Alfa model P-47 centro di gravita... Aiuto!!! - BaroneRosso.it - Forum Modellismo

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Vecchio 21 febbraio 08, 10:05   #1 (permalink)  Top
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Question Alfa model P-47 centro di gravita... Aiuto!!!

Ciao, sono possessore di un P47 Alfa model distrutto completamente al primo volo a causa del longherone delle ali probabilmente diffettoso!
Vorrei sapere ora che l'ho riparato/ricostruito dov'è il centro di gravita (cm dal bordo entrata dell'ala).
Grazie.
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Vecchio 21 febbraio 08, 10:26   #2 (permalink)  Top
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Sempre dov'era prima.....
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Vecchio 21 febbraio 08, 11:00   #3 (permalink)  Top
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Grazie...

Il problema che il modello era talmente distrutto che non si vedevano le linee che lo indicano!!! Per questo ho chiesto aiuto nel Forum!!!
Grazie comunque!!!
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Vecchio 21 febbraio 08, 11:12   #4 (permalink)  Top
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Se tra i pezzi che hai potuto avere la fortuna di recuperare ci fosse la parte in plastica sottile che riveste la parte inferiore dell'ala ci dovrebbero essere due bugnette (con la B non con la P) che indicano i CG, in alternativa , considerando l'ala ellittica senza freccia il classico calcolo del 1/3 della corda media calcolato dal BE dovrebbe andare bene.
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Vecchio 21 febbraio 08, 11:22   #5 (permalink)  Top
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Bugnette??? Si vede una bollatura ma è unica e centrale... dici che il calcolo a 1/3 va bene? Caso mai lo picchio leggermente!
Grazie.
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Vecchio 21 febbraio 08, 11:34   #6 (permalink)  Top
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Bugnette??? Si vede una bollatura ma è unica e centrale... dici che il calcolo a 1/3 va bene? Caso mai lo picchio leggermente!
Grazie.
Tutti gli Alfa hanno due piccoli rigonfiamenti (poco più grandi di un chicco di riso) sotto entrambe le ali , vicino alla sede che nel vero aereo ospita i carrelli, e sono il riferimento per il centraggio. In alternativa opta per il sistema classico, e come suggerisci, lasciandolo leggermente picchiato...
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Vecchio 21 febbraio 08, 11:38   #7 (permalink)  Top
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Bugnette??? Si vede una bollatura ma è unica e centrale... dici che il calcolo a 1/3 va bene? Caso mai lo picchio leggermente!
Grazie.
Se non ricordo male, dal sito della Alfamodels è possibile scaricare i manuali dei loro prodotti in formato pdf, lì troverai le informazioni che ti servono (C.G., escursioni comandi, motorizzazioni consigliate ...).

EDIT:

come non detto, non è in PDF ma semplice testo:

P–47 THUNDERBOLT 0201



Congratulations on purchasing this scale model, depicting the Republic P-47D Thunderbolt, a WW 2 fighter.The actual aeroplane was created according to the specification issued by the USAAC technical command, using the lessons learned during the first period of the WW 2. The semi-finished XP-44 lightly armed, lightly armoured interceptor project was soon completely rebuilt to the XP-47B. The new machine, powered by the eighteen-cylinder double row Pratt & Whitney R-2800 radial, with a turbo-supercharger, had, despite its weight around 6 tonne, became an excellent, yet heaviest single-engine fighter of the WW 2. Its prototype took to air for the first time on May 6th, 1941. It joined the combat over Europe in spring 1943. It was the first US-built fighter that provided USAAF with a degree of superiority over the enemy fighters. It bore the brunt of the most difficult period of air offensive against Nazi Germany and imperial Japan. Its significant feature was the measure of protection it provided to its pilots. It was apparently the safest fighter of the period. Due to its aerodynamic finesse, weight and sturdiness the P-47 could follow enemy into any dive he could muster, or, vice versa, use its superior diving speed to evade enemy attack. Besides that it provided an extreme measure of protection in dangerous strafing attacks as well as in an eventual crash landing. The P-47 Thunderbolts were series-produced in the B to N versions. The D-25 was its first variant with a full-vision bubble canopy. The M version was the "sprint" T'bolt with max. speed over 700 km/h, the N had a new wing of greater span and more fuel for the distances of the Pacific.
Altogether 15 329 of P-47's were built, 12 600 of that number of the D variant. Their pilots flew 546 000 missions, destroying over 7 000 aircraft, 9 000 steam engines and 6 000 vehicles. The most successful P-47 Thunderbolt unit was the 56th Fighter Group of the 8th Air Force, USAAF, that destroyed 1006 aircraft with 128 losses to their own numbers. The Thunderbolts served, besides the USA, in Bolivia, Brazil, Chile, China, Cuba, Dominican Republic, Ecuador, France, Guatemala, Iran, Italy, Mexico, Peru, Turkey, UK and the USSR.

Catalogue No.0201 The supplied set of decals enables you to build one of the three versions of markings:
  • I. P-47D, Pengie IV, HV-M, 419718, a penguin on a red background, pilot Cpt. Boleslaw Gladych
  • II. P-47M, HV-Z, 421108, Polish checker (red field at top right), pilot Cpt. Witold Lanowski, 61st FS/ 56 FG, Boxted, England, November 1944
  • III. P-47M, Pengie V, HV-M, 421127, a penguin on a white background, pilot Cpt. Boleslaw Gladych

Catalogue No.0209
The decal set enables you to choose from two camouflage and marking schemes of the 405th Fighter Group.

The model is not suited for complete beginners, but its control with ailerons and elevator would not bring problems to any modeller experienced enough with elevator/rudder control models, e.g. slow-flyers. The flight qualities and performance of this scale model of the P-47D Thunderbolt are close to that of much larger models, i.e. they are more docile, and provide fine as well as colourful experience in the air.

The model kit you have bought has several noteworthy features:
  • It is almost ready to fly: you have to apply decals, install the propulsion unit and the RC equipment.
  • You can utilise the kit's box as the transport and storage container for the finished model.
  • The model is moulded from extruded polystyrene foam with a tougher surface layer, making the model more resistant to surface damage. All exposed places are also covered by additional plastic reinforcements. The strength/weight ratio of the model is high, therefore the danger of damage in normal operation is very low.
  • When designing this model the maximum attention was devoted to its aerodynamic layout (e.g. the semi-symmetrical wing section, the symmetrical horizontal tail section were used), ensuring high aerodynamic finesse, with the resulting wide band of operational speeds and docile flying characteristics typical for much larger models.
  • The range of proven power units offered enables to build a scale model of flight performance corresponding with that of the best slow flyers, as well as with the fully aerobatic models.
  • To control the model you need the RC equipment suitable for controlling the slow-flyers - it would enable you to fly majority of the aerobatic figures (with the possible exception of those that require the rudder control).
One of the decisive factors, affecting the flight performance and behaviour of the model, is its weight. The weight of the model without the battery pack should not exceed 320 grams. With a double-cell LiPol battery would probably weigh in at 380 grams, with the six-cell 500mAh NiCd pack about 420 grams. The specified maximum weight should in no case be exceeded - the flight behaviour of heavier models deteriorates accordingly. Due to the brisk pace of development of the propulsion units and batteries, we recommend that you always check the maximum current drain and choose a controller that corresponds to that current.

Finishing the model

It is a simple task, yet we ask you to read and follow the subsequent text carefully.

When opening the cockpit canopy, use the following procedure:
  • Lift carefully (about 5 mm) the rear part of the canopy ( I )
  • Slide the canopy rearwards ( II )
  • Once the front lock is released, lift the front part of the cockpit canopy ( III )
  • Slide the released canopy forward and remove it from the fuselage. ( IV )
The decals

The model is sprayed with colours making up its basic camouflage scheme. The codes and markings are on the 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 you to follow the subsequent tips:
  • The larger decals that are to fit to a double-curvature surface need to be cut radially at several places around the circumference for a better fit.
  • Dip the decal cut out from the sheet with its backing paper in a lukewarm water for about 5 seconds, then leave it to soak through on a flat non-absorbent surface (glass plate etc.).
  • You may substantially increase the adhesion of the dried decal to the model by applying wallpaper glue to the area where the decal will be placed. However, ensure in advance that the glue would not create blotches or lumps when it dries - this is why the white (PVA) glues are usually not suitable.
  • Once the backing paper is sufficiently soaked (i.e. the decal moves easily on it), slide the decal over the edge of the backing paper about 5 mm, hold it with your fingers in required place on the part to be decorated and pull the paper from beneath the decal. If the decal does not slide easily enough, apply some more water around it with a paintbrush; this method would help you to replace the wrongly-applied decal, too.
  • Using a soft cloth or, rather a polyurethane foam roller, carefully smooth out the decal, gently squeezing the excess glue and any air bubbles from the centre of the decal to its outer edge. Do not squeeze out all of the glue! Once the glue dries, i.e. in a few hours, the decals would shrink somewhat and adhere snugly to the surface.
  • To increase the adhesion of the decals, you may use a decal setting solution, available for plastic scale modelling. Check that solution does not attack the styrofoam and follow the directions for its use.
  • The model could be oversprayed with a thin layer of transparent gloss or semi-matte acrylic or synthetic varnish (avoid spraying the transparent cockpit canopy matte, indeed) to suit your ideas regarding the surface finish of the real aeroplane. It is absolutely necessary to check beforehand that the varnish does not attack the polystyrene foam. To keep the weight down, spray varnish very sparingly, i.e. as a mist only.
A) RC equipment

The general layout of the electrical connection is on the diagram. We strongly recommend you to assemble and connect the RC equipment outside the model and check its function. Observe the recommendations of manufacturers as listed in the directions for use for the respective components. 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 so much more than it would cost…

Power unit
(motors with MPJet gearbox or MPJet outrunner 28/7…)
  • Power unit 1 is attached to the motor bulkhead by three screws 2.
  • The engine cowling 3 could be tack-glued to the fuselage by PU glue or Epoxy or by a piece of adhesive tape. If using an AC outrunner motor, enlarge the central opening in the engine cowling.
  • Slide the propeller back plate 4 to the gearbox shaft, install the propeller 5 to the back plate, the washer 6, (use the washer from the kit, not the one from the power unit, ensure the correct orientation) and tighten the complete assembly with the nut 7.
  • Snap the propeller boss 8 to the washer 6. When snapping the boss on, hold fast the propeller, not the model.
  • Check that the propeller rotates freely, without binding between the rotary and stationary parts.
C) Aileron control

The aileron servo should be powerful enough to overcome the friction in the control circuit - we recommend to utilise a servo of more than the 15 Ncm minimum torque. You can minimise the friction in the control cables by removing them from the tubes and lubricating them lightly with thin oil, e.g. the WD-40.
  • Place the connector 9 into hole in the servo single arm, at the distance of about 11 mm from the axis of servo's arm rotation. If the openings in the servo arm are too large, it is better to drill a new one of 1 mm diameter rather than bushing-out the old ones.
  • Insert a 6mm long piece of tubing 10 into the hole in the connector.
  • Insert the connector with the servo arm to the control rods, first to one, then to the other (fig. C1).
  • Modify the wing top skin opening as necessary for the size of the servo used; enlarge it carefully to the dimensions required, using a sharp modelling knife - if need be, open up also the bottom wing skin - the servo should fit into the opening tightly. The servo could be placed in the wing in an inclined or horizontal position (fig C2). Insert the servo into the wing opening and place it so that once the servo arm is inserted on its shaft (the axis of the servo arm should be parallel with the longitudinal axis of the servo) the control rods form a smooth curve, so that the set-screws 11 and 12 could be tightened. If the servo is to protrude from the upper contour of the wing section, it has to be in the area where the fuselage is open at the bottom. Devote a maximum attention to the positioning/attachment of the servo, ensuring thus a smooth control of the model.
  • Secure the servo against movement by applying a thin layer of PU glue or Epoxy around the perimeter of the opening in the top and bottom wing skin - in case the servo needs to be removed it is easy to pry it free without damage.
  • Tighten lightly the screw 12 so that the aileron trailing edges would be some 1,5 to 2,0 millimetres above the wing trailing edge (fig. C3).
  • Check function of ailerons: they should be at the maximum deflection of about 10 mm at the maximum deflection of the servo (fig. C3) - check for the correct sense of their deflection - it has to correspond with the deflection of the control stick! If they are not moving correctly, and you could not program the sense of the servo movement in the RC set, change as necessary either the position of the control rods in the control circuit arms or of the connector on the servo arm. Only then secure the connector against letting loose by the spring washer 13 inserted from below (the servo arm is outside of the model; use a thin tube, such as the ball point pen refill), and then secure the servo arm itself by the screw 11. Readjust the correct position of the ailerons and tighten the screw 12. Secure the control rods against disconnecting from the control arm by gluing a piece of tubing onto them (Fig. C4).
  • You can secure the connector by gluing a piece of tubing instead of the spring washer 13. If the tube is glued well, this simple method is fully satisfactory and, in case the disassembly would be needed, the tube would be simply cut away.
D) Elevator control, accumulator pack placement

For the elevator control a servo of the minimum 7 Ncm torque is required. Both moving surfaces are interconnected by a glued-in coupler. If one of the elevator halves deflects excessively (outside of the recommended angles), the coupler may become loose and the deflections (especially the maximum ones), may differ substantially. Restore their stiffness by gluing (Epoxy) a "U"-shaped connector made of steel wire of 1,5 mm diameter.
  • The servo is glued to the starboard (right) opening in the servo tray (plate) using CA, PU or Epoxy glue. Place servo so that its screws 12 and 14 could be tightened.
  • Insert the connector 9 into the hole some 9 mm distant from the axis of rotation of the shaft of the single-sided servo arm. Drill a new hole if necessary, insert a 6 mm long piece of plastic tubing 15 into the hole in the connector. Slide the assembly onto the control rod and place the arm on the servo shaft so that it would be about perpendicular to the elevator control rod axis ( fig. D1). Glue (PU, Epoxy) the elevator control rod outer tube to the inside fuselage wall.
  • Tighten slightly the connector bolt 12 - the servo arm and the elevator should be in neutral position.
  • Check that the maximum deflection (throw) of the servo corresponds to the elevator deflection of about 10 mm each way (fig. D2) - check that the sense of elevator deflection is correct and corresponds to the sense of movement of the control stick! If the deflection is not correct, and you can not program the servo by RC set programming, change as necessary either the position of the control rod in the control lever, or the position of the connector on the servo arm. Only then secure the connector from falling out with the flexible washer 13, slid on from below (the servo arm should be outside of the model), or by gluing a piece of tubing, and secure the servo arm by tightening the screw 14. Set the elevator to correct position and tighten the bolt 12. Secure the control rod in the control lever by gluing a piece of tubing onto it (fig. D3).
The battery is attached to the base plate by self-adhesive Velcro strips. The receiver is attached to the styrene wing/fuselage junction using the same self-adhesive Velcro strip. The receiver antenna could be led out from the fuselage belly behind the wing and either attached to the fuselage by adhesive tape or left to stream freely.
To facilitate the transport and storage, the wing of the model is detachable. The fuselage and wing are joined by the screw 16 - tighten with care. If you wish to fit the pilot into the cockpit, remove the cockpit canopy carefully (it is tack glued), install the glued and painted pilot bust and re-glue it back.
The other possibility is to insert and glue the pilot into the cockpit from below, after opening up an appropriate hole in the fuselage decking. Note: If you manage to get some plastic shavings/sawdust under the canopy, rest assured that its removal shall not be possible without removing the canopy itself.

Catalogue No.0201 If you have decided to build the M version (colour scheme II and III) glue the fin strake to the fuselage top decking. It is advisable to sand the edges to come into contact with the fuselage from inside of the strake to ensure that the strake would fit to the fuselage and fin without unsightly gap.

E) Flying the model

Balance the complete assembled model by shifting the position of battery pack along the base plate . The prescribed position of the CG is marked on the fuselage bottom cover surface by transverse lines (fig. E). When balancing the model, support it with your fingers. The well-balanced model stays level or slightly nose-down. Mark the correct position of battery pack on the base plate - it is best done at home; also check the RC equipment - i.e. the sense and magnitude of deflection (throw) of the ailerons and elevator and the function of the controller.

First, glide-launch the model over taller grass to cushion its landings and check its reaction to controls. If you can, set the non-linearity on the transmitter to 50 % both for the ailerons and the elevator. The powered flight will differ according to the power unit - the "280" will make the start just a bit more lively than with a slow-flyer, the AC motor will try to jerk the model from your hand- be ready for a pronounced torque from the propeller in slow flight when the controls are less effective.
Once trimmed in powered flight, try the marginal regimes - especially the slow flight and stall behaviour of the model. Once you become accustomed to the model, you may return the ailerons to normal zero setting. The model of the P-47D Thunderbolt, compared to other WW II fighter aircraft, has excellent flight properties and would stand a lot of abuse. But it is no slow-flyer/fun-fly machine or an aerobatic special and you have to adjust the piloting to this fact. You could be surprised by the reactions to the excess movement of the elevator, so please try these figures at higher flight altitudes.
Once the Thunderbolt passed the test-flying period, you need not to wait for a calm weather. Thanks to the wide band of available speeds and to the very good controllability it will be soon your decision when to go flying outdoors.

We wish you many happy landings

Alfa Model. Ltd.

A list of parts and tools necessary for finishing the model, that are not supplied in the kit:
  • Polyurethane (PU) , five-minute Epoxy glue, CA glue
  • Modelling knife, screwdrivers, transparent self-adhesive tape, 1 mm diameter drill bit.
  • Power unit with controller and propeller, battery pack, the tested recommended combinations are listed below.
  • At least a three-channel RC set with two micro servos (up to 10 g weight) and a miniature receiver (up to 10 g weight).
  • Extension cable (150 mm) to attach the aileron servo to the RC receiver.
  • Battery charger.
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Pensare senza imparare è pericoloso.
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Ultima modifica di icsunonove : 21 febbraio 08 alle ore 11:47
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Vecchio 21 febbraio 08, 11:53   #8 (permalink)  Top
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Grazie a tutti ragazzi!!!
Il mio problema è sorto dopo aver letto proprio quel manuale... e nel non avere sulle mie ali quei riferimenti!!! Il mio P47 si è letteralmente disintegrato: tipo un X-Wing in volo e tipo un cartoccio di carta alla raccolta pezzi!!!
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Vecchio 21 febbraio 08, 13:39   #9 (permalink)  Top
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Grazie a tutti ragazzi!!!
Il mio problema è sorto dopo aver letto proprio quel manuale... e nel non avere sulle mie ali quei riferimenti!!! Il mio P47 si è letteralmente disintegrato: tipo un X-Wing in volo e tipo un cartoccio di carta alla raccolta pezzi!!!
Lungi da me fare pubblicità ad un negozio...comunque nel negozio flynow hanno un p47 in esposizione che volevano a tutti i costi vendermi perchè è lì da un po'...credo che se chiedi loro ti possano fare un ottimo prezzo. Questo se il modello è veramente distrutto. Considera però che anche il mio fockewulf 190 è caduto 3 voltedi cui una rovinosamente....e continua volare davvero benissimo...quindi sappi che è solo una questione estetica (e da vicino!), non gli volere male solo perchè non è più bello come prima!
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Vecchio 22 febbraio 08, 09:34   #10 (permalink)  Top
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Lungi da me fare pubblicità ad un negozio...comunque nel negozio flynow hanno un p47 in esposizione che volevano a tutti i costi vendermi perchè è lì da un po'...credo che se chiedi loro ti possano fare un ottimo prezzo. Questo se il modello è veramente distrutto. Considera però che anche il mio fockewulf 190 è caduto 3 voltedi cui una rovinosamente....e continua volare davvero benissimo...quindi sappi che è solo una questione estetica (e da vicino!), non gli volere male solo perchè non è più bello come prima!
L'ho visto... ma già il mio lo avevo acquistato così senza che mi piacesse molto!!!
Quindi sei delle mie parti...
Ciao.
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