Category Archives: Ventus 2C

Ventus 2C: Canopy Frame

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Building the canopy frame is always a bit of a pain. Here’s the method we use. First applying loads of tape to protect the fuselage in the parts around the frame. Then apply three layers of wax (leaving each layer to dry and polishing it carefully with some soft cloth). Then apply some thickened and coloured epoxy resin (with a “fast” hardener) and wait for the epoxy to cure a bit. Then I applied a layer of 100gr glass fiber, followed by four carbon rovings (entire length). I again waited for the epoxy to cure a bit. And then the “construction work” begins. Using coloured epoxy, thickened with lots of microballoons (so it stays in shape when applied) I built up the canopy frame on top of the carbon rovings/glass base. The result usually looks quite messy, but that doesn’t matter. Just make sure you apply enough material, so that you can sand away enough to get the frame into shape. I usually wait a few days for the epoxy to fully cure before sanding the frame into shape. Before sanding, make sure you drill the holes for the front pin and the rear lock. I always sand the inner part of the frame before releasing it from the fuselage. I use 2mm steel wire for both the front pin and the lock.

Ventus 2c: preparations for building the wings

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With the fuselages and tail sections of both the Diana 4 and Ventus 2c well advanced, it’s time to start on the wings. I will do the wings of the Ventus 2c first. All previous wings I built with my mate Andi. These ones I will be doing by myself.

The first step is to mount the cut styrofoam parts to the building board (which takes a lot of measuring), clean them and glue together the upper part, prepare the obechi wood, draw out the layout of the carbon on the obechi (which takes even more measuring) and cut the carbon for all four surfaces.

We always build our wings “upside down”. I will first be doing the two upper parts, and then I will add the spars, in the same step as closing the lower part of the wing. All in all four “vacuum sessions”.

Each wing will be built in one piece. Once the wing is sanded and glassed, I will cut off the two outer segments and glue them back at the right angle.

A few details on how we build our wings:

  • We build the “traditional” way, around a foam core, cut with a hot wire. It allows for a light wing, perfect for the type of flying we do. The foam we use is from Schurg Modellbau in Germany. Our club purchased a truckload of the stuff decades ago, but it’s now running out, so we’ll be looking for a fresh supply – ideas for suppliers in Switzerland are more than welcome!
  • The foam cores are glued onto 0.6mm obechi (abachi) wood. A good supplier in Switzerland for this is RIK Modellbau in Mosnang.
  • We use carbon cloth to reinforce the wings at the front (carbon D-box) and rear (control surfaces), as well as around the wing joiner and underneath the servos. We’ve experimented with different types of carbon cloth over the years. Our favourite is 100gr Carbon Biax supplied by swiss-composite.ch. It’s good value, fibres are at a 45 degree angle, and it’s easy to cut and use.

Diana 4 and Ventus 2c: tail sections

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Earlier this week I picked up the rudder for the Diana 4. Fellow builder Georg built three of these for us, using the mould he made for the JS3 rudder. As usual it’s very nicely done and extremely light.

The tail sections of both the Diana 4 and the Ventus 2c are now as good as ready (of course the horizontal stabilisers and the Ventus rudder still need covering and painting):

  • 45 degree angle reinforcement to avoid torsion in the vertical stabiliser (3mm balsa, covered with 49gr glass on both sides);
  • vertical reinforcement to close the vertical stabiliser before the rudder
  • rudders fitted and brass tubes (pull-pull system with kevlar wire) fitted
  • elevator servo installed, including wiring

The pictures of the (transparent) tail section of the Ventus show best what’s where. We always prepare a sheet of 3mm balsa wood with 49gr glass on one side (glass applied in a 45 degree angle). The balsa wood reinforcements are then glued in with thickened epoxy resin and 49gr glass (also in a 45 degree angle). With the Ventus I also applied two thin carbon rovings – that’s because I felt like it and had it lying around, but it isn’t really needed ;-). Together, the two reinforcements give enough stability/torsional stiffness to the vertical stabiliser.

Ventus 2c: installing the motor bulkhead

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The Ventus 2c will get a powerful inrunner motor. This allows for a lighter motor with lots of power to enable easy handstarts on the slope. Urs Leodolter at Leomotion.com as usual helped me pick a really nice setup. With 6kg pull it should allow the Ventus to go near-vertical.

Installing the bulkhead was done using the usual technique. Once put into place using a few dots of 5min epoxy I fixed it permanently using 12hr epoxy and two small carbon rovings. See the more elaborate description, linked through under the “how to” section.

The usual 43mm RFM scale spinner – which we use for almost all our builds – is again a good fit – even with a difficult fuselage shape to build a motor into.

Ventus 2c and Diana 4 – fuselage servos

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It’s often the small things that take up a lot of time. I spent quite a few hours building the frames/setup for the servos in the fuselages of the Ventus 2c and the Diana 4, as well as the bulkheads for the landing gear and the towhook of the Diana 4.

The picture below shows:

  • The two units for the rudders. I will use the usual kevlar wire pull-pull system, using a small pulley that was designed and built within our club ages ago.
  • The servo frames for the elevator servos. These are built into the vertical stabiliser and then connected to elevator using a carbon rod with 2.5mm (Ventus) or 3mm (Diana 4) threaded metal rods glued into the ends.
  • The bulkhead for the towhook servo and the towhook entrance.
  • The landing gear with bulkhead and servo setup.

(Most of) the electronics

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Yesterday we got most of the electronics for our Diana4, as well as parts for my Ventus 2c and two other gliders that members of our building team are currently working on (a scale 1:3.5 SB-14 and another Moswey III). The parts were supplied by Leomotion, as usual.

For the Diana and my Ventus 2C we will be using:
Chocomotion 10/10 on the brake and camber flaps
Chocomotion 8/6 on the ailerons
For all wing servos we are using the Chocomotion servo frames and aluminium levers (10/7/5mm).
MKS HV6130H on elevator
Chocomotion 12/9.5 on Rudder

In addition, we will use for the Diana4:
Chocomotion 12/9.5 for towhook
Chocomotion 180/30 for retractable landing gear

All Diana4 will get a FES motor: a Dualsky XM5060EA3-14, with a Freudenthaler Scale Spinner (43/6/0degr – mit Versatz) and a GM 18×10 Scale Prop and a Castle 100 Light ESC.

I’ll also put a FES onto my Ventus 2c, but will still need to determine which motor setup.

We’ve used all components before and have flown hundreds of hours with them – this is our preferred setup.

Ventus 2c: Stabiliser and Rudder

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Rudder and stabiliser are both built around a foam core. As this plane is supposed to be “super light”, I used 1mm balsa rather than the usual 0.8mm obechi wood. I also used 49gr glass fiber (45 degrees) rather than carbon inserts, as well as a thin (7mm) glass fiber strip at the trailing edge of the rudder and stabiliser. The stabiliser will not have a separate spar, but the carbon tube that also marks the hinge for the elevator will give enough stiffness to the stabiliser. In the middle of the stabiliser is a piece of plywood (with a hole for the screw to fix the stabiliser to the rudder), fixed with two bits of kevlar (top and bottom) to keep it in place.

Last week I built the upper side of the stabiliser and one side of the rudder for the Ventus 2c. Today I finished the lower side, which is now curing in the vacuum bag. I’m using my new small KNF vacuum pump, which seems to be holding up quite well. To avoid having to walk over to the workshop regularly to check all is ok, I installed a cheap webcam in my workshop to guard the vacuum pressure, and put a timer on the plug so that the vacuum automatically switches off at midnight – all so that I can have an easy and worry-free evening :-). Unbagging is tomorrow and then I’ll get to work on the stabiliser of the Diana 4.

Diana4 and Ventus 2C: Wing joiners and ballast tubes

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In-between other tasks I’ve been preparing the sleeves for the wing joiners and the ballast tubes for the 4.5m Ventus 2C and the 5.14m Diana 4. I’ve also given my new vacuum pump a test run and have done most preparations to build the elevator and rudder for the Ventus 2C.

The sleeves for the wing joiners are done as usual: first liberally apply Teflon bike lubricant to the wing joiner and wrap it 1.5 times with a thin plastic bag. Then pull over a kevlar tube and wrap it with kevlar rovings. Then tightly wrap the whole thing with tear-off fabric, put a weight at the end and hang it out to allow the epoxy to cure. We always leave the sleeve on the wing joiner while building the wings and only pull out the wing joiner once the wing shell is done.

 

 

New Projects for Winter 2022-2023

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I’ve been doing some preparatory work for new projects over the last few months already – in between other tasks – but I now finally have time to start getting into building mode. An I have a luxury problem: too many exciting project opportunities! Work has started on the following new scratch builds:

  • A scale 1:4 Ventus 2C (4.5m): A few years ago I went to pick up a DG1000 fuselage that I purchased from a retiring pilot. In his workshop there was this really pretty fuselage, which he agreed to sell to me for a few Francs. When I showed the fuselage to colleagues on the club they got all excited: it’s a fuselage that was built by a colleague in our club almost 20 years ago, from moulds and plans that are still around. In fact there are also still a few built planes around. This summer my mate Georg did a full revision on his and stripped out the landing gear, with the result that he got a really wonderful and surprisingly performant 4.5m glider weighing less than 5kg. The plane fills a “gap” in my collection of gliders, in the sense that it’s easy to hand-start on days with little wind. I’ve decided to give this build priority for this winter. I’ve built the wing joiner, have the rudder and elevator parts ready to build. Together with Georg we also cut the foam for the wings.
  • A scale 1:3.5 Diana 4 (5.14m): this one will be 2nd in my priority list, and I’ll be building part of it alongside the Ventus. More on that in a next post.
  • A scale 1:3 Diana 2 (5m): The 5m Diana2 was the first Diana2 model built in our club and as far as I’m aware anywhere. It was a huge success within our club, but was quickly overshadowed by the smaller 4.28m, of which the Chocofly version has become famous as one of the best slope gliders around. I’ve been wanting to build the 5m version for ever. We still need to build a fuselage for myself and for Andi. I’ve yet to decide if I will fit it with my Baudis 5m Diana2 wings, or whether I’ll build my own set of wings. I built a wing joiner last week, but the rest of the plane will be for next winter.
  • A scale 1:3.5 Monnett Monerai (3.43m): My mate Richi has been planning to do a model of this US 12m kit glider for a while. It’s something very special. It’s also an easy build. Richi has done the plug for the fuselage pod (it’s a pod and boom glider) and is having the boom produced by colleagues in a professional glider manufacturer. I’ve produced the wing joiners for Richi and myself. I’ll work on this one on and off, depending on how other projects progress.

There may be one or two further surprises that I’ll report on as they appear :-)(I’m expecting something from the Ukraine, but the delivery of that is uncertain for understandable reasons) .