Stromberg carb procedures in 2020, With video link.

Builders,

These procedures come from extensive testing last year. If you want to know what my recommendations are based on, look at the testing in the two stories below. They are well worth reviewing, even if you are not a potential Stromberg user, because the stories show the extent of the practical evaluation I do to make Corvair powered aviation safer. Note that I have never sold Stromberg, nor ever made a dime off them, they are just a common carb that my builders have used, and as such, I take it as my responsibility to assist builders in doing so at lower risk. You would think every commercial person in Experimental aviation feels that way, but they don’t. I don’t need praise not a medal for doing this, its just the stuff that everyone should do.

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Stromberg Shootout, Pt #2 (2019)

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Shootout at the Stromberg corral (2019)

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There are two outfits in the US which are well known to work on these carbs. One of them touts being the best in the world, and claims understanding no one else has.  I spoke with them directly on the phone where they claimed to have built carbs to the Continental C-85-14F standard and they ran perfectly on a number of Corvairs. But, when pressed, they could not name a single customer, nor provide a picture, and admitted to no direct testing. As a pure test, Dan Sheradin and I set a carb up to the exact C-85-14F standard, and it hardly ran at all. Keep this in mind when people inevitably push back against my recommendations here: They will not be able to produce a single photo like the one below, of actual testing. Your money, your plane, your life, your choice of who to listen to.

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Here is a link to a you tube video where I explain how and why procedures have changed: 

https://youtu.be/L8Ahm52n5G8

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Above, Dan works on setting the float height, which is one of several mixture adjustments

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Categories of Stromberg users:

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A) You have a Stromberg on your Corvair powered plane, it has flown more than 50 hours, and you are happy with it;

Suggested action = Keep going, operate your engine in accordance with the New – M.O.P. Manual,  we have a long history of good service from Strombergs under these settings, and unless you alter the carb from its currently working settings and parts, logic suggests that it will continue to provide good service.

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B) You have a Stromberg, it is assembled to running condition or it has been overhauled, it may have flown, but it has not logged 50 hours of trouble free operation yet. 

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Suggested action = I highly encourage you to contact me 904-806-8143 and discuss sending it in to me, where I can test it on a running corvair at high power settings with excellent air-fuel meters and verify its operation. If there is something wrong with it, many of these adjustments can quickly be made.  There is a modest service fee for this, but it is small in comparison to the potential cost of operating an unverified carb.

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C) You are thinking about running a Stromberg, but you have not acquired one yet. 

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Suggested action = I’m steering builders away from these carbs unless you come across an fantastic deal on a carb you have previously seen work. When we started, lots of these carbs were around, unmolested, for. $200. Fifteen years ago overhauls were $400 and done with good US made parts, and primers were $25 used and $69 new.  Today the carbs are $350 needing a $600 rebuild, which can be done with parts of questionable origin and accuracy. The primers are $250. The “Experts” are changing $1,250 to overhaul a carb to a setting I know will not work on a Corvair. Under these circumstances, it makes a lot more sense for builders to use a new Rotec 34MM TBI for $850. it needs no primer. I am a dealer for these, and I run every single one before it goes out in the mail to a builder. Its just a much better value.

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For more info on carbs, look at this: Corvair Carb Reference page for 2020.

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To understand that carb testing has always been an integral part of my work, look at these links: 

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Stromberg Carbs (2012)

 

Carburetor Reference page (2013)

 

Ongoing Carburetor testing. (2018)

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Testing and Data Collection reference page

Builders;

I am collecting stories on testing we have done here. Virtually every month for the last 24 years has brought some type of testing or data collection on the Corvair flight engine. Some tests are fairly simple, such as building a new manifold and testing the output of a simple 1 barrel automotive carb, others like building and dyno testing EFI systems were more complex. This goes on continuously. Many of the tests go undocumented, or show themselves to be fruitless or economically unusable. Many test only provide a puzzle piece that is useful on another project years later.

Most alternative engine outfits are only interested in selling stuff, and more often than not, they did almost no testing before going to market. Many companies start selling engine before the first example has flown 100 hours, and I can think of a number of now defunct companies that sold engines long before even a single example had left the ground. The common element with all of them was viewing testing as just some useless overhead that cuts into quick profit margins. We are just the opposite. Remember that teaching builders about their engine is our primary goal. A a learning focused company, reasearch, testing and evaluation has provided the very material our program is made of.

Below are links to several stories that give a glimpse of the practical testing that has always been integrated into my work with the Corvair. Just stop and think about how many time you have read in a magazine article or sales brochure that the horse power output was from “Dynamometer tests”, yet, how many times have you ever seen a picture of any of these engines actually on a dyno? Personally I have seen at least 200 claims of HP output alleged to be measured on a dyno, yet I have only seen pictures of 4 different engines on an actual dyno run. In an era were virtual everyone has a cell phone, and every one of them is a camera, why do you think that 196 companies didn’t end up with a photo of their engine? Just maybe, the only “dyno” run they did was an imaginary one for the brochure.

I have said it before, If your goal is to Buy something, any salesman will do. If you goal is to learn, build and fly, to be the master of what you are doing, they you need someone you can learn from. I am willing to share what we have learned in many years of reasearch and testing with anyone who came to experimental aviation to learn and build.

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Above, the EFI 2,700cc Corvair in 2007, at power on my dyno. The urethane wheel directly reads foot pounds of torque off the digital scale.

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Click on any title below to read the full story of that test.

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Dynamometer testing the Corvair and O-200

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Dyno testing Corvairs, 2008

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Turbocharging Corvair flight engines, Pt #1

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Turbocharging Corvair Flight engines Pt. #2

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Torque, HP and Thrust tests

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Thrust testing 85 and 100 hp engines

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Testing Turbo Corvair and Rotax 912S.

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Panther Engine propeller test

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Ignition system, experimental “E/E-T”

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In Search Of … The Economical Carburetor

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Shootout at the Stromberg corral

Builders,

Most Experimental Aviation companies don’t do any more testing than they have to, its pure overhead, and lots of the stuff you see is rigged or slanted to persuade not to actually discover anything.  However, I look at my work in aviation predominantly as a learning and teaching exercise, to share with builders what they need to know to be the master of their creation, not just its owner.

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The next major testing will take place this coming weekend. With the help of other Corvair builders Like Paul Salter, Terry Hand, Jeff Moore and Dan and Tracy Sheridan, I have gathered a 1/2 dozen Stromberg NAS-3 carbs in a number of slightly different configurations to test in a wide range of power setting on a 3,000cc Corvair on my run stand I ‘m shooting to do them all the same day to minimize atmospheric variables. As always, I will just present the data and some thoughts on it, and suggestions to builders.

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Above, five of the six carbs on my workbench. There are small subtile variables between models and configuration. My Pietenpol always flew a Stromberg, and our second test mule the Skycoupe flew one, even when we turbocharged it. in 2004 Gus Warren and myself ran a series of comparative jetting flight tests on the Wagabond at the old hangar in Edgewater, and developed the configuration that is referenced in my conversion manual. We are just looking to expand that knowledge base a bit further.

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Would you like an example of how testing is better than “Hangar tales from local experts”? Try this: its always said that the mixture control on Strombergs isn’t effective, and you should just wire it shut. Here is what testing says: if the carb is assembled with worn parts, the mixture is less effective, but if properly overhauled, the mixture control can run the motor from so rich its smoking (9.5:1 air/fuel) to lean misfire/detonation (16:1) at any rpm above 1500.  It is true the mixture will not function as an idle cut off like a MA3’s will, but the Stromberg’s mixture can be much more effective than 95% of the people in your EAA chapter think.

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Above, my engine stand, with Stromberg #6 mounted. In the foreground is an integral part of the testing, it is a very sophisticated O2 sensor in the exhaust wired to a digital Air Fuel instrument that cost several hundred dollars. It logs the A/F ratio to a tenth of a point. Many pilots like to talk about using cheap one wire O2 sensors and $50 agues, and I have used these myself, and I wasn’t impressed with their accuracy nor reliability, and they have the ugly habit of defaulting to reading “Green” when they are in default.  Although this is also an O2 sensor, this one has a heating circut, run by the instrument. Look at the bonding jumpers which are installed to make sure there are no errors from grounding variations. This is critical, but ofter ignored.

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In the big picture, if your carb is set right, you can fly the plane without an O2 sensor or even an EGT.  If you think about it, Cessna 150s don’t even have a CHT gauge. They just have a specific engine configuration, including the carb and the cowl, and the plane is operated within parameters known to work. Our testing here is to expand the known configurations of Stromberg to support the same concept for Corvairs. Results to follow.

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For more info on carbs, look at this: Corvair Carb Reference page for 2020.

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Stromberg Shootout, Pt #2

Builders,

Dan and Tracy Sheradin arrived at 9pm Friday, after a long drive from NC. They were here to have some fun, and put a great effort into the Stromberg Shootout. Below are a few pictures of a long Saturday of testing which ran from 7:30am until midnight, with only a few short breaks.

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Tracy does a ‘Vanna White’ style presentation of our test carb line up. We ran them all today. That is a lot of carb, airbox, fuel line and throttle linkage changes on a hot motor in a single day.  We also paused to do compression tests and adjustments on my 3,000cc Corvair to insure we were running controlled tests.

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Above the engine running in front of my house with the first carb. The timing light is giving the RPM. Large round gauge is manifold pressure.

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Above, we ran two different kinds of plugs in the engine and tested fine valve adjustments to precision tune the engine. In the photo we are using a dynamic compression tester to measure trapping pressure in the cylinder, and comparing this with adjusting intake rockers.  It wasn’t the focus of the testing but it fit in with the series of tests.

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Above, this is what is inside a Stromberg. Hangar ‘experts’ claim these are “just a one barrel carb” but in reality they are a very well made, fully adjustable, robust carb. We disassembled three of the carbs to make internal adjustments.

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Above, Dan works on setting the float height, which is one of several mixture adjustments. the higher the fuel level in the bowl, it runs richer, This combined with main jets and air bleeds sets the air fuel mixture. A unique feature of the design is being able to set the float height on the table with the top of the carb off.

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After a full fay of testing, we looked at the results and chose to follow this recommendation from Bob Kachergius, “the Stromberg specialist.” We reset Terry Hand’s carb to this, and it will be the first one we run on Sunday. (Sunday update, I suspect we copied a number wrong, as this didn’t want to run well from 1,000-2,200 rpm. More later)

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Above, Dan got a kick out of looking at my decades old carb books, dating from my days at Embry Riddle. In looking through the book he saw that a scored 100% on the exam on MA-SPA  series carbs, but later found that I only scored 70 on a snap quiz on Strombergs…..he thought it explained a lot of why the day was taking a long time.

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Above, the engine running cleanly today

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More, after further tests..

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For more info on carbs, look at this: Corvair Carb Reference page for 2020.

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Corvair Carb Reference page for 2020.

Builders, Here is our Carburetor Reference page for 2020. It is a collected index of stories and videos about Carb Options for Corvairs.

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It is my personal recommendation that new builders plan around using one of two carbs, either a brand new Rotec TBI or a new Marvel Shebler. MA3-SPA. You can read though the stories presented here to gain more insight, and understand what has historically been used, and how we get to the current recommendation. Here are the most current Stories:

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New video on Rotec carbs for Corvairs.

Information on why this is the new ‘standard’ recommended carb

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Stromberg carb procedures in 2020, With video link.

Outlines why these are no longer a primary recommendation .

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New MA3-SPA – Available from SPA/Panther

The source for new MA3-SPA carbs

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Here is a sampling of recent testing:

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Shootout at the Stromberg corral (2019)

This is how we identified issues

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Stromberg Shootout, Pt #2 (2019)

This was looking for solutions and retesting.

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MA3-SPA Test Runs. (2019)

Testing to verify the quality of overhauls.

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Safety Alert: Excessively Rich MA3-SPA Jetting. (2017)

Alert  about some rebuilt MA3-SPA carbs which were jetted richer than stock.

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Critical Understanding #10 – Carb Ice (2017)

An article which became part of the MOP manual

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Inexpensive carb testing (2017)

We still look for solutions which would keep flying affordable.

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Critical Understanding #4, ANY loss of RPM is Detonation. (2016)

Understanding that lean operation leads to detonation.

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The notes below cover the broad variety of Carbs that have flown on the Corvair, and some thoughts on why I choose simplicity when it is available, and the development of our intake manifolds.

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Above, an overhauled NAS-3. While a proven workhorse, I no longer encourage new builders to plan on this carb. 

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An intermission to remind that very little good comes from discussion groups:

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Internet speculation vs First hand experience….. . 

A drama filled example of people “Chiming in” on discussion groups, and how inane some of the comments are.

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Speculation vs Experience Pt #2, Actual issue identified.

How I understood the issue by having personally tested the builders engine at a west coast college…..It was a propeller adjustment.

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Below is a list of stories have written on Corvair carburetors. You can click on any color title to read the whole story:

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Air / Fuel ratios on Corvair carbs.  (2016)

A look at the range of air fuel mixtures we use, and how we test this.

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So you like the idea of auto gas…. (2018)

Corvair run on auto fuel, but you have to know stuff like this.

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New Ellison Carb supplier, NV Aero.com (2016)

Steve Glover bought the rights to and all the tooling for Ellison carbs.

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Ma3-SPA carb orientation, (2016)

A dumb story about how internet discussion groups miss the point.

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Carb Orientation Pt. 2: Internet Reading Comprehension Failures.  (2016)

A second example of why discussion groups are better for drama than tech info.

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Running your engine “Over-square”? (2015)

Info on why not to lug your engine and why 2700rpm is min. static rpm.

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How I became a genius in 6 minutes (2014)

Why you don’t use a British car carb on a plane

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Fuel Injection – Corvair flight engines reference page  (2013)

Because in any Carb discussion, someone will incorrectly assume I have never tried FI on a Corvair.

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Stromberg Carbs  (2013)

The world’s most prolific light plane carb, but this is an older story, read the update at the top.

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MA3-spa carb pictures, Wagabond notes.

The MA3 is the most popular carburetor on Corvairs today. Please read the more current story above.

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Carb applications, choices people make

A story of why builders professional background tend to choose carbs.

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Intakes and Internet myths

Notes on why the intake works so well.

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In Search Of … The Economical Carburetor

A story of testing a $160 carburetor.

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A question of Carb location…..

A warning about top mount carbs.

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Deal of the Day,simple MA3 carb. (Sold at 1 am, 9/1/13)

Good photos of a straight MA3.

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Below are the Group numbers of our intakes and the numbers we assigned to the popular Corvair carbs. You can see how this is part of our Group numbering system by studying the complete numbering system on the “Prices” section of our main page, FlyCorvair.com. These are all discussed in my Conversion Manual

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Intakes and carburetors  group (3600)

3601(S)- Standard Intake manifolds

3602(A)- Marvel MA3-SPA

3602(B)- Stromberg NAS-3

3602(C)- Ellison EFS-3A

3602(D)- Sonex AeroCarb  –  38mm

3602(E)- Zenith 268

3602(F)- Rotec TBI 34mm

3602(G)- 1 barrel Carter downdraft

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Commentary on Carbs:

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When it comes to carbs, I have always liked Strombergs and MA3s because they have literally millions of hours feeding air and fuel into flight engines. I know them and trust them, but in recent years we have had trouble with rebuilt ones having consistent quality for builders to use them directly out of the box. In years past it was not this way, but today it is. These carbs were always my first choice to put on a plane because they are aircraft carbs, they are not just playing the role. They are doing the job they were designed to. Today, my recommendation is that builders focus either on a new Rotec, or a new MA3.  These are not the cheapest path, but without question, they are the most reliable.

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My father,William E. Wynne Sr. 1925-2017 was a lifelong military engineer who spent a lot of time working in places where the people who don’t like your project are literally going to try to kill you. He upheld that the piece of machinery that has the greatest reliability requirement is the combat firearm. In these tools, reliability is an absolute requirement. All other considerations about them – weight, accuracy, firepower, cost, etc. – all are meaningless if you ever need to use one and squeezing the trigger produces a soft noise rather than a loud one.

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Notice that the requirements of aircraft carbs are very much like combat firearms. When you push the throttle in, you really want to hear a loud noise, not a soft one. If your glide path leads to a place 200 feet short of the runway threshold, and pushing the throttle in gives the undesired soft noise, you will not be comforted by thoughts of how cheap, how light, how available, easy to tune or install it was, or any other factor that made it attractive in the hangar. Reliability alone gets you back to the airport.

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Consider this: The MA3 was designed about the same time that the Soviet Red Army adopted a device called the AK-47. Sixty plus years later, both of these devices have been used in countless numbers all over the  globe. Both are often criticized as outdated, inefficient, inaccurate and stone age. Notice that their continued use in the face of all criticism is justified by the same three word sentence, “It is reliable.” People who have held either one in their hands, stared at its metal parts and though about how they would need to count on it, will have some appreciation for that three word sentence. If I can teach you only one thing about experimental aircraft, let it be this: There is no characteristic more important than reliability. Anything you could get in trade for reliability isn’t worth it.

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Thoughts on ‘Alternative’ Carbs:

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It is my strongest recommendation not to use any type of motorcycle carb. This includes a Revflow, a Keihin, an S&S, an Altimizer, a Mikuni, a Harley-Zenith, and especially not a Bing. If I were required to list all the ways that a motorcycle or other non-aviation design carb could fail, I would have a long list. For example, the Bing throttle isn’t connected to the cable, and many CV motorcycle carbs have this “feature.” The two biggest failures  that I can name is  throttle systems that are operated by bicycle cables and the fact that most  motorcycle carbs don’t have any way in which you can attach a serious fuel line.  A piece of fish tank tubing and a hose clamp is not serious, and if it works on a Rotax 503 in a cowl-less pusher application, that doesn’t mean it will live in a sealed engine compartment in a traditional aircraft. Throw in that they have no mixture control, and often don’t fit where aircraft carbs do, and you get to a better understanding why there isn’t anyone saying how well the combination worked on the first 100 hours on his Corvair powered plane. My least favorite carb in this genre is the Bing. It has a tendency to lean out on long manifolds, and it will actually shut off if subjected to ram air. In 2012, we had a builder who insisted on using one and did $3,000 in detonation damage to his engine on the first flight. The same plane would have flown perfectly fine on a $500 Stromberg. I am sure the bystanders to this event were far more willing to see the issue as a Corvair problem than to understand that it was caused by a poor German motorcycle carb mis-applied to a proven engine. Carbs salvaged off snowmobiles, outboards, imported cars and lawn equipment are never going to have a good record on planes, and their advocacy is limited to people who wish to impress others with cleverness, but never actually impress people by going flying. Again, I don’t find it my responsibility to define all the ways that will not work for people who don’t wish to go with something proven. I spend my time trying to illustrate positive examples of how to do things that will work economically, but above all else, reliably.

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Thoughts on part #3601- Intake Manifolds:

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The Intake manifolds that we make for Corvairs evolved slowly over time and testing. Originally we made individual manifolds out of welded sections of mild steel tubing. We tested both 1.375” and 1.5” tubing, both on the ground and in the air. After a lot of evaluation, we went with the larger size from 2001 on.  In 2003, we started having the main tube of the manifolds bent by a CNC tubing bender as a single piece. This eliminated a lot of welded joints and gives the manifolds a much cleaner appearance. We looked at several different materials and selected thin wall 304 series stainless steel tubing. The primary reasons for this choice are that it is essentially immune to stress cracks when TIG welded and purged correctly, it remains clean on the inside and will not rust even if the aircraft sits for a long time in humid weather, and it is as light as an aluminum manifold because the aluminum would have to be made much thicker to have the same strength and crack resistance. After 15 years of continuous production, our manifolds still have a perfect track record.

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When first looking at the layout of the manifold, many people think that it will not have sharp throttle response, or the length of the runners will hurt the power output. A builder with a background in motorcycle racing confessed that he first thought of a steamship’s engine telegraph where the bridge swings a big lever on a pedestal that rings a bell in the engine room and makes a hand on a clock face point to the words “Full Ahead.” After he built his Corvair engine, he was surprised to find out that the throttle response on it was just as fast as a typical car. On aircraft, the limiting factor on how fast it can change rpm is the moment of inertia of the propeller assembly. On Corvairs, this is inherently low and the engine accelerates noticeably faster than other aircraft engines, even with a long intake tract.  Look at any modern car; designers are going to great trouble to make the intake runners much longer, not shorter. They are after more torque in the rpm range that direct drive engines fly at. A long intake tract doesn’t mean less power, and I am not sure where that myth started, but you can take a look at things as diverse as a tunnel ram with dual quads on a V-8 and see that even 7,500 rpm drag cars benefit from longer runners. But you need not be concerned with theory.

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I have years of dyno testing of most every type of intake length and carb configuration that conclusively shows that the length of the intake run has no effect on power output.  For years this was a favorite Internet debate topic among people who had never seen a Corvair turn a prop, but felt certain that the world needed to hear their impression of how it worked in their imagination. A number of these people also advocated putting the carb on top of the engine. I am going to flat out say that I have never found a single good reason to do so, and there are a number of very good safety reasons to have it on the bottom. I have seen people run every carb on top from Bings to Webers, and none of these installations worked nearly as well as even Bernard Pietenpol’s 1960s installations that featured tractor carbs mounted below the engine. I have seen more than one person plan on running an AeroCarb with a fuel pump mounted on top of a Corvair engine. Such a combination is virtually guaranteed to leak fuel onto the engine in operation. If a person is that interested in cremation, they should just find the professional service in the Yellow Pages and skip all the hassle of building a plane. I will not knowingly assist anyone who puts a carb on top of an engine or uses the leak prone stock Corvair mechanical fuel pump, and especially not in combination.

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There are always “experts” who claim that individual runners to each intake will make more power, that something is wrong with the offset intake pattern on the Corvairs intake log, or that the log should be removed. These are all myths that I long ago disproved with our dyno on back to back runs. In section 3700 look at the photo of Mark Petniunas’ EFI engine running on my dyno; it has individual runners and made no more power; the offset intake patter appears on many other aircraft engines such as Rangers and Allison 1710cid V-12s (good enough for P-38s P-40s and P-51Bs, probably good enough for homebuilts). The log part of the head is an important part of the mixture distribution, and it is structurally part of the head. If you mill it off you will weaken the head and blow the head gasket because the upper row of head bolts will no longer have a stiffener. Do not listen to anyone who suggests such modifications to the heads.

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We make several different manifolds for the Corvair. The most common is the 3601(S) which is the standard manifold for anyone mounting a Stromberg, MA3 or any other float type carb on their engine. This fits all the Zeniths, KRs, Tailwinds, etc. The second design is a 3601(E) which is the same manifold with the carb flange rotated 13 degrees forward. This is specifically made to serve Zenith builders who are putting a flat slide carb like an Ellison, Rotec or an AeroCarb on a tricycle landing geared airframe. The rotated carb flange provides clearance to the nose gear.  The 3601(C) manifold is specifically made to fit a Corvair into a Sonex or Waiex airframe using the Wesesman’s installation components. They have ones specifically for Panthers also. If you need further guidance, look at out parts catalog or give me a call or send a note.

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Corvair College #44, The “Operations College” at The Zenith Homecoming

Builders;

We are rapidly approaching Corvair College #44, which will be held at the Zenith Aircraft Factory In Mexico MO, September 20-21st. This will not be a ‘usual’ College. This will be an “Operations College.” 

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Instead of building and testing engines, I am going to very intensely focus on the operations of the engine in the airframe. Sebastien Heintz, president of Zenith has long upheld his homecoming / open house events as much more of a learning opportunity than sales events. As such he has organized forums and training sessions of many kinds, and our educational work with Corvairs has fit right into this. This year, by covering Operations, we can focus on installations, props, testing, evaluation and decision making. These are subjects I want our builders to know well, just as they know the insides of their engines. It is also information that should appeal to many builders.

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I am currently working on a 50 page Operations Handbook, a functional, bring in the plane guide to all aspects of Corvair Operations. I have reviewed and refined these ideas over time with Dan Weseman,  they are the procedures that have long proven to work for Corvair builders and pilots. This will be available at the College, but I will also have it available afterwards, as I want all people using our conversions to have this information in a neatly packaged form where they will have it with them as they need it, sort of a Pilot’s Operating Handbook for the Corvair engine.

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We will be going over many things, working with a live running Corvair engine. I want people to fully understand setting the timing, setting prop pitch, how to lean the engine, and proper instrumentation installation. In addition to this, we will have instruction by discussion of the Handbook. I will be spending the majority of the time at the Homecoming covering these topics in a small group setting where individuals can have each of their questions answered in detail until they fully understand the topic. There are many things in life I’m not good at or don’t understand,  dancing, tofu, fashion, computers, flower arranging, Volvos, international finance, modern art, most cats, ‘reality’ tv, why some people prefer Unicorns vs Ponies., But, I am a very good instructor on the topics we will be covering. If you are available, make plans to attend the Homecoming.

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Above, a Video link about the event which we shot last month at Oshkosh:

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The Zenith open house is open to all experimental builders, not just people currently working on a Zenith ( The Heintz’s are here for the long run, they figure you will eventually be a Zenith builder. ) It draws several hundred serious builders every year, and it also is a major gathering point for component suppliers and industry people. Both of the last 2 EAA presidents have been guest speakers at the event. It is a very pro-homebuilding event in an excellent setting. Surprising things happen there like this: EAA Major Achievement Award.

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Previous Corvair Colleges at Zenith were held just before the Open House, but in the case we are going to ‘imbed’ College #44 in the Open House so the maximum number of aircraft builders can get a good chance to study the information we are sharing.

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Would you like a visual on how long we have been working with Zenith Aircraft and holding events at their location? This is a picture from a 2005 Corvair event at the factory…..notice neither Sebastien nor myself had any gray hair then. We have a long history of productive and cooperative relations with Zenith. Read: 14 Years of Corvair Powered Zeniths.

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How do I find out more information about the Open House? 

You can look at their webpage http://www.zenithair.net and read all about it, including dates, location, maps, accommodations and the schedule for the event.

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Is there an on line sign up for this College?

No, Just show up. If you want to discuss the event in advance or have a question, call or text my personal cell, 904-806-8143.

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Is there a fee for this College? 

No. The Homecoming is free, Zenith only charges a modest fee for the banquet held on the first evening

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I wanted to know if you guys can get a look at my core engine while you are at the College?

Yes, I will be glad to, (We generally refer to these as ‘parking lot tours’ )  I will also be glad to transport parts like cases cranks and heads back to Florida.  Even if you are just planning on having these worked on a few months later, sending them back with us gets them in the system and gets the ball rolling.

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Will you be test running  motors?

I will have one motor with me as an operations demonstrator, If you have a motor which needs a break in run, we need to talk about it and plan in advance. Call me soon.

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Will there be flying Corvair Powered planes there?

Yes, we have ad 3-5 every year for the last 10 years.

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Is there on site Camping? are their Motels? 

Yes, the Mexico MO airport has good camping, but no hook ups. The town is a few miles from the airport, and it has a number of hotels and motels. Do not wait too long to plan, they fill up with several hundred people coming to town.

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Do you have links to previous colleges there?

Get a look at this story: Photos from Corvair College #34 at Zenith A/C

and: Corvair College #30 Running Engines,

and: Corvair College #30 Good Times

and for more general information:

Corvair College Links:

Corvair College reference page

Corvair College History….in photos

College engine build options for closing the case

Basic Corvair College Skills, examples of learning

College Tech

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WW.

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Myths and Misconceptions in the world of Pietenpols

Builders,

Because there is no “Factory” associated with the 90 year old Pietenpol design, the transfer of experience and ideas to new builders flows through many places, predominately social media. A really large chunk of this info is harmless, but some of it is not. Myths and misconceptions are shared and spread by often well meaning people who mean no harm, but they cause it anyway. The harm ranges from the lost opportunity for the recipient to actually learn something, to sending people on a time and money wasteful detour that leads to many people quitting, straight on through encouraging people to fly with passengers in aircraft that are unairworthy, by a standard Bernard Pietenpol himself stated.

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The number #1 way you can tell you are looking at “an opinion” , not a piece of data: It is delivered without a reference, and particularly without testing nor personal observation. If someone chimes in to say “Lean the cabanes back, it will be alright This is a near worthless opinion. If someone says “I have the same engine on my flying plane, N 177XW, my wing LE is 4.25″ aft of the firewall, my EWCG is 10.3″ and my EW is 737 pounds, it is in CG with a 194 pound pilot” , this is a useful piece of data to work with. The Weight and Balance data provided by Ryan Mueller and myself is that kind of data, for 20 different planes. Yet, some people will proceed down the building and flying path, armed only with opinions and no data.

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Some questionable ‘advice’ comes from people with flying planes. Its not bad data, but it is often not applicable to a different engine, or different size pilot. Much of the time, it is delivered as “This worked great for me” which is fine, but it doesn’t address the question, ‘Is this the best way it could be done on the new plane being built? This is most commonly done with CG comments. A person reporting that the plane flies ‘good’ at the aft CG limit, almost never has personally flown one near the front limit, far less flown the same plane, the same week, on each end of the limit. Enter the photo below:

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My Pietenpol, 1996, Edgewater Florida. The reason why the cowl has a 6″ wide expansion in it is simple. I carefully measured, and in a single day, made a mount 6″ longer and plugged the cowl for test flying. In the picture is Gus Warren who did a lot of the work with me and covered much of the flying. It was an instant improvement in safe flying behavior. I can comment on the difference between the same plane flying at 15″ and at 20″. This is what testing looks like, and this produces data, not opinion. Read more here: Evolution of a Pietenpol and here: Evolution of a Pietenpol pt. 2

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Common Pietenpol Construction Myths:

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“Having threaded sections on the diagonal cabanes will allow the plane to have the CG corrected later.” This is a myth. Study the weight and balance articles, and understand that many builders missed their target by several inches on the wing position. The articles show that moving the CG just 1″ requires moving the wing 1.3″. Builders need to just study examples of planes close to theirs, make a calculated fine tuning adjustment in the wing position, and make the diagonal cabanes rigidly attached to the front vertical cabanes.

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“I did a W&B measurement on my plane and it is 1.5″ from the aft limit, it will be fine when it is covered.” This is a myth. If you look at just the covering on the wing with its 60″ chord, the weight of the fabric on it will logically be near 30″, and this is 10″ behind the aft limit. Now think about the fuselage, which has almost no covering ahead of the front cockpit, but a lot of it 6′ aft of the wing, and then there is all the tail surfaces, all the way back. The covering on a Piet can easily weigh 35-40 pounds, and nearly every bit of it is going to drag the CG backward. The effect is strong, and not easily countered. A W&B check when uncovered is not a substitute for a plan right from the beginning.

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“Having an axle location near the wing leading edge will make the plane hard to fly” This is a myth. Look at the 35,000 American certified light planes which had tailwheels made in the 1940’s and they all have the axle close to the wing leading edge when they are in the flight level attitude. No one speaks of these aircraft as hard to fly.

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“Having the axle a few inches further back can’t make much of a difference in the plane’s potential  to end up on its back” This is a myth. Ask any person who knows what a Cessna 120/140 axle extender is. Before them, if the Goodyear brake jammed a disc (an issue on floating discs) many planes ended up on their backs. This modification moved the axle a few inches forward, and very effectively prevented the airplane from going over, even with a locked brake on pavement.  A few inches difference on axle placement makes a big difference. One of the few light planes of the 1940s to have the axle a few inches back from the leading edge is a Luscombe, and these are the most common light plane to go over.

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“My buddy Mongo has brakes on his A65 powered Pietenpol, the axle is 10″ back from the leading edge and he says it never feels like his plane is going to nose over.” This is a misconception. The reason why this isn’t good data because it fails to mention that Mongo weighs 265 pounds, and he is flying with the CG several inches behind the aft limit. On any plane operating within BHP’s specified CG limits of 15-20″ having brakes on an axle located 10 inches behind the leading edge in an open invitation with a filled out RSVP to put the plane on it’s back.

 

A few words on wood:

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in 2010, I took this picture of the awning outside BHP’s shop in Cherry Grove. The frame had been there 8 years earlier, on my first visit, and I suspect it was BHP’s personal work. You have to appreciate the values of a man who ended up with an apparently straight aluminum Piper spar and thought that its best use was an awning frame. If you look closely at the photo above, you can see the diagonal bolt holes where the lift strut used to be attached.

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OK, BHP liked wood so much he thought aluminum wing spars were good for awning frames. So why didn’t any of his planes have wood lift struts or wood cabanes? This is a question you should really ask yourself before using wood on your plane.

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I have all the volumes of Juptner’s “US Civil Aircraft” , it catalogs in detail, the first 800 aircraft certificated in the US. Volume one starts in 1927, when BHP’s was testing his first ideas. I have scanned it quite closely, and I don’t see any aircraft with wooden struts. I suspect that once metal airfoil shaped tubing became available, no one thought of using wood anymore.

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People always point out that WWI biplanes had wooden struts, but they almost never have considered that the interplane struts on a biplane are always in compression, and they are almost never longer than 4-1/2′. There are also dozens of biplanes in “US Civil Aircraft” , and none of them use wood struts.

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Wood has obviously worked before on Pietenpols. The issue I have with it is how people choosing wood struts gloss over that these are not in the plans, and they often downplay variations in the wood and the difficulty of drilling precision holes in wood to match the fasteners. I understand why people like the look, but you honestly have to ask yourself is appearance a valid reason the deviate from the plans, the most common material, and to do so with little or no engineering.  Think it over.

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William.

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Evolution of a Pietenpol

Builders,

In the previous story, The small world of Experimental Aviation , I mentioned how much N-1777W changed over the years. He is a look at some of it:

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This is the plane at Oshkosh 1970. The picture made it to the back cover of Sport Aviation in January 1971. Notice it once had 140HP heads, and other well meaning, but weak ideas. If you have the Tony Bingelis book “Firewall Forward” the Pietenpol/Corvair pictures in it are all of this plane, in this era. Bingelis didn’t like auto engines, and his writing spread a lot of old wives tales. He was a good guy and a highly influential writer, but he held opinions that testing by his contemporaries like Wittman and Monnett showed to be wrong.

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Fast forward to 1995. Want to know how I became the expert on Pietenpol weight and balance? Want to know why I think it is annoying when people who can’t do a simple calculation, or have never weighed a plane on electronic scales question my work on Piet W&B?  Start with this photo: The reason why the cowl has a 6″ wide expansion in it is simple. After getting the plane, I found out the weight and balance, done on bathroom scales was dangerously wrong. I carefully measured, and in a single day, made a mount 6″ longer and plugged the cowl for test flying. In the picture is Gus Warren who did a lot of the work with me and covered much of the flying. It was an instant improvement in safe flying behavior. I have written extensively about this testing and work, you can find the links here: Corvair – Pietenpol Reference page, but today, the majority of Pietenpol builders willfully ignore the information. Much of this is driven by people in the Pietenpol community who personally dislike me for my tone or experience.

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Above, same plane 1999. This is an entirely different motor mount, the first high thrust line (#4201-C Pietenpol Motor mounts, now on the shelf, ready for shipping.)  and a completely different set of gear legs.(New die spring landing gear on a Pietenpol, 10 a.m.-4 p.m.)  Bring up the topic of axle location, gear leg length, CG changes or thrust lines, and people will tell you they think it makes no difference. Of course their opinion is not based on any testing, just a guess, something they heard from a guy. When I speak of these things on a Pietenpol, it was because for a number of years, ready to cut up a good flying plane, or a mount that I had made a month before, in search of something better. Some opinions are made of guesses, mine are made of testing.

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If you look in the upper corner of the picture, there is a blond girl sitting in the grass. She was getting away from her job as a newspaper editor. She liked planes a lot, and had a very pleasant way about her. Her name turned out to be Grace.

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Above, side view of the same plane, taken just before Corvair College #1. Notice how much longer the gear is than when the fuselage was orange. Also note where the axle is located. In the last few years, we have had two Corvair powered Pietenpols heavily damaged by being put on their back, even though I warned people to move the axle forward if using brakes. It is frustrating to not be able to motivate people to correct things like this before an accident. When you see what I was willing to rework on my own aircraft to make it better, it is obvious that I don’t operate things in a condition that simple work and modest money will fix. If you are too tired to improve things, pick a different hobby, this one has potentially harsh penalties for the lazy.

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-ww.

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Info page, Corvair College #43, Barnwell SC.

Builders,

This is the general information page for Corvair College #43. It is being posted on 6/12/18. The on line sign up link is attached below. 

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Background:

Corvair College #43 will be held at Barnwell SC, 9-11 November 2018:  This is our flagship College.

For a look at the 2015 Barnwell College, check this out: Corvair College #35 Barnwell builders video.

For a look at the EAA film about the 2013 Barnwell College, click here: New EAA video on Corvair College#27, Barnwell 2013.

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Barnwell has been the home of nine previous Corvair Colleges. P.F. Beck and crew have the logistics down so well that we have no difficulty having a productive event for 90 builders. If you are planning on going, do not delay in signing up, it is an excellent setting and they are very gracious hosts.  The Technical expertise at the College will be provided by myself and Dan Weseman from SPA/Panther.

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Ken Pavlou holds the Cherry Grove trophy at CC#31 Barnwell 2014. His aircraft is named “The Blue Speedo.” Read more: Ken “Adonis” Pavlou advises aviators: “Life is short, Live Large”

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Late tech questions. This is about 1 am on Sunday, nearing the end of a 19 hour day. If you want to pack a lot into a College, good, that is how we do it. However, the free form of the lesson plans allow each person to take in and digest at their own rate and pace. Read a 2013 story here: Who is William Wynne?

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A prankster Bill Reynolds testing the ragged limits of the No Politics  rule we have a Corvair Colleges. Read about Bill’s son Jack building his Corvair here: Video of rebuild and run of Corvair, from a 13 year old.

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Above, The Weseman/SPA Panther and a ’66 Corvair Corsa on the flight line at Barnwell #31 . Read this to understand how SPA distributing  our parts for the last 20 months has greatly improved customer service: Outlook 2016, New order page and distribution method.

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Above, Bob Lester’s Corvair powered Pietenpol sits on the ramp at Barnwell at sunset on Saturday night, CC #31. Read more here: Bob Lester’s Corvair/ Pietenpol nears 800 hours.

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Is there an on line sign up for this College?

Yes, this is it: https://eventregistration2017.wufoo.com/forms/cc43/

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Is there a fee for this College? 

Yes, Signing up on line for College #43 is required, and the fee is $99. 100% of this money goes to the local hosts and the Barnwell airport, they provide food an drinks while we are there for three days. The technical support we offer at the College is provided without cost to builders.

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 Will there be a chance to build an ‘Engine in a Box’ at this College?

We are looking for two builders who would like to buy, assemble and test run a 3.3L “engine in a box kit” For an overview of the 3.3 engine read this story: Build a 3.3L Corvair at the May 18-20 Workshop/Open house. If you are interested in one of these motors, Contact SPA/Panther at 904-626-7777.

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OK, my project needs progress, what do I do? 

First, sign up for the on line registration. Second, SPA by calling 904-626-7777, or call my number 904-806-8143. We will be glad to speak with you about making sure you are prepared for the event. Making plans early is the key to making progress at the event. At the last hour of a College, prepared builders often say some version of ‘I can’t believe how much I learned and accomplished.’ No one has ever followed that statement by saying ‘I regret being smarter and advancing my goals.’

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Keep in mind:

 We will also be glad to transport for parts like cases cranks and heads back to Florida.  Even if you are just planning on having these worked on a few months later, sending them back with us gets them in the system and gets the ball rolling.

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Will you be test running the motors?

Yes. We will have my test stand with us, and perhaps run as many as 10 of the engines being worked on.  The goal is positive exposure and progress, but above all else, learning.

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Will there be flying Corvair Powered planes there?

Yes, we have had 6-10 every year for the last 10 years.

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Is there on site Camping? are their Motels? 

Yes, the Barnwell airport has good camping, but no hook us. The town is a mile from the airport, and it has a number of hotels and motels. Do not wait too long to plan, they fill up.

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 For more general information and Corvair College Links:

Corvair College reference page

Corvair College History….in photos

College engine build options for closing the case

Basic Corvair College Skills, examples of learning

College Tech

Running an Engine at a College, required items. #2

Running an Engine at a College, required items. #1

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Wewjr.

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Yearly Condition Inspection on Corvair Engine

Builders:

Get a look at the logbook entry below; This isn’t a joke, it is for real, it was ‘signed’ by an alleged aircraft mechanic six weeks ago in the Chicago area. It was done as a condition of sale for a Corvair powered aircraft which was sold as “Airworthy” and “Inspected” for a new owner who trusted the seller and his mechanic. It is complete bull shit, this doesnt constitute an airworthiness inspection nor a valid log book entry. This is no small matter, log book entries are subject to federal laws.

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I earned my A&P license at Embry-Riddle Aeronautical University a generation ago. Our classes on documentation were taught by Professor Robert Routh, a retired NTSB administrative law judge. I am well versed in valid inspections and their documentation. Many homebuilders mistakenly believe that the FAA is somehow lenient on enforcement with homebuilts. I will grant they can appear arbitrary, but when they get focused on a case, they run it just as if it were an airliner. My FAA office is Orlando, and in our area, such an entry if discovered would be grounds for revocation of the mechanics license. That may not even be possible here, because I suspect the name and number are made up.

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As a homebuilder working on your own plane, you don’t have to be concerned about what the jackasses are doing. You are going to finish your own plane, get the repairman certificate for it, and then you are going to do all your own inspections. You will be independent of what others. The Corvair, sets you apart from other homebuilders, because for 28 years I have been teaching builders how to be skilled builder-operators, not just the person who bought something. Your willingness to learn, and our demonstrated commitment to builder education is the perfect alloy to free you from putting your life in the hands of clowns.

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Condition Inspection

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Yes, this is a real log book. Who cleans a $1.50 spark plug?  Why was the timing not set? Where is the oil change? Where is the test run? This is what you get when an uninformed person wants to make a quick buck and a seller wants to imply something is airworthy. Your life is too important to trust it to such people.

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What is this inspection?

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Experimental aircraft don’t get Annual inspections like Certified planes. Instead they get a Condition inspection, which, if an intelligent person with respect for human life is conducting it, is done to at leastthe same standard as an annual on a certified plane.  If you took a Cessna 150 and the average homebuilt and just kept flying them with no further inspections, the homebuilt would break first. No homebuilt has the production numbers nor the refining of a 150, far less having been certified, built by professionals and maintained by them. For this reason, homebuilts need better and more frequent inspections than certified aircraft, but of course they rarely get them. Set yourself apart from the lazy herd, be determined to never have anything in your plane break that you could have found with an inspection. An issue caught on an inspection is an in flight emergency or a tragic disaster prevented. 

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Who can do this inspection?

This inspection is required by the FAA for the plane to be airworthy.  To do the inspection the person conducting it must have been the builder of recordandhold a repairman certificate for that specific plane.  Alternatively, an A&P mechanic can also conduct the inspection.

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Below, I’m going to list all the steps that I consider a minimum to conduct an effective and valid Condition inspection on a Corvair Engine. These are gathered from my writing. There is nothing new here. As evidence read this:  Critical Understanding #12 – Yearly Condition Inspection 

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Now, two Comments:

A)   No one can conduct an inspection without documented standards they are checking the plane against, period. For example, an A&P can’t verify the timing on a Corvair if he doesn’t know what it is supposed to be. So no one would do that right? Guess again, I have seen more than 200 logbook entries for Condition inspections done by A&P mechanics that make no reference to ever checking the timing. These were all done for second owners of planes, people who bought a Corvair powered plane, and had no idea that the timing was ever to be checked. In the last 15 years, I have never had a single A&P ever call me and ask what he was to check on a Condition inspection on a Corvair. This means that almost all of the inspections were useless exercises that made people feel “Safe” when they were not.

B)    I have seen dozens of homebuilders who never followed up their airworthiness inspection with getting a repairman’s certificate for their plane. An inspection done by a builder without this is not valid, and if there is an accident in the plane, don’t expect the insurance company to pay nor the Feds to be nice either. Think this doesn’t happen? Guess again. I have personally looked at the books of a Lycoming powered homebuilt that had 9 consecutive non-valid inspections because the builder didn’t have a repairman’s certificate. But wait, it gets better: Because he was an airline pilot, he deceptively wrote “A+P” after his inspections to look like A&P. When I called him on this he explained that he was just writing the abbreviation for Airline Transport Pilot, ATP, and then he has the real BS line of saying “The ATP is really the superior rating to the A&P”. Before jumping to conclusion that no one ‘normal’ would do this, know that the guy is a retired flag rank officer and he flew more than 50 Young Eagles in a plane with fraudulent documentation.  If anyone thinks they could dance around that detail when you meet the Feds, they are delusional. Have an accident in that plane and the FAA, would charge the pilot with falsifying federal records, his insurance wouldn’t be valid, and he would he personally liable for civil action.  Flying a uninspected plane is something that people try to justify all the time. Just don’t be one of them.

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Below, I’m going to list 11 steps that I consider a minimum to conduct an effective and valid Condition inspection on a Corvair Engine. These are gathered from my writing. There is nothing new here.

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One)Get a copy of FAR-43 and read appendix D, it lists the minimum of items to be done to a power plant on an annual inspection. Your Corvair will need everyone of these done. The logbook entry when complete will specifically state that “This engine has been inspected in accordance with the scope and detail of appendix D”(https://www.gpo.gov/fdsys/pkg/CFR-2002-title14-vol1/pdf/CFR-2002-title14-vol1-part43-appD.pdf)

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Two)Conduct an up to date information search to make sure your engine is up to current standards. All valid inspections require the inspector to reference the source of his technical data. If someone wants to claim on their insurance form the have an engine to “WW standards”, they have to reference my most current manual, (2014) and the technical updates I publish like the critical understanding series.  This means that the plane will have Denso Plugs, it will not have Chinese rockers, it will have a 5th bearing, etc. You can’t pass an annual inspection on a Cessna ignoring all the AD’s published in the last 10 years, and no logical person is going to argue that a Corvair engine that reflects none of the advancements we have made in the last decade is really as safe as reasonably possible.  The Log book should specifically state the date of the manual being followed and that all Corvair Service Bulletins have been addressed.

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Three) Run up test. This is done to verify that the engine is running correctly. The full static rpm is to be noted, on each ignition, along with the OAT. The idle setting, and the drop with carb heat applied. The mixture, if equipped is to be tested. All engine instrumentation is to be checked for function. Any deviations from accepted levels or function are to be corrected.  Charge and Load test the battery. replace it if it fails or retire it if it is more than 5 years old. NEVER put a trickle charger on an AGM battery like an Odyssey.

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Four) Open the cowling completely, Perform a full visual inspection for leaks and cracked or broken parts paying particular attention to wiring chafing and any exhaust leaks. Wash the engine and dry it. Re-inspect it clean. This process should take at least one hour without interruption. Inspect the inside of the cap, the rotor and the wires. visible  wear is not acceptable. Oil leaks on the engine are not considered acceptable and are to be corrected as detected Carefully inspect balancer for any type of degradation of the elastomer. None is acceptable.

This is a good time to Check the prop. Re-torque the propeller to manufacturers specs. and enter this number in the logs, along with the next required interval for torque.

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Five) Fluids and filters: The oil and filter must be changed, no matter how recently it was. The old filter must be cut open and inspected, and the element saved for later comparison. Any increase in the amount of metal compared to a previous element is reason for further inspection. Log Book to reflect, brand, type and quantity of oil.  Clean or replace air filter, and note this in logs. Bracket brand air filter elements must be replaced at inspection, no matter how many hours they were used. Replace all fuel filters, drain and clean all sumps, including the carb float bowl.

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Six)Spark plugs, Denso only. While we used AC-R44F plugs for many years, We switched over to Denso plugs , both regular and iridium. We have several heat ranges we use with different displacements and compression ratios. They are the easiest, quickest, lowest cost way to add a much greater margin of safety against detonation to your engine. There is no reason why, years after we tested these plugs, that builders should not be using them, yet perhaps half the flying planes still have AC or some other brand plug in them. For the people who say “But AC’s worked fine, I’m still going to use them”  consider that before laparoscopic surgery, people s gall bladders were removed with surgery that was close to a midlevel broad sword wound. If you needed the operation, how would you feel if the doctor said “we are going old-school, it works fine.”

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Seven)Compression test: Learn more here: Compression and Detonation Testing, #2 . Perform a DIFFERENTIAL compression test. Note the compressions for each cylinder, and where the leaks are. Instead of 60/80 being minimum, make 68/80 minimum. anything less than 72/80 requires another inspection in 5 hours.

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Eight)Timing set with light on both ignitions Critical Understanding #4, ANY loss of RPM is Detonation.   Set the timing on BOTH, A and B ignitions, at full static rpm. Note the timing and rpm in the logs for each ignition. Make sure the RPM drop on the back up ignition is within limits.

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Nine)Two minute test Critical Understanding #6, The “Two Minute Test”   Write the OAT, DA, CHT, RPM and oil temp and pressure in the logs

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Ten) One person test flight Critical Understanding #7, The Most Qualified Pilot, ALONE.

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Eleven) Log book entry. Date and sign the logs with the final statement “I , xxxx xxxxx swear that I have inspected this engine, entered the data in the logs and declare this engine to be airworthy” put down your repairman’s certificate number or your A&P license number.

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NOTE: If the plane’s insurance specifies the engine is being operated  “In accordance with William Wynne guidelines” as some insurance does, this means the insurance will not be valid if the compression numbers in in the logs say “130 -125-….” indicating an automotive tester was used or if they find the motor to have NGK or Bosh plugs. Your plane, your choice, do as you wish, just answer for yourself what is to be gained by doing it differently, and what the potential cost is.

-ww.

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:)