Anzani Engine Project

[David Paule]

The weather was pretty decent for December, and we looked at the crankshaft with the connecting rods still installed. It seemed like a good day to disassemble it.

The connecting rods have slipper pads and retaining rings that I’m calling slipper rings. Under the slipper pads are the connecting rod big ends, and then the journal bushings. The first photo shows the arrangement. You can see the way the bottom end of the connecting rods is shaped. The rings go outside the connecting rods and the bushings go under the connecting rods. They are independent and all three assemblies – four if you count the connecting rods – move independently.

In the second picture Roger is working on the special nut-removal tool. Two of the nuts and the tool are shown in the third picture. The nuts are tubes with square grooves or notches in the top end for cotter pins. The bolts have round heads with fat screwdriver slots, so fat that Roger or Craig brought a special tool for that. Both the heads of the bolts and the nuts fit snugly in between the slipper ring flanges and, being round, there was no way to turn them with a conventional tool.

When I’d started disassembling the engine quite some time ago, I logged the disassembly torque. It was the only way I could get any idea of the original torques. We continued that here, and were somewhat dismayed to find that all eight nuts (two on each slipper ring assembly, two assemblies per journal, and two journals – or two to the third power, or eight, if you like math) were finger tight. They are merely lock nuts, jam nuts, essentially.

It was a bit harder to remove the bolts than the nuts. They were threaded into the slipper ring half that was on the nut side. The torques for these were:

Forward journal, forward slipper, 175 and 190 inch pounds torque,

Forward journal, aft slipper, 90 and 160 inch pounds torque,

Aft journal, forward slipper 160 and 150 inch pounds torque,

Aft journal, aft slipper, 120 and 150 inch pounds torque.

The average is 155 to 160 inch pounds torque, not counting that 90 inch-pounds value.

The slipper rings have one inside edge rounded off. The inside edge not shown is squared off. The rounded edge is against the connecting rods, where there’s a fillet radius.

Once the slipper rings were removed, the connecting rods came off easily. They were individually stamped with identifying figures. Unfortunately those didn’t particularly relate to the cylinder position, and in a glaring oversight, I didn’t note which connecting rod went to which cylinder when we removed the crankshaft from the case.

The connecting rods ride on brass bushings on the journals. The brass bushings are interesting parts, with grooves on the edges to ensure that they mate tightly. Inside, there is a circumferential lubrication groove. If you look closely, you’ll see that the groove isn’t centered. The journal’s oil hole is both large diameter and centered, and the groove fits over the hole.

The mating bushing half is identical. When they are together on the journal, they are reversed, with the slots on different sides of the hole. When we took off the first one, we couldn’t believe that was the way it was intended. We were very careful on the second one to ensure that we didn’t inadvertently flip one half around, but sure enough, it was the same way. Then we observed on the crankshaft, in the preservative marks, that both were assembled that way. Good confirmation.

The crankshaft is pressure lubricated and that oil comes into the journal between the journals and the bushings. It would then seep out from the ends of the bushing and get into the bottoms of the connecting rods. From there it would lubricate those, and then escape from between the slipper rings and from the spaces at the ends of the slipper rings. The only other path for oil to lubricate this area is splash lubrication, and I suspect that’s where a lot of oil for this area comes from, just loose oil flying around in the case.

[DutchNostalgicWings]

David,

thank you for the update on your project. Things are a bit on the slow end overhere. Latest news is that a jack will be created so we can test the engine and calculated its performance. We still are in doubt of what the Anzani is able to deliver and wether its enough to power the Pietenpol.

André

[David Paule]

If you can use a long enough prop to take advantage of the slow speed of the Anzani, you'll get more efficiency and more thrust. But the Pietenpol might need a longer landing gear.

The propeller that we have for this engine is 203 cm diameter and 196 cm pitch. The pitch appears unreasonable at first, compared to other props for Pietenpols, but it's appropriate for the lower engine speed and faster airplane that it was originally designed for, and we merely copied the design. Perhaps a pitch of 156 cm might be more appropriate for a Pietenpol.

If yo go back to the very first posting in this discussion, on page 1, you'll see how a low drag nose can be created around the domed version of the Anzani. You might be able to make something similar for yours, and that will help the propeller efficiency.

[David Paule]

Twas the night before Christmas all over the place,
When we were suddenly confronted by an old flying ace.
There was icing reported and turbulent air,
He said "File me a flight plan, I gotta get there."
Outside sat his aircraft all ready to run,
And the old man walked out to that P-51.
"bad weather's no problem," he silently mumbled,
The prop came to life. . . that big Allison rumbled.
He eased in the throttle, the roar shook the ground,
He taxied on out and he turned it around.
He went through the run-up and seemed satisfied,
Then he said to himself, "I'm in for a ride."
So he lined it up straight as he poured on the coal,
The tailwheel came up as he started to roll.
Up off the runway, he sucked up the gear,
And that mighty V-12 was all you could hear.
He screamed overhead with a deafening crack,
The blue flames were flying from each shiny stack.
He pulled up the nose and started to climb,
No ice on that airframe, it didn't have time.
On top of the weather with the levers all set,
He looked up above him and saw a Lear jet.
With jet fuel and turbines there just ain't no class,
Gimmee pistons, and props and lots of avgas!
Now he was approaching where he wanted to go,
But weather had covered the runway with snow.
How will he land it? We just have to guess,
Because the only way in was a full I-L-S.
Then over the marker, he started his run,
The ceiling was zero, visibility was none.
Still going three hundred and he felt the need,
For an overhead break to diminish his speed.
Over the numbers he zoomed, along like a flash,
Pulled into his break, we just knew he would crash.
Oh, why do they do it on these kind of nights??
Then over the threshold, we saw landing lights.
"I'm on a short final with three in the green,
And I see enough runway to land this machine."
When he tied down that Mustang, they all heard him say. . .
"Next year, I'm stickin' with my reindeer and sleigh."

Don't know who wrote it, but whoever it was, thanks!

[David Paule]

First thing - our best wishes to everyone for a very happy new year!

Yesterday afternoon, we took the crankcase down to a local engine rebuilder to have the case cleaned and the oil pump shaft bushings line-bored. We expect to get those back late next week.

The rebuilder had a 1928 Ford Model T crankshaft on display that was even more flexible than the Anzani crankshaft. I still can't believe something like that would work. For comparison he brought out the master rod for some large radial engine. What a world of difference! The master rod weighed more than the Anzani crankcase.

He told us to be careful with the clearances. He said not to get them too small. Keep them large. That rang a loud bell. Colin Smith, Croydon Aircraft Co., sent me an email this week that included a similar caution:

"My experience with operating older aircraft engine over may years, has been
to avoid the temptation to reducing the original clearance, especially in
air cooled engines, and be ever mindful of the wonderful benefits that
castor oil offered to early engine manufacturers."

Thanks to both of you. We'll try. I've got to confess that Roger and Craig had thought that the clearances ought to be smaller than we were finding, so these comments were quite timely.
.

[David Paule]

Regarding oil:

Colin, from Croydon Aircraft, in New Zealand, writes:

"Re: Castor Oil as a lubricant.
Due to the normal heat range encountered during combustion on a number of these earlier engines ( quite low compression ratios) castor oil did not burn, therefore produced no or little carbon, but was exhausted still as a lubricant, which also helped with the cooling of the exhaust valves, but made somewhat of a mess and stain of those parts it came in contact with."

André Jans, from the Netherlands, writes:

"In the beginning he (http://www.bleriot.org/docs/HansFurrer.htm ) did use Castor oil but stopped as the oil messed up the engine (and plane) and using it is not really required. He says that regular oil (without special doping) works fine as well so he stopped using Castor oil."

===============

Colin also said:

"In one other of your photographs of the piston rings, you mention the little vertical marks on the inner face. This method of stamping with a suitably made punch was an old fashioned means of attaining the correct tension (or pressure) of the ring against the cylinder wall."

André and Colin, thanks very much.

[David Paule]

We got the crankcase back from the engine shop today, and learned that the cylinder hold-down bolts are individually numbered. The numbers are at the crankcase end. The crankcase sockets for these are stamped to match.

Also saw Service Bulletin No. 1. I'd bet that's the only one. It's from about 1927 or 1928, nine or ten years after the engine was built. It says that the engine should be converted from a dead-loss lubrication system to having a drain tank, with a remote pump to a supply tank located above the oil pump. In addition, the oil pump gasket, used as a shim to restrict the oil volume (!) should be removed.

The original oil system attempted to pump just enough oil to lubricate and cool the engine, but not so much as to make it impossible to carry enough oil along on the flight. As the engine operated, wear caused the oil consumption to increase - or it would if the pump would permit that. Mechanics would compensate by using a gasket to restrict the oil volume pumped.

Next up is some more cleaning and then the engine goes out for dye pentrant and magnetic particle inspections.

[David Paule]

I relocated the project to the airport. It had been in my garage. We now have lights and heat, a substantial improvement.

Craig and Roger asked me to obtain a parts cleaner, so that's on the list. There are a few more infrastructure requirements besides that. The smallest one is to supply some pencils. Yeah, I forgot that when we met this week.

Here is a photo of one of the crankshaft journals, showing some scratching. We should have looked at the associated journal sleeve, but we didn't. It was more of an intro to the new shop than a work session, after all.
.

[Maxim08]

David,
Just found this thread which is fascinating. Looking forwards to more posts.
Regards,
John

[David Paule]

We met at the new airport location, and enjoyed having a heated shop. Big improvement. Plus, there are reasonable tables available. Work stools are still lacking and I've got to find some. We're needing to stand.

I borrowed a parts washer but didn't think handling the waste products would be easy since the washer likes to have 20 gallons of fluid. Instead, I bought three gallons and a separate waste container and some disposable but reuseable aluminum cooking trays and that's working out acceptably well. I'm using Stoddard solvent, a common petroleum fluid used as paint thinner and even barbecue lighter fluid. It's considerably safer than leaded and dyed avgas, which is also available. It's at an airport, after all.

I'll be returning the parts washer one of these days.

Roger and Craig cleaned some of the crankshaft bushings, a connecting rod and the crankshaft. The front bearing on the crankshaft is a ball bearing with two separate rows of balls. One row is for radial loads and the other for thrust loads. It is fully populated with balls and there's no cage. Kind of an unusual bearing, but Craig said it felt good.

He was unable to get the back bearing clean enough to rotate.

Both bearings are pressed on to the crankshaft.

Here's a picture of the crankshaft, and a close-up of the front bearing with one of the oil passage holes, as yet still clogged. The bearing has a number: 03941.