Truth In Advertising - Are We Wrong?

[daleandee]

Just a few points of clarification regarding the aerovee. The original 2.0 motor did not have issues with the crank/hub. There were only 2 failures of a crank before they came out with the 2.1 motor. One was due to the builder not supporting the crank correctly when pressing off the hub. The other was due to a prop strike whete the hub wasn't removed for inspection of the crank.

I don't want to rehash this but at that time I was flying an older Aerovee with the 10 amp dynamo and I recall on the old Yahoo Group there were four reported breaks. That's a small number and, as you note, some were either builder error or an unreported prop strike. Yet there was a reason Sonex upgraded the crankshaft in the Aerovee & began offering factory installation of the prop hub (other changes came also for the 2.1). I've only read of one reported break with the new crank.

Have you seen these: viewtopic.php?f=21&t=7488

(4:50 in this video)

https://www.youtube.com/watch?v=2F413qW8X3Q

The title of this thread is truth in advertizing. I'm not trying to be argumentative or cast any shade on Sonex but rather to give a true picture and say that these earlier issues were quickly addressed (as was the breaking of Corvair cranks early on).

Sonex has been very good at making these airplanes even better as over the years as there have been many changes, upgrades, and even needed revisions. We need this great comapny to continue to survive and grow but how they have overcome a few obstacles is also very important to show their successful history.

Dale
3.0 Corvair/Tailwheel

[gammaxy]

I suspect the total number of broken cranks is higher than any of these estimates. We just had another one in November. A young guy was on an adventure flying one across the country, even made a really nice Youtube video of the adventure until the propeller fell off.

Sounds like it wasn't a 2.1, but statistically, it seems there are likely to be more of these issues out there. Hopefully we are able to learn from the break and get the message out to folks with the same engine to know what to look for. I'm concerned that young/new guys like this one (who weren't around in the Yahoo days) are buying older engines that never got flown much and may be completely unaware of the possibility of a hub break.

viewtopic.php?f=21&t=7488

[kmacht]

I wasn't saying that the 2.1 crank isn't a better design, just that the 2.0 crank did not have widespread issues at the time that the 2.1 version of the motor came out. The change to the 2.1 motor was not specifically to address failures being seen on the older 2.0 version. Many aircraft were and still are flying behind the 2.0 crank and if installed correctly it works just fine. The 2.0 crank was a regular aftermarket VW crank that had the nose of the crank where the alternator pulley normally mounted machined to accommodate the taper fit hub. Because it started as an aftermaket crank it still had a groove behind the nose of the taper that isn't in an ideal spot from a structural perspective. When they went to the 2.1 crank it was a custom crank made specifically for Sonex so they took the opportunity to eliminate that groove as well as a few other features on the crank that were not necessary in an aerovee. Similar to the aerocarb vs aeroinjector, they both worked just fine but when the aeroinector came out with the 2.1 motor it was a better design that improved the carb but wasn't necessarily done because the original aerocarb was failing.

I put a little over 100 hours on my aerovee with the 2.0 crank with no issues at all but when I brought it home to do a number of upgrades (mostly bigger alternator and fuel injection) I fully admit that I changed the crank and hub over to the Force 1 design. I think it is just an overall better design than either the 2.0 or 2.1 crank as the hub itself is actually supported by the #4 bearing.