Alternative Corvair Cooling, 1993.
Builders,
When I got started building flying Corvair Engines in 1989, one of the most persistent old wives tales about the Corvair said that the engine cold never be operated without the cars blower fan, it just simply couldn’t cool itself in a plane. I knew that was a myth, and later I had a chance to show that even a car didn’t need one.
.

.
Above, my 1967 Corvair Monza, the only car I own through most of my years at Embry Riddle and the first years of my work in aviation. The picture above was taken at the Spruce Creek fly-in outside of Daytona Beach. I worked there for many years, and was eventually the EAA-288 chapter president. Parked next to a P-51 is appropriate; GM owned 51% of North American Aviation when Mustangs were built. That is why the first engine in A models was a Allison V-1710. GM owned 100% of Allison into the 1990s.
.

.
Driving back from NJ to Florida after Christmas, the blower bearing on my Corvair let go in South Carolina, and the magnesium fan broke itself to bits on the shroud. I pulled into a Walmart to assess the damage; It was MacGyver time. The cardboard box is a forward facing scoop, it is braced with ropes. The round waste paper basket funneled the air into the cars cooling shroud. Note the throttle linkage going through the bucket (kind of draggy) engine cover fit in the back seat by 1/4″.
.

.
Ok, so the prototype wasn’t very pretty, but what do you expect from a guy that looked like that? The system worked great, and drove the 400 miles back to Daytona without a hitch. No generator, but it didn’t need one to operate the ignition for hours. I could put my hand in front of the heater outlet and the air poured through, even with the ventilation fan turned off. The air wasn’t nearly as hot at the defroster. The only issue that it had was driving the 2 miles from I-95 exit 262, past the Speedway to our house, 1235 International speedway Blvd. , pictured above. The car didn’t like sitting at the 6 stop lights. Even with such experience, I had 10 more years of people telling me that the engine would never cool itself in a plane without a blower fan.
.
-ww.
.
Pietenpol first flight; Honolulu International.
Builders,
In the previous stories, I mentioned that my old Pietenpol, N-1777W was built in the Hickam AFB hobby shop in the mid 1960s. Below is a look at the first page of the log book #1. Plenty of things have changed in the last 38 years of aviation, and I trust that making test flights in a Pietenpol out of Honolulu International is not likely to be repeated today.
.

.
Above, a look at the logs. The plane flew it’s first 3.5 hours on a Ford model B, and then this was removed and replaced with a Corvair. The plane flew nearly 100 hours in the fist months of 1970, area flights between Honolulu and Dillingham. In the spring of that year, it was packed up and shipped to Torrance CA, and from there flown to the first Oshkosh.
.
-ww.
.
Critical Understanding #12 – Yearly Condition Inspection
Builders,
I am skipping over #10 and #11, but I will go back and cover them later. Be aware that I may expand this slightly in the next week also. If I do, I will put a revision date in the title.
.

.
Above, my original copy of AC43.13 1A /2A from my training at Embry Riddle. In front of it is a logbook from a 1940 Taylorcraft BL-65, NC-24373. Even though a lot of people claim there was no private flying in the US during the war, nor gas for planes, the previous page shows the plane was purchased in southern California on 3-28-45, and was obviously being flown a lot that week, even though Hitler was still alive and the battle of Iwo Jima was being fought. You can correct a lot of myths with logs. Note the 3-30 entry saying “Engine running hot as hell”
.
Homebuilts don’t get traditional Annual inspections, they get a condition inspection. Certified airplanes used for hire also get the same inspection on 100 hr intervals, but since you can’t rent out a homebuilt, it dosent apply. But the ‘scope and detail’ which is specified in appendix D:
( https://www.gpo.gov/fdsys/pkg/CFR-2002-title14-vol1/pdf/CFR-2002-title14-vol1-part43-appD.pdf)
Is a beginning point of all of these inspections, and from it you should develop a personal inspection checklist.
.
Some important points:
Just because you own or even built your plane, doesn’t mean you can inspect it. You need a repairman’s certificate for your specific plane to inspect it or you need an A&P mechanic. If a guy the second owner of s a Flybaby, but he built one before and had a repairman’s certificate for that Flybaby, it doesn’t count, because the certificate is for a specific plane, not the type. Several years ago I looked at a plane that had 8 years of entries in the logs that said “A+P” looked official, but it turned out the builder and owner had never gotten a repairman’s certificate for the plane, and what he was doing was deceptively writing AtP or Airline Transport Pilot (which he was) in the logs. 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. Good thing the plane was only used to fly about 50 young eagles. Flying a uninspected plane is something that people try to justify all the time. Just don’t be one of them.
.
As far as your Corvair goes, these things need to be on your list:
.
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. Oil leaks on the engine are not considered acceptable and are to be corrected as detected.
.
Change the oil and filter, Oil must have more than 800 PPM Zinc Phosphate
.
Cut the filter open and keep a sample of the element in a plastic bag to compare.
.
Change the plugs. If your plane has R-44F’s in it, go to Denso W20FP-U’s or better yet Denso IWF20’s While 44F’s have worked for decades, these are an important improvement.
.
Inspect the inside of the cap, the rotor and the wires. visible wear is not acceptable.
.
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.
.
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.
.
Carefully check the full function of all engine controls.
.
Carefully check the integrity of all engine instrumentation sensors and systems.
.
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.
.
Carefully inspect balancer for any type of degradation of the elastomer. None is acceptable.
.
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.
.
Verify , with a voltmeter, that the charging system is functioning to capacity. Note in the logs RPM required for the charging system to register 13.0 volts
.
Re-torque the propeller to manufacturers specs. and enter this number in the logs, along with the next required interval for torque.
.
Perform a “Two Minute Test” Write the OAT, DA, CHT, RPM and oil temp and pressure in the logs
.
Date and sign the logs with the 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.
.
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.
.
Eyeballing Prop Blades for Performance.
Builders,
.
Pictured below are two carbon fiber, ground adjustable prop blades from two known and respected US manufacturers, who have been on business 30 years (L), and 80 years (R) respectively. Let me share with you what you can tell by eyeball about the performance of each of these different blades.
.

.
Above, A Warp Drive blade with nickel leading edges on the left. There are more than 150 of these flying on Corvair powered planes. I have been a WD dealer for more than 20 years, and you can look at pictures of my Pietenpol from that far back and see a 66″ two blade on it. The prop on the right is a Sensenich Saber blade, in the correct airfoil and pitch distribution to be a fair comparison to the WD prop. It has not flown on a Corvair, it was directly provided by the factory as a test article, the blades still have the node marks from their in house vibration survey. I have been a Sensenich dealer for almost 15 years.
.
Here is what you can tell about their performance comparison by Eyeball : Nothing. The only valid commentary that will come, will be from impartial testing, period. Plenty of people will offer some comment on nearly any prop, but will they buy you a new one if it doesn’t work? I haven’t seen that yet. Ask any group of people at an airport or an EAA meeting about a kind of prop, and wait for the first guy to answer, then ask the four questions his expert opinion neglected to include: Have you ever flown that type of prop on the engine I asked about ? Are you a dealer for that brand so you would have full access to their support staff? Have you ever had any formal training on propulsion, A&P work or worked in a prop repair station? Has anyone ever paid you a dime for you opinions on props, or is your advice worth exactly what you charge for it, nothing?
.
Without even asking, you can pretty much guess the answer to the questions. On the other hand, even though I had Dr. Ernest Jones as a mentor in propulsion at ERAU, am a 25 year A&P, have been a prop dealer for decades, Have worked in a certified prop repair station, and was paid about $80K a year by a global prop manufacturer, my experience tells me that you can’t tell anything valid by eyeball, only real testing counts. Show the picture above to the guy at your EAA meeting who dispenses advice on every subject that comes up, and ask him which blade will perform better. Regard it as a study of aberrant humans, not valid performance advice.
.
-ww.
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:
.

.
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.
.

.
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.
.

.
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.
.
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.
.
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.
.
-ww.
.
Inexpensive carb testing
Builders,
Inexpensive carbs, the testing of the day. Dan Weseman had been looking at an adaptation of a specialized carb for a while. Today was the day we ran it for a long time and ran a lot of flow and hot start tests. It worked pretty good. It is made in America and costs about $400 new.
.
.
Above, the carb feeding a 2700cc Corvair on my run stand outside the SPA/Panther factory.
.

.
Above, The carb and adaptor to our standard Corvair manifold. The carb is aimed at 200 cid industrial forklift engines. It is not approved for aircraft use by the manufacturer, so if you need support from their tech department, it has to asked in a way that doesn’t threaten the job and livelihood of the guy answering your questions. For people who have a hard time reading between the lines: Don’t call nor email the manufacturer.
.
The 1/2″ thick aluminum adaptor was drawn by Dan at is desk, sent to his CNC machine, I tapped the holes, and it was on the run stand start to finish in 60 minutes. Note the carb mounting holes are recessed below the gasket line.As Dan said, some days it is fun to be at work.
.

.
Above, the carb in action. On the same engine, under the same conditions, it gave up less than 40 rpm to a perfectly tuned MA3-SPA. This is the stuff you learn testing. Visually, you can see from the adaptor above, the carb has a much smaller throat diameter than the MA3. If I show an internet discussion group the smaller carb, 90 percent of the people would state that it would be a terrible power loss. Testing proves that it isn’t. This is why talk is cheap, testing costs money, and being ignorant costs a fortune.
.
-ww.
.
Today’s contest: Identity this Corvair motor mount.
Builders,
OK CONTEST IS OVER!
The correct answer is Kitfox 5, 6, and 7, tricycle gear. Three guys guessed this, and I will send each of them a tee shirt, as soon as they write back with their size and address. Mike Maury was the first guy to mention this, because he has been waiting for this for a long time, and he is the “Outlaw Kitfox” guy mention in previous stories. He was say it in about an hour and mentioned this, but I didn’t say he was wrong, I just left it alone. Later, 2 other guys Bob Krause and Ken Paxton, followed Mike, and notice, I didn’t say they were wrong either. Don’t be mad, it was a great brainstorming session of classic homebuilts.
Dan and Rachel built several of these mounts, Mike’s is just the first one pictured. If you are a Kitfox guy, you can call Rachel direct at SPA/Panther for pricing and delivery. 904 626 7777 ext #1. These were several years in development, and now they are an on the shelf item. Progress. -ww.
.
Here is todays contest: Use the comments section to identify this motor mount. Bonus points for knowing which models of the aircraft it fits, and the landing gear configuration. First builder with the right answer gets a tee shirt, and the first smart aleck who guesses Cessna 162 will get a sack of rubber dog poop flown in from Hong Kong:
.
.
xxxxxxxxxxxxxxxxx
.

..
Above, the mount on a rotating stand. Picture was taken today in the SPA/Panther factory. Mount design and layout is by Dan Weseman, fabrication by Mr. Travis, aka “Retro Black“.
.
.
.
Above, right side up. Notice it has it’s own custom MA-3SPA intake and Custom exhaust.
.
Could be some hints here: Mounts at Oshkosh and Colleges.
.
May the most eagle eyed builder win. Start typing, if it takes two tries to guess right, we will send your tee shirt with the sleeves torn off, Larry the Cable guy style.
.
-ww.
.
xxxxxxxxxxxxxxxxxx
.
The dummy motor pictured has actually made about six trips to Oshkosh as my display motor, when it was cosmetically more youthful. We dressed it out with accessories to look real, but it spared risking a real engine getting damaged by weather or in transit It has no valuable parts inside. Every year, after the last day of the show, I would unbolt it from the stand, and leave it right out by the road overnight to see if anyone would heist it. Inside it was a note saying “I hope you had fun carrying this boat anchor all the way to the parking lot.” A potentially fun joke, but no one ever took it.
.






