Author: William Wynne

Friends,

We are 30 hours away from leaving for Oshkosh. Dan and Rachel Weseman are also heading up, and we will both be at booth 615 in the North Aircraft Display area, between Zenith and Vans. The Wesemans are bringing The Panther prototype airframe to display all the progress they have made in the few short months since Sun N Fun. Because they are good friends and we wanted to do something to support their new effort, I offered to assemble the 3,000cc Corvair that will power Panther #1. Here are a few photos of the completed engine. It will also be on display at the booth.

Above, the engine is a 3,000 cc engine with a Weseman bearing, Falcon heads and all of our Gold System Parts. The engine features some of the latest developments and a unique fuel system. The pictures of this engine are a good visual complement to our previous post on 2012 Engines For Sale. Other than the intake and the injector, this engine is the same as the ones that we assemble for builders. This engine is also an excellent blueprint for anyone building their own engine from our parts. The valve covers are one of our powdercoated sets with welded on oil filler and breather lines.

Above, a rear view of the engine. Behind the harmonic balancer is an alternator driven off the crank through a flexible coupler. It is a joint project that Dan and I have been working on. It retains the balancer and cannot put bending loads on the crank. I have never been a fan of belts on the back of the engine, but this system does not use one. The alternator is the same Yanmar unit we traditional use on the front of the engine. The set up will be flight tested after Oshkosh.

The intake is a custom stainless part made in our fixture so that it mates with our traditional welded on head pipes. On the bottom of the intake is the Precision mechanical fuel injection unit. Dan has designed the Panther to have tremendous airframe strength. The test wing took more than 9Gs at gross weight in a sandbag test conducted after Sun N Fun. Although Dan designed the plane to be easy to fly, it will be capable of impressive aerobatics. With the intention of ultimately being able to fly it with inverted systems, Dan has selected the Precision injector as his fuel delivery system.

Here is a good frontal view of the Corvair. It is only 28″ wide. This is 4″ narrower than an O-200, 6″ narrower than an O-235 and several inches narrower than a VW. The Corvair is a tough compact package. Six cylinder engines will always end up as a smaller package than a four-cylinder one of the same displacement. This view shows our new simplified adjustable starter motor bracket that eliminates the previous link arrangement. The single oil line runs direct from the Gold Oil Filter Housing to Dan’s bearing. Braided stainless hose and full flow AN hose ends look and work great but are not as expensive as people think. This hose was easily assembled from $36 in parts.

Of course Dan’s plane is going to use one of his bearings.  Originally a heat-treated casting that matched the finish of the Corvair’s cast case, the Wesemans switched to CNC machining the same design out of solid billets of aluminum. As part of their commitment to keeping aviation affordable, they did not raise the price when making this improvement. It goes without saying that this unit is entirely made in the U.S. out of U.S. material. With well over 200 of these bearings in the field, it is by far the most popular bearing. It has three strong cards to play: It is by far the lowest cost bearing, it is retofitable in the field to existing engines, and it is readily available, as the Wesemans now have them machined in large groups to have them on the shelf.

The photo is also another good look at the simplified starter arrangement. We have four-part kits for engines with Weseman bearings that consist of the new starter ear, two machined aluminum spacers and a pre-made tail bracket that allow any of our starters with a bolt on ear to be adjustably mounted on an engine in 15 minutes without fabrication or drilling. We will have these sets at Oshkosh.

Looking at the above photos and thinking about the Corvair’s well deserved reputation for strength and cool operation, it is easy to understand much of the popularity of the engine. I have been working to develop the Corvair flight engine continuously since 1989. The engine has matured tremendously during this time, but it has never lost it basic simplicity in the 52 years it has been an experimental aircraft powerplant. While others may be captured by engines sold as “new and exciting,” the Corvair remains a very popular option for builders looking for “Old and Proven.” 

I have said many times that the Corvair isn’t for everyone. We sell assembled engine just like the one above for roughly half the price of a Rotax 912, but there are plenty of people who pathologically purchase imported mechanical items. We can teach people to build a Corvair just like the one above for less than $8,000 in parts, but learning things and getting their hands dirty are alien concepts to many people who claim to love experimental aviation. For the rest of us, the Corvair is a great opportunity to have a proven and affordable powerplant.-ww

In the above photo, from left to right, Spencer Gould, Dan Weseman and Mark “Petz” from Falcon Machine at work on Spencer’s engine at Corvair College #23. Dan is covering the installation of his 5th bearing onto Spencer’s engine. Originally built as a plain 4 bearing engine, Spencer elected to add Dan’s bearing, a fairly easy upgrade that does not require the engine to be disassembled. Dan’s presentation on how to do the process complemented the clear directions that come with his bearing.

Above is the same process from a different angle. Here the prop end of the engine with the Safety Shaft is sticking straight up. Installation is easier on the bench, and it is easiest if the pistons and rods are not yet installed, but Dan has demonstrated many times that the upgrade to his bearing can be done without ever removing the engine from the airframe. He now has well over 200 bearings in the field, and they have been proven over 5 years of service. Upgrading an engine requires a shorter hub to keep the same length of Studs, Shaft and cowling. The Wesemans offer this machine service to builders who already have one of our Black Hubs or a Standard length Gold Hub. Builders that are planning on using a Dan bearing from the start order a Short Gold Hub from us.

Above, is a good look at the clean lines of an engine equipped with a Front Starter and alternator. Note that the engine has just one oil line on it, running from the Gold Housing to a Weseman Bearing. In its final installation, the engine will have a Gold Sandwich between the Filter Housing and the filter, and two short lines feeding a large cooler mounted on the engine baffling. This is another view of our new Starter Bracket. The outboard side of the triangular bracket is slotted allowing the adjustment of the starter engagement. This eliminates the previous system that had a drilled link plate. Spencer’s engine has the oil fill in the top cover because it is going on his single seat design, and he is planning on a form fitted cowling that would come too close to the right hand valve cover to have room for our standard oil fill location. The left hand valve cover has our standard crankcase vent line and oil return. The engine uses our Short Gold Hub because it has a 5th bearing. The bearing is one of the Weseman’s original cast housings, before they went to billet CNC production.

Another view of the engine. The welded on intakes were welded on the heads by Mark Petz at Falcon Machine. Like most flying Corvairs, Spencer’s engine has one of our E/P Distributors. Oil filter is a K&N 1008, the plugs are AC-R44Fs, my first choice for both of these. The dip stick is an aftermarket one for a 289-302 Ford, with the tube shortened 5″. The engine hardly needs more than a set of ignition wires and a baffle set to be installed on an airframe. None of the engine systems need to be mounted on the firewall: The engine is largely a self-contained, neat package. The engine will be flown with a HD oil cooler because the airframe is designed for strong maneuvers and solid acrobatic work, and excess oil cooing makes sense on a plane that will be flown at full power and slow climb speeds. On the run stand, engines can be operated without oil coolers because the oil comes up to temp very slowly with the engine uncowled.

Above, Spencer’s engine at power on the stand. Note the size of the cooling baffle we use on any engine we are running on the ground. We recently had a builder extensively damage the engine he built by running it on the ground without any type of cooling baffle or cowling.  In every photo we have of running engines at the Colleges, especially brand new ones being broken in, they have a generous amount of cooling air being pumped through them by the baffle. Prop wash over an uncowled engine does not work, period. Without a cowl or a cooling baffle box, none of the air has any reason to flow down through the cooling fins on the head. How long does it take to hurt the engine? How much running is OK? Answer the question for yourself this way: If you just spent $5,000 and a lot of time to rebuild the V-8 in your classic muscle car, how long would you run it without a radiator?

Actually this isn’t a fair comparison. A v-8 in neutral turning 2,000 rpm is only making 10 or 15 hp, it is not pulling any load. It has a several hundred pound mass and lots of oil to heat up. Conversely, a Corvair with a flight prop turning 2,000 rpm has to be at half throttle and may be making as many as 60 horses. It doesn’t have the mass to heat soak either. You could run the V-8 longer without damage.

Keep in mind, if you hurt your newly overhauled v-8, it may leave you by the side of road later. If your flight engine is wounded by cooking it during break in, it may choose to get even with you later, and it is much more likely to do so on a full power climb out than it is idling on the ground. In the end, what exactly was to be gained by running the engine on the ground without cooling? Building a box too much work? Few scraps of sheet metal cost too much? Building the most elaborate cooling box will never take 10% of the time nor 5% of the cost of rebuilding your engine. The longest time I ever run an engine without a cowl or cooling box (once it is fully broken in) is 45-60 seconds, and only 5-10 seconds of this are much above idle. I would do this while setting the timing on an engine after maintenance. On many of our cowling designs like the Zenith cowls, you can just pull the top hinge pin on the passenger side and remove the top access panel. The cooling system will stay in place with the exception of a 4″ square hole. You will have full access to work with the Distributor and set the timing. Our cowling design took factors like this into consideration, and that is why it makes a lot more sense than trying to scab together a cowl from leftovers of some other engine.

Above, Spencer enjoys the finest form of air-conditioning on the planet, prop blast from an aircraft engine created by your own hands. A close look at the exhaust on the run stand shows that I have oxygen sensors on both sides to run an air/fuel meter (lean-rich gauge).  Initially, I liked the idea, and a number of well-known Corvair pilots like this instrumentation as well. Here is the turn off for me: The sensor works on a tiny signal difference, and it is very prone to any type of grounding issue. This is a pain, but not too hard to overcome. My real objection it that when the device loses its signal, its default position is reading perfectly in the green arc. I find the very concept annoying. Would you use an oil pressure gauge that indicated 45 pounds every time the wire was disconnected? How about a fuel gauge that always read 1/3 full when it was having an issue? To me, I want instrumentation that when it fails, it clearly indicates that it is dead, it doesn’t provide misleading info. There is probably some electrical reason why the air-fuel meter reads green when it is dead that makes sense to an engineer at a computer, but if I put it in a plane, it has to make operational sense to me. Lest you think I am making a mountain out of a molehill, than consider that the airliner hitting the 14th street bridge in D.C. was primarily caused by an instrument error on the EPR gauge; the airliner that went into the Everglades 30 years ago had the crew fixated on a failed instrument light; there are enough stories about professionals being undone by faulty instrument data that homebuilders should consider this issue with attention. In my personal opinion, almost any Corvair engine can be well served by 2 simple EGT probes in the exhaust. EGT systems are stupid reliable, and when they are disconnected they don’t read.

Above four of the major contributors to the modern Corvair movement: From left, Mark from FalconMachine.net, Dan Weseman from SPA.com, myself, and Spencer Gould.

Today, Spencer’s day job is aeronautical engineering for the world’s greatest aircraft powerplant company, Pratt-Whitney. Contrary to the popular image of serious engineers being challenged by practicality, Spencer is a multi-faceted renaissance man of aviation. He is a very skilled pilot of complex aircraft, he is the master of CAD drawing and machining, he can fly any RC aircraft with skill, he has designed and flown dozens of them. He designed and has built 98% of his own composite acrobatic aircraft, the SP-500, and has a broad array of practical knowledge in the world of aviation. If you need a technical solution to a structures issue, a finite element analysis, or a process, Spencer always has valid input. In the years between his graduation from Embry-Riddle Aeronautical University and Pratt, he worked as a powerplants engineer for Piper in Vero Beach.  During that time, Spencer was an adjunct member of  The Hangar Gang, and covered a lot of our CAD work. Designs that I had for the Gold Oil System, the modern Hubs and our 5th bearing were refined by Spencer’s CAD ability, and they went directly to CNC production from code we e-mailed to the machine shop. He was and remains a very important force multiplier in our efforts, an asset that few other engine programs could claim to match.

If you are new to homebuilding, stop and think about this: The Corvair not only has appeal to people whose day job is far from aviation, but it also has great appeal to builders like Spencer who are immersed in aviation, men who understand all the issues involved in powerplants. Spencer could afford any piston engine he wanted for the front of his aircraft. Yet he selects the Corvair because after careful evaluation, it all adds up to the right choice for him. The engine isn’t for everyone, but no builder new to aviation need worry that the engine isn’t capable of meeting the demands of educated professionals and amateurs alike.-ww

Friends,

Here is another builder’s story from Corvair College #23. Below is a sequence of photos of the 2850 cc 110hp engine we assembled for Zenith 750 builder Roger Grable from Missouri.  All of the action pictured took place at the College.  

We met with Roger and his wife Sarah at CC#22 in Texas a few months ago.  It didn’t take long to understand that he knew engines fairly well, and had considerable experience working on them. His questions were observant and thoughtful. He spent #22 carefully considering a plan that made sense for his project and timetable. By the end of #22, Roger made the decision that he wanted to have us assemble a 2850 for him, and this would keep his fast paced 750 project moving.  I have no problem building an engine for a guy with Roger’s approach. He still wanted to learn as much as possible, and that in my book is what makes him a good Corvair guy.

Above, Roger and I stand beside his engine on the run stand.  Every engine we run has the oil system primed for 20 minutes with an electric drill. The only oil we use for break in is Shell Rotella T 15w-40. In every engine we add ZDDP. You can get it from a lot of places, but Clark’s sends it with camshafts they sell. We run the engine for 25 or 30 minutes without stopping, at 1500-2000 rpm. This has proven over hundreds of engines to protect the cam and lifters, which are the primary thing you are concerned with during the first hour.

Above, a number of the builders at CC #23 admire the smooth power of Roger’s 2850. The engine is equipped with a billet Weseman bearing and a very nice set of Falcon heads. We configured the engine for a heavy-duty oil cooler. On aircraft like Zenith 750s, the slow climb speed capability and the high angle of attack challenge the stock oil cooler capacity in hot weather. Thus, we set the engine up with a cooler block off plate and a Gold Sandwich Adapter and a 20003 series aircraft oil cooler. The baffle kits the Wesemans offer are fitted for either the stock cooler or the 20002 or 20003 series. When complete, the oil system is contained on the engine, none of it is mounted on the firewall or cowling. This gives the engine installation a clean, organized appearance.

Above, Roger keeps an eye on the oil pressure. His engine is equipped with our new high volume pump. For these, I carefully  use the mill and expand the capacity of the oil pressure bypass, to prevent the engine from having a very high peak oil pressure on start up with cold oil.  When the engine is first started, several minutes of operation to warm the oil is a good idea, and we do this at 1000-1200 rpm.  In a few minutes the oil will regulate at 50 psi or so. When the engine is at full temp, this will settle down to 45 pounds of pressure. This slight reduction in regulated oil pressure between 140 and 205 degree oil is a Corvair characteristic. Beside Roger in the yellow shirt is his grandson Graham of Kansas. The young man proved to be very smart and good company. Many of the builders though Graham was 20 or 22 years old by his manner; it was a small surprise that he is far younger, still in high school. He is very interested in flying, and it is easy to guess that he will do very well. The kind of younger person who defies all the common media stories about youth.

We often get inquires about complete engines. Most of these are from people who only know about the low price of the engine. They have no other attraction, they know almost nothing of our development or support. Experience has taught me that any guy who decides to buy an engine he never heard of before after reading a one paragraph news release is not a guy who is in things for the long haul. Any guy who thinks you’re a genius in 1 minute is just as likely to decide you’re a fool without reason. Steady people who consider merits thoughtfully are typically the people who succeed in homebuilding. To understand an extreme case of people who are only interested in price shopping, I had a guy ask about a 3,000cc engine. He said it was priced at $50 more than his other choice, a four-cylinder, geared, tiny displacement computer controlled, imported car engine. I pointed out that philosophically these were radically different concepts in aircraft engines, and he needed to think his choice over a bit.

His response was to ask if I would sell him an engine but not the Conversion, Installation and Operations manuals, so it would reduce his cost and make up his mind. I calmly asked him why I would sell an engine to anyone who told me they didn’t want any instruction on how to operate it. I hope he is happy with the other engine, I don’t work with people who know the cost of everything but the value of nothing. Roger and his family impressed me as the perfect antithesis of such people. We have room in the Corvair movement for many types of people, but I can make a good argument that experimental aviation and flying in general has had quite enough of people who have no interest in learning anything.

Above, Roger and his grandson Graham. The picture provokes a thousand thoughts on where their adventure will lead. Will they both be there for the first flight? Will his grandson solo in the plane? Will Grandfather be the first passenger in his log book?  I watched the two of them at the College, they were having a very good time together. Roger, obviously proud of his grandson, and the young man accompanying his grandfather on an important and fun trip. Both of my grandfathers passed before I was born. Looking at these two made me think about it many times during the College. I have been very lucky in many ways, but as a young man I would have treasured having a grandfather. In person it was easy to tell that Roger’s grandson felt the same way about Roger.-ww