V0.18 Challenge--Clerget 9B Aero Engine--UPDATE #6

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chrisb
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Re: V0.18 Challenge--Clerget 9B Aero Engine--UPDATE #4

Postby chrisb » Fri Aug 24, 2018 12:05 am

Awesome. I enjoy your posts with these great models, which get even better with your documentation.
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easyw-fc
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Re: V0.18 Challenge--Clerget 9B Aero Engine--UPDATE #4

Postby easyw-fc » Fri Aug 24, 2018 3:35 am

ppemawm wrote:
Thu Aug 23, 2018 9:21 pm
easyw-fc wrote:
Thu Aug 23, 2018 8:07 pm
you can use 'Part' container
If you examine the tree in the first image you will see extensive use of Part containers. There are times, unfortunately, when Draft>clones, Draft>arrays, and Part>mirrors do not play well with bodies and parts when it is time to move components around in an assembly. At least, that is my humble experience.
Part container is the right candidate for your needs. I use it intensively too to create assemblies of STEP models, in conjunction with my Manipulator WB to align parts and sub assemblies.
If you have some issue with Part container and Draft>clones, Draft>arrays, and Part>mirrors, you may consider to post some example that is creating these issues to help in fixing those.
ppemawm wrote:
Thu Aug 23, 2018 9:21 pm
Once we have Assembly3 integrated with FreeCAD proper, then perhaps life be all good. If it can handle this model I will be impressed.
A3 developing branch is in high developing cycle; it would benefit a lot if you could test one of your complex models in this branch too.
There are pre-built images of the three OSes that can be downloaded for full testing evaluation here:
https://github.com/realthunder/FreeCAD_ ... 3/releases
freecad-heini-1
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Re: V0.18 Challenge--Clerget 9B Aero Engine--UPDATE #4

Postby freecad-heini-1 » Fri Aug 24, 2018 2:38 pm

Congratulation for your great work ppemawm. From time to time some new Freecad users complain that Freecad is slow and that they are not able to set a coincident constraint between two lines in the sketcher. They should have a look at your work to realize how far they are behind you. I hope they realize that they need to learn to work with Freecad for month / years to reach this high level.
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Wilfried
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ppemawm
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Re: V0.18 Challenge--Clerget 9B Aero Engine--UPDATE #4

Postby ppemawm » Fri Aug 24, 2018 3:40 pm

easyw-fc wrote:
Fri Aug 24, 2018 3:35 am
If you have some issue with Part container and Draft>clones, Draft>arrays, and Part>mirrors, you may consider to post some example that is creating these issues to help in fixing those.
Good suggestion. If I can reproduce some of these problems I will report them in a new post. So far, I have not been able to narrow it down.
And, unfortunately I cannot share this file.
easyw-fc wrote:
Fri Aug 24, 2018 3:35 am
it would benefit a lot if you could test one of your complex models in this branch too.
Another good suggestion. When I complete this engine in a month or two I will consider doing this, although for my purposes, I do not need a fully constrained assembly. But, it would be good to learn something new for the future.
freecad-heini-1 wrote:
Fri Aug 24, 2018 2:38 pm
I hope they realize that they need to learn to work with Freecad for month / years to reach this high level.
It is not as difficult as it may appear although one must be committed to experimenting with and learning all of PartDesign tools and maybe 10% of Part and Draft workbenches (mostly arrays, mirror, clones, shapestrings, helix, etc.). I started by creating 100's of very simple models that eventually needed all of these tools, then, practiced and practiced with the use of Placement properties, and recently the Attachment modes which debuted with with V0.17. If you learn to not attach sketches or datums to vertices, edges, or faces then the frustration is minimal when making changes. Once you get this far after a few months of part time effort, building complex models like this engine is just more of the same. And, loads of fun and satisfaction.
"It is a poor workman who blames his tools..." ;)
triplus
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Re: V0.18 Challenge--Clerget 9B Aero Engine--UPDATE #4

Postby triplus » Sat Aug 25, 2018 9:05 pm

ppemawm wrote:
Thu Aug 23, 2018 7:16 pm
The main engine file has grown so large (139 Mb) that it is no longer practical to add new models due to the delay in opening the file, recomputes, and frequent auto save. As a consequence, I have created a new file for each of the accessory assemblies: magneto, oil pump, and air pump. These are quite complex machines in themselves. My plan is to merge these with the engine file upon completion so that everything is in one file for reference.
Yes here things still aren't all that optimal ATM. I was rather optimistic FreeCAD 0.18 will be Link enabled. Therefore you could at least avoid "merging" and achieve "linking" with ease. But i guess merging and manually placing could continue to be the recommended option when it comes to FreeCAD 0.18. We'll see.

P.S. A bit more work and i guess more fun? ;)
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ppemawm
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Re: V0.18 Challenge--Clerget 9B Aero Engine--UPDATE #5

Postby ppemawm » Sat Sep 15, 2018 4:56 pm

The housings for the air and oil pump accessories are now complete and merged with the engine assembly file which has grown to 175.1 Mb. A few screenshots of the progress thus far follows with some brief comments:

Picture27.jpg
The air and oil pumps are located on the central support housing that supports the engine in the aircraft. Each are gear driven from the main gear on the distributor similar to the dual magnetos. Both models were created "in-place" using the pilots in the central housing as reference origins.
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Picture28.jpg
The oil pump consists of a right-angle worm drive gearbox with a camshaft to drive dual pistons for the pump.

An accessory reduction gearbox is also mounted on the oil pump mainshaft to drive the speedometer.

In the detail view you can see a closeup of the pressure regulator screw that requires knurling on the adjustment knob. This is simulated with two crossed helices and Draft>array>polar to minimize recompute resources.
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Picture29.jpg
The air pump includes a right-angle worm drive gearbox, crankshaft, reciprocating piston, and appropriate valving in the head. Most of these housings were fairly straight forward to model with the exception of the gear case.
Picture29.jpg (240.46 KiB) Viewed 831 times
Picture30.jpg
The gear case is a complex housing as these views show. Trying to visualize the housing from the original drawing was the real challenge. The author of the drawing helped me considerably by graciously sending me an Adobe 3D of his model in addition to a few drawing revisions. With that help I was able to faithfully reproduce the main housing features with FreeCAD.
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Picture31.jpg
Over 30 features were required to fully describe the housing (less a few fillets that just would not cooperate). These panels show the not too intuitive or logical sequence I had to use to obtain a valid solid with my approach. The panel sequence in the screen shot is from left to right, top to bottom.

In my original approach the model kept failing geometry check (BOP enabled) which was finally traced to Revolution094 highlighted in the Model tree. I finally solved this by moving the revolution to earlier in the tree. Why that worked I do not know, but V0.18's capability to rearrange the tree is invaluable.
Picture31.jpg (183.66 KiB) Viewed 831 times
.
One thing I am learning with V0.18, correct me if wrong, is that it may be preferable to insert fillets and chamfers as soon as possible in the tree as you add features. This has allowed me to include fillets that would just otherwise fail if left to the end of the process. If all of the fillets and chamfers are the last features then any upstream changes in the sequence or geometry of the features results in all of the fillets failing, requiring them to be painfully recreated. Now that we can use origin planes and attachment offset for sketches in lieu of locating them on faces or edges the model is exceptionally stable to changes...EXCEPT for those pesky fillets and chamfers which necessarily have to reference edges.

Next step is to finish up the internal components of the magnetos then move onto the internal components for the gearboxes and pumps for the air and oil systems. I am estimating about 90% complete overall. So far I have invested about 250+ hrs since the beginning of June, working 2-3 hours per day. Light at the end of the tunnel is beginning to glimmer in the dark. Hope it is not a train.

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.14713 (Git)
Build type: Release
Branch: master
Hash: 5c40496cf3b5939b96a0179eec1918754378aeaf
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: English/UnitedStates (en_US)
"It is a poor workman who blames his tools..." ;)
thschrader
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Re: V0.18 Challenge--Clerget 9B Aero Engine--UPDATE #5

Postby thschrader » Sun Sep 16, 2018 12:58 am

no words...
god bless you man.
chrisb
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Re: V0.18 Challenge--Clerget 9B Aero Engine--UPDATE #5

Postby chrisb » Sun Sep 16, 2018 1:00 am

And again, the model became even more impressive!
Please let me ask a couple of questions: Do you use any additional workbenches? And what hardware do you use? Does it create additional delay to have such an amount of bodies, or is it for each body anew?
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ppemawm
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Re: V0.18 Challenge--Clerget 9B Aero Engine--UPDATE #5

Postby ppemawm » Sun Sep 16, 2018 3:06 pm

chrisb wrote:
Sun Sep 16, 2018 1:00 am
Please let me ask a couple of questions: Do you use any additional workbenches? And what hardware do you use? Does it create additional delay to have such an amount of bodies, or is it for each body anew?
Thanks for your feedback.

My intent with this model is to demonstrate the capabilities of V0.18 PartDesign workbench for these kinds of mechanical designs. I only use Part>Mirror, Draft>Array, and Draft>Clone to duplicate bodies because those are missing in PartDesign. I also used the InvoluteGear workbench and Part>Helix and Draft>Shapestring in this model along with a simple macro which gives the coordinates of an arc to assist in attachment offset for sketches. Otherwise, it is all PartDesign. I did not use the fasteners workbench because all of the engine fastener's dimensions are not ISO since they are from the 1900's.

My hardware consists of a Toshiba laptop with touchpad, I7-4710HQ CPU, 16 Gb RAM, and 1 Tb hard drive.

Once the engine file reached about 100 Mb it was no longer practical to keep adding parts, not because of graphical performance, but because of the time to open the file and the time taken for recomputes and autosave which were several minutes. Consequently, I decided to start a new file for the accessories since they have together hundreds of additional parts. Each body in the accessories file is created in its proper location in 3D space so when completed the accessories file can be merged with the main engine file. Graphical performance does not suffer unless all bodies are toggled visible. However, it now takes about 13 minutes to open the main engine file!
"It is a poor workman who blames his tools..." ;)
chrisb
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Re: V0.18 Challenge--Clerget 9B Aero Engine--UPDATE #5

Postby chrisb » Sun Sep 16, 2018 3:15 pm

ppemawm wrote:
Sun Sep 16, 2018 3:06 pm
My intent with this model is to demonstrate the capabilities of V0.18 PartDesign workbench for these kinds of mechanical designs.
And these models really do that job!
Thanks for your answers. How do you guarantee the position of the accessories? Do you have a master-master-sketch?