1/4 scale Anzani Fan Engine

[creast]

This engine has been discussed in several threads on this forum and after creating a 3D model from Ken Rector's plans I have bitten the bullet to try and make one myself.
I will probably make some changes to suit my manufacturing capabilities as the project progresses and I suspect this will be a long project.
I am aware that some casting kits may still be available in the USA but as I enjoy foundry work I will attempt to cast many of the parts myself using 3D prints for both sand and lost PLA/ Resin investment castings.
First off I printed the front crankcase half which took 4 hours and then many hours of body filler and sanding to reduce print lines which show up horrendously on the casting. In most cases these can be dressed back on the casting but I decided to spend more time on the pattern.
I decided to run with the model having zero draft as it was created which may be risky but a test mould showed it was workable. The rear cavity however needed significant draft to achieve a self supporting greensand core. The draft angle ended up being 12 degrees and may be because my Petrobond sand is getting tired and in need of rejuvenating.

 

[creast]

The crankcase half was clamped on the mill bed and a pilot bore made through the nose of the casting and its face squared off.
The case was then transferred to the lathe using a spigot mount to clamp the casting square to the bore and allow the rear recess to be gingerly bored out.
Another fixture plate was machined to match the bore of the casting and the latter was superglued on its face to the fixture which enabled the nose to be bored out to size and faced to length. Heating with a blowtorch enabled the casting to free itself of the fixture.

 

[petertha]

Nice. I don't want to deflect your build post into a casting discussion, but just curious what is the alloy source/recipe for that casting? Do you do anything in the way of post hardening / artificial aging? How would you describe it relative to say off the shelf 6061-T6 from the standpoint of common machining, fine thread tapping etc. Looks like it replicated those webs quite nicely, about how thick are they? (I'm casting illiterate, just ordered a few used books to absorb some basics).

 

[creast]

Nice. I don't want to deflect your build post into a casting discussion, but just curious what is the alloy source/recipe for that casting? Do you do anything in the way of post hardening / artificial aging? How would you describe it relative to say off the shelf 6061-T6 from the standpoint of common machining, fine thread tapping etc. Looks like it replicated those webs quite nicely, about how thick are they? (I'm casting illiterate, just ordered a few used books to absorb some basics).

Peter,
Most of my castings are from an alloy wheel rim as it is a castable alloy and cheap to obtain. Machining properties are pretty rubbish really as most castable alloys don't machine as nice as wrought alloys like 6061. The swarf is fine chips and I do find threads are way much weaker.
It is difficult to get a nice bright shiny cut on this alloy
I have tried age hardening with little success and the process is way lengthy to actually do as a hobbyist, like 8 hours at controlled temperatures.
I know most foundry folk say don't try and cast wrought alloys but I have on occasion. they don't flow as readily but machine better but can be gummy so very sharp HSS tools are best. Again you will be working with annealed properties on the finished casting.
Some people say quenching straight from the casting setting helps but I have not seen any noticeable effect.
The webs are 3mm thick.

 

[creast]

Today was started with my first problem.
I clocked up the bore on the mill as datum for drilling the eight crankcase bolt holes and on checking the centre drill positions for each boss it was obvious that something wasn't quite right. Without a co-ordinate measuring machine it would be difficult to dial in the correct positions.
Maybe the casting shrinkage wasn't quite as expected or irregular due to section changes or whatever.
To solve the problem, I made a guide tube with a chamfer to locate on the bosses and guide a custom centre punch to mark each boss.
The holes were then drilled off these punch marks manually.
Hopefully this can be translated to the rear case!

 

[creast]

Next challenge was casting the rear case which was the afternoons task.
The first attempt showed bad shrinkage at the cylinder mounts but may just be salvageable.
I tried another, This time the shrinkage was resolved but there was significant sand pull out or ingress and again just may be salvageable given the machining allowances. Hmmm!
I know I wasn't making life easy by not re-working the model to have at least some draft but I think I can get away with it.

 

[creast]

Progress has not been great. So far I have cast three rear crankcase halves and all manner of niggles with all of them.
I machined the casting with shrinkage and managed to get it to clean up. bored it out and then found discrepancies in the alignment of the ribs and cylinder mounts.
If these castings were die cast life would no doubt be easier!
The biggest problem is establishing the correct datum for machining and the fact that two castings with differing volumes and maybe different shrinkage rates due to casting temperature will not necessarily produce matching halves.
Because the castings are quite small, less than 75mm dia, there is not much scope for error.
Anyway, I ended up matching the very first casting to the front case which looks pretty darn good. I have picked up off the front casing holes to allow studs to be fitted and clamp the two together. Hopefully I can then use the front casing bore on a mandrel/fixture to machine the rear datum bore.

 

[creast]

Boring the rear casing whilst locating from the nose bore went without a glitch and the assembly was transferred to the mill to face off each of the cylinder mounts.
Next stage is to bore these faces plus tapped holes to accept the cylinders . The central mount had a casting defect but luckily this will be machined out.
Bit of a beak now for a week off.

 

[Olli-Matti]

Well done creast! The case looks beatiful. Going to be watching this thread closely.

I would be interested to know how are you planning to hold the case to get the cylinder center lines to meet the crankshaft center line precisely and bore the cylinder mounts? Is it a one setup operation with a rotary table or three separate operations?

I have zero experience in building a radial engine so just wondering. This would be an interesting subject maybe in the future for me.

 

[creast]

Well done creast! The case looks beatiful. Going to be watching this thread closely.

I would be interested to know how are you planning to hold the case to get the cylinder center lines to meet the crankshaft center line precisely and bore the cylinder mounts? Is it a one setup operation with a rotary table or three separate operations?

I have zero experience in building a radial engine so just wondering. This would be an interesting subject maybe in the future for me.

Hi Ollie,
Thanks for the kind comments but I think it looks better in the photos than in the eye
This is not quite a radial but a bit more than the V-twin Vega I made. I am still working up to doing a real radial.
As to the case boring situation, I intend to first clamp the back casing in the mill vice and use an edge finder to set the x datum zero from the fixed jaw to the split line.
The case halves would be re-assembled and clamped in the vise and the flat levelled with a digital level, after which the edge finder will be used to find the Y centre and zero.
The bore will be 28mm so I need to use a boring head in the mill.
There may be some tweaking on the way to shim or whatever to achieve the crank alignment but it is a one off engine so I won't get sacked by Henry Ford for not making it a production item .

Well that's the theory anyway lol.
Rich

 

[Peter Twissell]

When aligning the cylinder faces to the crankshaft, most important is that the faces are parallel to the crank axis.
Small errors in the position of the cylinder bores, both along and across the crank axis will not be a problem in terms of the piston / rod / crankshaft geometry.
Nice work - I do like the Anzani engines and I may well build one for a flying model.

 

[creast]

When aligning the cylinder faces to the crankshaft, most important is that the faces are parallel to the crank axis.
Small errors in the position of the cylinder bores, both along and across the crank axis will not be a problem in terms of the piston / rod / crankshaft geometry.
Nice work - I do like the Anzani engines and I may well build one for a flying model.

Thanks Peter.
I did my best to achieve that using a snug fitting dowel rod from the spindle nose. I don't have sophisticated measuring equipment to verify that but I am sure I will find out on assembly.
Rich

 

[creast]

Today I managed to squeeze a three hour session in the workshop and managed to bore out the cylinder mounts which was very tedious starting from 10mm dia to 28mm in 0.25mm cuts on the boring head. Mind-blowing tedium!
Still, it has to be done
Oh, and I forgot to drill one of the tappet holes so that will have to be revisited later.

 

[GreenTwin]

Very nice casting/foundry work you have there !

Some people insist that draft angle must be used always, but sometimes you can get away with no draft angle if you are lucky.

I researched a T6 tempering process, and it is an 8 hour first temper at an exact temperature, followed by an immediate water quench (hot or cold), and then I think four hours at 400 F.

The T6 process really seems to help getting rid of the gummyness and tool bit buildup, and makes the part feel harder/stronger if there is a way to sense that. Seems to cut cleaner on the lathe, and drill and tap more cleanly.

The digital controllers are not expensive, and I have purchased one, but have not got it completely set up.

If the temperature is not closely controlled, then you can actually hit overtemperature, and the castings can sag, as I sadly found out on a few parts.

Great work; this is going to be a nice engine, I can tell already.

.

 

[creast]

Very nice casting/foundry work you have there !

Some people insist that draft angle must be used always, but sometimes you can get away with no draft angle if you are lucky.

I researched a T6 tempering process, and it is an 8 hour first temper at an exact temperature, followed by an immediate water quench (hot or cold), and then I think four hours at 400 F.

The T6 process really seems to help getting rid of the gummyness and tool bit buildup, and makes the part feel harder/stronger if there is a way to sense that. Seems to cut cleaner on the lathe, and drill and tap more cleanly.

The digital controllers are not expensive, and I have purchased one, but have not got it completely set up.

If the temperature is not closely controlled, then you can actually hit overtemperature, and the castings can sag, as I sadly found out on a few parts.

Great work; this is going to be a nice engine, I can tell already.

.

Thanks Pat,
It has not been an easy ride for sure having made 3 rear casings and two front so I have to be careful how I work on this and not scrap it!
I have a small kiln with PID controller and did try to age/precipitation harden a part once before but am unsure if I did it correctly (pretty sure I did) or if the fact I am using alloy from an auto wheel rim of unknown analysis.
Maybe one day I will repeat using a certified source of alloy.
Cheers
Rich

 

[GreenTwin]

Our resident aluminum scrapper guy "ArtB", who makes and sells aluminum ingots in his large scrapping furnace, mentioned the other day that all aluminum car rims that have been manufactured in recent years are made from 356 aluminum, so I would say you have the correct alloy.

I looked for my exact data on T6 tempering, and of course I could not find it.
As I recall, it was 1,000 F for 8 hours minimum, followed by an immediate water quench.
Cold water quenches are said to potentially cause warpage, compared to hot water quenches, but I did not have any warpage problems using cold water.
Then 4 hours at 400 F.

I was very pleased with my T6 results.

The books say that anything less than 8 hours at 1,000 F does not work.

If I were using aluminum castings for engine work, I would definitely use the T6 temper method on them.

.

 

[creast]

After having a week off on vacation I got back into the workshop.
I decided to bite the bullet and try my first go at casting iron using my diesel fired furnace.
The iron was from an ornamental fire surround I had kicking around and the broken pieces had nice uniform grey structure at the breaks.
I have never tried this before and it became apparent that I need to up the nozzle rate which is a frugal 0.5 gal/hour to a more generous rate.
After 40mins for a meagre 1kg in a A5 crucible the iron was molten but not sparkling so I boosted the burner with additional propane for another 15 mins.
I still wasn't convinced the iron was hot enough but decided to pour anyway.
Surprisingly the mould filled and hopefully these flywheel halves will machine up ok! Oh and I realised I hadn't put the recess feature for the shaft but this can be machined.
Now to order a bigger nozzle

 

[GreenTwin]

That's just an awesome iron pour, especially for a first try !

If you are runing a siphon nozzle, such as a Delavan, note that you can up the flow rate considerably, such as over a 4:1 ratio, or higher, just by increasing the compressed air pressure.

I operate my nominal 1.0 gal/hr nozzle at 2.7 gal/hr (diesel), but have operated it up to 10 gal/hr in experiments, and it will actually work at 10 gal/hr.

My furnace interior is about 13" x 14", so you may need proportionally less fuel flow with a smaller furnace.

And a slight amount of 75% ferrosilicon will improve fluidity, but more importantly will eliminate chills (hard spots) in the thinner sections.

And the rule is to leave iron castings in the mold until they are completely cool, which may take 24 hours.
If you pull an iron casting out of the mold when it is still hot, you generally get a lot of chills and hard spots.

Once I started casting gray iron, I never considered using anything else.
I do use some aluminum for making permanent patterns.

That is a great effort for sure.
Most impressive.
Welcome to the iron club.

.

 

[creast]

That's just an awesome iron pour, especially for a first try !

If you are runing a siphon nozzle, such as a Delavan, note that you can up the flow rate considerably, such as over a 4:1 ratio, or higher, just by increasing the compressed air pressure.

I operate my nominal 1.0 gal/hr nozzle at 2.7 gal/hr (diesel), but have operated it up to 10 gal/hr in experiments, and it will actually work at 10 gal/hr.

My furnace interior is about 13" x 14", so you may need proportionally less fuel flow with a smaller furnace.

And a slight amount of 75% ferrosilicon will improve fluidity, but more importantly will eliminate chills (hard spots) in the thinner sections.

And the rule is to leave iron castings in the mold until they are completely cool, which may take 24 hours.
If you pull an iron casting out of the mold when it is still hot, you generally get a lot of chills and hard spots.

Once I started casting gray iron, I never considered using anything else.
I do use some aluminum for making permanent patterns.

That is a great effort for sure.
Most impressive.
Welcome to the iron club.

.

Thanks Pat
I am running a standard Danfoss nozzle via my home made gear pump.
I did add ferrosilicon slightly above the 1:800 ratio I read somewhere on the net.
Hmmm. I did pull the casting after 30 mins so hope I haven't done harm!!
Just ordered a 1gal/hr nozzle to try
Rich

 

[GreenTwin]

It will be interesting to see if 30 minutes is ok, or if that is too short a time period.

Perhaps 30 minutes is enough.
I err on the side of caution with an overnight cool, but that my not really be necessary.

.