Sonex Speaks About Their Products

  The following text was copied off the Sonexplans Yahoo Group. In the three lengthy posts that follow, Jeremy Monett, the Sonex general manager, addresses the benefits of the AeroCarb and AeroVee Engine. It's great reading for anyone undecided on the AeroCarb or AeroVee.

-- Jeff Shultz (June 2006)

AeroVee and AeroCarb vs. the Competitor's Products (3/24/2006 10:10 AM) - (SonexTalk, Msg #22025

Hello again Sonexplans, Sonextalk, and AeroVee eGroups-

Sorry in advance for the length of this posting. As you will soon find out, we have a lot to say on this subject.

There has been a lot of discussion about some of the AeroVee Competitors in the VW AeroConversion Market. We wanted to take the opportunity to state a few facts and provide a list of questions for those who are researching alternatives.

In the past, there have been many individuals parading on the internet and in e-mail groups portraying themselves as Aircraft Engine Experts. We respectfully request that these individuals share their resumes as openly and honestly as we have. It will be quite an eye-opening experience for many a reader to find out just how many flight hours many of these "experts" actually have behind any kind of an engine conversion...let along any airplane! There are also fairly regular postings from individuals who have not done adequate research before making statements. They are not intentionally trying to harm products or companies making statements that are not factual, they are simply misinformed.

We want to extend a huge Thank You! to those that have AeroVee building and flying experience (This means you Tony Lewis, Mike Singleton, Drew Waterworth, and Tony Spicer) for taking time out of their busy flying schedules to share their experiences with the group.

On to the subject at hand.... The AeroVee and AeroCarb vs. the Competitor's Products.

It is my humble opinion that AeroConversions, Inc puts out the best VW-based Aircraft Conversion ever developed in the AeroVee 2180 Engine Package.

It is easy for anyone to design and build something heavy and complicated. It is a tremendous challenge to design and build something that is elegant, simple, and light-weight. The AeroVee has been thoroughly tested and has exceeded our expectations for power output, reliability, and ease of maintenance. Also, a complete and detailed AeroVee/Sonex Firewall Forward Guide is shipped with every engine, saving many hours of head-scratching, part sourcing, and guesswork.

We feel competition in all markets is good for the consumer. Price is of course only one of what should be many considerations. We only ask that all consumers gather as many facts about pricing, quality, design, what's included, and the ability for these companies to deliver what they promise before making a decision.

First, the facts about the AeroVee:

-John Monnett, the Sonex, Waiex, and Xenos along with the AeroVee 2180 co-designer has the most VW Aircraft Conversion design and flight experience of anyone on the planet....almost all of it in aircraft he designed. He and his team's original ideas have been copied by just about every competitor offering VW Conversions....which we consider the highest form of flattery. The same KISS philosophy that goes into the Sonex Airframes is applied to his brand name AeroVee Conversions.

-The first "x-casting" Accessory Case to be designed and flown on a VW powered aircraft was by John Monnett in 1973 on his own aircraft design, the Sonerai I.

-The AeroVee with the original "x-casting" was the first aircraft engine to utilize a stator alternator.

-"AeroVee" brand name Engine Cores and Components were used on three record setting flights in two different aircraft. Dick Rutan's VariEZ at Oshkosh 1975 set the FAI record for Class C-1a Group with an AeroVee Engine installed by John Monnett and Mike Core. Mike and John led a team of volunteers who worked all through the night to help make Dick's flight a success. An AeroVee Engine also still holds two world speed records in the Monex Airframe in the C1aO class... 185 mph in a closed 100km course and 182 mph over a 500km closed course...using only 10 gallons of fuel, by the way.

-To more modern history, the reason the AeroVee 2180 exists is that we did not like any VW conversions available on the market when we first began the development of the Sonex in 1997.

-The AeroVee 2180 is the lightest Type I/Type III Aero VW Conversion offering dual ignition and electric start ever produced.

-The AeroVee 2180 is the first Aircraft Engine to utilize the Magnetron Industrial Ignition System. This was quickly copied by the competition.

-The AeroVee 2180 is the first Aircraft Engine to use a sophisticated adaptation of a modern electronic coil ignition system. We anticipate this will also soon be copied by the competition in short order.

-The AeroVee 2180 is the only Aviation Engine that we know of that offers a "Dual-Plus" Ignition. You have to have four independent ignition unit failures for the AeroVee to stop running.

-All AeroVee ignition systems are driven off of one moving part...the crankshaft/flywheel assembly. Heavy, expensive, complicated Magentos and their mechanical drives have been completely eliminated.

-All AeroVee Core Engine Components were all selected by the design team for their suitability as an aircraft part.

-The AeroVee Crankshaft is Forged -AND- Nitrided 4340 Steel. The shrink fit design of the AeroVee prop hub yields one of the most robust prop hub attachments available on any aviation engine. (Note that our competitors use a very different shrink-fit hub design. They do not open up the nose of the crank case, which limits the thickness of their shrink fit design)

-To our knowledge, the AeroVee is the only VW-based AeroConversion to use Propeller Drive Lugs for the propeller-to-prop hub interface...a much more reliable and effective way to transfer load to the propeller.

-The AeroCarb with only two moving parts, infinitely adjustable needle jet, and many mounting options makes it the simplest and most versatile carb ever offered for aircraft use. It also includes a cockpit-controllable mixture control/fuel shut-off and doesn't require carb heat. Note that most competitors are still using complicated/obsolete carbs from the distant past. Note that the AeroCarb is 1 lb lighter than the Bing Carb supplied with Jabiru Engines (2 lbs, 14.4 oz for the Bing and 1 lb. 13.2 oz for the AeroCarb).

-All major Aviation Insurance Providers classify the AeroVee as one of the "most favorable" engines to insure. No AeroVee builder to date has had any problem getting insurance. Note that it's not something we thought we needed to advertise since we wouldn't sell a product that people couldn't insure. We will make sure that this is made abundantly clear in our web page and all future literature and advertising.

-Competitor's VW-based Engine Conversions with similar displacement (2180cc) to the AeroVee should put out approximately the same horsepower. Where the AeroVee enjoys the greatest advantage over the competition is the way the conversion was researched, designed, tested, and produced using the latest technology.

Now, for some opinions:

-The more "off the shelf" brand-new Racing Automotive Engine Core Components that are used in a conversion, the lower the initial cost -AND- the easier and less expensive it is for the builder (or second or third owner) to locate and source components needed for routine maintenance. In our opinion, the Performance Racing Automotive environment these component parts were designed for is much harsher than Aviation Use, where the oil is changed very regularly, compression ratios are lower. The AeroVee uses more "off the shelf" brand-new Racing Engine Core Components than any of its competitors.

-On propellers, there are no good, reliable, and affordable ground (or air)-adjustable propellers in existence. In our opinion, a wood or composite-coated wood-core propeller is the best choice for a direct-drive engine that produces its power at high rpm. Any extra money ($4000-$5000) spent on adjustable propellers is much better spent on a Jabiru 3300.

-At any of the fly-ins, all you have to do is go look at the competitors engines and then come look at the AeroVee. You will have an immediate feeling of an elegant, light-weight and sophisticated design that will deliver the flight performance and reliability you are looking for.

On the subject of arming yourself with information before you make an Engine or Carb Decision for your Aircraft Project:

When you go to select your VW AeroConversion Engine, we strongly suggest you ask whatever manufacturer the following questions. The answers to these for the AeroVee are included below for your reference.

1. What is included with your "complete engine package" and what is the price? 2. What other items will I need to fly my engine and what are their costs? 3. What is the total "flying" FWF Weight of your conversion including cooling baffles, exhaust, and carb and manifold? 4. What type of aircraft are your conversions flying in and how were they tested? 5. When (what year) were your conversion components developed and first flown? 6. What is the performance of your conversions in these aircraft? 7. What kind of Firewall Forward Support do you provide? 8. What kind of support is given after the sale and is there a dedicated technical assistant who can be easily reached? 9. What kind of warranty is offered on your component parts?

Answers to these same questions for the AeroVee and AeroCarb:

1. What is included with your "complete engine package" and what is the price? =Everything you see in this image except for the exhausts (intake manifold, carb, and dual ignition are all included) =Total package price is $5995 (2-into-1 exhausts are $395)

2. What other items will I need to fly my engine and what are their costs? =wiring, fuel lines and fittings, battery, air filter, cooling baffle material (plans included in the AeroVee kit). Total of about $200 of additional items. Note: all of these additional items are listed for you as a "shopping list" by supplier and part number in the AeroVee FWF Manual)

3. What is the total "flying, wet" FWF Weight of your conversion including cooling baffles, exhaust, and carb and manifold? =The AeroVee 2180 FWF package weighs 167 lbs "wet".

4. What type of aircraft are your conversions flying in and how were they tested? =AeroVee Conversions have flown in the Sonex, Waiex, Xenos, Sonerai, Zenair 701, Flitzer, and Dragonfly and are have been sold to builders 10 more aircraft designs. These will be flying in the coming months. Watch for a revamped AeroConversions site coming soon, which is the next project for Mark Schaible (the architect of the web site)

5. When (what year) were your conversion components developed and first flown? =the modern AeroVee 2180 Conversion was developed from late 1998 through 2002, when it was first offered for sale. We flew 4 different iterations of the AeroVee in the Sonex Tri-Gear Prototype and made roughly 60 significant design changes through the 4-year development process. There is presently an AeroVee-powered demonstrator Waiex, Sonex, and Xenos being regularly flown at the Sonex Factory here in Oshkosh. I love them all.

6. What is the performance of your conversions in these aircraft? =cruise 130 mph. Top speed 150 mph at sea level. =The rest of the performance specs are located on our newly revamped web site under "80 hp 2180 AeroVee":

7. What kind of Firewall Forward Support do you provide? =the best manuals and assembly guides in the industry. =A Complete Assembly DVD and Manual is sent out with every AeroVee Engine Kit. Each AeroVee Engine also includes the very detailed and comprehensive FWF Sonex/AeroVee Installation manual

8. What kind of support is given after the sale and is there a dedicated technical assistant who can be easily reached? =phone/fax/e-mail support provided by Sonex Aircraft, LLC. All inquiries are responded to quickly and efficiently by technical experts who have developed ,assembled, and flown all of the AeroVee and AeroCarb Products. Phone (Tech Line): (920) 230-8324 Hours: 10AM-12PM, 1PM-4PM M-F CST Fax (920)-426-8333 E-mail:

9. What kind of warranty is offered on your component parts? =Also, the best in the business. You break it, you bought it. A defective part and it's replaced at our warranty expense. It wears out and you can purchase a new one shipped directly from the factory as quickly as possible.. Just like the Sonex, Waiex, and Xenos all parts of the AeroVee Conversion are identified clearly by part number, saving both customer and factory time and money. Any replacement/service AeroVee Engine parts are available for individual purchase by AeroVee Engine Builders.

In summary, the AeroVee is the perfect fit for your Sonex, Waiex, or Xenos...or any homebuilt designed around direct drive VW AeroConversions. AeroConversions, Inc has been approached by many airframe manufacturers who are looking at using the AeroVee/AeroCarb in their lines of aircraft.

It is tough to find another conversion that offers so much for the price. In my opinion, the AeroVee is in a class by itself in the Aviation World and continues to gain market share and popularity as a result of it.


-- Jeremy Monnett

General Manager
Sonex Aircraft, LLC
Tel (Info/Orders): 920.231.8297
Tel (Tech Line): 920.230.8324
Fax: 920.426.8333

AeroCarb vs. Bing Carby on the Jabiru Engine (4/27/2006 11:39 AM) - (SonexTalk, Msg #22615

Hello again JabiruEngines Group:

cc: Sonextalk, Sonexplans, Waiexplans, AeroVee and Xenosplans Groups.

As promised on the JabiruEngines Group a couple of days ago, here are our thoughts and observations about using an AeroCarb on your Jabiru Engine vs. the Standard Bing Carby supplied with the Jabiru Engine.

The AeroCarb exists (and has become a great option for many a homebuilder on a wide range of engines) because of the Bing Carburetor. We encountered many troubles and needless complications when installing Bing Carbs in our own factory Sonex Aircraft. While it has been claimed by Jabiru that "all of these issues have been fixed" we continue to see these surface as new builders complete and fly their Jabiru Powered Aircraft. Note that the most recent issues reported did have Bing Carbs with the "Economy Tuning Kits" installed.

With over 30 years of experience using throttle-body type carbs, we knew there was a better way and that we were just the design team that could introduce a better Carb for the Jabiru Engine. The result of our extensive R&D and flight testing is the AeroCarb.

The AeroCarb represents the better carburetor option for your Jabiru Engine in every measurable way, including but not limited to:

1. Increased flight performance. 2. Better Fuel Economy 3. Lower Cylinder Head Temps 4. Lower Exhaust Gas Temps 5. Lower Oil Temps 6. Simpler Installation due to the elimination of the fuel pump. 7. Simpler Installation due to built-in control cable mounts 8. Allows for Aerobatics 9. Simpler Starting (no primer or choke required) 10.Impervious to carb ice 11.Lower Maintenance and Less Prone to Clogging 12.Weight Savings

Next, to put some flight performance and test numbers to back up each of our claims:

While almost all of the Sonex Pilots with the 3300 Jabiru Engine are flying with an AeroCarb (including Sonex Prototype Serial Number 0001, Xenos Prototype Serial Number 0001, and Kerry Fores Serial Number 0009), there are some Sonex Pilots who insist on using the Bing carb. The reported performance and temperature data reported by these pilots has served as the control group as we compare them to those flying with the AeroCarb. This data was compiled using the same prop on the same airplane with the only difference being the Carburetors.

1. Increased flight performance:

All Jabiru Engines powered by alternative carbs perform better than the standard Bing. (Note that the Ellison Carb costs twice as much as the AeroCarb and still requires the use of a fuel pump.)

In an impromptu comparison flight, Kerry Fores in his AeroCarb equipped, 3300-powered tailwheel Sonex was able to catch up with a Bing-equipped 3300-powered tailwheel Sonex in a shallow climb and, once level, was able to easily pull away. Both aircraft have the same propeller. While this is "unscientific" data, it is the only head-to-head comparison we know of to date. While we're confident the pilot of the other aircraft would not mind being identified, we will not identify him without his permission. This flight was witnessed from the cockpit by another builder, who is now flying his own AeroCarb equipped Jabiru 3300-powered Sonex.

2. Better Fuel Economy:

The AeroCarb provides better fuel economy because of two primary features. An infinitely adjustable main needle jet along with cockpit adjustable mixture control.

During initial tuning the fuel metering needle is set for optimum performance with the cockpit mixture control in the full-rich position, as detailed in the owner's manual. Once in the air, the pilot can pull the mixture control until the engine just begins to run rough, then richen until it smoothes out. This means the engine is always running at or near peak fuel efficiency. The AeroCarb saves between 3 and 4 gph vs. the standard Bing Carb in climb-out conditions and a little over 1 gph in an economy cruise over the Bing Carb. At $4 per gallon, the AeroCarb will pay for itself in much less than 100 hours of flying....then it's just more money in your pocket.

On Kerry's recent cross-country from Oshkosh to Sun and Fun and back (with his 3300 Jabiru powered Sonex) he had the opportunity to collect extended data on fuel consumption, particularly during the 1190 SM flight home which he was able to fly almost entirely at or near 8500 feet and 2950 rpm. With a fuel flow gauge fitted, which has proven extremely accurate over the past year of flying, cruise fuel burn rates ranged from 5.2 to 5.7 gph. Over the course of the entire flight fuel burn averaged 5.55 gph for time spent flying (fuel used/flight timer time), and 5.16 gph average for all time spent with the engine running (fuel used/hobbs meter time). Specifically, 88.76 gallons of gas were consumed, 17.2 hours were recorded on the Hobbs, and approximately 2400 miles were flown. The round trip flight included 8 stops (5 for fuel, 1 to wait for Lakeland airport to re-open after the airshow, and, of course, 1 each at arrival in Lakeland and back home in Oshkosh.

3. Lower Cylinder Head Temps:

Sonex Aircraft, LLC created its own laser-cut and pre-bent cooling baffle system for use with either the 2200 or 3300 Jabiru. We have been running these successfully in our factory aircraft with AeroCarbs with all temps well within the green. These baffles are available to any Jabiru Engine Owner, purchased through Sonex. We had two very recent reports of "high cylinder head temps with your laser-cut metal cooling baffles". Both of these reports were from pilots who insisted on using the Bing Carb, who were running up to 350 degrees on the center and aft cylinders.

Kerry has been flying the aluminum cooling baffles on his aircraft for all of the airplane's 190 hours. He developed the aluminum baffles after struggling with the Jabiru-provided fiberglass baffles. The hottest cylinder is cylinder #6 which in cruise at 2950 rpm and with an OAT of 55 degrees would top off at 320 degrees, but would quickly drop below 295 at 2800 rpm or less. The next hottest cylinder was #5, which never went over 287 and averaged 278. It must be pointed out here that in local flights around the patch when the engine is not being operated almost continuously for over 8 hours, #6 cylinder seldom tops 300 degrees. Cooling for #6 cylinder, with the metal baffles, can be dramatically improved by replacing a large cowl seal over #6 cylinder with a piece of aluminum which will add two or three minutes to the time it takes to remove/install the baffle.

4. Lower Exhaust Gas Temps:

EGT is the primary indicator of optimum fuel consumption and power output. The AeroCarb puts that control in the pilot's hand. By being able to pull the mixture lean in flight, power output is optimized and fuel consumption minimized. Without this control a pilot is at the mercy of a properly tuned Bing carb, a properly profiled needle, and the ill effects that come when the carburetor is no longer operating as efficiently as "new". The actual temperature to which you can lean changes from day to day, but with the AeroCarb the range is about 1285 degrees to 1425 degrees before engine performance diminishes from lack of fuel.

The Bottom line is that the pilot is in control of this most critical component of engine operation whether operating at full throttle in a zoom climb or cruising at altitude.

5. Lower Oil Temps:

Due to lower cylinder head and overall lower engine temperatures by running with the AeroCarb, oil temps have been observed 20 to 30 degrees lower than those running with the Bing. We also observed the elimination of the big heat-generating muffler and instead created our own straight-pipe exhaust system on the Sonex, which was also one of the reasons for these lower oil temps.

Oil temps with the Sonex/Jabiru 3300 oil cooler installation ranged from a low of 168 degrees on Kerry's flight to Florida, to a high of 185 degrees. Oil pressure in cruising flight ranged from 49 psi to 54 psi. On a hot day of playing around the oil temperature will climb to 220 degrees, but will fall off quickly when flight attitude is stabilized or the throttle is brought back from the firewall. When the temperature falls below 40 degrees, the air inlet for the oil cooler can be closed off entirely. Oil temps should be allowed to climb high enough to burn out the moisture in the engine, but not so high as to impede proper cooling and lubrication.

6. Simpler Installation due to the elimination of the fuel pump. Also eliminates vapor lock:

Anytime we can eliminate another mechanical system on an aircraft that can fail, we jump at it. The variable fuel pressures delivered by the fuel pump can also result in vapor lock, which is eliminated when the AeroCarb is used.

7. Simpler Installation due to built-in control cable mounts:

Those of you who have accomplished a Bing Carb installation know exactly what we're talking about. Most Bing Carb installers fashion their own custom brackets and modify the Bing Carb throttle control to make the installation somewhat workable. The AeroCarb has a built-in Throttle Cable Clamp along with Mixture Mount, greatly simplifying your cable routing. The new "pull-type" installation now available on the AeroCarb offers an even cleaner and simpler installation along with more flexibility in cable control routing.

8. Allows for Aerobatics:

Because the AeroCarb lacks a float bowl and delivers fuel largely based on the suction of the engine, it is the perfect carb for those intending to do positive G Aerobatics. (A reverse fuel and oil system would have to be added to do longer duration inverted flight).

9. Simpler Starting (no primer or choke required):

A properly tuned AeroCarb will have your Jabiru starting on the first or second blade every time. We have never installed a primer and have never required a choke.

10. Impervious to carb ice:

Due to its design with no venturi and no butterfly, no factory AeroCarb installations have ever used carb heat. There has also never been a documented case of carb ice in any AeroCarb installation or any of the carbs in the same family including the Lake Injector and POSA carbs which are well into the tens of thousands of flight hours.

11. Lower Maintenance and Less Prone to Clogging:

Due to its minimal part count and simple design, the AeroCarb represents a quantum leap in reduced maintenance compared to the Bing Carb. Also due to the AeroCarbs clean, straight-through fuel orifice and as long as standard aircraft fuel filtration is used, fuel clogging due to debris or water in the fuel system are non-existent.

12. Weight Savings:

The AeroCarb itself weighs just over one pound less than the Bing Carb. There is additional weight savings in the simpler installation of approx 3 or 4 lbs with the deletion of the fuel pump (for those aircraft that can use gravity feed), carb heat box, and associated scat hose and clamps.

Answers to some frequently asked questions we've fielded from various pilots of Jabiru Engines with Bing Carbs looking at making the switch to the AeroCarb along with prospective Jabiru Engine customers:

Q1: How does the use of the AeroCarb affect my Jabiru Engine Warranty?

A1: To date, there has not been any concern expressed by the Jabiru Engine Factory or any of the Jabiru Dealers Worldwide in using the AeroCarb to unleash the potential of your engine. To our knowledge, they have honored all engine warranty issues brought to their attention regardless of AeroCarb use. That said, if you "cook" your Jabiru Engine using an AeroCarb because you weren't monitoring temperatures or didn't have your Carb tuned properly, then you will be paying for the repairs to your engine. Follow the detailed instructions in your AeroCarb set-up Manual and you will have one of the coolest running Jabiru Engines...with better fuel economy to boot.

Q2: The Bing Carb has been flying on Jabiru Engines all over the world for years. Why are you trying to reinvent the wheel by going to an AeroCarb?

A2: Our best comparison to the modifications we make to the Jabiru Engine to make it better is the after-market Auto Market. There are many thousands of catalog and web site pages filled with different versions of carbs, manifolds, exhausts, fuel injectors, ignition systems, and misc accessories for just about every automobile on the road. These different versions make various claims as to increased performance, weight savings, better cooling, and better fuel economy just to name a few.... All the same things that the AeroCarb offers Jabiru Engine Pilots. Our question is, once you learn all of the advantages the AeroCarb brings with it, why would anyone fly with a Bing Carburetor?

We further understand why Jabiru must continue to defend their standard Bing Carb. We're frankly quite surprised that Jabiru has not come out with an alternative carburetor especially given the extensive feedback we have provided to them.

We realize that the AeroCarb represents an additional up-front cost. (Jabiru suspended the exchange program mainly due to the flood of Bing Carbs coming back to them) The AeroCarb will, however, pay for itself many times over given the significant fuel economy savings it provides. In our current world reality of ever-increasing fuel costs, this savings becomes more significant every day.

In closing, we have always invited anyone (including the Jabiru Factory and Dealer Network) to provide accurate performance and fuel burn data that shows the Bing Carb in any way outperforms the AeroCarb. In every head-to-head comparison we have done and seen, the AeroCarb has won pulling away.

We hope that all readers take this note the way it was meant: an open and honest comparison between the Bing Carb and AeroCarb. We continually have our own customers ask "Why should I bother with the AeroCarb when the Bing Carb works so well?" We hope this posting definitively answers that question.

Sonex Aircraft represents a growing group of Jabiru Enthusiasts...not only here at our factory in Oshkosh, WI but our worldwide group of builders and pilots. Our core interest is in seeing the Engine continue to succeed and to do whatever we can to assist in developing the worldwide support network. We are particularly pleased with all 3 of the current North American Distributors who we enjoy very positive working relationships with. We continue to hear positive feedback from Jabiru Engine Customers worldwide about their positive can-do attitudes and excellent service.

Sonex Aircraft has one of the most extensive and successful resumes for customizing the Jabiru Engines to our particular use. This has paid off in a huge way with Sonex Aircraft having the most "Jabiru Engine Fleet Time" of any other design (other than of course Jabiru's own aircraft). We've spent countless hours developing a very detailed Firewall Forward Installation Manual along with being the originator of the highly successful Straight-Pipe Exhaust System for the 3300. We also developed our own laser-cut and formed metal cooling baffles (a snap to install) and pioneered the use of the AeroCarb as an upgrade (in every measurable way) to the Bing Carbys shipped standard on the Jabiru Engine.

For those wanting more information on the products Sonex Aircraft Offers, check out freshly revamped and very extensive web site. You may specifically be interested in some of the aftermarket products we offer for the Jabiru Engine:

As always, please feel free to contact Betty, John, Kerry, Mark, Heather, Jason or myself at the numbers or e-mail below.


-- Jeremy Monnett

General Manager
Sonex Aircraft, LLC
Tel (Info/Orders): 920.231.8297
Tel (Tech Line): 920.230.8324
Fax: 920.426.8333

RE: AeroCarb vs. Bing Carby on the Jabiru Engine (4/28/2006 5:42 PM) - (SonexTalk, Msg #22659

Hello again JabiruEngines List:

cc: Sonextalk and Sonexplans Groups.

Sonex Aircraft agrees that this debate/exchange of fact is good for the Jabiru Engine's continued development and refinement. As with all written communication, it is near impossible to express emotion and inflection. Rest assured we intend for these postings to be read in a positive state of mind and with the utmost respect.

Sonex Aircraft again reiterates that we are HUGE supporters of the Jabiru Engine and continue to fly behind the engines with great confidence. We feel the Jabiru Engine (particularly the 3300 Jabiru) enjoys a niche in aviation unmatched by alternatives. Combined with the efficiency of the Sonex Aircraft Designs, you have the best performance-per-dollar available in the market today.

To our knowledge, none of the existing Jabiru Dealer Network (or the Jabiru Factory in Australia) has tried an AeroCarb. Sonex Aircraft, on the other hand, has given multiple tries to the Bing both ourselves and through our customers providing feedback on their own Bing installations. The vast majority of our customers have reported switching to the AeroCarb and have solved their particular problems.

As an additional comment, we have never and will never push our products on anyone. Nor would we ever want to. If you are flying successfully and happily with the Bing Carburetor- Excellent. That is what we are all for in this community. We are simply making these products available to the homebuilder that wants simpler, cleaner, and more efficient options for their Jabiru.

We wanted to provide brief rebuttals to both Pete Krojte's and Andy Sylvester's replies on the AeroCarb vs. Bing Carb Subject. We have the portions of their replies we would like to comment on.

Jeremy (Sonex Aircraft) has provided a very good sales commercial for the Aero Carb and it may well offer an advantage on installations where there is not enough room to properly install the Bing carb.

In our experience, the AeroCarb offers an advantage on all installations, not just those with limited space....We're also not sure what makes a "very good sales commercial" but we would think it would be a collection of facts about a product that offers distinct advantages over an existing product, as is the case in the AeroCarb vs. the Bing.

If properly installed with the engine using a prop that loads the engine per Jabiru suggestions there are few problems with the Bing. Let's face it - if the Bing was a problem for a flight training operation resulting in down time or decreased performance we would have heard about it long before the AeroCarb came along.

The AeroCarb is superior because it provides the proper air/fuel mixture for all loading conditions experienced in the respective flight conditions, regardless of what propeller is used. This is also independent of rpm operating range. Because of its fixed needle and "automatic" mixture control, the Bing does not accomplish this. Changing a propeller to achieve proper "engine loading" should never be necessary for successful carburetion of any Aircraft FWF Installation. Note that we've flown over 20 different propellers with the 3300 Jabiru/Sonex/AeroCarb combination and have not noticed more than a few percentage point swing in performance, which is exactly what the propeller engineers predicted. The cockpit mixture control gives the AeroCarb and Jabiru Engine much greater versatility.

In our experience (again over 2000 hours) and in inquiring of Jabiru Australia about the topic we feel carburetion has little to do with CHT's. The only explanation for differences in CHT's due to carbs might be the difference in placement of the carb and its effect on airflow exiting the ducts in a cramped cowl.

In our experience a properly tuned fuel/air mixture supplied to the engine has a significant impact on CHT's (and EGT's and oil temps). We have conclusively proven this by flying two identical set-ups with the only variable being the carb.

On the subject of the Metal Cooling Baffles, when one of the individuals Andy referred to was asked multiple times by us for any kind of additional information i.e. pictures of his installation and any specific temperatures or performance numbers, we never received anything. This makes it impossible for us to help. Proper installation from our experience is the key here. We provide the most comprehensive FWF installation manuals in the industry for all of our engine offerings.

On that subject we respectfully ask/beg/plead that any users of our products please contact us directly for assistance. We are here to help and as yet have never failed at solving particular issues...when they are brought to our attention and our recommendations for a fix are followed.

It may be true that the Aerocarb is simpler to install but that is offset by more complicated operation.

This one has us confused. How exactly is the Aerocarb more complicated to operate?

On this point over the years we have agreed to disagree and I'm sure will continue to disagree.

We could not agree with this more. We would reiterate that we would be very interested in more specific performance data from a wide range of Jabiru Engine Installations in increasing the database of knowledge for the community. We are extremely confident that all of our claims (based on our own flight experience) will show the superiority of the AeroCarb in every measurable criteria.

On to some answers to other questions posted to the JabiruEngines Group:
Q1: What is the configuration for a non-gravity feed fuel system like mine?

A1: You have a number of options. These are detailed on the bottom of the AeroCarb Specifications web page:
Q2: Do you retain the mechanical pump standard on the Jabiru?

A2: Most of those using a fuel pump/pressure regulator set-up have used the standard mechanical fuel pump.
Q3: Do you retain the electric pump?

A3: Many pilots who must run with fuel pumps choose to add a redundant electric pump. As long as you have a pressure regulator installed before the inlet of the AeroCarb, this will work fine.
Q4: Given the relatively higher (and erratic) fuel pressures provided by fuel pump(s) compared to a gravity system, would a fuel pressure regulator be required as well?

A4: Yes, this is also detailed on the fuel diagram through this web link:
Q5: If so, can you tell me which fuel pressures regulators others are using or which vendors/models you might direct me to?

A5: AeroCarb users have installed and flown a wide range of "low pressure" regulators. The AeroCarb runs best on 1 to 2 psi of constant fuel pressure. We have not run a pressure regulator at the factory as all of our installations to date have been gravity feed. If we ever have a choice, we would prefer to eliminate fuel pumps and pressure regulators entirely. If we can't eliminate them entirely, our next choice would be to use a header tank system.
Q6: It has been said that leaning the mixture in the AeroCarb is accomplished by restricting the fuel flow into the carb and that if the throttle is advanced before richening the mixture that carb will lean out and the engine may quit. Is this true?

A6: As in all aircraft that have ever used a cockpit mixture control, if you descend without readjusting the mixture, you will lean out your mixture and all your temps will go up. If you continue to ignore your temp warnings and run lean, then your engine could quit. Operate the carb properly and monitor your temperatures carefully as a pilot and you won't have any trouble.
Q7: Is leaning accomplished by restricting the flow into the main jet? What is the method of changing the mixture..I would assume that moving the metering rod relative to the needle would work. What is the actual case?

A7: Yes. The mixture control is an independent circuit in the AeroCarb. The mixture is adjusted in the air to restrict the amount of fuel flowing through the carb. It is operated as you would any other mixture control.
Q9: Also since the AeroCarb is gravity fed what is the effect of fuel head or pressure?

A9: Surprisingly little. Fuel pressure will obviously decrease as fuel burns off, but very little fuel-to-air mixture change is observed in any of our installations between full fuel (16 gallons) and low fuel (1 gallon). We suggest accomplishing a test by putting your aircraft in a "climb-out" flight attitude (we put the sonex tail in a ditch and tied it down and ran it) with your lowest fuel level to determine if you have sufficient head pressure in all conditions to run the engine.
Q10: Is it your policy that if I purchase a Jabire Engine from my local dealer, that I cannot get the metal cooling baffles from Sonex Aircraft?

A10: All Sonex, Waiex, and Xenos customers worldwide should purchase their Jabiru Engines through Sonex Aircraft. If you do purchase from your local Jabiru dealer, you can still purchase the metal cooling baffles and other FWF accessories, for $250. If purchased through Sonex Aircraft, our customers pay the same price and then have the option of receiving support directly from Sonex Aircraft or Jabiru USA.

As always, please feel free to contact Betty, John, Kerry, Mark, Heather, Jason or myself at the numbers or e-mail below with questions or comments.


-- Jeremy Monnett

General Manager
Sonex Aircraft, LLC
Tel (Info/Orders): 920.231.8297
Tel (Tech Line): 920.230.8324
Fax: 920.426.8333

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Updated: 11 Jun 06