The beauty of the open house weekend is the open format. The factory invites vendors to display their products, provides a loose schedule of discussion forums surrounding everything from new builders to building techniques to design updates. Everyone is friendly and willing to share what they know and have experienced.
This is most apparent in the Corvair engine tent. Corvair engine builders come from a vast variety of backgrounds. I met individuals who are commercial airline pilots, another gentlemen who was a farmer, another a music teacher. The common thread we all share is the desire to not only build our own engine, but to understand every last part and what it does. We aren't just consumers of, we are masters of our builds.
Several builders came to the weekend with engines in the final stages of assembly. These Corvair events are the best place to show your work and confirm with both the experts and other experienced builders what you've prepared and work through the final prep before first engine run on William Wynne's test stand. The is NO COST for doing this, just a willingness to learn and share with others.
With an engine on the build table, I was able to observe how the conversion products go together. In Bob's situation, his motor was real close to being ready to test run, so we helped get it mounted up to the test stand. A fairly simple process as the test stand provides intake runners, exhaust, starter battery and fuel delivery (carb, etc.). The test propeller is also installed at this point.
Bob goes over test stand install, point by point with William. Over the course of 40+ of these events and hundreds of engine test runs at his home shop location, William has a fined tuned procedure to go from work table to stand. These checklists are essential to ensure a successful test run and more importantly everyone's safety.
Once everything is together on the stand, the engine is pre-oiled. This coats all the internal wear surfaces prior to start-up but more importantly confirms oil is flowing correctly through all the passages and oil galleries. This ensures nothing got missed and the engine will be lubricated properly on first start-up and going forward into operation. William has a custom made oil pump drive shaft, made from a discard distributor shaft which is powered by an electric drill motor. It is inserted in the distributor hole and drives the high volume oil pump - this is opposite from normal operation, where the oil pump gears drive the distributor. To the untrained eye, this might seem a bit mickey-mouse, but is very simple and brilliantly effective!
What's the best way to see oil flow? The furthest distance that oil has to travel from the pump is to the front right rocker arm. What we want to see is oil dripping steadily from each rocker arm (12 in total). It takes several minutes for the pump to push oil out through the crank, into the block and across the push rod tubes, but eventually all 12 are receiving a steady stream. Of course the only way to see this is with the rocker covers off. Again, a simple set up William developed is seen below. It uses a spare set of rocker covers modified and mounted as a drip tray:
As the drill and shaft powers the oil pump, the engine is gently turned over by hand using the test prop. Here Bob rotates his engine awaiting confirmation of oil delivery. There was almost a casino atmosphere as everyone tried to guess which rocker arm would start to drip next!
With confirmation that oil was circulating properly and to all areas of the engine, we helped Bob install his rocker arm covers. As the rocker gasket sealant set up, we listened to William go through a final pretest checklist with Bob. This includes a procedure to install the distributor and set the preliminary engine timing. Once complete, it was time to wheel it outside for first run!
The engine stand is by itself a brilliant piece of homebuilt engineering. It connects to the trailer hitch of a vehicle and is chained up just like any trailer should be.
Once everything is confirmed as secure and everyone is clear of the prop (standard airmanship rules) a new engine is born!
Nothing sounds as smooth and powerful in this engine horsepower class. And when I say smooth, check the two videos below. Note that the engine doesn't vibrate at any any throttle setting... clearly the 6 cylinders, pistons and valve train are well balanced!
For those wondering, that prop is actually turning about 2300RPM - it looks much slower in the video due to camera shutter speed among others. For a real good explanation see this article:
Here is a close up video of the rear of the engine in operation. The engine is rock solid and completely still - the vibration/unsteadiness is from my hands only. Really impressive!
What a great moment sharing this accomplishment with the engine builder! Here Bob does the "mandatory" Captain Morgan pose behind his engine at the end of a flawless break-in run. A true master of his engine!
This blog post was too long coming and I promise for those still tuning in it won't be so long for the next one - thanks for your patience! Stay tuned for more from my Zenith weekend :)
I don't know if I was tired from the drive, relaxed from the dinner and beer or the steady beat of rain on the fly of my tent just after tucking in for the night. Perhaps and most likely it was a combination of all of the above, but boy did I ever sleep solid!
For airplane people, being woken up by a departing turbo-prop is the sweetest alarm clock there is!
Morning dawned overcast, but the rain had moved on and things stayed dry for the balance of the weekend. The Zenith staff arrived early and I captured this great shot as the hangar opened it doors in preparation for the weekend:
I wasn't long before the staff started to bring their factory demonstrators out of the hangar and onto the ramp for the day:
As the morning started to brighten up, I dove right in at the Corvair tent and started taking notes and photos of the Corvair engines on display. Lots of learning just by seeing.
One of the neatest products available in the conversion catalog is the rear mounted alternator which easily fits between the engine block and firewall - directly driven by the harmonic balancer, it eliminates a belt/pulley drive on the front and moves more of the installed weight towards the firewall
Nice custom stainless exhaust routed down and out at the rear of the cowling - Ron and I will have no problem making this and the mount in the shop. Someone questioned why no mufflers and the best answer is mufflers prevent the engine from developing maximum horsepower - I think they sound better without too!
It didn't take long for the parking lot to start filling up with visitors and the Corviar tent got busy real quick. What appealed to me was the open format of the engine building. No formal schedule to stick to and lots of opportunity to chat with other builders and the join into chats with the experts.
As I continue to sort through more of the tons of photos I took, I realize it's getting late and I have to work in the morning. Stay tuned for more.....
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Husband, father and 911 dispatcher. Long time pilot with a licence that burns a hole in my pocket where my student loan money used to be. First time aircraft builder. Looking to fly my own airplane.