Our main designer Georg, having just taken the first fuselage out of the mould, spent much of today working on the newly built fuselage to allow him to fit the wings, elevator and rudder. He just shared the below picture with our building team. Methinks it looks awesome. Still a lot of work to do (I’ve yet to start on my wings), but this will be one nice-looking plane….
Between work on the mould and first fuselage I’ve also started work on the rudder. Georg as usual did the design prepared the plan for the main parts. Also the rudder will be light, and made out of plywood and a bit of carbon at the trailing edge. As we’re only doing three rudders it’s quickest to cut the ribs by hand. Yesterday and today I spent a few hours sawing, filing and sanding, and am pretty happy with the result so far (I’m not used to cutting ribs by hand :-)). Now I need to do the edge and then wait for my fuselage to start assembling the whole thing.
In my previous post I mentioned that we’re using a new glass and carbon layup for the fuselage. The picture below explains how we built it (in German). Previously we only used glass, but we decided to use carbon on this fuselage as it’s very long and thin, with a short nose, and we want to keep the weight of the tail as low as possible. The new layup is heavily inspired by one of Chocofly’s main builders and designers, who gave some very useful tips on how he does the fuselages.
As the first fuselage came out at 1.4kg, with the center of gravity at the trailing edge of the wing, it looks like we got it right. We need to check if we’re happy with the robustness of the fuselage and might make some small changes for the next one we built, but so far it looks ok.
On Thursday we built the first fuselage for the VT-16 Orlik. The first fuselage out of a new mould is always a bit of an adventure, as you need to get to know the mould and the “difficult spots”. Also, we were experimenting with a new glass and carbon layup (see next post), including using for the first time carbon in the fuselage. Today Georg cracked open the mould and shared pictures of the result. It came out very well! Weight of the empty fuselage is 1.4kg, and the center of balance is just at the trailing edge (which means we got the weight of the tail right). Two more fuselages to build over the next few weeks.
The fuselage mould is ready, as is the stamp for the canopy. Both came out very well – no air pockets or broken edges on the mould. Both the mould and the stamp are now polished. The canopy stamp is sent off to a friend who will produce the canopies for us. Our paintmaster Andi yesterday spray painted the fuselage mould with white 2K paint. Tomorrow we hope to build the first fuselage – I cannot imagine a better christmas present :-).
Time to start work on the fuselage mould. Our shaper Richie kindly also prepared the separation plane (Trennebene). Getting it to fit exactly around the fuselage mould was a full morning of work still. After that the fuselage mould was centered exactly into the separation plane (a laser really helps with that), and the space between the plug and plane filled with paste. Georg then spent a few hours waxing both the plug and the plane. On Tuesday we then built the first half of the fuselage mould. First a coat of moulding resin, reinforced with a few glass fibers. Then several layers of glass. Since we will only be building three or four fuselages out of this mould, we’re not overdoing it on the amount of glass (160-280-280-280-160, with two extra layers of 280 aroung the edges).
At the same time we also build the stamp for the canopy. A plug was prepared by our shaper Richie. Georg made a glass mould around that plug. We then coated the mould with a few layers of moulding resin, and then filled it with a mixture of ground shells (used for bird cages 🙂 ) and resin, as well as a piece of foam in the middle.
While the resin on the mould and stamp is curing, Georg will add the feet to the first half of the mould.
I’ve yet to decide what “nationality” I will be giving my Orlik – I’m hesitating between a Swiss or a Czech registration number. In any case, it will definitely need the nice Orlik logo on the nose. I’ve found many different versions of the logo on pictures on the web. Here is the result of scanning and editing the logo from what I think was the nices version, using the excellent Silhouette Studio software. Click on the picture for a PDF version, should somebody need this. 
While our shaper Richie was busy finishing the fuselage plug, our designer Georg has started work on the wings. The wings will be built using our usual technique: foam core, carbon joiner and main spar, carbon inserts, abachi and glass coverage, before spray painting the entire wing. As we want to go for a light-weight glider, we will be saving on the thickness of the wing joiner (using spare “old” wing joiners that were left over from earlier projects well over a decade ago), as well as on the amount of carbon going into the wing. And of course we’re doing six control surfaces, no airbrakes and a modern thin wing profile.
We’ve spent a few days cutting foam. Georg, the super fast-builder as always, then went full-speed ahead and built his wings in little over a week. They’re ready to go to the paintshop, and weigh little over 800gr each (for a 4.6m wingspan aircraft!). Andi and I hope to start building our wings together next week.
Our shaper, Richie, finished the plug! I’m always amazed at how he pulls this off, investing many hours of work sanding, covering with glass, filler, sanding etc. The result however looks awesome – as always. Now comes the hard work of making the moulds as well as the stamp for the canopy. Our designer Georg now has the plug and is preparing it so that we can start making the moulds shortly.
When we started this project we decided that building “scale” was less important than building a performant glider (we build our planes for flying – a lot!). The original VT-16 was built with a combination of ribs and foam, at the time a very modern construction. We decided to take this a bit further and build our Orlik with different techniques, including a modern design high performance wing and going for a very light weight glider. As the fuselage is pretty long and big, with only a short nose, that means we need to save every gramme we can on the tail. Hence the decision to build a light weight Balsa/Carbon/Plywood elevator – not the standard foam core/carbon inserts/glass coverage. Our designer Georg made a pretty nifty combination of those materials, allowing an elevator that’s sufficiently robust, but should be around 115-120 grammes once finished. Following Georg’s design and example I built mine. It was more work than planned – especially having to cut and saw all pieces by hand – but the result if pretty cool. 107grammes total weight, before covering.
The inner four ribs are plywood. The wing spar and trailing edge have a layer of carbon epoxied in, in addition to balsa and plywood. The hinges are glass fiber, joiners carbon and 2mm steel, the rest is balsa.
Also note that the original Orlik had an all-moving tailplane. We’re not great fans of such tailplanes so decided to go for a standard elevator setup.
Our shaper, Richie, has started working on the plug for the VT-16 Orlik. The frames for the fuselage plug are for the first time computer designed and laser-cut – until now we’ve always done this by hand. He’s finished filling the gaps between the frames with foam and done a first rough cut. Now the long and difficult job of sanding the whole thing into shape starts. In the meanwhile Georg has started work on designing the wing. We’ll be using the same landing gear as for the Urupema – the necessary parts have been ordered and we hope to cut 3mm glass sheets for the sides of the landing gear soon.
Even though I’ve still got enough going on in the workshop, it’s time to start planning ahead for the coming winter. So far we’ve done a new project with our building team every two years, and the team’s fingers are starting to itch to get into something new. Richie was going through some books with oldtimer gliders and found the Czech VT-16 Orlik. The original Orlik had it’s first flight in 1959 an was all wood, but filled with foam. It’s got a very characteristic shape and there are not many RC models of it around, and certainly none in a “modernised” version with a thinner airfoil. It didn’t take much for the rest of the team to enamour itself with the plane and decide that we want to build this one.
Fortunately there are many relatively good plans available for this plane on the web. I’ve had the best ones enlarged to our usual 1:3.5 scale. The fuselage is huge, 2.13 meters long. We’ll build the 16m version, which gives a wingspan of 4.6 meters. The length of the fuselage and size of the elevator are great for the model version, and we’ll probably stick to scale (we usually need to enlarge the elevator). We had some discussion on doing the wings in wood/ribs, but decided to build it in our usual method – foam cores, covered with abachi/carbon/glass and carbon spars. We will do the rudder in Balsa/ply, covered with tissue, to save weight and give it at least this little “scale” detail. As usual we will also omit the airbrakes and do four or six control surfaces. Wing profile will probably be MH-32. This will give us a nice all-rounder. We build our planes to fly – a lot.
Richie will now start work on the fuselage plug (which is a huge amount of very messy work – but he likes it and is a true master at this), and Georg will start desiging wing and control surfaces. In Autumn we will probably do the fuselage moulds and start building the wings, in the hope that we can maiden the first Orlik in spring 2022.
To be continued…
You must be logged in to post a comment.