DIY Oil Drum BBQ: part 2

Now that the warm weather is coming back we decided to carry on with the assembly of the BBQ. After browsing online, it seemed that the most convenient thing to do would be to use the second barrel as a support for the main barrel. In order to do so, we cut the top off the second barrel to make a cradle:

We've had a few very successful BBQs so far with friends, however the lid is still incomplete. It is ready to be assembled, but we don't have a handle yet.. We are looking for a nice wood dowel to make the handle, it seems like the best option in terms of heat and durability. In terms of use, we usually use only one side of the BBQ when we are less than 5 people. Despite its large size, we also regularly use it to cook our food for just the two of us instead of the kitchen stove. We also had a BBQ for 15 people where we had to use the whole surface and it got very hot! The food was ready for everyone in a very short amount of time. So far we've made burgers, sausages, fish, buffalo wings, and vegetables and it all came out nice! The large grill allows to move the food around to have different amounts of heat, which is convenient to cook multiple different things together. I imagine the lid will allow us to do some more advanced cooking too.

Finally, a word on the steel's durability. It seems the winter didn't affect the steel too much, it's rusting outside but not loosing its strength at all. The BBQ remained outside the whole time, unsheltered, and only the hinges seem to have rusted. After the first BBQ in autumn, we also noticed that the mesh supporting the charcoal caved in. We did use a lot of charcoal that time, but we feel it should have been able to support that amount of weight. This means we need to replace the struts stiffening the mesh, or put something underneath (a brick) to keep the mesh flat.

DIY Oil Drum BBQ

Life has been quite eventful these past few months for me. Most importantly for this post, I moved house, from a small apartment, to a comfy house. My housemate and I immediately decided it wouldn't be a proper bachelor pad if we didn't have a BBQ. Having mastered the home-made Jack Daniel's Barbecue Sauce, we are now in the process of making a BBQ from an oil drum.

We acquired two authentic oil drums, complete with remaining oil. These are the standard 55 gallon steel drums.

The design we are going for is a horizontal barbecue with a hinged lid. It isn't cut in half, as we would like to open and close it for optimal cooking heat.

First things first, we gathered a few tools and bits and pieces:

 - an angle grinder with two thin blades

 - heavy duty door hinge

 - metal tubing and mesh for the coal grid

 - a nice stainless steel mesh for the meat (and veggies of our veggie friends..)

 - a large handle for the lid

 - brackets and screws to attach everything

First: Cut the barrel!

The first step consists in marking up and cutting the lid. We chose to keep the sides whole to save weight on the hinges, and for a stronger structure of the BBQ. That step used up two small angle-grinder discs. Beforehand, the drum needs to be rinsed with washing up liquid, and a lot of water.

The next step was to fit the brackets for the grids. The charcoal rests on a grid lifted off the bottom. This should improve air circulation, and protect the steel from the heat. That grid is made up of really cheap mesh (1 inch pitch), reinforced with 4 steel rods (6mm diameter) to prevent it from sagging too much. The other grid is a nice stainless steel grid cut to dimensions. We chose to go for 2 separate grids so that we can lift one and add some more coal while cooking. 

A very important parameter is the distance between the charcoal and the meat. At the moment, we took a wild guess after looking at other barbecues. The distance is about 20 cm. We cut up the grid accordingly of course, but we are not outruling the posssibility to move the coal or the meat up and down. But we'll look into that after the first test...

Afterwards, we started the fitting of hinges on the lid. These need to be properly aligned for a smooth motion. They are heavy door hinges attached with 6mm bolts. Probably over-kill, but it should last a while.

The build was paused during the winter since we had no use for it.We did have an inaugural BBQ in this state. A second post will describe the rest of the assembly! 

Beginning of welds

I had ordered the tubes in January (26 meters of it for extra mishaps), and started gathering all the tools that I need for soldering. So far, I find that I need:
- a Dremel (135 watt, with a good cutting disc, and a good metal brush)
- a lot of flux
- a lot of 40% silver solder rods
- a blow torch (I am using Mapp gas which in my opinion is too powerful for such small welds..)
- a good workbench. I am using a sheet of steel placed on bathroom tiles, placed a workbench. The insulation provided by the bathroom tiles is excellent so far!
- a set of diamond files (possibly different diameters of round ones)

Welding the tail section's top.

The assembly process has begun, and hopefully it'll start taking shape within the next few weeks!

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.