9-Cylinder Aircraft Engine Model

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ppemawm
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9-Cylinder Aircraft Engine Model

Postby ppemawm » Fri Feb 21, 2014 9:55 pm

This project was a study in using Draft arrays and Part Design polar patterns. The parts were created from dimensioned drawings readily available on the Internet. Although the assembly looks somewhat complicated, it is actually quite simple when you consider that you only have to generally model only 1/9 of the common components or part features. The crankcase housing was the most time consuming to model since the polar pattern did not seem to function properly for nine features such as the cylinder bores. One workaround was to use three sets of three equally spaced features.

The complete engine assembly was created in one file from four subassembly STEP files: rotor, gearbox, crankcase, and cams. Each part was modeled in its respective subassembly file using parametric sketches located at mating faces. This helped to keep the files from growing too large and degrading performance. Fasteners are not included in the assembly models to save additional file space.

Edited to include computer,FreeCAD specs., and performance:
Hardware: 2012 TOSHIBA Satellite P750 Laptop, 64 bit OS, Intel I7 2670QM CPU @ 2.20 GHz, 8.0 Gb RAM
FreeCAD Configuration: OS: Windows 7
Platform: 32-bit
Version: 0.13.1828
Python version: 2.6.2
Qt version: 4.5.2
Coin version: 3.1.0
SoQt version: 1.4.1
OCC version: 6.3.0
Performance: The cutaway is the largest file (15.8 Mb), and it takes about 3 minutes to open.
9-CYLINDER RADIAL AIRCRAFT ENGINE_cutaway.JPG
9-CYLINDER RADIAL AIRCRAFT ENGINE_cutaway.JPG (71.47 KiB) Viewed 8959 times
9-CYLINDER RADIAL AIRCRAFT ENGINE_composite.JPG
Note the symmetry that can be exploited to minimize modeling time.
9-CYLINDER RADIAL AIRCRAFT ENGINE_composite.JPG (213.89 KiB) Viewed 8959 times
9-CYLINDER RADIAL AIRCRAFT ENGINE_rotor.JPG
This is the complete rotor including the rolling element bearings, but it does not include the actual tooth profiles for the many gears in the cam assembly and planetary gearbox.
9-CYLINDER RADIAL AIRCRAFT ENGINE_rotor.JPG (36.02 KiB) Viewed 8959 times
9-CYLINDER RADIAL AIRCRAFT ENGINE_pushrods-rockers-head_detail.JPG
These subassemblies were a bit tricky to model due to the various compound angles required for the axis of the valves and pushrods.
9-CYLINDER RADIAL AIRCRAFT ENGINE_pushrods-rockers-head_detail.JPG (58.72 KiB) Viewed 8959 times
Last edited by ppemawm on Mon Mar 03, 2014 5:38 pm, edited 2 times in total.
"It is a poor workman who blames his tools..." ;)
danielfalck
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Re: 9-Cylinder Aircraft Engine Model

Postby danielfalck » Sat Feb 22, 2014 12:21 am

Very impressive !
triplus
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Re: 9-Cylinder Aircraft Engine Model

Postby triplus » Sat Feb 22, 2014 12:33 am

Nice.
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NormandC
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Re: 9-Cylinder Aircraft Engine Model

Postby NormandC » Sat Feb 22, 2014 3:35 am

ppemawm,

Your projects are awesome. Thank you for sharing them. :)
jmaustpc
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Re: 9-Cylinder Aircraft Engine Model

Postby jmaustpc » Sat Feb 22, 2014 3:44 am

I just have to say ...I'm "epically frustrated" how useless FreeCAD is .... can anyone recommend a commercial application that will produce results ...there is nothing wrong with my methods ...its all FreeCAD's fault.... :lol:


Great work ppemawm! Thanks for showing your excellent model :)

I think it would be good with this forum if everyone would post the
1) Help about data for the FreeCAD version they used to create the model posted,
2) also a quick summary of the computer used e.g. cpu, ram,
3) the approximate amount of time it takes to open the file (for big complicated models)

The above information could be useful in the future for bench marking. Also the FreeCAD version may be important since many people are using a version over a year older than others, as well as special branches like Assembly etc.

Jim
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NormandC
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Re: 9-Cylinder Aircraft Engine Model

Postby NormandC » Sat Feb 22, 2014 3:54 am

jmaustpc wrote:I just have to say ...I'm "epically frustrated" how useless FreeCAD is ....
Sorry, but that was "epically frusterated". :P

And he did have a point on how OCC deals very poorly with fillets. Fillets are the Achilles' heel of most CAD modelers, but OCC is easily the worst of the CAD kernels on that. Have a look at my topic on "resilient modeling strategy", FreeCAD is simply unable to create the fillets that are on that demo part, I tried it and couldn't find a way. Solid Edge (which uses Parasolid) does it without a second thought...
jmaustpc
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Re: 9-Cylinder Aircraft Engine Model

Postby jmaustpc » Sat Feb 22, 2014 5:01 am

normandc wrote:Sorry, but that was "epically frusterated". :P
:lol:
normandc wrote:And he did have a point on how OCC deals very poorly with fillets.
If that was the case then why not name the topic something sensible and descriptive like "fillet - unexpected results" or whatever. I accept that FreeCAD has limitations, but really if you put a inexperienced driver in a Formula 1 car, they probably wouldn't make one lap before they crashed it. :) Sure, not all, but most of his problem could be worked around or came about due to bad practice.
normandc wrote:Have a look at my topic on "resilient modeling strategy", FreeCAD is simply unable to create the fillets that are on that demo part, I tried it and couldn't find a way. Solid Edge (which uses Parasolid) does it without a second thought...


Yes I did, it was really fascinating! :) I think you should put that on the wiki somewhere. Perhaps we could have a page on training with links to both FreeCAD specific training information and another group to general CAD training?
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Bressan52
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Re: 9-Cylinder Aircraft Engine Model

Postby Bressan52 » Mon Nov 16, 2015 7:49 pm

MASTER!! Congratulations!!! Veeeeery inspiring to us FreeCad newcomers.
--
Bressan
japie
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Re: 9-Cylinder Aircraft Engine Model

Postby japie » Sun Dec 13, 2015 3:40 pm

Nice work!

I would like to use the step file to see how this engine will look inside a small tractor puller... :-)