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

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

Postby ppemawm » Mon Jun 18, 2018 5:10 pm

I stumbled across Pierre Jansen's website https://www.pjvision.nl/ while searching for a project to challenge and demonstrate the capabilities of FreeCAD's development version. I intend to create a complete parametric model in all its gory details from Pierre's CAD drawings using the PartDesign workbench. Hopefully, I can duplicate his model (less rendering) as shown on his website. Pierre created his exceptional model and rendering using Bentley's high-end MicroStation V8i modeller and the Luxology rendering engine from measurements taken from an actual engine.

The Clerget 9-cylinder engine is unusual (to me, at least) in that the cylinders rotate and the crankshaft is stationary. So far, all of the major rotating housings have been completed as shown in the following screen grabs with a few comments about the process:

Picture1.jpg
The Part tree is organized into rotating, stationary, and reciprocating subassemblies. I wanted the rotating bodies in one part so that I could easily rotate them as a complete unit to facilitate timing of cams and valve components and to check for clearances within the engine.
Picture1.jpg (216.56 KiB) Viewed 6812 times
Picture2.jpg
The horizontal assembly includes the aero hub for attaching a propeller, front bearing housing, cambox, split crankcase, cylinders, rear bearing housing, air intake, and the distributor/drive gear components. The gears drive the air/oil pumps and magnetos.

Once individual components were created extensive use of Draft>Arrays minimized modeling effort. Although not shown clearly in the pictures, all fasteners created from the workbench or ScrewMaker 2.2 are included in the model. Lock washers were imported from McMaster-Carr.
Picture2.jpg (192.85 KiB) Viewed 6812 times
Picture3.jpg
The crankcase features were created in the sequence shown above from left to right. Cylinder solids were first created in a PolarPattern followed by a revolve of the crankcase support ring and then pads between the cylinders. PolarPatterns duplicated all the features nine times.

PartDesign fillets were applied in one go without any problems but note that the fillet on the pad between the cylinders was included in the Revolve sketch to make this possible. Learned that by trial and error. Normally I leave fillets until the end but in this case it was necessary to do them earlier in the tree.

The Groove tool was used to split the crankcase and its Edit>Duplicate into two halves. Unfortunately, this approach is not parametric. I tried using Clone and Draft>Clone but did not like the resulting complexity in the tree when added back to the crankcase part.
Picture3.jpg (189.48 KiB) Viewed 6812 times
Picture4.jpg
Revolve was used to create the solid cylinder. Since the fins were equally spaced it was possible to use LinearPattern to duplicate most of the grooves forming the fins.

The head details were fairly straight forward pockets although several separate sketches were used to keep them simple as possible.

The most difficult features were all the detail around the spark plug bosses. Revolves and grooves to form the bosses were located by sketches on a datum plane then mirrored across the global plane.
Picture4.jpg (239.06 KiB) Viewed 6812 times
Picture5.jpg
The induction pipes were most interesting but a little tricky due to the offset from center. The tube was created using the elliptical face highlighted on the upper flange and a 90 deg revolve with a Datum line axis then a pad to extend the tube vertically.

The collar for the lower mounting flange is a separate body fused to the induction tube with the PartDesign boolean tool. A groove sketch provided the clearance feature on the lower flange.
Picture5.jpg (142.9 KiB) Viewed 6812 times
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The extensive use of Draft>Arrays has created a large file (66+ Mb already) which slows FreeCAD's response significantly so it is likely I will delete all the arrays in my working file and only use them for display purposes. Next up are the major stationary parts such as the engine mounting structure and crankshaft. Stay tuned for an update.

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.13826 (Git)
Build type: Release
Branch: master
Hash: 3b02ff2a9481f0883063c7e24c312978ef0ce642
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)
Last edited by ppemawm on Mon Oct 08, 2018 3:36 pm, edited 6 times in total.
"It is a poor workman who blames his tools..." ;)
Jee-Bee
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Re: V0.18 Challenge--Clerget 9B Aero Engine--Work in Process

Postby Jee-Bee » Mon Jun 18, 2018 6:28 pm

It would be great if somebody with lage models and some programming experience would be able to add some tricks that heavy models can speed up.
For example remove small features (ratio compared to zoom/ distance) or don't calculate features or models that are suppressed.
triplus
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Re: V0.18 Challenge--Clerget 9B Aero Engine--Work in Process

Postby triplus » Mon Jun 18, 2018 8:06 pm

ppemawm wrote:
Mon Jun 18, 2018 5:10 pm
The extensive use of Draft>Arrays has created a large file (66+ Mb already) which slows FreeCAD's response significantly so it is likely I will delete all the arrays in my working file and only use them for display purposes.
What you could try out is download the binary for your platform from here:

https://github.com/realthunder/FreeCAD_ ... 3/releases

This builds are a part of ongoing Links, Assembly 3, Topology naming effort ... If your existing geometry will open correctly you will notice there is an additional Array oriented command in the Draft Workbench utilizing the Links feature. It would be interesting to see on just how much difference it can make in your use case and on your model.
chrisb
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Re: V0.18 Challenge--Clerget 9B Aero Engine--Work in Process

Postby chrisb » Mon Jun 18, 2018 9:16 pm

Great model, and thanks for the explanations! May I ask how long you need to create such a model?
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easyw-fc
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Re: V0.18 Challenge--Clerget 9B Aero Engine--Work in Process

Postby easyw-fc » Mon Jun 18, 2018 9:44 pm

ppemawm wrote:
Mon Jun 18, 2018 5:10 pm
a large file (66+ Mb already) which slows FreeCAD's response significantly
if you have a graphic GPU card, the A3 branch should also speed up a lot your model handling
https://forum.freecadweb.org/viewtopic. ... 60#p239881
EDIT: make a backup before opening the file with the new branch.. it is still in experimental mode...
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ppemawm
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Re: V0.18 Challenge--Clerget 9B Aero Engine--Work in Process

Postby ppemawm » Tue Jun 19, 2018 1:06 am

chrisb wrote:
Mon Jun 18, 2018 9:16 pm
May I ask how long you need to create such a model?
I started 4 June and have been working about 2 to 3 hrs/day so far.
triplus wrote:
Mon Jun 18, 2018 8:06 pm
It would be interesting to see on just how much difference it can make in your use case and on your model.
easyw-fc wrote:
Mon Jun 18, 2018 9:44 pm
the A3 branch should also speed up a lot your model handling
Thanks for the suggestions. I may look into it if the performance gets unbearable as the model grows. Mostly the delay is when it autosaves. Graphic manipulations are more than satisfactory. I can also 'Skip Recomputes' before trying intensive operations such as thickness or sweep features.
"It is a poor workman who blames his tools..." ;)
chrisb
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Re: V0.18 Challenge--Clerget 9B Aero Engine--Work in Process

Postby chrisb » Tue Jun 19, 2018 6:01 am

ppemawm wrote:
Tue Jun 19, 2018 1:06 am
I started 4 June and have been working about 2 to 3 hrs/day so far.
Thanks for the information. That sums up to something between 30 and 40 hours which seems to be pretty fast. I would guess it's not always straight forward and you invest a considerable amount of time in planning too.
I would like to hear from others who are experienced users of high end professional software (Solid Works, Solid Edge, Catia, Creo, ...) a pure guess how long would it take with such a system.
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Jee-Bee
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Re: V0.18 Challenge--Clerget 9B Aero Engine--Work in Process

Postby Jee-Bee » Tue Jun 19, 2018 7:29 am

I think With creo it should go faster. Creo is quite strong with patterns what speed the process up.
Another nice feature that Creo have and i think SW also have is a rib function. than you draw a bunch of lines and the rib function give them a with extrude and a draft.
What for assembly nice is that when you have a pattern in a part in assembly mode you can follow the pattern of the part

For the on the side it is possible to use a pattern that handle the growt as wel... but i.m not sure if it works out.
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microelly2
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Re: V0.18 Challenge--Clerget 9B Aero Engine--Work in Process

Postby microelly2 » Tue Jun 19, 2018 8:14 am

Jee-Bee wrote:
Mon Jun 18, 2018 6:28 pm
It would be great if somebody with lage models and some programming experience would be able to add some tricks that heavy models can speed up.
For example remove small features (ratio compared to zoom/ distance) or don't calculate features or models that are suppressed.
I wonder whether a method to split some heavy faces into smaller parts may help.
https://forum.freecadweb.org/viewtopic.php?f=8&t=26366
it is still an idea, but I tested large Draft arrays too. Using smaller segments can improve performance for rendering.
Jee-Bee
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Re: V0.18 Challenge--Clerget 9B Aero Engine--Work in Process

Postby Jee-Bee » Tue Jun 19, 2018 8:21 am

microelly2 wrote:
Tue Jun 19, 2018 8:14 am
I wonder whether a method to split some heavy faces into smaller parts may help.
I think we talk both on different things. i talk about let say holes in a big plate or radii/ chamfers on corners etc and i think you talk about complex splines....