hub to fit over.
Great Plains Aircraft, a distributor of the Volkswagen Type 4 engine, released a Service Bulletin
after investigating this and a similar accident. Their examinations revealed that the bolt did not
fail; rather, the bolt loosening and backing out is a result of the tapered spacer spinning on the
shaft. They further stated that normally about 51 percent of torque is transmitted through the
tapered spacer to the tapered crankshaft. They noted that if the tapered spacer breaks loose, the
entire load is distributed to the rest of the crankshaft. The length of the tapered spacer is about
1.250 inches, with the remaining length of the crankshaft/propeller hub taper about 1.200 inches."

You're not comparing apples with apples here.
This was a type 4 VW which is a completely different animal.

These days people don't tend to build type 4's anymore with the prop on the pulley side as we've learned the design of the crankshaft on the type 4 just can't be used for this purpose.
They only safe way to convert a type 4 for aviation use is to put the prop on the flywheel end. (but this is not very practical on a Sonex)
More info here:
http://www.greatplainsas.com/service2.html

Also,
Great Plains never sold Type 4's as complete engines. They only sell conversion parts.
The problem is that you can't buy Type 4 cases new anymore.

[daleandee]

All I am saying is I am not putting out misinformation. Dale, the turbo is 100+ HP. I think someone said in a video it may be close to 110 HP. I consider it name calling when someone says I am putting out disinformation. I will happily leave this forum and just mind my own business if this continues. Let's be civil and respectful of each other!

No need to get defensive and leave the forum Jake. Your perception is misplaced, I believe, as I didn't perceive any intent at name calling. Relax and understand that my reference about the turbo HP was made in jest and not meant to offend ... but the Sonex site does give 100 HP as the output for the Turbo Aerovee. From their web site ...

The AeroVee Turbo is rated as a 100 horsepower engine at sea level, and yields significant performance enhancement to the Sonex line of aircraft without breaking the bank.

Apology accepted!

;)

Dale
N319WF

[MichaelFarley56]

Jake, thank you for being the only person to actually answer Aldo's question. Just like Jake said, the AeroVee 2.1 crankshaft is a very robust design and if taken care of, it is extremely reliable.

Okay, I think we're all done with this thread. The topic has drifted away from the original question to the point I'm locking this conversation.