New project : La-9 (rc warbird) for 3D printing

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HardRock
Posts: 83
Joined: Tue Mar 13, 2018 5:50 am
Location: Russian Federation

New project : La-9 (rc warbird) for 3D printing

Postby HardRock » Mon Oct 12, 2020 10:23 am

New design of radio controlled airplane - La-9.
Wingspan: 1.4m
Engine: glow OSMAX 55AX / Electric

Now shell is done
Image
Image
Image

Airplane will have printed landing gears. Kinematics of LG also simulated and optimzied in FreeCAD.
phpBB [video]


Test rudder part
Image


OS: Ubuntu 18.04.4 LTS (Unity:Unity7:ubuntu/unity)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.
Build type: Release
Branch: unknown
Hash: b0d7850406e046f3b7a8cd5da261e7d54df6bd99
Python version: 3.6.9
Qt version: 5.9.5
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: Russian/Russia (ru_RU)
Last edited by HardRock on Thu Oct 15, 2020 6:46 pm, edited 1 time in total.
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Chris_G
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Re: New project : La-9 (rc warbird) for 3D printing

Postby Chris_G » Mon Oct 12, 2020 12:32 pm

:o :shock:
Wonderful !
I am already eager to see the next episodes.
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Zolko
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Re: New project : La-9 (rc warbird) for 3D printing

Postby Zolko » Mon Oct 12, 2020 12:59 pm

HardRock wrote:
Mon Oct 12, 2020 10:23 am
New design of radio controlled airplane - La-9.
Wingspan: 1.4m
Nice. What's the scale ? I'm beginning to work on a FockWulf 190 at 1/10th scale, span = 1050mm, and ideally I'd do all the warbirds at that scale. Next-up will be the Spirtfire.

Now shell is done
How did you do it ? What is the wall thickness ? What's the printing method ?
try the Assembly4 workbench for FreCAD v0.19
install with Tools > Addon Manager > Assembly4 — tutorials here and here
HardRock
Posts: 83
Joined: Tue Mar 13, 2018 5:50 am
Location: Russian Federation

Re: New project : La-9 (rc warbird) for 3D printing

Postby HardRock » Tue Oct 13, 2020 6:59 am

Originally designed for 1:7 scale (1400mm wingspan), but very easy may be scaled to any size using DraftClone tool :)
I think that 1:10 (980mm) version will come first because I need airplane in this scale for FPV air combat ( https://www.youtube.com/channel/UChmk02 ... WxCNsKCMPw )

Mostly it done by stretching surfaces (Surface workbench) between sketches, in short.
Very often used operation - Part - Slice apart. Also usefull - Draft Upgrade / Draft Downgrade, Curves Join edges in BSpline.
In long story, there are number of "shell reconstuction" was done. For example for vertical stabilizer. Orignally VStab was designed using Curved Shapes workbench, but then leading edge was reconctructed using skeches and Sufrace.

Additional care was taken for trailing edges. Wing, wing fairing, elevator and rudder have cutted trailing edges.

Because this is a Shell, it have zero thickness. This is good for 3D printing in general and allow your to use not only 3D printing, but other materials like foam (using foam cutter). When you have only external walls (shell), you able to make any internal structure for any construction method.

Also, there is no way to make so complex design as solid body in FreeCAD because lot of bugs :)

PS: Time to time you need to export / import parts (Im using STEP format) with losing history to keep project size small and avoid bugs.
HardRock
Posts: 83
Joined: Tue Mar 13, 2018 5:50 am
Location: Russian Federation

Re: New project : La-9 (rc warbird) for 3D printing

Postby HardRock » Tue Oct 13, 2020 7:05 am

LG animation done with Spreadsheet where LG angle around axis is defined and all parts has references to parent part.

So in this case very easy to start animation

Code: Select all

import FreeCAD
from PySide import QtCore
class LGAnim(object):
	def __init__(this):
		this.angle 	= 0
		this.timer	= QtCore.QTimer()
		this.data	= FreeCAD.ActiveDocument.getObjectsByLabel('LGData')[0]
		this.dir		= 0		
		QtCore.QObject.connect(this.timer, QtCore.SIGNAL("timeout()"), this.step)
		this.timer.start(1000/25);
	def step(this):
		if (this.dir == 0):
			if (this.angle < 80):
				this.angle = this.angle + 1
				this.data.lg_angle = this.angle
				App.activeDocument().recompute()
			else:
				this.dir = 1
				this.timer.stop()
				QtCore.QObject.disconnect(this.timer, QtCore.SIGNAL("timeout()"), this.step)
				QtCore.QObject.connect(this.timer, QtCore.SIGNAL("timeout()"), this.rearm)
				this.timer.start(1500)
				
		else:
			if (this.angle > 0):
				this.angle = this.angle - 1
				this.data.lg_angle = this.angle
				App.activeDocument().recompute()
			else:
				this.dir = 0
				this.timer.stop()
				QtCore.QObject.disconnect(this.timer, QtCore.SIGNAL("timeout()"), this.step)
				QtCore.QObject.connect(this.timer, QtCore.SIGNAL("timeout()"), this.rearm)
				this.timer.start(1500)
	def rearm(this):
		this.timer.stop()
		QtCore.QObject.disconnect(this.timer, QtCore.SIGNAL("timeout()"), this.rearm)
		QtCore.QObject.connect(this.timer, QtCore.SIGNAL("timeout()"), this.step)
		this.timer.start(1000/25);
	def stop(this):
		this.timer.stop()
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Zolko
Posts: 1189
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Re: New project : La-9 (rc warbird) for 3D printing

Postby Zolko » Tue Oct 13, 2020 7:41 am

HardRock wrote:
Tue Oct 13, 2020 6:59 am
Mostly it done by stretching surfaces (Surface workbench) between sketches, in short.
Very often used operation - Part - Slice apart. Also usefull - Draft Upgrade / Draft Downgrade, Curves Join edges in BSpline.
In long story, there are number of "shell reconstuction" was done. For example for vertical stabilizer. Orignally VStab was designed using Curved Shapes workbench, but then leading edge was reconctructed using skeches and Sufrace.
Additional care was taken for trailing edges. Wing, wing fairing, elevator and rudder have cutted trailing edges.
the cockpit seems very well made, how did you do that ? And also the wing root fairing, the vertical rudder transition to the fuselage ... really nice work. I'm beginning to do that for the FockWulf and I'm struggling.

PS: Time to time you need to export / import parts (Im using STEP format) with losing history to keep project size small and avoid bugs.
yes, I do that too. As for the animation, I use the Assembly4 function.
try the Assembly4 workbench for FreCAD v0.19
install with Tools > Addon Manager > Assembly4 — tutorials here and here
HardRock
Posts: 83
Joined: Tue Mar 13, 2018 5:50 am
Location: Russian Federation

Re: New project : La-9 (rc warbird) for 3D printing

Postby HardRock » Tue Oct 13, 2020 8:31 am

Cocpit is really easy. First you need to cut fuselage to get space under sliding and rear glass. I will be yout base line.
Front (bulletproof) and side glasses has straight sufrace (on FW190 too, as on most WW2 airplanes), so you need to make that surfaces from base (bottom) line on cocpit and then cut by fuselage shape. Also cut fuselage with glass and then join cutted parts together.
Sliding part - just surfcaes between two sketches, whose edges was joined using join curve from Curves workbench to make surface smooth without extra edges. Sketches consists of line (side) and bspline (top) part.
Rear glass - sufrace between sketch and fuselage part.

Wing fairing:
Draw fairing profile from side as sketch, project on fuselage. After use freehand BSpline from Curves workbench to make top/front contours. Use fill surface from Surface workbench to make fairing surface (rear part). Extra adjustments of top/side contours may required to get better result.
Faring above wing - just surface swept along projected path above wing and then cutted by wing (and wing cutted by this surface).

Vertial stabilizer to fuselage:
Vstab similat to cocpit and also made from base line that goes under fuselage in front part. After you need to cut fuselage and cut vstab, then join.

Rudded - just surfaces.

Wing - surfaces between profiles

Wing / elevator tips - Curved Shapes workbench.
HardRock
Posts: 83
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Location: Russian Federation

Re: New project : La-9 (rc warbird) for 3D printing

Postby HardRock » Tue Oct 13, 2020 8:38 am

Another usefull workbench - Defeaturing. Sometimes you need to copy / remove faces or wires.
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Kunda1
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Re: New project : La-9 (rc warbird) for 3D printing

Postby Kunda1 » Wed Oct 14, 2020 2:00 pm

HardRock wrote:
Tue Oct 13, 2020 6:59 am
Also, there is no way to make so complex design as solid body in FreeCAD because lot of bugs
Please make sure to report these bugs when you encounter them to help us improve FreeCAD
Alone you go faster. Together we go farther
Want to contribute back to FC? Checkout:
#lowhangingfruit | Use the Source, Luke. | How to Help FreeCAD | How to report FC bugs and features
HardRock
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Location: Russian Federation

Re: New project : La-9 (rc warbird) for 3D printing

Postby HardRock » Thu Oct 15, 2020 6:07 pm

Kunda1 wrote:
Wed Oct 14, 2020 2:00 pm
HardRock wrote:
Tue Oct 13, 2020 6:59 am
Also, there is no way to make so complex design as solid body in FreeCAD because lot of bugs
Please make sure to report these bugs when you encounter them to help us improve FreeCAD
OK, hold on, I can reproduce lof of bugs in simple freecad project file :D