Category: Installation Components

Builders:

Today’s deal of the day is an early generation black hub / starter and alternator arrangement. These parts actually flew on our Zenith 601XL in 2004. They have been used on another test engine. The parts are used, but in fairly good condition and airworthy.

Before there were Gold hubs and 5th bearings, this was how Corvairs were converted. Today, there are still a great number of aircraft in the Corvair fleet operating systems identical to these. This set up can be directly used on a 4 bearing engine, or it can be used by a builder using a Gen. 1 Dan Weseman bearing.

If a budget minded builder wanted to use this with a 5th bearing, it would require the hub modification and a switch to gold starter brackets. It would still be an economical proposition. The ring gear is an FRA-235, the style we have not used in 5 years. Today we use disc style ring gears that do not have spokes. If the edges of the spokes above are polished to remove stress risers, they have a good track record. Otherwise they are prone to developing cracks in the spokes. I put a lot of effort into explaining the concept and asking people to periodically inspect these, but many builders did neither. Today, all of these are eliminated by only offering the disc style ring gear, but for builders willing to put closer effort in, the spoked wheels was more than a pound lighter. If a builder wanted to upgrade to a disc style ring gear on this arrangement, it will bolt right on.

This is a good opportunity for a builder working to a tight budget to get launched on an affordable engine.

The parts in this package are:

Black hub, Ring gear, puck, front alternator pulley, starter, brackets, tail bracket, alternator brackets, 20 amp alternator, and drive belt.

These parts cost more than $1,250 new. As the ‘Deal of the day’, we are selling them for $475.

If you would like them, email me directly at:

WilliamTCA@aol.com

I will cover the shipping in the US.-ww.

Builders,

Several people have been discussing these types of cowls for their Corvair powered planes. Clearly they work on 65 hp Cubs, why not on a Corvair powered Piet? Well, they can and do, but there are subtile points to the design of these things that are just as critical as enclosed cowls. I am quite sure that Piper learned these by trial and error before standardizing the “J-3 Eyebrows” that people tend to use on 65 hp Continentals. As we go over this, keep in mind that when Piper went to 90 Hp engines in Cubs after the war, they switched to regular pressure cowls. Every Super Cub has one of these, and there is little argument against the proof  that they work better, even on slow planes. However, if your heart is set on a J-3 style cowl, please read the following notes to avoid harming your engine.

Above, Frank Metcalfe’s plane at sun n fun. This installation works. Look at how large the eyebrows are in relation to other examples. If a 65 hp Piet and a 100 hp Piet are both climbing at 55 mph (They will have a very different rate of climb) it makes sense that the 100 hp plane will need more cooling air. Yet, I see too many Corvair powered planes with eyebrows that are smaller than the ones on a J-3. Think that over.

Above, our Pietenpol in 1999. This system worked great, but the two versions I made before it didn’t. TLAR (that looks about right) does not apply here, evaluation and testing does. In a phone call today, a Piet builder told me that a set of Corvair eyebrow scoop drawings are circulation on the net. What is the first question to ask? Have they ever flown and been proven on high hp Corvairs in hot weather? He was not so sure. If you want advice on down parkas, I am not your guy. If you need advice on cooling systems that work in hot weather, ask the guy in Florida.

Above, several details, some visible, some not. Notice that the scoops extend downward. They capture air that would run under the front cylinders at high angle of attack and ruin cooling. Notice the rounded nose bowl and spinner. If you want to have a flat plate as big as an end table, you will need to have much larger scoops to make up for this. Note also that the alternator is in the back. If you have a front one, it will work, but again the scoop must be bigger. (Dan Weseman has just finished testing his rear alternator, and it is the only one I endorse) The most critical part of this whole equation can not be seen: under the cowl there is a 3.5″ diameter hose connecting the two sides together. Without this, you are hurting the engine. You have a choice: connect the two sides, or use scoops 50% bigger. If you copy the size here, and then use a very blunt cowl and no transfer hose, than you are not doing anything positive for yourself, my reputation as an engine instructor, or the Corvair movement.

OK, now we get to the big quiz: Would you rather spend an hour reading something that requires a little thinking, or would you rather fry the heads on your engine, spend $1,000 or so, and loose half a seasons flying doing a rebuild? Right now you are thinking that 100% of the builders thinking of J-3 cowls are going to choose the first option, but you are not right……

This link : http://www.flycorvair.com/pietengineissue.html

goes straight to a 16 page story ( it has pictures, it is only about 5,000 words) about how I had to rebuild Gardiner Mason’s engine several years ago after he used TLAR to design a very blunt cowl. I like Gardiner, so he just bought the parts, I did the work, then wrote the story. KNOW THIS: I am not ever going to assist anyone for free to rebuild another engine that cooked it because: “I saw that story but I didn’t have time to read it because 1) It was sooo long 2) The big game was on 3) I didn’t think it applied to me because my plane is gray not red.” All future rebuilds will be done at the shop labor rate that Lockwood Aviation charges (the US importer of Rotax engines) Just read the story, learn something, save yourself a $1,000 in damage and preserve a little of my sanity. Please.

Above is Gardiner’s plane, the focus of the 16 page story. It does not look like it has a J-3 cowling, but it functions like one. This is a blunt cowl. This means you need bigger scoops. It isn’t hard to put some effort into making the front end smaller. It doesn’t just help cooling, the plane will be faster and look better. On a Pietenpol, a plane with a bad cowl and poor windshields actually has less elevator and rudder feel.  If the entire fuselage is bathed in a foot thick boundary layer of very turbulent air, you can feel this when it gets back to the tail.

 So, you were planning on reading the 16 page story after watching Dancing with the Stars and the Celine Dion concert? Keep in mind that this website has story tracking on it, and I will tell if 600 people read this but only 150 click on the link to the Gardiner story. Lucky for all the Celine Dion fans it doesn’t keep track of who didn’t read what. Just how many people didn’t. Don’t worry, I will still be able to tell who read it by reading the Pietenpol archives and seeing who writes in asking what to do after their engine severely overheats…….

Below is a sample from the 16 page story:

” Here is the major cooling issue of a propeller-driven aircraft that many builders don’t understand. When the plane is climbing at a 10 degree angle of attack, the blade roots near the cooling inlets have a 20 degree difference in their angle of attack between the effective angle of the ascending and the descending blades. They pump very different amounts of cooling air into each side of the engine. This is not theory, it is fact. Get into a light plane, fly to a safe altitude, slow it down to its best angle of climb speed and set it to full power. Notice how much rudder you have to put in to hold the aircraft heading. You may have been told that this was some swirling slipstream or “P” factor. Discard those ideas. A strand of yarn behind an engine on a test stand will show you the air even at zero airspeed doesn’t corkscrew much, and “P” factor does not apply to aircraft in steady flight like a continuous climb on one heading. What is going on is far more simple; the ascending and descending blades are making very different amounts of thrust. You feel it in the rudder pedals, the engine feels it in differential cooling.”

Above, the Pietenpol of Kurt Shipman. This plane won the Bronze Lindbergh trophy at Oshkosh. Before anyone starts saying how nice work Kurt does, keep in mind that there were 24,500 other planes at Oshkosh that year, and the judges were able to find four others that they thought were ‘better’ than Kurt’s. So he beat out 24,495 other planes…..that still isn’t first place. Nice try Kurt, maybe you can do better on your second home built.

Seriously, I flew in this plane and it is phenomenally well done. Look at the cowl. This is a typical pressure cowl. This is built off the nose bowl mold that Piet builder/flyer Shad Bell made. Rounded edges and reduced area like this make a huge difference. If you don’t have a committed feeling about cowling design, I highly encourage you to look at this set up. It works very well, and has a front alternator. Either system you choose, use all the available data that has been flight proven in hot weather, do a good job, and don’t alter the details without good reason.-ww

Builders,

In the last few days we have featured some stories on Carbs. Today I went to the mail box and picked up a package that happened to be my MA3 carb returning from overhaul.  It was gone about two weeks.

Above is the MA3, freshly overhauled by D&G Suppy in Niles MI, (269)-684-4440. This is the FAA fuel system repair station that is run by Russ Romey. We have been sending builders there for 10 years. He is an excellent source of rebuilt MA3’s and Stromberg NAS-3s.

Several points here; It is hard to see, but the carb is sitting on my receipt from Russ. Although we are friends, note that the overhaul cost me the same price as he charges any other person, $650. Years ago, a handful of people on the web, led by Lon Wall of the Corvair Underground inc, frequently spread the lie that I made money and kick backs off the products I recommend to builders. This was Lon’s explanation why I suggested people shop with Clarks rather than him.

He didn’t understand that he lost the business solely because he wanted to sell builders cast pistons and old rod bolts. His claims went on the net for several years, mostly unchallenged or unmoderated. They sounded good to a handful of people who liked a good conspiracy theory or hated me since I first used the term “The Corvair authority”, (All of them missed that the acronym TCA at the time was a FAA airspace called a Terminal Control Area, and the letters stuck in aviators memories, and “WilliamTCA” my email address, predates our name “FlyCorvair” by several years.) Let the receipt be one more piece of evidence that my endorsements are not for sale.

My allegiance is only to the best interests of builders. In the last 10 years, lets conservatively say 1,000 people have built a complete corvair aircraft engine. On average, between cams, pistons, bearings cylinders, balancers, gaskets etc they spent $1,750 each on parts from a Corvair parts house.  Thats $1,750,000 in shopping. The lion’s share of this went to Clarks. I did not make a single dime off any of this. If Lon or any other parts house wanted a part of it, all they had to do was sell the parts we recommend and not offer advice like using cast pistons in flight engines. Evidently, he couldn’t do this.

Second; An MA3 is a simple carb, I have been an A&P for 22 years, I am qualified to overhaul this myself, but parts are expensive, more than half the price of the complete job. In the end, I am glad to pay Russ a few hundred dollars to make it perfect. I have no problem paying another American aviation professional for his expertise. This is how the infrastructure of aviation as we know it in this country stays in place.

If someone chooses to buy a Rotax with their two German Bing motorcycle carbs, they are only fueling the trade deficit, and doing nothing to support American manufacturing and aircraft maintenance systems. And no, a person who took a 40 hour Rotax ‘mechanics’ class is not a trained aviation professional, they are just an extension of a foreign companies sales staff.  For a reality check, my A&P training at Embry Riddle had the strict FAA requirement of 2,800 classroom hours.

If I had told the maintenance department chairman, Dick Ulm USMC ret. that I was ready to evaluate airworthyness on aircraft at the end of my first 40 hour week in the program, he would have laughed his ass off, and then punched my lights out. If I then complained to the University president, Kenneth Tallman, Maj. Gen. USAF, ret., I am pretty sure it would have had the same result. If anyone asks in 5 years why S-LSA”Light Sport category” failed live up to any of its potential to do positive lasting good for aviation, at least part of the blame will be on the fact the ASTM ‘certification’ standards on these planes are a bad joke, and the maintenance on them is done by woefully underqualified people.

Third; This carb is going on our own Wagabond, the plane that my wife will also fly, and we will bring the dog. The day it flies it will not have a radio, a transponder, a GPS, a Glass anything, an interior or a fancy paint job. Those things don’t make planes fly. It will however have this carb and it will have a 5th bearing, and a very well-built engine. Aviation is about good decision-making, and placing any of the first items ahead of the latter ones is an example of poor decision-making, and no one can offer a rational argument otherwise. Looks and tech toys come after airworthness items. If you have budget left over, add those things if you wish, but only after it is mechanically as good as you can make it.

It is a free world, and  you can use any carb you like on your Corvair.  Physics, Chemistry and Gravity also think it is a free world, and they fully support your right to make a poor choice, even one that will harm you if it doesn’t work within their system of laws.  If you wanted to run a German motorcycle carb, don’t be mad at me if it doesn’t work. I didn’t make up the laws of the physical world. I am just the messenger here to remind people that Physics, Chemistry and Gravity are great allies if you play by their rules. They are also absolutely remorseless in dealing with people who feel like the rules don’t apply to them. Be advised, if they find you guilty, the penalty phase of the system moves much faster than our criminal courts, and does not have an appeals system.

It is no secret that I like aircraft carbs. Look at the photo above, the lettering cast into the body says “Marvel Schebler Aircraft”, the logo in the middle is a propeller. This was not designed for use on motorcycles. Look at the silver throttle arm. I could literally hang the entire weight if the engine off this arm. It is not fragile. In contrast the throttle cable on a Bing carb is a tiny bicycle cable, the exact same kind that you see on cheap bmx bikes at Wal-mart. A long time ago I flew ultralights with set ups like that, and justified it by the low landing speeds. Today, I am older and somewhat smarter, and I would not fly in any plane that used a bicycle cable as a primary engine control, especially not one where the carb is going to close if the cable breaks. If the cable falls off an aircraft carb, suction alone will generally make them run at full power.

In mechanical situations, I am a traditionalist. If we are going deer hunting, no one can argue that my choice to bring a .30-06 will not work. If we were going to sea in a storm, no one could argue that my choice of going in a USCG 44′ motor lifeboat would not work. If we needed a light truck engine, no one could argue that my choice of a 350 v-8 would not work. If the goal is to put a carb on a Corvair flight engine, no one can argue that my choice to use a MA3-spa will not work. They might say it was expensive, (valid, but not in the big picture) hard to find (not valid, just call Russ) or less efficient that EFI (not valid, see my testing), but no one can even begin to say that this carb is not reliable. It works and does this task with stone reliability, end of story.

Above, this side of the carb shows the accelerator pump, and the bronze mixture control arm. the orange plug it covering the threaded fuel inlet port which an AN fitting goes in. Just to beat a dead horse, let me point out that Bing carbs on Rotaxes just have barbed slip on fittings for rubber hose and hose clamps for fuel inlets.

The intake in the background is for our Wagabond. It is stainless, just like our others, but I elected to have it powder coated. It has a longer, one of a kind up pipe between the carb flange and the main pipe, on production manifolds this is about 1/2 that length. The small tube was for a primer line when the plane  was equipped with a Stromberg carb. Going to an MA3, I have deleted the primer system. I will just have to find a plug to fill the hole….or maybe just screw a NOS nitrous fogger nozzle into it….-ww.