Text: Pierre Rondel
Photo: Joël Marin, Pierre Rondel, Olivier Dumaine.
Introduction
The Asw-17 isn't new and has been around for a few years now. But it's one of the rare gliders, I'd even say legendary, that hasn't aged a day and remains one of the best choices even today! I bought mine in 2021 and fly it every summer. Here's a quick debrief of this glider.
Presentation
The ASW-17 1:4.5 from FW Models is a high-performance large-scale RC sailplane designed for experienced pilots who value realism and efficiency. Built at approximately 22 % scale, it features an impressive 4.44 m wingspan and a sleek fiberglass and carbon-reinforced structure.
The model is optimized for excellent thermalling performance at low speeds while remaining agile and stable when flown faster. Its modern airfoil and refined aerodynamics provide smooth handling across a wide flight envelope. Equipped with multi-section flaps and ailerons, it offers precise control and effective landing configurations.
The robust construction ensures durability without excessive weight, typically resulting in a flying mass of around 5kg for the standard version to 6 kg for the hardshell version.
Mine is a hartschale version which means no sandwich material, just pure carbon skin. I waited for it 10 months ago, but the delivery time is now above one year and probably much more from my understanding.
When visiting FW in Germany I also collected the one of my friend Matthieu, as the shipping cost for this parcel dimensions are just going crazy recently. On my side, I purchased separately Revoc covers for wings, tails and rudder, because I found the dark grey color of the FW optional bag too dark for sunny weather. I therefore opted for an outer aluminum cover set with inner soft fabric, and asked REVOC - Custom to have one bag per wing instead of 1 bag for the 2 wings, which they kindly accepted, so I can protect the wing at the slope.
Below the weight of the different components :
- Left Wing: 1457 gr
- Right Wing: 1522 gr
- Tails + joiner: 127 gr
- Wing joiner: 241 gr
- Fuselage with Canopy: 1024g
For a total weight before assembly of: 4371 g
I was a bit surprised and disappointed by the difference of 65g between left and right wing. I hope it won't be visible in flight.
Overall, the moulding quality is very nice, the wing surface is shiny, and the wings seem indestructible. The canopy is perfectly adjusted. The hole of the elevator servo in the rudder is pre-cut. Control horns and clevis exit are already cut on the wings, which prevent the installation of an LDS. But given the recorded dive speed above 300 km/h, I prefer to stay with traditional installation anyway.
Assembly
Let start the assembly with the wing servos installation. For the servos, I go for the MKS HBL6625 for flaps and intermediate flaps, and the MKS HBL6625mini for the aileron.
As the servo holes on the ASW-17 wings are tight to insert a large servo frame, I choose to equip my model with premium servo frames from Tomas Liu Studio (https://tomas-liu-studio.com/).
Those are very high quality and made of strong carbon. Because they maintain the servo by the 2 side screws, they allow, once the servo frame is glued in place, to insert the servo and slide it in place easily.
But Tomas Liu is not only offering servo frames and servo heads to go with. It is a wide choice of clevises, carbon control horns, carbon rod or threaded shaft, without forgetting cyano glue, or tools.
Finally all servos, including elevator servo will be using these high quality servo frames, MKS HBL6625 mini for elevator, MKS HV747 for the rudder, MKS HBL6625 and MKS HV6130 in the wings.
Unfortunately I couldn't use the servo horns because I needed longer horns to obtain the throws I wanted. So I replaced them with metal MKS servo horns and ball clevises from MPJET. This shows that Tomas Liu hardware is greatly customisable and adaptable, which I like a lot !
To finish with the wings, I designed and 3D printed servo covers with a teardrop-shaped protrusion because the servo arms protrude slightly. Later I also created home made pushrod exits 3D printed in white PETG. In flight, I didn't notice any real difference in terms of noise or whistling.
For the elevator servo, installed in the fin, I chose the MKS HV6130 for its light weight and strong power. Here too, I started with a Tomas Liu servo frame, with standard servo arms.
The problem with the elevator control linkage is that the ball joint isn't held laterally and can move, potentially rubbing against the inner wall of the fin. This can cause stiff spots in operation and possibly a poor return to neutral. To avoid this, it's essential to center and hold the ball joint's position. Therefore, I glued a small tube with a 3mm inner diameter to each stabilizer half, which pushes the ball joint back and automatically positions it. I secured the tail with a 1mm piano wire.
Let's move on to the fuselage, the radio tray, and the engine. For this part, I went very "old school" with a plywood tray and fiberglass fabric extending up the sides. The rudder servo is a MKS HV747 located in the front of the fuselage.
I then created an inverted mezzanine to house the propulsion battery. I produced several parts using 3D printing, such as the vertical antenna mount, the bracket for the dual green MPX connector for the receiver battery, and the wing connector brackets (8-pin) secured with screws in the fuselage root.
After many simulations on e-Calc, I decided to go for an Aerodrive SK3 4250-410 motor with a GM 16 x 10 Scale propeller.
The Spinner, an RFM scale 40/05/32 was a bit difficult to source, so additional shipping cost. The ESC is a Sunrise Model 80A 7.4v BEC. I don't plan to use the BEC, but I bought a double battery source power with magnetic switch from Jeti. I will use 2 batteries Li-Ion 2s of 3000mAh to power the servos and receiver. This should give me plenty of flying time.
After cutting the glider's nose to the correct size, I made and securely glued a 2 x 2 mm epoxy frame. The controller is mounted on a small plywood plate with two plastic cable ties.
The unpleasant surprise came when I tried to balance the glider and realized it was too nose-heavy. I had to reduce the size of the propulsion battery to help, opting for a lighter 6S, 2800mAh graphene battery. Even so, I still had to add 20g to the rudder.
In total, the final flying weight is 6.1kg, which is within the acceptable range, but I was aiming for something around 5.8kg, like my friend Matthieu Mervelet's. It would be easy to save 200 to 300 grams by removing one of the two receiver batteries and instead of using a radio tray, mounting the radio components directly onto the inner fuselage using mini radio trays. That'll be for next time!
An incredible glider in flight!
The first flight took place on the south-facing slope at the Col du Glandon on a beautiful summer day. I immediately felt at ease with this glider. It's incredibly precise in roll and handles like an F3F glider most of the time. It has a high cruising speed. In thermals, it performs very well despite its weight, but you should avoid high-angle, low-speed spirals as it becomes more difficult to control due to its wing loading.
The rudder is very powerful due to its large surface area, and the pendulum-like elevator is smooth and precise.
On the other hand, it transitions extremely well and allows you to quickly explore a huge volume of airspace, making it possible to consider some great strategies in terrain soaring.
But it's not in thermal chasing that the Asw-17 excels. As soon as the conditions are a bit stronger, it shows its true character, especially in its hardshell version. It accelerates to reach crazy speeds, exceeding 300km/s at its peak, follows perfectly straight trajectories with extreme precision and allows for beautiful, wide-ranging aerobatics.
The most incredible thing is that despite the large aspect ratio, with the right aileron differential setting, it rolls perfectly on the axis. My glider weighs 6.1kg and Serge's 6.5kg.
4-steps rolls are surprisingly easy, and vertical maneuvers have a wide range of motion. Inverted flight with low passes is spectacular and gives the pilot a thrill, but ultimately remains safe despite the glider's size.
Landing, despite the six control surfaces on the wings, remains a delicate phase in my opinion, due to the model's inertia, which causes it to roll very, very much. It's best to choose relatively large landing areas to avoid any scares.
Over time, the rudder hinge (made of Kevlar or tear-away fabric) has slightly delaminated; I'm not entirely sure why. This results in a small lateral offset at the rudder's base. I glued it back on, and it seems to be holding, but it's something to keep an eye on. In extreme cases, it's possible to cut the fabric and install proper hinges. We'll see how it holds up over time.
Conclusion
Well, as you've probably gathered, I've fallen under the spell of this glider. Admittedly, I don't fly it every day like I do with my F3F gliders, but every time I do, I get a real thrill from piloting it. I understand better why the Asw-17 remains a benchmark that has never been dethroned by more recent models. I know the waiting list is very long, even getting longer, but it's worth it. There's also the possibility of finding them second hands, so don't despair!
Overall, the ASW-17 1:4.5 glider stands out as a realistic, elegant, and high-performance glider perfectly suited for slope or flatland flying, whether powered or as a pure glider. In short, this glider is highly desirable!
Characteristics
- wingspan 4440 mm
- fuselage length 1670 mm
- takeoff weight 6.1 kg
- area 72 dm2
- airfoil thickness 10%
- scale 1:4,5 / 22%
Manufacturer website:
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