Hello SonexBuilders.net
We’d like to cover several items discussed in this thread:
Aluminum Cases: In 2013 Sonex Aircraft acquired an aluminum Type 1 crankcase and weighed it side-by-side against our mag case. The weight difference was far-more than 10 lbs. Here are the results:
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Magnesium Crankcase: 24 lbs.
Aluminum CrankCase: 43.2 lbs.
Weight difference between Aluminum and Mag Case: 19.2 lbs!
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See the following pictures of these weights:

- Magnesium Case Weight
- Aluminum Case Weight
Keep in-mind that, although an aluminum case build-up of the AeroVee may still fit within the Sonex’s 200 lb FWF weight limit, it is dead weight that is not doing anything for you in-terms of providing additional power. The increased weight of an AeroVee Turbo, UL Power or Jabiru 3300 installation offset their weight penalties with increased horsepower and 50 lbs of allowable gross weight increase due to the increased power on-tap.
Case Machining and Heads: Sonex Aircraft has ended its vendor relationship with MOFOCO. Cases are now being machined by the original case supplier in Brazil — the supplier that casts and machines all Type 1 magnesium cases for all aircooled VW parts suppliers worldwide. High quality heads are now being sourced from EMPI, and the job of machining of the secondary ignition spark plug holes has been returned to our pre-MOFOCO machining supplier.
Although there have been an unacceptable frequency of service issues with MOFOCO heads, it’s important to note that the majority of heads supplied by MOFOCO have been good. If you have MOFOCO heads and they are working well, don’t fix something that’s not broken. If you have service issues with your MOFOCO heads, we would encourage builders to contact MOFOCO directly to have your service issues addressed. If you do not receive satisfactory service from MOFOCO, please be sure to let us know via our technical support email address.
Prop Hubs: As you’ve seen in other threads on this forum, there have been a few cases of excessive prop hub runout found. As a percentage of total number of hubs produced, the number of instances of this issue have been very isolated. We are reviewing the machining and quality check processes for prop hubs with our machining supplier and our staff to help prevent future occurrences. If you have interference of the prop hub shaft with the nose of the crankcase and/or have observed runout at the face of the prop hub flange or excessive prop tracking issues, please contact our tech support email address with runout measurements and any other relevant data and we’ll take care of you.
A General Note about VW Conversions: As we’ve posted to Sonex and AeroVee forums many times through the years, it’s important to keep in-mind that the AeroVee and all of its competitors in the VW aircraft conversion world have the same set of core parts suppliers available to choose from. The beauty of the VW aircraft conversion and the key to it’s low cost is that there are so many parts suppliers to choose from, however, the worldwide supply of parts and the quality of parts supplied by vendors is often a moving target. Challenges in the core parts supply line are also challenges for our competitors. We work very actively to source the most-appropriate combination of core parts for the application, balancing economy with quality to best suit the mission of the AeroVee. Sometimes subtle changes in supplied parts from vendors don’t effect quality, but they do create some confusion for builders (such as the most-recent AeroVee manual revision addressing the proper identification of connecting rod orientation). Note that many parts offered in the aircooled VW racing aftermarket are for “high-rev” applications and are therefore overkill for an aircraft conversion, which operates in a much-lower RPM range. We focus more on the low-RPM, higher torque “off road” configuration and components. If considering alternative parts for your AeroVee, use caution! There aren’t many parts in the VW supply chain that we haven’t tried at one time or another in our 40+ year history working with VW conversions, and there’s usually a reason why the AeroVee doesn’t use a given part.
As always, please feel free to contact us directly with your questions at the sources listed below.
Regards,
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Mark Schaible
General Manager
Sonex Aircraft, LLC
phone: 920-231-8297
fax: 920-426-8333
http://www.SonexAircraft.comhttp://www.AeroConversions.comSales Info:
sales@sonexaircraft.comOrders:
orders@sonexaircraft.comAccounting:
accounting@sonexaircraft.comTech Support:
tech@sonexaircraft.comBuild a Sonex Aircraft in Your School!
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