The 100” Build-Ruary Blanik

[DJSomm1]

I had the idea to build a LET L-13 Blanik with master series techniques. In the past, it would have been a one-off build, but now that I have a good CAD program and a needle cutter (See here), I am able to draft a set of plans, and test their accuracy with CNC precision. We won’t know the weight until the model flies, but the wingspan is close to 100 inches. If the build goes well, I intend to release the plans to the community.

This is the start of the fuselage core. Each joggle in the structure indexes to a specific rib. The nose is an open-top box for simplicity, and the tail section is an inverted T to reduce weight. The nose and tail frames index together at former H to form the fuselage core.


Notes for version 2:
• Put a chamfer on each corner to make clearance for the glue joints, and make the slots a hair wider.
• Mark the centers of both the formers and the skins to make alignment easier.

 

[Inq]

I have a good CAD program and a needle cutter (See here),

Thank you for referencing your needle cutter build. It's hard to find these hidden gems if you don't know what you don't know so you know to do a search. Bookmarked.

What CAD did you decide on?

 

[DJSomm1]

I appreciate the encouragement.
I am using DoubleCAD for drafting, and GRBL-Plotter for cutting. Once you learn the interfaces, these programs are a powerful combo.

 

[Inq]

I appreciate the encouragement.
I am using DoubleCAD for drafting, and GRBL-Plotter for cutting. Once you learn the interfaces, these programs are a powerful combo.

I volunteer and host a user's group at our local library and next week I wanted to start a series on using CAD... mainly for 3D printing. I was looking at FreeCAD so far. I need to look at this one too. Thanks.

 

[FlyerInStyle]

I volunteer and host a user's group at our local library and next week I wanted to start a series on using CAD... mainly for 3D printing. I was looking at FreeCAD so far. I need to look at this one too. Thanks.

I would reocmmend autocad lt, if youa re in an educational administration you can get it for free (even if your organization doesnt pay for it)

 

[DJSomm1]

Here is this morning’s progress. The bulkheads indexed into place exactly as intended, and the lower fuselage skins have been pre shaped.

 

[Yankee2003]

Here is this morning’s progress. The bulkheads indexed into place exactly as intended, and the lower fuselage skins have been pre shaped.
View attachment 234356 View attachment 234357 View attachment 234358

Very nice.

 

[DJSomm1]

Thanks. I am working on this between chores around the house. I want to have the lower skins attached by lunch, so I need to get back to chores.

 

[Inq]

I would reocmmend autocad lt, if youa re in an educational administration you can get it for free (even if your organization doesnt pay for it)

If it were just me... I'd go for that. But ANY cost would eliminate about half of the audience from doing it. I started a thread some time back and got some great input...

https://forum.flitetest.com/index.php?threads/cad-software-suggestions-again.71592/

 

[Inq]

Here is this morning’s progress. The bulkheads indexed into place exactly as intended, and the lower fuselage skins have been pre shaped.
View attachment 234356 View attachment 234357 View attachment 234358

... hmmm. I didn't know you pre curve them. I was wrongly assuming the Master Series planes (I haven't watched YT yet) that you simply bent them around ribs/formers, but this makes sense. Can you recommend one of the YouTubes that walks through the process better than others. More about the techniques than the plane??? Thanks.

 

[DJSomm1]

The fuselage is starting to take shape.

 

[DJSomm1]

Can you recommend one of the YouTubes that walks through the process better than others. More about the techniques than the plane??? Thanks.

I think the Spitfire and Mustang build videos, the original MS plans explain the techniques best.