Newbie 3d/CNC modeller

[GauntHugster]

Hi there, I'm an enthusiastic but impatient and frustrated 3d and laser CNC modeller looking to progress from my CAD, 3d and laser CNC dabbling to a final design, build and fly. Use Moi 3d and Lightburn software with Ender 3 V3 Se and Sculpfun s10 10w. Ambition is a LWPLA and balsa 250g Percival Mew Gull.

[Simon Chaddock]

Wow!

I applaud your ambition but 250g is a tough target with balsa and LW-PLA..

The Mew Gull is a beautiful looker but it was designed as a racer so is not blessed with much wing area which adds to the difficulty.

You might do better to ignore the 250g limit until you have some experience in LW-PLA construction techniques which can be rather complex, hence the popularity of buying the STL files for planes designed by professional organisations.

It does seem most LW-PLA designs rely on carbon tube or rod reinforcement at least for the wing, tail plane and fin rather than balsa.

Sorry to be a bit negative but you have set yourself quite a challenge.

 

I have made some scale sub 250g RC planes but I build the airframes from thin (2 or 3mm) foam sheet with limited balsa reinforcement using paper plans & traditional "knife and glue" techniques. I have used LW-PLA for parts that need a particularly complex shape where the ease of fabrication outweighs any weight penalty.

Nothing like as elegant as the Mew Gull but this 40" span Super Cub is made from 2mm foam sheet. It weighs 242g ready to go. It even says so in big letters on the wing!

 

I hope you find the help you are after and if you do build a Mew Gull please keep posting as it progresses. I will be following with interest.  

[FlyinFlynn]

I am currently pursuing a somewhat 'return to my roots' theme and am building a balsa and tissue model for use with an RTP pole. I intend to power it with a couple of small brushless motors, an esc or two, a micro Rx with a single servo on the elevator.

 

Part of the fun is coming from lasering the parts from 1.5mm balsa sheet. I start with the free plan from AeroFred, I chose a Bristol Beaufighter because... why not!  The workflow is -  crop the formers one at a time in Adobe Acrobat, save the former as a .JPG, import that into LibreCAD and trace around the shape. Save that as a .DXF which I import into Vetric Aspire where I scale it to the size measured from the Acrobat crop, add the stringer cutouts, add the second half with the mirror function and tidy the shape up and finally save it as a .SVG which will import into LaserGRBL for cutting on a 3 Watt laser. I may be tempted to go for a stronger laser with a air pump option sometime but the balsa will all be 1.5mm. thats 1/16" to the imperialists 🙂 so I expect to get through with a couple of passes... if not....laser upgrade time!.

  The free plan from AeroFred

 

 The part to be worked on cropped from the plan

 

 The shape traced and the stringer locations marked

 Stringer cut outs added and the shape mirrored to produce a full former

 

 The file loaded into LaserGRBL ready for the cutting.

 

It's pretty time consuming but very gratifying when you see the part releasing from the balsa plank.

 

No plastic filament was harmed in this build 🙂

 

 

[GauntHugster]

Thanks to Simon and FlyinFlynn for the welcome and thoughts. I've played at lot with CAD (name free version and I'e given it a try!) and vector files to create .dxf for laser cutting and think there's a good case for frame as per this method and wood and cowling/curves lwpla. The Arno Diemer/Peter Rake/Tony Lewis planes interest me but have found them fiddly builds with too may parts and joins that don't help structurally. I thought a bit of 3ding might be suitable. I've got spare microelectronics and am trying to mimic the Minimum RC and MicroAces type scale and weights. Interesting re. wing area, flight mechanics aren't my thing, but hoping a mew gull or 30s type racer style might offer opportunities.