New, Sleek Heli Pics and Info

Banshee

In spring 2010, developed by various circumstances, the idea of building a separate 700-Electromechanics: The “Banshee” was born. His name was given by the helicopter’s direct ancestors from the movie “Avatar”.

The decisive reason for us to develop a simple 700 mechanics, was that none of the helicopters on the market designed for the mechanical stresses which we aspired. Basically, it was also about us, try something new, something never before seen in this form in any 3D heli this size. Designed for more than 2 kW continuous and 10 kW peak power of the Banshee should be prepared by the mechanical load for any future developments in electric propulsion segment and thereby satisfy the demands of being one of the quietest helicopter in the market. We were always striving to find new design solutions to old problems and new challenges, although it was clear that not everything can be completely reinvented. In the course of a year we tried to test the mechanical, technical, acoustic and aerodynamic design of our helicopter mechanics to develop further.

The basic idea was, therefore, a 3-stage belt drive for:

• extremely quiet running noise, mechanical and thermal robustness • at maximum power throughput, easy maintenance and construction, and • • uncompromising lightweight construction.

It was us above all is a simple, extremely sturdy, yet lightweight construction that all requirements of a modern pilots in this context: In our view, therefore a faster, aerodynamically shaped, yet very aerobatic heli without compromising (many thanks go to Jan Henseleit of this trend). Our most important principle was at all times: Form follows function!

It was clear that the pure drive belt not only brings benefits: The somewhat lower efficiency but you can ignore in today’s drives. Extensive tests have shown that the efficiency of the air is not noticeably worse than in a geared transmission. Our focus was on making the belt drive losses as possible and run the belt is not under a small radius. Car rotations are possible without problems.

In the following we will elaborate a little on the development details of the Banshee.

Transmission:

The 10-mm hollow intermediate shaft is a double-clamping executed free-wheeling, which is grown all loads. Even with abrupt unloading and loading phases, a slippage of the freewheel is not to provoke. The engine waste heat from the engine is decoupled from the rest of the transmission belt. The main belt is due to the enormous torque designed to be very massive. With the integrated main belt tensioner that can easily be tightened, he should be, against our previous experience, but even lengths. Thus, there are no long gaps between main rotor and idler shaft to adjust the much-discussed backlash.

Chassis:

The chassis is constructed in one piece and the very compact design and integrated mounting brackets extremely rigid. An additional brace between the top mounts and the lower bearing blocks and tail pipe between the two terminals provides a very lightweight and sturdy construction. Thus, the twisting of the chassis to prevent under heavy loads. This results in a very direct implementation of all power and control impulses. The hollow 10 mm main rotor shaft is mounted on three occasions and over the top mounts very short run to keep the bending moment is low. Thus, a pure chassis weight of only 135 grams in the execution of 2 mm CFRP plates. The internal chassis width is 55 mm. Due to the large motor section may nevertheless engines are built up to 65 mm in diameter.

Linkage:

The servos are exactly aligned with the swash plate and integrated into the bearing blocks bolted. This results in nearly vertical rods and thus a geometrically clean articulation. We opted for a classic and Swashplate Swashplate Guide.

Tail Boom:

To keep the design as simple and easy as possible, it was our goal, Banshee, with a powerful rear belt equip. It should generally known weaknesses of a belt drive can be solved. A major goal of our entire development was an extremely quiet running, so a rigid drive never came into question. We use the 2100 mm HTD belt has excellent strength properties, and at a width of 7 mm transmit power of 1 kW and relaxed more. One could skip the belt by skillfully arranging the Anpresslager be reliably prevented even under extreme loads. Thus one of the biggest problems had been solved rear belt drives – so much for theory. Practically, it is so that a belt of this length under heavy load in spite of his taut side Kevlarzugstrangs expands greatly. As a consequence, “ringing” he cheerfully towards the tail boom Leertrumseite ahead. The first prototype also showed that the belt is under extreme stress furthermore tends to strong vibrations. The first tests showed last year with a spring tensioner Although an improvement, but the strap could not be prevented from swinging. In the worst case, the spring led to an additional excitation of the oscillation and thus to an increase in amplitude. The final solution was, therefore, a spring damper system: it stretches the belt to automatically prevents ringing and oscillation. Thus, the belt remains even at low belt tension and extreme loads absolutely quiet. Another advantage is that you the belt with large temperature differences no longer needs to tighten manually. We must note here that the idea and the development of our belt tensioner and spring damper before the announcement of the Compass held 7HVs and thus represents creative individual performance. But you can see that Sebastian Zajonz, just as we appreciate the advantages of the rear belt drive, and it further developed. The first prototype was further found that a 25 mm tail pipe at high loads in 700 Helimechaniken bends strongly, even the Heckabstrebungen overwhelmed miserably are. For this reason we went to the step in the direction 30 mm carbon fiber tail boom. This is all the more stable worlds, the rear strap can be performed more gently and as a “delicacy”, the rear struts are not needed anymore!

Rotor Head:

In the current prototype is still used for the rotor head and swash from Jan Henseleit, with an adjusted of us Swashplate is used. However, it is a separate head in planning, here we are breaking new ground.

Focus:

All installed components are located above the tail pipe. The battery position is set up to maximum upward. Thus, the main mass is as close as possible to the rotor plane. Batteries with 55 mm width and 65 mm height to fit into the chassis and are secured with three Velcro straps. Here, the battery is inserted flush to the front edge of chassis to achieve the optimal focus.

Cover:

The cover was designed by us with CAD is extremely narrow (10 cm at the widest point) aerodynamically shaped and in good faith. It is important to find a compromise between functionality and aesthetics and form a shell around the chassis. Of course, a certain similarity with the TDR hood can be seen, but the results necessarily due to the standards set.

Technical Features:

• 3-speed belt drive • Automatic rear belt tensioner / spring damper • Main belt tensioner • 30 mm tail pipe without braces • Straight swashplate • Extremely narrow, rigid and compact design • focus near the rotor plane • Double Clamp Freewheel

Technical data:

Weight of the empty hood mechanics including: 1.6 kg Weight with standard equipment (3xBLS452, 1xBLS251, Jive 80 + HV, Pyro 700-52, AC-3X, Radix SB 710 mm, 105 mm tail blades, hood): ~ 2700 g Main rotor blades: 690-720 mm Tail rotor blades: 105-115 mm motor: up to 65 mm diameter main rotor speed: 900-2300 r / min variable ratios between the engine and the intermediate shaft: 1:3 – 1:4 (18 – 24er pulley) reduction to the intermediate shaft Main Shaft: 1:3 standard translation main rotor to tail rotor: 1:5,54 speed gear ratio main rotor to tail rotor: 1:4,15 Battery Size: Maximum width of 55 mm and 65 mm height

Development Team:

Sigmund Dichtl: developer and creator of the Banshees Christian Köperl: Designer, CAD / CAM / CNC, test pilot , Hans Jörg Schilp: co-developer, FEA, test pilot

The entire helicopter was developed in-house performance, engineered, manufactured and built. Nevertheless, we want to not miss at this point, our friend Tom for the lasers of the first prototype parts, our club mates Florian for the milling of the 4 – or 5-axis parts, and our positive sense “heliverrückten” Friends for countless discussions welcome to . thank

Another supplementary note to the following figures, which reveal one of the Banshee with a self-designed and-built motor 5425er. YGE is installed as a regulator and a 120 HV Western Robotics BEC comes to the power supply is used.

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