AeroVee Frequently Asked Questions

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Is the AeroVee available as a Pre-Assembled Engine?

No. We have poured all of our energies into providing a complete engine kit package that is easy to build and empowers the builder to have a higher awareness of their aircraft engine, saving money be performing all of their own maintenance to an engine with outstanding performance and low initial cost.

How Easy is the AeroVee to Build?

Very easy. Assembly time required to build the AeroVee Engine Kit is approximately 12 hours, not including time for paint drying or time required for prescribed heating and cooling of parts for shrink-fit assembly. The AeroVee requires no specialized tools. Standard SAE and Metric wrenches, feeler guages, and a torque wrench are just about all that is required. You can preview the AeroVee Engine Kit project by watching the AeroVee Assembly DVD, available for $5, including postage within the U.S.

What is the TBO (Time Before Overhaul) of the AeroVee?

Because the AeroVee is an Experimental aircraft engine, there is no requirement to publish or specify a TBO. We don't publish a TBO, and we really don't approach overhaul with a TBO mentality. There is no magic hour at which any engine suddenly needs service, whether certified or not.

The AeroVee will last anywhere between 700 and 1200 hours depending upon how well you treat it. If you do a good job following our instructions to assemble the engine, as long as you keep the temperatures in the green, change the oil at proper intervals, keep the valves adjusted, and provided you are flying often-enough (a big caveat with all aircraft engines), you will easily see 1000 hours out of your AeroVee. As long as you have good compression and the engine is not burning oil, the AeroVee is good-to-go. You will notice when the engine is not providing quite the same static RPM and that's typically a good sign that some level of overhaul should be considered.

The really great news is that core parts for the AeroVee are readily available either through us, or from numerous aftermarket VW racing part suppliers, at incredibly low cost. A routine to moderate overhaul of an AeroVee will cost between $200 and $500. A worst-case-scenario overhaul involving replacement of all the core parts will cost approximately $2,000 in parts.

Does the AeroVee require AvGas or can I run Auto Fuel?

The AeroVee can run on either AvGas: (aviation gasoline 91/98 minimum grade conforming to ASTM D 910) or Auto Fuel (automotive gasoline with a posted (R+M)/2 of 90 or greater conforming with ASTM D 4814). We give instructions to set-up a different compression ratio for AvGas (8.0:1) vs. Auto Fuel (7.0:1).

There are many customers flying Auto Fuel in the AeroVee quite successfully. As a factory, however, our preference is for 100LL AvGas. 100LL maximizes the overhaul period for your engine and maximizes the available power output from your engine. At 3.5 gph in cruise, we feel there is no good reason to not burn avgas in these engines unless it poses a logistical problem.

What about Ethanol Fuels?

All parts and materials used in the AeroVee and AeroCarb are fully compatible with Ethanol. Flying ethanol blended Auto Fuel with low ethanol concentrations, as is being mandated for auto fuel in many states, does not pose any particular problems for the AeroVee and AeroCarb. As is the case in all aircraft fuel systems, however, you will want to be wary of potential problems with your aircraft's fuel system installation regarding increased risk of vapor lock and phase separation with these fuels (note that Experimental aircraft are not subject to STC regulations, and therefore, use of auto fuels with ethanol, or other alternative fuels in experimental aircraft is not prohibited). Also be aware of the potential effect of ethanol content on auto fuel octane ratings and your AeroVee's compression ratio requirements.

AeroConversions is currently testing Ethanol blends of E85 and higher in the AeroVee engine as part of the E-Flight Initiative, however, use of these fuels by AeroConversions customers is not approved for the AeroVee at this time.

How can I tell if the AeroVee is Suitable for My Airframe?

The basic criteria of engine suitability for any airframe is the total powerplant installation weight range acceptable for the aircraft and the horsepower range acceptable for the aircraft. Your airframe's manufacturer will be able to tell you what the acceptable installation weight and horsepower range is for their particular aircraft. Be sure to check-out our AeroVee Installations Page for a listing of known AeroVee installations.

Do you provide AeroVee Engine Mounts and FWF Installation Packages for my Aircraft?

We do not provide motor mounts or specific, flight tested AeroVee installation packages for aircraft other than our own line of Sonex Aircraft. We use the AeroVee/Sonex installation as a baseline (the AeroVee/Sonex Installation Guide is included with all AeroVee Engine Kits) and customizations for the unique traits of other airframes are left up to the builder.

If there are other examples of your airframe flying with direct-drive air-cooled engines such as the AeroVee, other VW conversions, or engines such as the Jabiru 2200, you will want to look to those installations for more information about configuring your installation. Be sure to check-out our AeroVee Installations Page for a listing of known AeroVee installations. In some cases, motor mounts and installation support for the AeroVee may be provided by your aircraft's manufacturer.

AeroConversions technical support staff can also offer assistance in looking at pictures or diagrams of your planned installation for advice and troubleshooting, however, we can offer no guarantees, as we have never personally performed an AeroVee installation on your particular airframe of choice.

As the AeroVee gains popularity, we are counting on the builder support communities for each airframe design to support one another with successful installation considerations. As more aircraft of a certain type are built and flown using the AeroVee, the larger the knowledgebase that will become available to other builders. We are confident the AeroVee can be successfully installed and flown on just about any airframe. As is the case with any engine installation that is not specifically supported by an airframe manufacturer's instructional documentation, however, it may take some experimentation on your part as the builder to get things just right.

Can the AeroVee be installed in the Pusher Configuration?

No one that we know of to-date has completed a pusher installation using a modern AeroVee (available since 2002). All of our factory AeroVee installations have been tractor installs. Many VW conversions, including earlier versions of the AeroVee (sold in the 70’s and 80’s) have been used in pushers, however, and there is no reason the AeroVee could not be modified for a pusher installation. The primary design challenges for this installation are:

  1. Designing and building a motor mount system (perhaps a bed mount) sufficient for the Aerovee. The AeroVee engine case has two threaded bosses in the front of the case that are suitable for attachment to a bed mount.
  2. Designing and building a cooling duct system that will deliver sufficient cooling air where it's needed most- In the combustion area of the head.
  3. Designing and building an exhaust system that clears the prop at the back of the engine.

For new engine installations, we do defer to the airframe manufacturer for how they solved the design issues above. This is particularly true if the airframe manufacturer has flown with another direct-drive VW-based engine. Similar motor mounts, cooling baffles, and exhaust systems can then be used on these aircraft.

We are always happy to provide feedback on any proposed AeroVee installations and are not shy expressing if we think something is a good or bad idea.

How do I select a propeller for my direct-drive AeroVee powered Aircraft (other than Sonex Aircraft)?

There are a handful of people in the world that understand the proper design and selection of propellers for different engine and airframe combinations. We have put our trust in Sensenich Wood Propeller Co. and their design engineers, who are among the leading experts in their field, and we recommend that all AeroVee customers consult with and purchase from Sensenich directly for their prop needs. Sensenich has generated a large database of recommended propellers for homebuilt aircraft, playing to the strength of the AeroVee, other direct-drive VW engine conversions, and direct-drive Jabiru 2200 engines. For initial prop selection on AeroVee powered Sonex Aircraft, we simply made Left-turning versions of the Jabiru 2200 propellers we were already using. It's a great way to get close on the very first prop.

How do I select a propeller for my AeroVee powered Sonex Aircraft?

We have gone through a thorough and scientific testing process with a wide range of propellers for all Sonex Aircraft models. We work most closely with Sensenich Propellers and have flown many different models and sizes of their fixed-pitch wood and wood-core composite coated propellers. The recommended propellers for use on Sonex Aircraft are listed on the Propeller Page of the Sonex Aircraft web site.

Is it possible to use an Adjustable Pitch or Feathering Prop?

No, we have not found a ground- or air-adjustable propeller that is appropriate for use with the AeroVee. We have instead fixed all of our development focus on light-weight, simple, inexpensive, reliable and high-performance two-blade fixed-pitch wood or wood-core, composite-clad props. Even on the Xenos Motorglider, where many would assume a feathering-prop would be required for optimum soaring efficiency, we have opted instead for slim-profile wood-core, composite-clad Sensenich props that avoid the cost and complexity of feathering props while retaining very low-drag characteristics in engine-off soaring.

What is Sonex Aircraft's approach to propeller selection and how does Sonex Aircraft measure and compare performance with the various propeller manufacturers?

After more than 30 years of testing hundreds of different propellers in a quest to achieve maximum performance out of a wide range of airframe and engine combinations, there are many things we have learned.

Generally, performance increases will happen in very small increments when using different propeller makes and models. In rare cases, you can see huge performance increases when the first prop is totally "out of the performance box". With the two companies we have been working with, Sensenich and Prince, they have been very close to an optimized prop with their first design.

When measuring performance, it is very important to do an "apples vs. apples" comparison. This means flying the props you wish to compare in identical atmospheric conditions flown on a triangular course to account for wind speed and direction. Sonex Aircraft, LLC has developed a very large database of prop performance over the past 10 years for all 3 of our standard engine options... not only from our own prop tests (approx. 20 different propellers on our factory aircraft), but also using reports from flying customer-built Sonex Aircraft.

We have made no secret that we prefer to pitch props on the climb side of things, which will give you maximum power when you need it most-on climb-out...especially if you're operating out of a short, grass strip with obstacles. It does not hurt to allow direct drive engines like the Jabiru or AeroVee to "turn up" at Wide Open Throttle (WOT), so in most cases the climb props can obtain the same top speeds as cruise props, just at a higher rpm. It is therefore very important to record performance data at various tachometer settings when comparing two or three different propellers to each other.

Is it possible to use a Reduction Drive with the AeroVee?

No. We do not advocate or support the use of reduction drives with the AeroVee Engine. The AeroVee is designed for direct-drive applications only.

There is no question that a degree of improved propeller efficiencies can be reached using a reduction drive. However, reduction drives come at what we feel is an unacceptable cost to complexity and weight. Instead, keep the weight off and design the propeller to turn up higher rpm and play to the strengths of your simpler and lighter direct drive engine.

Our Xenos Motorglider is impressive to watch climb out using the purpose-designed 56-inch diameter Sensenich propeller.

We feel with the great combination of price, weight, and performance the AeroVee delivers that it will continue to take marketshare away from the more expensive and complex alternatives without sacrificing performance on a wide range of aircraft.

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