I finally got to put most of the bits of my VT-16 Orlik together.
Unfortunately I had a mishap with the wings. When cutting the foam cores we forgot to cut the angle to the fuselage, leaving it at 90 degrees. As we started building the wings before we had the first fuselage, we didn’t notice this mistake until we tried to fit the wings to the fuselage and had a 12mm gap at the trailing edge on both wings. Fortunately this wasn’t too difficult to solve (with a big saw), but did take a few hours of unnecessary work.
A lot of work to do still, but it’s always very motivating to see the result of so many hours of work.
I’ve been flying my Moswey III without a pilot seat – it’s been on my “to do” list since I finished the build. In-between work on the VT-16 Orlik I got inspired and decided to experiment a bit with bending plywood. The sodastream gas canister and water bottle looked like the perfect shape to form a leftover bit of 2mm plywood into a nice looking seat. I soaked the plywood in water for a few hours, bent it over the canister and bottle and let it dry out overnight. Then added a stick and seat belts. I’m not usually one big on scale details, but I’m pretty happy with the result.
In-between working on the wings with Andi, I also installed the motor bulkhead and the landing gear into the fuselage of my Orlik. The bulkhead and landing gear frame were cut out of 4mm plywood and fixed with thickened epoxy resin. The motor bulkhead has a ring of carbon roving around it for extra safety. The bulkhead is installed at a 3.5 degree downward angle to avoid the plane pulling up excessively on full throttle.
For the motor we will be using the Dualsky XM5060EA-14SE. We’ve used this motor or its predecessor in most of our previous builds (the Urupema, JS3, and also my SZD-54). I really like this motor. It is sufficiently powerful for our use and especially also very quiet. We will be running it on our usual 6S setup (either with a 2x3S 3300 or a 3700mAh battery, depending on how much weight we will need in the nose). If all goes well the weight of the motor and batteries will be enough to avoid having to add much further weight to the nose.
Over the past few weeks Andi and I have been building the second and third pair of wings. We built them in the usual manner: foam cores, with carbon wing spar and carbon D-Box and carbon inserts over the control surfaces and a kevlar triangle over the area with the wing joiner. Andi built the upper sides of all four wings (we always build them “upside down”). We then “closed” the lower side together, after cutting the wiring channels and inserting the various carbon spars. The wings spent 12 hours in vacuum (-1.5 Bar) to cure. The result looks good, especially after an afternoon “sanding session”, where we sanded down the abachi wood on the wings to get an even surface and nice leading and trailing edges.
Today we release fuselage nr.2 (mine!) from the mould. Cracking open the mould and checking the result of almost a full day of work (the 2nd fuselage took us 6 hrs) is always an exciting moment. It came out without any major flaws and is 20gr lighter than the first fuselage. Nr.3 is due to be built on Monday. After that we’ll finish work on the 2nd and 3rd pair of wings – the upper sides are already done, but we’ll need four half-days to insert spars and close the lower side of the remaining wings. More on that later.
Yesterday we built the second Orlik fuselage. We’ll take it out of the mould tomorrow (we usually let it cure for around 48 hours). While waiting for the fuselage to cure I’ve assembled the landing gear and started preparing the electronics for the fuselage.
The landing gear will be very similar to the one we built for the Urupema, two glass boards held by aluminium rods, a 100m wheel, hinge up front and suspension with rubber bands at the rear. Georg arranged for one of his contacts to cut the 3mm glass board on his CNC milling machine.
As for the electronics in the fuselage, we’ll be using the usual components: an MKS HV6130H Servo for the elevator and a Chocomotion/Fox 12/9.5 for the rudder and towhook. The rudder will be operated using our usual pull-pull system with a kevlar wire. The towhook is the well tested self-built version. I’ve also prepared the plate and screw for the bungee hook, also standard equipment on all our gliders (we launch our larger gliders using a bungee system on our airfield).
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.
Richie Oberholzer is one of the key members in our building team. He’s built the fuselage plugs for all our recent projects, but also regularly has his own unique projects – all of them scratch-built. One of his latest ones is his 8m wingspan EB29-R, which he’s been working on along other projects in the last few years, and which he maidened on 1 April 2021. On his request I put together a couple of videos and pictures of this absolutely amazing project. They can be found on this separate page.
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 :-).
Unfortunately I had some mishaps during the past flying season, but the grey months of winter are a good time to fix the damages.
My Inside F5J (sold by Hoellein) is my most-flown plane during our club’s Hahnenmoos excursions – the reason is that I fly it in early mornings and late afternoon/evenings, when conditions are suboptimal for flying the bigger stuff. We often practice formation flying or fly far out to find the smallest bits of thermals. Unfortunately this also results in the occasional mishaps. During our club’s Hahnenmoos excursion in June my Inside F5J suffered a mid-air collision. The left wing was “impaled” by a full-carbon F5J glider coming from behind. This resulted in the left outer wing being ripped off in-flight and my poor Inside crashing to the ground from an altitude of almost 200m. Fortunately it weighs less than a kilo and I had the wits to engage what was left of the airbrakes, so the damage of the impact was not too bad. The left outer wing was beyond repair and most other parts suffered a bit of damage. Nothing that a few days of work couldn’t fix though. Most work was stripping the light-weight foil from the wings and covering them anew. Already in summer I bought a second Inside F5J kit, from which I took the parts to build a new left outer wing. Unfortunately I ordered the wrong foil (non-transparent), and only noticed this when I started covering the Inside again yesterday. I decided to use it anyway rather than buy new foil. My Inside will not win any beauty contests, but it’s fully functional again and looking forward to many more hours of relaxed flying.
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.
My new Moswey III has spent many hours airborne over the past few months. It’s become one of my three favourite planes (next to the JS3 and the 4m Diana2). It thermals incredibly well, is a breeze to land, and I just love how you can throw it into a tight curve without having to worry about a stall. It’s wonderful to fly, and worth all the hours and frustration put into building it.
Our club (mg-eh.ch) has always had a special relationship with the Moswey. The plane was developed and built in our region, including just across the lake from our club’s airfield (Horgen). Moreover, the first ever rc-model of the Moswey was built within our club as far back as the 1970s and most of the commercial versions available today (the kit from albmodellbau and the small version from oldgliders, as well as the fully moulded version from Chocofly) are based on the work within our club or have been developed with involvement of members of our club – or both.
Over the past five decades, many Mosweys have been built and flown within our club, but with a few new builds finished or nearly finished, it was high time to organise another Moswey day. On 11 August 2021 we managed to get four of our Mosweys together. All were 4m versions, three self-built from an albmodellbau kit (lovingly called “Zitrönli” (little lemon), “Fröschli” (little frog) and “Schneewittli” (little snowy white), and one fully moulded Moswey 4 from Chocofly. Unfortunately we didn’t have many thermals that day, but the air was quiet and the flying wonderful – we even managed to get a bit of formation flying in. Some pictures of our planes are below. More pictures, including of our Mosweys in flight, can be found on our club’s website: mg-eh.ch/galerie/moswey-fliegen/.
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.
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