Construction

As already for the Aspirin the motto was again “As simple as possible, but as sophisticated as necessary!”. So for a high-performance DLG some effort is required. Again highly precise moulds for all parts were CNC-milled. Especially for the wing the most accurate reproduction of the desired contour is important.
Wing geometry was transferred into CAD with self-programmed tools, which avoids airfoil distortions that otherwise can easily occur in the tip region.
To be able to employ reasonable servos in the wing without parts sticking out, they were mounted in the middle of the wing. This saves mass inertia around roll and yaw axis. At the Aspirin this way was not chosen initially, fearing flutter problems.
But with our stiff and free of play RDS system (since the Aspirin readily installed with two DS281 in the wing without weakening cut-outs) and adapted flap reinforcements the flutter boundary is sufficiently beyond the speed range occuring.

Wing

The SALpeter wing is available in a multitude of versions. The standard competition version provides superior stiffness and strength for the highest launches at lowest weight. This of course requires acribic manufacture from materials with better specific mechanical properties.
Therefore Rohacell is used as core material, which compared to Balsa is more pressure resistent and allows better contour accuracy. From our point of view the most reasonable is the reinforcement with carbon lattice fabric (Disser wing), as this brings the lowest additional weight. It is strong enough for throws above 60 m and offers the best handling.
Based on this standard version many different measures for further increasing stiffness and robustness can be taken. CFK-D-Box (normal or spread-tow), full carbon and full Kevlar are possible.

The flaperons are hinged on the lower surface by Kevlar-Elastic-Flap, which compared to the silicon hinge allows slightly better stiffness and precision. The smooth connection and air tightness ensure minimum disturbances of laminar flow over the flap combined with high robustness. The gap on the upper surface is closed with a special foil seal.
For the electrical connection of the servos a two-row pin connector is directly plugged in the servo connectors, such that soldering work is reduced to a minimum and redundance is given.

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SALPeter competition with CfK-D-Box spread-tow

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SALPeter Disser-Wings

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Standard-Wing und D-Box-Wing (normal fabric)

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It may sometimes be romantic…..

Fuselage

The fuselage is made as integral part in pressure bladder technique using UD and braided carbon. This ensures ultimate strength at lowest weight, as no more bonded joints are necessary. Furthermore inaccuracies in alignment of tailboom and pylon are eliminated – everything perfectly reproducable. In the pylon the elevator horn is hidden aerodynamically.
The tailboom is reinforced with high-modulus UD carbon. Through the different fibre angles bending and torsional loads are taken optimally. Cross section is flat oval, to maximize area moment of inertia at lowest possible weight.
The more slim, but FAI conformal, nose is best filled with 4 of the newer AAAA-NiMH cells in block arrangement, with the receiver behind. An alternative configuration is e.g. 2×2 2/3AAA cells, slightly overlapping with the receiver.

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2,4 GHz – Fuselage

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Full-Carbon Fuselage

Standard is equipment of the fuse with two servos. No messing around with linkages from the fuse and maximum flaperon torsional stiffness were again the reasons for that. The slightly smaller canopy makes the fuse even more stable, while still allowing good access from the top to the RC components.
The wing is fixed with two screws and two bolts in all directions after well-proven principle.

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Electric connection Wing-Fuse

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Connection Fuse-Wing by front-pin, torsion-pin and M4 plastic screws. To the right of the screw is the ballast tube for about 30 grams.

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Below the wing 30 g of ballast can be fixed (with other systems), to extend operation range to higher wind speeds.
If desired the pod is made from non-shielding material to use 2.4 GHz receivers without protruding antennas.

Tail surfaces

The tailplanes are built in negative moulds again, ensuring best reproducability of flight characteristics. Therefore the technology with CNC machined Rohacell massive core without glueing joint was developed by us to series-production readiness. This way extremely light and robust tails can be made, which have redefined the limits of possible.
The complete set weighs about 10.5 g! They are equipped with Kevlar hinges, to prevent a migration of the flap under the pressure of the torsion spring. The elevator is fixed with two screws on the pylon. Vertical tail is bonded to the boom with the help of an enclosed template.

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