Ok, more delay?

Yes and no… I have decided to make this project my first project in which I will use a CNC to cut the parts.

Will this cause more delay?… yes. In the sense that the CL415 would be flying sooner without it. But in the overall scheme of things, I do believe that the benefits outweighs this drawback.

I have to acknowledge the fact that I am not getting younger, and especially my eyesight is not improving. Reading without glasses has become impossible (but anything beyond 4 feet is still razor sharp), and I find that doing accurate (sub)millimeter work has become very tedious.

So I have decided to delegate the precision work to a machine.

This does mean that I will have to build a CNC machine also. But there is a fair amount of information on that topic, thus while it will take some time, it should not be too difficult.

I will document my adventure into CNC land on another blog:

The first post is scheduled for the 1st of April (no joke!). From then on there should be regular posts on the construction. In the beginning there will be a series of daily posts, but after a few days that should slacken to updates when progress only.

This blog will pick up whenever I do something specific for the CL415.


No, I have not given up on this project.

However life sometimes throws a curveball.

I intend to restart this project in a few weeks… until then.

Engines and work table

The engines arrived a couple of weeks ago, in fact just after the previous update was posted. They look really good and give a solid impression:


I especially like how they can be ‘reverse mounted’, which makes construction of the nacelles easier and lighter.

But that is not all I have done since then, the wood was ordered and has arrived. I was not too happy about the packaging of the wood, but everything is at least usable, and only 1 piece does have a really annoying ‘ding’. The quality looks good.

I also had a piece of stainless steel cut into pieces of 2x2x4cm. These are nice heavy (and have right-angles) blocks that I can use to fix things into place while the glue cures/dries. This instead of having to use needles like I have done in previous projects. I quite dislike needles and hope that the steel blocks will make a difference.


One more thing I did was building a new work-table. The old one was too small, and not perfectly flat. The new one is big enough to build the main wing in 1 piece and has an excellent “flatness”. What I did was taking a big sheet of plywood of 2.44x1.22m and 18mm thickness. I had the shop saw off several small stripes from the side and used these to reinforce the bottom such that it does not flex. Btw the whole things is glued, no screws or nails. And as the reflection shows, the top is painted as well. Really smooth…


I put a Turmeric on top for scale, the Turmeric has a span of 1.5m. The table is now 2.44x0.6m. I also made it much higher than usual (ca 95cm), so most of the work can be done without having to bend over. Very convenient. The bottom reinforcements can be seen (looking like dual-jet exhausts) as well as the wheels that I put on one end. The table is quite heavy, so it is not possible to lift and manipulate it on my own. The wheels allow me to lift one end, remove a strut and put it on the wheels. Then I can lift the other end off the remaining strut, and wheel the table to another place and repeat the process in reverse.

The table itself rests on 3 points, so there are no torsion forces on it. There is only little space between the table and the struts to minimize the possibility of tipping.

Next up is finishing my current build (a Thermy-3). The structural work is done, but I need to finish it up on the servo’s, engine and the covering. Given that I have other stuff to do as well, it may take another month or so before I can report on the first cut for the CL-415.


Having a plan is one thing, its quite another to translate the plan into a list of items to be purchased. That took longer than expected, but I finally have a pdf parts list. Some of the plan is still TBD (to be defined) those parts I will have to make up as I go along. Most of these are due to changes I want to make upon the original plan. Like flaps, rudder, or attaching the nacelles to the wing permanently. I am also still unsure of the wing/fuselage coupling. There is no clear indication how this is done.

Btw: The pdf document will be updated continuously as the build progresses.

With the parts list in hand a map was created that maps each part onto a standard item that can be purchased.

This looks as follows:


(Click the image for a larger version)

The ordered items itself can be seen in the PDF parts list. In the present version there are two alternatives one with prices from the Balsabar shop and one from Balsabaum (both in germany).

However care should be taken when comparing prices. While the Balsabaum is slightly cheaper, this does not factor in the dimensional and quality differences. Still, prices were generally a bit lower in the Balsabaum shop. But the dimensions of the items in the Balsabar shop did match the dimensions of the plan better, making for less work when creating the parts. So in the end it’s a toss imo. (I went for less work…)

The order has been placed, and should arrive next week.

Flaps final (?)

Of course one should always be carefull when saying ‘final’, but I like following flap design:


The flap is a little smaller than the previous one, and the top is rounder (the hump is gone). While I do not have any numerical data the design seems similar to both the real one and to the visuals in the videos that were referenced in the previous flaps post.

Here are the pictures that show how the flaps will look like when extended:


Flaps at 15 degrees


Flaps at 30 degrees


Flaps at 45 degrees

The hinge point is closer to the wing to prevent the slot from becoming unreasonably big.

The thickness of the wing at the point of the flaps is approximately 26mm, which is big enough to mount the control rods internally.

The intention is to hinge the flaps at 4 points like the real one. But it is not sure yet if they will be distributed like the real one. This because of the placing of the ribs. Keeping the same spacing as on the real one would require extra ribs (or parts of the ribs). In the motor/prop calculations that were made it was checked what would happen if the weight comes out a little high, and that was not too bad. So there is at least the option of mounting them realistically.