TDR II (English)
Because of the long drawn-out narrow canopy you don´t see that the boom length made it possible to use up to 800 mm size blades.
As well as the old TDR, this helicopter allows a wide range of setups and applications. This pot and boom helicopter reaches very fast flying speeds. This makes it predestinated for spacious and elegant flying. The extreme stiffness and strength of the mechanic makes it ready for extreme 3D too.
The base is again a 2-stage gear with helical cut gearwheels; the size is adapted on the actual available motor power.
The placing of the components is done completely new to receive a mechanic that allows an aerodynamic canopy which is extremely important for fast speed flying.
To make this possible, the motor was shifted behind the main shaft and the battery came from under the helicopter to the front. So the central mechanic is very compact and flat and therefore extremely torsion-resistant. This helps to protect the parts from damages in case of a crash.
To integrate the servos in the mechanic in a way that they do not stick out at any side and to realize linearity even with high collective and cyclic pitch ways a new swash plate drive (LDS Linear Drive System) has been constructed. Instead of servo levers gearwheels are mounted on the servo. They move a gear rack which moves the swash plate. This guarantees that even with high collective pitch, cyclic pitch is completely unchanged.
Because of the adjustable preload of the gear rack system there is no play.
Together with the new very flat swash plate which includes a bearing with a big diameter there is an extremely high stiffness achieved.
It is perfect to use servos with bigger movement angle for this helicopter. Normally all programmable servos allow this (see technical data). By variation of the point of connection to the blade grip arms also standard servos can be used.
Different motor pinions enlarge the multiple spectrums of possible gear ratios from approx. 9:1 to 15:1. This opens the possibility to use the TDR-II in a wide range of applications, from speed flying over 3D up to scale helicopters. Both gear stages have a pair of pinion – brass / gearwheel – high temperature resistant PEEK which allows to handle more than 15kW without problems. The main gear of the rotor has imposing 35mm height.
The tail rotor is driven by a 8mm belt, which is constantly tightened by a feather also during different load situations.
The boom is a very stiff and light aerodynamic profiled high quality CFK-tube. The belt and the tail rotor linkage have got enough space.
The twin vertical stabilizer is extreamly stiff so that it serve as the third landing gear when using the retractable landing gears at the front.
The complete mechanic is running with extreme low noise and never looks like getting to any limit. It convers the motor power e.g. into speed without the common roaring sound of other helicopters.
The batteries are fixed in a fast change system that allows to fix the battery in front of the helicopter within seconds. Batteries from 12 – 16S, divided in 2 packs, can be easily mounted in that way. Maximum possible size of battery is found in the technical datasheet.
The rotor shaft is hollow, outside diameter 15mm, 2mm wall thickness. The intermediate shaft has 12mm outside, also 2mm wall thickness. The feathering spindle is massive with 10 mm diameter.
The rotor is designed for up to 2800 RPM and has an adjustable blade dumping. With a simple box spanner the damping can be adjusted on the field within seconds. No dismounting of the rotor is necessary.
Over all the TDR-II impresses with a lot of impressive solutions, which make this helicopter outstanding.
The TDR-II comes in standard version with glass fiber canopy and carbon fiber landing gear. Additionally a high-end carbon canopy and a retractable landing gear is available. The retractable landing gear is mounted quickly also on the flying field. So practicing with or without is easy.
The TDR-II is an extreme fast pot and boom helicopter that reaches 265km/h horizontal speed with retracted gear.
A very interesting aspect is the possibility to modify the TDR-II into a TDS (the pure full covered speed machine). Only the tail, including a fin and the upper mounted tail rotor, as well as a completely closed canopy have to be changed. The prototypes of the TDS have flown already with outstanding success.
They came in on the first and third place at the IRCHA 2015 speed competition in the unlimited class even though the machines were ready only a few days before so that the setup was not perfect at this time.