Author Topic: 8 cylinder Marchetti Radial Cam Engine  (Read 8733 times)

Offline BillTodd

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Re: 8 cylinder Marchetti Radial Cam Engine
« Reply #15 on: November 02, 2015, 05:44:37 PM »
Thanks Chuck, I'll pass this on to Wesley. i know he reads this forum but i also know he's been distracted by the fantastic offer of a  US scholarship,  so he may miss your .

Bill
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Offline BillTodd

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Re: 8 cylinder Marchetti Radial Cam Engine
« Reply #16 on: January 04, 2016, 09:24:47 PM »
Another update from Wesley...

He is initially making  a pair of cylinders as a test . Here are picture of the cylinder valves , piston etc.
Bill
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Offline BillTodd

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Re: 8 cylinder Marchetti Radial Cam Engine
« Reply #17 on: May 08, 2016, 01:31:33 PM »
Another update.

Wesley has been busy studying but has been making progress , a very fine flywheel has been constructed with thin spokes to allow a minimally restricted view of the cam mechanism...

Well ... it works!  The two cylinder test is a triumph - it really is working well

 http://www.dailymotion.com/Wesley_Tech  (this is ad sponsored so disable any ad blocker or it will hang)
Bill
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Offline BillTodd

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Re: 8 cylinder Marchetti Radial Cam Engine
« Reply #18 on: August 15, 2016, 01:18:14 PM »
More progress:

Wesley has almost completed the other 6 cylinders and started work on the air distribution system and a  stand for the model.

Now he has to master the art of tube bending and how to work with a dead tree !

Plans are afoot for an IC version ....
Bill
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Offline BillTodd

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Re: 8 cylinder Marchetti Radial Cam Engine
« Reply #19 on: October 17, 2016, 08:13:05 PM »
Wesley's progress continues even with the pressure of university work  :NotWorthy:

He's all but finished the other six cylinders and has been working on the peripherals...

Take a look at this stand and weep  - can you believe this is his first time working with wood?  This kid's got real talent  :praise2:

He's even produced a high resolution version of the companies logo for an engraved name plate.

 
Bill
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Offline BillTodd

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Re: 8 cylinder Marchetti Radial Cam Engine
« Reply #20 on: December 12, 2016, 12:14:56 PM »
There was a discussion earlier in the thread about vibration :
Quote from: Bill Todd
To my eye the Marchetti looks to have a greater problem : 8 pistons, conrods, bearings etc. all stopping and starting at one time

Something that Wesley has pointed  out , that had not occurred to me at all,  is that the Marchetti cams move the pistons in a pure sinusoidal motion . 

So it is possible that the Marchetti engine could well have been smoother than one with a crank.

Bill

Yes, an eight cylinder at 45 degrees would have helped with the fourth order torque problem :-) 

>Aircraft  never rolled under own power.
Actually the Caminez did fly: (perhaps you mean the marchetti?)

"The Fairchild-Caminez 447 was first flown in an Avro 504 from Farmdale, Long Island, New York, in 1926. It was successfully endurance-tested in 1927, and was the first ever axial engine to receive a US Dept of commerce type certificate. "


To my eye the Marchetti looks to have a greater problem : 8 pistons, conrods, bearings etc. all stopping and starting at one time
Bill
wy omnibus Latinis taurus stercore?

Offline Wesley_NL

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Re: 8 cylinder Marchetti Radial Cam Engine
« Reply #21 on: December 18, 2016, 09:00:35 PM »
Hi everyone,

I am the builder of the model Marchetti engine discussed here. Roughly two years ago I got interested in the Marchetti after reading about it on oldmachinepress.com and douglas-self.com. I was eager to experiment with the mechanism and contacted Bill because he made the animation featured on that website. He helped me with information and ideas but also asked me to keep him updated about the progress I made. With it, he kept everyone on this forum informed with the progress.

Since his previous update, more progress has been made. A separate stand is made with an air filter, air lubrication and air flow regulator (see attached picture). The nameplate is finished and of course there are also setbacks, this time with the cylinders. A short time after they were finished (few weeks), a very noticeable corrosion appeared. See the attached picture. I don't know what the precise material is (I got this material from leftovers) but it's not regular brass. I am not yet sure how to prevent this kind of corrosion. My current plan is to use sand paper to remove the marks and then apply a transparent protective layer (wax, varnish or plastic spray). Hopefully that will prevent the corrosion from reappearing in such a short time.

There is more and bigger news:
As of today I have made a website available that is intended to help people learn how to understand and build this specific engine. The main reason for this is that in order to create the cam curves, some interesting but also challenging mathematics are required. I realise that this could be a problem for many model builders. Therefore I have put time and effort into making a website with step by step instructions. All model builders who have basic knowledge with a CAD program should now be able to build a Marchetti engine without having to overcome the maths obstacle. You can visit the website at: http://marchetti-engine.com/

If you have questions, feel free to contact me! I would also love to hear about other possible cam action projects! It is a beautiful mechanism :)


Offline BillTodd

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Re: 8 cylinder Marchetti Radial Cam Engine
« Reply #22 on: December 19, 2016, 04:18:13 PM »
Animation based on Wesley's Cam design
Bill
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Offline Wesley_NL

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Re: 8 cylinder Marchetti Radial Cam Engine
« Reply #23 on: December 19, 2016, 07:09:05 PM »
I'm happy to see that the instructions are useful!

Online kvom

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Re: 8 cylinder Marchetti Radial Cam Engine
« Reply #24 on: December 19, 2016, 07:26:43 PM »
I downloaded the Solidworks PDF from curiosity.  I'm wondering what you don't also include the SW parts files for download.

Offline gerritv

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Re: 8 cylinder Marchetti Radial Cam Engine
« Reply #25 on: December 19, 2016, 05:35:28 PM »
Bill Long's animation makes it look like a beating heart. Amazing.

Gerrit
Programming is like a Hit-n-Miss engine

Offline Wesley_NL

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Re: 8 cylinder Marchetti Radial Cam Engine
« Reply #26 on: December 19, 2016, 08:13:23 PM »
I downloaded the Solidworks PDF from curiosity.  I'm wondering what you don't also include the SW parts files for download.

I'm currently a student, if I would start releasing Solidworks models it might backfire due to licence restrictions. I am not willing to take that risk, that's why I put some time and effort into making those instructions as helpful as possible. If you want to build a Marchetti engine, making the cams with perfect geometry is really the hardest part.

Offline Wesley_NL

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Re: 8 cylinder Marchetti Radial Cam Engine
« Reply #27 on: December 31, 2016, 12:23:29 AM »
Progress has been made on the website http://marchetti-engine.com/. The following parts of my work and research are now publicly available:

  • A remake of the historical company logo, available in high resolution and also in dxf format
  • An explanation with all the details on how the mathematical solution of the cams is obtained
  • All details on the method I used to estimate the original dimensions of the engine invented by Paul Marchetti
  • An interactive calculator which visitors can use to calculate their own cam geometry

Feedback and questions are always welcome!

Offline BillTodd

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Re: 8 cylinder Marchetti Radial Cam Engine
« Reply #28 on: December 31, 2016, 02:13:55 AM »
Great stuff Wesley  :NotWorthy:

Lovely animations too 

Interesting analytical derivation, not to difficult follow (but I'm glad you didn't ask me to help with the maths - that's way above my head  :headscratch: )
Bill
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Offline Wesley_NL

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Re: 8 cylinder Marchetti Radial Cam Engine
« Reply #29 on: March 13, 2017, 07:44:44 PM »
Hi all, there's more progress:

An oil reservoir is created for lubricating the engine from the top downwards. The brass tubing on the inside of the engine is also completed and looks quite amazing! The air supply through the wooden stand is finished and the frame + wooden stand are ready to be assembled (see pictures). My next challenge is to create the tubes leading from the engine to the cylinder heads (see figure "Air_distribution_cylinderconnection.jpg". As far as I can see now, this is the last remaining challenge before final assembly.

Also, you can now toy around with the Marchetti engine because the online calculator got a big upgrade:
- You can link to it directly: http://marchetti-engine.com/calculate
- It actually shows each of the wheels rotating, so people who are new to the mechanism can immediately see what's going on
- Hovering your mouse over the graphical area allows you to examine the mechanism at any orientation you like
- You can enlarge it by double-clicking on it (double click again to size it back)
- Enter crazy values, it's really a toy now :)

For those wanting to build their own Marchetti engine: the default parameters are my best estimation of the true historical dimensions. The main website shows the research, elaborating on how exactly those values are obtained. If you want to build the Marchetti engine on a different scale, all you have to do is scale those default values. Then you can export the cam coordinates for your own CAD model (instructions are also on the main website).