Status just before Christmas

I have not made much progress since the last post because of work getting in the way.. However, I have decided that I will be using 3, 4, 5 and 6 mm Stainless Steel tubes. So I have grouped the different sizes found on Schleicher's plans (ranging from 12 to 30mm) and replaced by the corresponding size. This is very approximative, however I have received advice, and read on forums, and it seems like it will be strong enough.

Rendering of the tubes in the current assembly

After adding all the tubes (custom frame objects in Inventor), the image above shows you the result! It's about 1.84m in length and it weighs around 555g as is. Expect a little more when adding the reinforcements for the landing gear, the wooden top, as well as the supporting structure for the wings. I am unsure how much soldering silver I will need, but I wouldn't be surprised if it were near 100g. And of course a lot more weight will come from wooden sections, covering, and electronics... By the way, this fuselage will require at least 22 meters of tubing!

Side view of the fuselage

Top view of the fuselage

Inventor indicates that the center of gravity stands 126mm from the cockpit's aft end tube. I am curious to know how this will change as we go! This will deeply affect the amount of lead in the nose, and the overall mass.

I was tempted to modify the geometry slightly in order to optimize Schleicher's design for a smaller scale, but the more I look at it, the less I feel I need to. Two sections I do not expect to reproduce are the landing gear, and the wing's attachment.

Next up: Making a wing/fuselage junction, refining the landing gear, and ordering the material!

Main tubes are defined!

Here we are! Using Schleicher's detailed drawings, I was able to reconstruct most of the main tubes in the fuselage. Some interpretation from the NNZC's photo album is still necessary though.

Initial 2D drawings assembled in 3D.

For this, I first redrew the 2D views from Schleicher, then used Inventor's projection tool to locate intersections in 3D

After linking and projecting the 2D views in 3D.

Quite time consuming (almost 8h), but the next step will be looking into more detailed plans to spot the missing smaller tubes. One essential bit I am missing is the landing gear, and the wing box.

Stay tuned...

Major change in strategy

We have received detailed drawings of the tube-frame of the ask 13 from Schleicher themselves! As a consequence I am scrapping the drawings made initially on Louis's plans.
The drawings from schleicher contain enough information to fully define the drawing on Inventor, which is a great plus! I am only having to use some photos to clarify the path of some tubes in 3D.
New snapshots will follow soon!

Stay tuned!

Status of the ASK-13 (03/11/2013)

Since to my knowledge the are no plans for this scale model, I will be drawing a new one inspired by Louis's plans as well as photos and drawings of the original one. So far, I have the .dxf files of most wooden elements which I am copying and pasting into a 3D Inventor® model.

Fuselage tail being drawn up in Inventor®

Once this is done, I intend to fit tubes of different sizes to carry the loads in the fuse. These will be located where they would be in the real glider. However at times I may have to modify it slightly in order for the drawing to make sens for a remote controlled glider. The advantage of using this method is that all the dimensions are already provided, I only need to click where I would like to have tubes.

I am very thankful that the .dxf files have been given publicly, this would otherwise be a much more difficult task. On the other hand, since they do not provide any idea where the tubing should go, I need photos of the frame without the Dacron cover. These are usually difficult to come across, but my aeroclub regularly maintains our gliders so I was able to obtain several. In addition, the NNZC gliding club has a rich set of photos which I have feeling will help a lot.

New Project: Winter 2013-2014

This winter's project is going to be a big one for me! I am building a scale model of an AS K-13 glider. This model will be approximately 4 meters in span and flown via remote control. The design is based on Louis Kulicka's plans.

Louis's design incorporates a wooden fuselage and wooden wings, however, the original glider had a steel tube fuselage, and wooden wings. This is where it gets tricky: I am going to reproduce Louis's model with a stainless steel tube fuselage.

The idea came when I saw Paolo Severin's work on large RC scale models. Being a keen glider pilot and RC pilot myself, I naturally wanted to reproduce my first solo glider. At this point, I am not certain of which decoration it will have, but it will be as structurally exact as possible. In order to do so, the wings will be built in wood by my father, and the stainless steel tube fuselage will be made by me.