Hahnenmoos week – some of the finest slope soaring

Our annual club outing to Hahnenmoos was great again. Even with some Corona restrictions and a very bad weather forecast we got plenty of opportunities to fly. Here are some videos and pictures.


Re-organising the website

Originally this website started out as a blog tracking the building of our scratch-built JS3 – mostly as my own online “notebook” to track how we build our planes. Over time it has evolved in an overview of multiple builds, both from scratch, but also kits and ARF planes. I was astonished to find that I’ve got more than 125 posts on it.

Unfortunately, it has also become very hard to find information on a single plane. So it was time to slightly reorganise the site. You will now find a new tab “Models”, under which I’ve listed the various models that are described in this blog. For each of these models I will over the next few months construct it’s own page, with data and a few pictures for that model, but also with a link to all related blog posts. Until then, the links on the models page will lead you to a page with all the blog posts related to that model only. I hope that makes it easier to find information on a specific plane.

Users may also notice that I removed the “build gallery”. I initially included this to allow access to full size pictures in the blog. As I hadn’t updated the build gallery for a while, and all blog posts now link directly to the full size pictures, I decided to remove this page.

Finally, I’ve also reopened the blog posts for comments. I closed this a few months ago as a result of the huge amount of spam I was getting. I hope that the new spam filter prevents this, but still allows those who want to comment to do so. Note that comments will need to be approved by me before they appear on the page.

As always, thanks for visiting my site and feedback welcome.

Diana2 Flyday!

Save the DATE!

Diana 2 Fly-Day…… Sunday 16.August 2020 at
Modellfluggruppe Zürich, Eglisau (https://mgzh.ch/unser-flugplatz/).
Bring your personal Diana 1 or Diana 2 and Fly with us!
Lets see how many we can get together…..World record??

Saturday 15th will be also first time DONs Grill & FLY

Please sign in on the Doodle Link before the end of July 2020…to make sure you can be part of it!

Looking forward to see you all there
ChocoFly Team


Watching Paint dry

Watching paint dry is not really my thing. Andi managed to secure a slot in the paintshop on Saturday and spray painted the wings and all small parts. The fuselage should be done in the next few days. I’m now waiting for the paint to harden out, after which the hard work of polishing starts.

I’ve been using the time to build a small glider, based on the mini-Uhu, but remote-controlled. Originally this was for our upcoming indoor glider-tow competition, which has now been cancelled due to the Corona crisis. I’ve also built a new Clik21 indoor plane, which had been lying around in my workshop for a while. I love that small indoor plane. I’ve built (and sold) multiple versions of it already, always trying to make it lighter improve it further. My current one weighs 93gr (no battery), but with a pull-pull rudder and elevator it wasn’t very precise to fly. Hence my wish to build another one. The new version looks again much improved compared to the previous one, with more stable ailerons and rudders, and a total weight of 95.6 grammes (without battery, i.e. flying weight 110gr).

I also finalised the Urupema decals and spent much time making the rudder control horns. Georg helpfully documented how he made his control horns, which I’ve copied. I’ll post a picture of the painted Urupema as soon as the fuselage comes back from the paintshop.


How and why do we do it?

We’re regularly getting questions not just on how but also why we build our own gliders, and if it’s really worth the hundreds of hours of work that go into them. On 14 December 2019 we were invited at the 35th international aeromodelling symposium in Winterthur (CH) to give a presentation on our work. Unfortunately I was unable to attend, but the other three members of our building team, Georg, Andi and Richie, explained how and especially also why we do this. I put together the slides for the presentation, which are now uploaded here. It’s mostly pictures, with some text in German. The two videos were included at the end of the slide-show are available on my Vimeo channel:

JS3 slope start

JS3 on our airfield


IDS system for the wing control surfaces

I wrote earlier about our servos, but not in detail: we will be using KST X08plus for the ailerons on the outer wing of the 5.14/18m version, ChocoMotion 8/5.0 for the ailerons, and Chocomotion 10/9.2 (in size identical to the KST DS225MG, but more powerful) for the rest of the control surfaces (6 Servos in the 4.28/15m wing and 8 Servos in the 5.14/18m wing).

Today I received a large package from Servorahmen.de in the mail. Servorahmen.de provides servo frames with Integrated Drive System (IDS) for all the servo types we will be using. We have used their IDS system on most of our gliders in the past few years, including last year’s scratch-built Diana2 (1:3.5). The frames fit well, are robust and good value. The IDS system can be fully integrated into the wing, so no ugly protruding levers or large holes in the wing surfaces. Most importantly, they provide a wing surface control that is extremely direct and completely without play. Fitting the IDS frames requires more effort than standard systems, but the result is definitely worth it. Below are two pictures of the system built into my 1:3.5 (4.28m) Chocofly Diana2 that I hope to maiden soon. The Chocofly Diana2 is identical to my scratch-built Diana2 (which was designed by members in our team), except that the wings were built in a mould.