Congratulations on purchasing this scale model, depicting the Focke Wulf Ta 183 Huckebein, a WW 2 fighter project. The actual aeroplane was actually not built at all, yet its features considerably influenced the fighter design in the post-war period.
The author of the aerodynamic layout of the Ta 183, Mr. Hans Multhopp, was born in 1913. After two years of study at the Technische Hochschule in Hanover, he carried on at the University of Göttingen - from 1934 he studied aerodynamics under the leadership of professor Ludwig Prandtl - the father of modern aerodynamics. During the studies he designed and built with some of his colleagues several gliders - other activities were not allowed in Germany by the Treaty of Versailles. Already during the university period he wrote a seminary thesis whose subject was the lift theory of a wing. Multhopp was not involved in theoretical work only, as, during his study, he participated in experimental measurements in the Aerodynamische Versuchsanstalt - AVA, a German analogue to the NACA. In 1938 he accepted an offer of collaboration from Kurt Tank, then the director of the Focke-Wulf Flugzeugbau, that promised a joining of the theory and practice. Since 1940 Multhopp worked as Tank's assistant in the department of developmental aerodynamics, in 1943 he became a chief designer.
The Ta 183 was one of the German second-generation jet fighter designs that were to be powered by the axial-flow Heinkel Hirth HeS 011a of 13 kN planned thrust. This engine differed from the existing Junkers Jumo 004B of (9 kN) and BMW 003a (8 kN) not only by the substantially higher thrust, but also by its design, optimised for much higher operational altitudes. The utilisation of the first jet fighter, i.e. the Me 262a Schwalbe, was considerably affected by the problems with reliability of the Jumo 004 engines at altitudes above 11 000 m. The Ta 183 was optimised to deliver the best performance between 8000 and 14 000 m, i.e. at the altitudes necessary to combat successfully the high-flying B-29 bombers, whose operational ceiling was around the 10 000 m limit. The calculated maximum speed of the Ta 183 was 960 km/h at 12 000 m.
The design scheme of the Ta 183 differed from the existing fighters - a notable peculiarity was its T-layout of the empennage, where the horizontal surface was placed atop a long rearward-swept vertical tail surface. The wings as well as the horizontal stabilizer and elevator were also swept back to postpone the onset of compressibility effects at high subsonic Mach number the Huckebein was to be capable of. The aerodynamic layout was tested and proven in the AVa wind tunnel and it underwent some modifications, the first layout having an anhedralled horizontal tail.
The production of the Ta183 was approved at the session of the Luftwaffe's high command (OKL) on 27th -28th February 1945, where the machine was chosen from among other companies' projects for realisation. However, only the drawings were to be finished before the end of war in Europe.
Contrary to the fate of many other projects, the end of war did not spell end to the Ta 183. Kurt Tank, helped by Argentinian secret services, escaped there from Germany, taking with him the microfilmed technical documentation of the Ta 183. Together with some of his former colleagues he redesigned the machine into the NAMC Pulqui II. As proved later, the changes did not do any good to the design and the Pulqui II was manufactured in only five examples. The second set of microfilms was found in the Reich's Aviation Ministry (RLM) building in the captured Berlin and ended-up in the Soviet Union. Together with other material seized in the vanquished Germany it undoubtedly served as a welcome contribution to the development of the Soviet own designs, as it also happened in United States, Great Britain and France, respectively.
From the purely external similitude the Huckebein's closest was probably the Lavochkin's line of jet fighters, concluded with the series-built La-15, yet, due to the system reigning at the time in the Soviet aviation research and development, that the TsAGI Central aero and hydrodynamic institute's provided all design bureaux with results of its research, a remote external similarity could be traced in the MiG-15 as well
The model you have bought is based on the original project. It differs from the final Ta 183 by its anhedralled wing (the final version had a slight dihedral - i.e. the wing tips were higher than the wing roots), by a change of the fuselage shape around the jet pipe and especially by the method of control. The project presumed controlling of the aeroplane by the rudder and elevons on the wings (doubling the function of elevator and ailerons). The movable aerodynamic surfaces on the horizontal tail were to be utilised as trimming surfaces only. This layout is fully sufficient in the normal flying, yet it may become a distinct drawback in critical flight regimes. Therefore the model has a conventional elevator and aileron control.
The model is not intended for complete beginners. But it is an ideal model for modellers starting to play with electric ducted fans. Thanks to the thrust/weight ratio any catapult is unnecessary - the model is hand-launched. It also glides very well and its characteristics are similar to other models. Any modeller with enough experience in controlling models by elevator and rudder, e.g. slow-flyers, shall easily control this model by ailerons and elevator.
The Ta 183 Huckebein model you have bought is noteworthy by several features:
Finishing the model
It is very simple, yet we suggest that you study the following text very carefully.
The model is finished in the base camouflage scheme, as used by the Germans at the very end of the WW II in Europe. As, of course, the real machine never materialised, the final finish of your model is also a matter of applying your fantasy. The tactical markings and the national insignia are of waterslide decals. Their primary advantage is the negligible weight and a minimum risk of damaging the model during application. They require, however, an attention and care. Therefore we recommend that you follow the following instructions:
A) RC equipment
The general layout of the electrical connection is on the diagram A. We strongly suggest that you assemble and connect the RC equipment outside the model and check its function. Observe the recommendations of manufacturers as listed in the directions of use for the respective components. Check that the sense of rotation of the ducted fan is correct and insulate the cable connections. Check the compatibility of the receiver with the crystal used - the over-the-land range test of the transmitter, albeit it may seem unnecessary nowadays, may save you later much more than it would cost…
B) Gluing the wings
Both wing halves 1 and 2 are butt-jointed and glued to the fuselage 3, using the Uhu Por contact glue. The bending moment is taken up by the steel joiner 4, glued into the wing halves by either the Epoxy or expanding (foaming) polyurethane glue (PU). The wing could be joined to the fuselage by two procedures. In the first one both wing halves are glued to the fuselage in one work step - in that case a slower-curing (half hour) epoxy or the PU glue has to be used to cement the wing joint. In the other procedure the first half of the wing is glued to the fuselage first, and only after the glue has cured (hardened), the other half is to be glued, which, alas, has to be held in the correct position relative to the fuselage during the gluing of the first half. The following description presumes gluing of both wing halves in one step.
The position of the wing on the fuselage is defined by the marked outline of its root. Before start of gluing, check that both wing halves have the same angle of incidence. This check is necessary as there are always some manufacturing tolerances, and the eventual differences of the angle of incidence of respective wing halves may affect the flight characteristics of the model. Mark the eventual corrections on the fuselage as necessary. The wing-fuselage joint would be covered with the fillet anyway, so do not be afraid of using pins to hold the wing half in the proper position. We strongly recommend to dry-run the whole procedure - fit the parts without glue at first.
C) Aileron control
Ensure that the aileron control servo is powerful enough to overcome the friction in the control circuit - we recommend to use a servo of more than 15 Ncm torque.
D) Attaching the horizontal tail, elevator control
Glue the horizontal tail 12 around the circumference of the vertical fin with the Uhu Por. To improve the strength of the joint it is optimal to glue the protruding spar of the horizontal tail into the vertical fin using the expanding (foaming) polyurethane glue (fig. D-1). To simplify the adjustment, use the visible seam in the separation plane of the vertical tail and on both halves of the horizontal tail. Position the horizontal tail surface on the vertical tail longitudinally so that the leading edge of the vertical tail would intersect the centre of the leading edge of the horizontal tail (fig. D-2).
For the elevator control a servo of at least a 7 Ncm torque would be suitable.
E) Power unit
In the base version the model is fitted with a DC electric motor Speed 300/6V. Any manipulation with the power unit should be always done outside the model. The power unit could be simply removed after loosening of screws. When running the power unit outside the fuselage its shroud must not be deformed so that the rotor would not come into contact with the static parts. Otherwise a major damage to the power unit would ensue. The rotor spinner and the rear streamlined are glued with the Uhu Por - to disassemble them only a small amount of petrol put on the glue joint suffices to loosen the bond. To reassemble utilise the UHU Por. The fan rotor is screwed to the back plate. Once pulled and with the screws removed the motor with the back place could be removed from the shroud. Due to the high motor shaft revolutions it is prudent to lubricate the bushings from timer to time, using a drop of high quality liquid lubricant.
The recommended accumulators for the Speed 300/6 V:
NiCd 7-8 × 500 mAh, NiHM 7-8 × 700 - 1000 mAh, 8-10 a capacity controller (e.g. SMM-08).
The model was tested with an AC MPJ 25.25/26 motor with the same set of batteries as used with the Speed 300/6 V and with the TMM1210-3 controller.
The motors are set in the shroud by their outer diameter. Using the MPJ AC motor, you have to file away the inward projecting pegs; using the smaller-diameter motors, you have to provide for their centring by a suitable packing. The backplate is either pressed or glued to the motor shaft.
The motor in the ducted fan installation is almost without cooling, which does not make any problems when flying at normal regimes for about 5 minutes. It is necessary to let the motor cool down between flights. Do not expose the model and its power unit to the sunlight for long periods of time, especially behind a window of a car.
The batteries are attached to their plate by a piece of the self-adhesive Velcro tape. Also the receiver is attached with the self-adhesive Velcro to the bottom of the carrying plate, which is in turn glued in the fuselage spine. The receiver antenna is led out of the fuselage back to the vertical tail. It is recommended to test whether the running motor (especially at the full rpm), does not cause any interference with your receiver - the interference demonstrates itself by oscillation of the servos. It this happens, move your receiver further away from the motor, battery and power cables - the best place is the rear fuselage underneath the elevator servo. (fig. E).
F) Model assembly
Both fuselage halves 3 are glued together by the Uhu Por. Smear the contacting surfaces with a thin layer of the glue and let dry. By joining the halves together a connection is created that fulfils all requirements of safe flying. Accuracy when assembling the model is of prime importance. The Uhu Por joints could be disassembled, using the common household petrol-based stain-cleaning liquid (test on a scrap of polystyrene foam that it does not dissolve the plastic) applied to the glue seam. The petrol weakens the joint and the parts could be separated without damage to the plastic. Once the necessary work is done, the fuselage could be re-glued. We do not recommend use of other glues, in such case the fuselage could not be unglued, but only cut apart, leading to a damage to the model.
For normal use the access to fuselage is ensured by the removable cockpit canopy. To remove the canopy 14, slide it some 5 mm forward, lift its rear end and slide the canopy to the rear to remove it from place. Reverse the process to put the canopy back in place (fig. F).
G) Flying the model
Thanks to its aerodynamic layout, especially the swept-back wing, the Ta 183 model has some flying characteristics that make it different from other models with unswept wing. Devote therefore your maximum attention to the following text.
Check the adjustment of the ailerons - in neutral position of the servo both ailerons must have their trailing edges 5-6 mm up. The maximum aileron deflection should be about 15 mm.
Both halves of the elevator must be neutral when the servo is in neutral position. The maximum throw of the elevator is about 13 mm.
If your RC set allows for that, set on it the 50 % non-linear deflections for both elevator and ailerons.
The compete assembled model balance by shifting the position of the battery on the plate. The required position of the centre of gravity is shown on the bottom fuselage by two transversal lines (fig G). When balancing the model, support it with your fingers, as sharp items may damage the polystyrene foam. The well-balanced model stays level or slightly nose-down. Mark the correct position of the battery on the plate. It is best done without hurry and stress at home, as is the RC set functional check, i.e. the correctness of the sense and magnitude of the deflection (throw) of the ailerons and elevator and the operation of the controller.
First, glide - launch the model over higher grass to cushion its eventual falls and check its reaction to controls. The glide testing is very important, as, besides the abovementioned advantages, it also helps you to get rid of eventual psychical blocks. It is convenient if somebody would launch the model for you, at least for the few starts at the beginning, but going all alone is also perfectly possible, if you have some model test-flying experience.
Launch the model horizontally, without bank, with a velocity of at least 5 m/s. It is important to test the model reactions to the elevator - you are going to pull only. You may feel the reaction of the model are somewhat more sluggish than with the other models you have flown, but do not forget - at the higher speeds in the powered flight its reactions will become much more lively. It may surprise you how far the model will glide on idle, especially once you master the bleeding off of speed. This feature will come to you handy later during the landing approach calculations.
For the first powered flight give the full throttle and launch the model exactly the same as in the glide tests. The model trimmed for glide will behave under power like somewhat tail-heavy one, so be ready to push immediately. It is necessary to consider the thrust characteristics of the ducted fan that differ absolutely from the propeller ones. Especially at low velocities the propeller driven models have substantially higher acceleration than the ducted fan-driven ones. Therefore climb slowly, an effort to climb steeply at small speed may easily lead to a stall, that is, especially with the swept-wing models, rather dangerous. The sharply-swept wings - the Ta 183 is a fine example here - suffer from flow separation on the outer sections of wing. This brings forth several annoying results: As flow around no wing is absolutely symmetrical, the separation occurs inevitably on one side only and the natural attempt to correct the roll using ailerons may actually worsen the flow situation on the wing. As the separation and the ensuing loss of lift happens behind the centre of gravity, the machine shows the tendency to buck, i.e. to increase spontaneously the angle of attack. Thence comes the acceleration of flow separation on the complete wing. The result of these phenomenais a tendency of the swept-wing aircraft (and of course models, for the matter) to stall viciously, and/or fall into a spin. The transition is much brisker than with the straight-winged models and the recovery takes much more height. If you start the recovery too soon or too abruptly, it is probable that it had not gained enough speed and the model would become stalled again. The only remedy is to push at the first signs of impending flow separation at the wing. The question is how to tell that the stall is threatening. Close to stall, the Ta 183 behaves like a real jet - it loses directional stability, the nose visibly starts to oscillate laterally. This phenomenon is apparent especially during a climb - push immediately! In the horizontal flight this behaviour is not so pronounced. It applies generally that flying the sa a a a wept-wing models requires more caution - the stall-spin situations may develop quite easily also at quite high speeds. A classical example is a too tight a turn or an Immelmann turn of too small a diameter. All turns should be rather gradual, long drawn out, as is the rule with the real jets of the given period.
If the prescribed rigging is observed, the flight behaviour of the Ta 183 is very good - the information above describes some of the peculiar features due to this aircraft's geometry that are worth knowing. This knowledge enables you to avoid critical situations and, if need be, cope with them successfully. Flying is without problems to the wind strength of 5 m/s. Bear in mind when landing, that the landing speed is much lower than the maximum one. You have to start bleeding the speed soon enough, otherwise your strip may become pretty short to you…
We wish you many happy landings.
A list of parts and tools necessary for finishing the model that are not supplied in the kit: