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Welcome to ShredAir’s RC translations.

We offer English translations of selected articles from German RC magazines. Whenever possible, the original German article and the corresponding English translation will be posted as PDFs, the original complete with photos and the translation text only.
We welcome suggestions for translations but cannot guarantee availability of the German original.

Dieter Mahlein

Segelflugmesse

This RC soaring fair in Schwabmünchen, Germany, was a remarkable event. Many well-known manufacturers displayed and demonstrated their products. Here is the complete document in German and the English translation of text and captions.

 

Author: Redaktion Großsegler
Photos: Redaktion Großsegler,
Philipp Gardemin, Horst Kropka,
Urs Pircher
Magazine: Aufwind 5/2012
Translation: Dieter Mahlein

 

english pdf german pdf

Breath-taking!

A 6.66-meter DG-1000

While I was looking around for a scale glider which can handle pedal-to-the-metal hot-rodding, I came across Modellbau Egger in Feldkirchen, Austria. Owner Markus Egger recently had begun to offer a 3rd-scale DG-1000 spanning 6.66 meters. The model is all-molded using fiberglass and carbon fiber sandwich construction. This particular glider piqued my curiosity, because I wasn’t just looking for any model: I wanted it to be 3rd-scale, fit Florian Schambeck’s AFT-25 self-launch system (SLS), have an airfoil with a wide speed range, and be strongly built in all-molded glass and carbon construction.

Looking around for gliders fitting these parameters, you’ll notice they are few and far between. The fuselages of 3rd-scale gliders rarely are big enough to fit Florian’s AFT-25. But I wanted to use it because of its high reliability and my favorable past experience with it. The DG-1000 by Modellbau Egger fit my requirements like a glove.

I personally met Markus in Austria over the Easter holiday and saw a DG-1000 for the first time in his shop. It did look stunning fully assembled in all its glory! The quality of the composite construction impressed me as did the solidity of the wing with its hard surface and torsional and bending rigidity. One can hardly twist the wing, but even the ailerons and flaps are torsionally very stiff, which can be a tough feat to accomplish.
Surface quality is very good even if it can’t quite compare to the high-gloss art pieces produced by Jaro Müller, for example. The square, solid carbon joiner measures 30 x 30 millimeters in cross section. After a lengthy and informative chat with Markus and close inspection of all parts, I decided to order a DG-1000.

Four weeks later, exactly as promised, my DG-1000 arrived as ordered, all shiny white with blue wing bottoms. Gear and SLS doors were cut out cleanly and hinged. Included were precisely machined formers for the landing gear, fiberglass control horns, and all servo covers. The rudder came pre-hinged.
The elevator can be actuated by one or two servos, up to 15 mm thick, installed in the stabilizer; the elevator can be ordered cut in half for independent two-servo operation. Also installed were the spoilers by Florian Schambeck, whose locking mechanism and exacting construction makes them some of the best on the market today. The cap strips for the spoilers came finished and precisely installed.
A very nice idea and feature are servo well boxes made from fiberglass and molded into the wing at the factory. They tie top and bottom wing skins together and make for easy and secure servo installation and strong, slop-free linkages.
Seat pans and front and back instrument pods are included in the kit, and the cockpit can be built out in detail with the optionally available cockpit kit featuring scale instruments, sticks, levers, harnesses, etc.

I equipped my model as follows:

- Schambeck SLS AFT-25XS with controller YGE 120 HV.

- two 5s 5,000 mAh LiPo packs for the SLS.

- one each Hitec HS-7950 servo for flaps and ailerons.

- two Graupner DS-3288 servos for the elevator.

- two Graupner DES-707 BBMG servos for the spoilers.

- one each Graupner DES-707 BBMG servo for the retract and the rudder.

Author: Heli Negele
Photos: Oliver Hoppe
Magazine: Aufwind 6/2011
Translation: Dieter Mahlein

Data:
DG-1000 by Modellbau Egger
A scale glider fully molded in carbon and glass fibers.

Wingspan: 6.66 m
Length: 2.85 m
Airfoil: HQ/W 2.5 series
Flying weight: 19.8 kg
Price starting at 3,975 Euros; available at Modellbau Egger,
tel. +43/676/7274672|
www.modellbau-egger.at

Photo Captions:
I’m not sure if these match the photos in the magazine; I don’t have a copy yet. --Dieter

  1. Maiden launch using the SLS by Florian Schambeck.
  2. (several photos) Extending and retracting the AFT-25 SLS is fully automatic.
  3. This is an impressive two-seater with excellent flight characteristics and performance.
  4. The built-out cockpit looks very good; there is no limit to scale detailing.
  5. The massive wing joiner transfers loads efficiently.
  6. The horizontal stabilizer simply is bolted to the fin.
  7. The joint between inner and outer wing panels. Thanks to the four-piece wing, the model also is easy to transport.
  8. The big spoilers and deployed flaps allow precise landing approaches.
  9. The glider is strong enough for high-speed hot-dogging.
  10. Low passes -- with SLS deployed or retracted -- are spectacular.
  11. The sleek silhouette of the DG-1000 is exciting to look at.

To finish the DG-1000, I only needed to install the retract, the electronics, and the canopies; of course, this can be ordered pre-done also. As is the case in the full-size, the canopies are side-hinged, and the hardware to do so is included.
To install the servos, I used servo frames from RC-Solutions available through Emcotec. These are CNC-machined from aircraft plywood, fit very precisely, and are available for many servos. They fit perfectly into the fiberglass boxes for a very solid installation.
The control horns still needed to be glued in. For the wing, I used M3 ball-links at the horns and M3 clevises at the servo ams with M3 threaded rod connecting the two. This safe and slop-free linkage is well-matched to the DG-1000.
The rudder servo is mounted near the main former and actuates the rudder with stainless steel cable in pull-pull fashion. Green Multiplex connectors hook up the wing servos to the fuselage wiring harness.

After mounting the canopies and installing the landing gear and the battery packs, it was time to balance the model. The manufacturer supplies the CG location for the fully assembled model, but also for the complete fuselage with empennage but without wings. I liked that very much, because models of this size are much easier to balance without the wings attached.

After two weeks of leisurely evening building, the DG was finished and ready to be weighed. The model weighed 19.8 kg (43.56 lbs) complete with finished cockpit, scale pilot and SLS; not bad for sailplane of this caliber.

I programmed the model relying completely on my experience. I chose larger than suggested aileron throws, because I wanted a good roll rate for aerobatics; the flaps follow the ailerons at 50 percent throw.
I mixed crow (flaps down, ailerons up) with the spoilers, which really slows the glider well for landing. For thermaling, the flaps are dropped 5 mm, the ailerons a little less; the trailing edge reflexed up 4 mm for speed, which reduces airfoil drag.

But let’s go already, maiden this thing! I chose to take off using the SLS right away. With the help of a slight head wind, the model lifted off cleanly after about 25 meters. If it’s calm, however, the model behaves differently: Like in the full-size, the nose gets pushed down somewhat for the first few meters of take-off roll, which can easily be corrected with judicious use of up-elevator input.
I climbed to about 300 meters altitude and retracted the SLS. A few clicks of up, and the DG-1000 was circling smoothly. Obviously, this model has excellent thermal and glide performance. It is surprising how slowly and tightly it will turn, which allows circling in small thermals without a hint of stalling. After a 40-minute flight, I greased the DG-1000 onto the runway. A few more flights were needed to fine-tune the CG, to my taste slightly aft of recommended.

Time to wring ‘er out. Climb to 500 meters and start a 60-degree dive: Incoming!! -- The onlookers and I were impressed with the acceleration. Low pass at just under 300 km/h (~186 mph), as measured by pitot tube, and pull up into a big loop. Amazing how well the HQ/W-2.5 airfoil carries momentum. The wings were solid, no twist whatsoever, and there is very little bending even in tight maneuvers.
The speed range is large thanks to full trailing edge camber control. When cambered, the glider flies nicely and slowly and is easy to land, while reflex coupled with a decent dive turns it into high-speed 7-meter model carrying amazing momentum.

I have about 50 problem-free flights on my DG-1000 now. Thanks to its 3rd-scale, 6.66-meter size and AFT-25 SLS, this DG-1000 combines its attributes such that it is the perfect scale glider for me. The quality of construction and the impressive performance of the rock-solid carbon-and-glass wings make for a wide flight envelope. Add to that the characteristic look of the DG-1000… what else could you want?

A True Winner

Stobel V3 by LE-Composites

As one would gather from the V3 moniker, this model is developed from its predecessors Stobel V2 and Stobel DLG. All Stobel models are precisely tailored and carefully optimized for F3K competition. Particularly important are maximum launch height, minimum sink speed, effective landing aids, and good thermal ability even when fully ballasted. Ever more important also is the ability to penetrate in order to make it back home from down-wind thermals or slope lift off of tree rows, for example. Numerous contest successes show that the Stobel V3 fulfills these parameters quite well. Joe Wurts, the 2011 F3K world champion, used the Stobel V3 almost exclusively during the fly-off. But just because this glider is a pure-bred competition machine doesn’t mean a motivated sport pilot may stop reading now. To the contrary, such a pilot will profit from the good flying characteristics and the robustness of this model.

The changes over the Stobel V2 are the wing and, lately, a larger vertical stabilizer. The latter has 50% more surface area, and, according to the manufacturer, gives less adept throwers much more launch height due to reduced tail wagging upon release. The wing retained the planform of its predecessor and therefore is hard to tell apart. There is a slight increase in dihedral for better circling, and the airfoil is slightly thinner with reduced camber to squeak out some more launch height. The fuselage remains the same, including its clever ballast solution: to add ballast, loosen the rear wing bolt, push in the desired amount of ballast, and tighten the wing bolt. The ballast bar is now securely fastened.

The wing is of all-molded construction using carbon and glass fibers. The D-box features spread-tow for the outer skin with fiberglass behind the spar. The inner skin also is fiberglass with “Disser” carbon rovings at 45-degree angles. This yields a very stiff and strong wing with favorable mass distribution; no worries about flutter during launch here. The wing is completed at the factory with flaperons cut, hinged, and actuated by slop-free RDS. The digital servos are included in the purchase price.

As is common in this competition class, the one-piece fuselage is constructed entirely from carbon fiber. This makes it stiff and light, weighing only 36.5 grams including the canopy.
Like the wings, the tail group also is fully molded, but with a solid, CNC-machined Rohacell core inside. This core is covered with fiberglass and reinforced where needed with unidirectional carbon fibers; a strip of aramid fiber becomes the hinge. The complete tail group weighs 12.5 grams.
Also included in the purchase price are all accessories needed to complete the model, a set of protective wing bags, and ballast in the form of one each aluminum and steel slug weighing 20 and 50 grams respectively.

Author: Michael Böhm
Photos: Stefan Gantzkow, Michael Böhm
Magazine: Aufwind 6/2011
Translation: Dieter Mahlein

Data:
Stobel V3 by LE-Composites
A F3K competition model

Wing span: 1,498 mm
Weight: 248 g
Wing area: 21.2 sqdm
Wing loading: 11.7 g/sqdm
Airfoil: LE-Composites
Center of Gravity: 73-77 mm
Price: 650 Euros; available at LE-Composites, tel. 06400/9879777
www.le-composites.de

Photo captions:

  1. The Stobel takes hard launches with ease.
  2. The ergonomic shape of the throw peg is easy on the launch fingers.
  3. The tail group is molded with solid foam core.
  4. Sufficient space inside. Steel ballast seen installed on the left,
  5. Don’t give up! Thermals can be caught even at this altitude.
  6. The sleek look suggest good flight performance.
  7. Hand catch on the wing tip for immediate re-launch -- a matter of seconds!

The build quality is very good, with shiny surfaces indicating high-quality molds. Minor air bubbles in the surface are due to building extremely light, and they do not affect the overall appearance of the model.

Because the Stobel V3 comes highly prefabricated, completion is quick. The instructions are clear with many photos and include all necessary information and dimensions. Care must be taken with the rudder and elevator linkages. These are actuated by a single string pulling against a spring. Follow the instructions carefully for a light-weight and slop-free linkage.
In the wing, only the wiring plug has to be soldered on and the ergonomically-shaped throw peg installed. The wing and tail surfaces come ready for mounting to the fuselage.
In the fuselage, the wiring plug needed to be installed and the ballast holder assembled from its three formers; the assembly was then glued in with 5-minute epoxy. I used Dymond D-47 servos for rudder and elevator, and glued in the included servo tray with 5-minute epoxy also. Careful here to assure sufficient space remains for ballast installation and removal! After the linkages were prepped and threaded through their exit openings, the vertical stab was glued to the tail boom.

I installed a 4-cell GP-350 battery and a Graupner SMC16Scan receiver into my plane. So equipped, all-up weight was 248 grams, and no nose weight was needed to achieve the rear-most recommended CG.

For safety, I used traditional over-head throws for the maiden flights. The first discus-style launches yielded smooth climbs with out much tail-wagging. Indeed, launch height was so good that onlookers hardly believed they resulted from the throw only.
Slightly cambered, the Stobel floats extremely well and signals thermal lift immediately. Should a good thermal be encountered, increasing camber will allow uncomplicated and effective circling. Rudder input alone suffices to maintain the circle, and draggy aileron inputs rarely are needed.
The plane picks up speed noticeably when the airfoil is uncambered. This is good for searching around for lift. If even more speed is desired, slight reflex will immediately cause acceleration, while still maintaining a surprisingly low sink rate. Very important here is to mix in the proper amount of elevator trim in order to avoid repeated elevator inputs canceling the speed advantage.
For landing with flaperons dropped, down-elevator compensation is needed. The Stobel V3 slows quickly and is easily directed toward a hand catch. Agility on final can be increased by mixing plenty of rudder to aileron input. The manufacturer-suggested throws work well as a basis to customize from.

My conclusion: For a fair price, one gets a model which is capable of winning any F3K contest. Construction is excellent, as is the quality of materials used. But more important is this: no matter if you’re fighting for every inch of altitude in mediocre condition or buzz from thermal to thermal on great days, the Stobel V3 is fun to fly. Its docile flight behavior and robustness make it the go-to plane for competitors and sport pilots alike.


Last Update:
March, 2013

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