P-47D Thunderbolt plans are available from: Airborne Plans Service for AU$50.00 plus P&H2 (AU$3.00 within
The Thunderbolt, commonly known as the "Jug", was one of the toughest and most successful single seat fighters of WWII. It was designed as a rugged, heavily armed, long range fighter with a top speed of over 400mph.
The first production Thunderbolt flew in 1941, the earlier type being the Razorback P-47B. Later Thunderbolts ,designated P-47D, featured a bubble canopy giving the pilots much improved visibility. Over 15,000 Thunderbolts were built making it the most produced American fighter ever.
The Thunderbolt makes a challenging project for the scale modeller. Scale reference material is plentiful and this particular aircraft offers many choices for colour scheme and markings.
Airborne's P-47D Thunderbolt is approximately 1/8 scale and although the scale is relatively small for R/C aircraft, the model is quite reasonable in size with a span of 1.52m and length 1.25m.
With its deep fuselage and stubby elliptical wings, the completed model looks far from tiny. Yet this model will conveniently fit in the back of my ute in one piece ready to fly at the flying field.
A good .60 two stroke or .65 - .90 four stroke engine will be required for the powerplant. I used an old OS 61 rear exhaust on mine. The plan offers the option of fixed or retractable undercarriage. Simple sport mechanical retracts could be used and for just a slight increase in weight, would make the model far better for in-flight appearances.
The model also features flaps which are essential on a scale fighter such as the Thunderbolt. 6 channel radio control is required to accommodate all functions. My prototype model included an extra function:- a retractable tailwheel.
BUILDING THE MODEL
The fuselage is made up in 2 sections. Firstly, the top half frame, from the centre line to the top, is built up over the plan, stringered and planked. When set, the top shell is lifted off the board and the bottom half of the fuselage is built up directly onto it.
Cut out all the ply and balsa formers F1 - F8. These are all cut horizontally through the centreline for rejoining later. The formers are shown on the plan as a joined unit. Frame up the top fuselage half by first pinning the spruce longerons over the plan, then gluing the top formers at right angles to them. Also glue the lower section of the fin post at the tails end. Pre-join the top spine S1 - S3, then glue to the formers. Glue the tailplane seat TS into position then add the square balsa stringers. Glue the doubler sheet between F1 and F2. While the frame is still on the building board, plank the fuselage from the bottom up. Compelte the top with the cockpit floor and sheeting across the tailplane seat. Allow glue to set before lifting the top fuselage off the building board.
Mark the position of the radial engine mount on the firewall FW and drill holes for the bolts, fuel tubing and throtle cables. Fix blind nuts through the rear of the engines mount.
Next make up the firewall/fuel tank box. Note that the position of the FW (or length of the box sides TS) can be varied to suit fittment of the motor to be used. Make adjustments if required before gluing the box into the top fuselage.
Glue the doubler F2a onto F2, then commence gluing all the lower half of the formers onto the top fuselage shell. Add spines S4, S5 and S6 to hold the formers rigidly.
Cut out the plywood fuselage doublers and glue into formers F1 -F5. Add the wing bolt plate WP between the doublers at F5. Temporarily tack on F2b onto F2a with a few spots of glue than add all the lower stringers onto the frame. Glue in the doubler sheets between F1 and F2. Plank the lower half of the fuselage starting from the centreline then working around to the bottom spine. Allow the glue to dry.
Sand the fuselage to smooth out the planking joints. Carefully draw the outline for the wing position and a line for the angled cut behind F5a. Cut out the section for the wing then cut through between F2a and F2b. Slice through the fuselage for the angled cut behind F5a. Remove the under wing section and line the rear angled cut with plywood.
Cut out a section at the rear of the fuselage to accommodate the hardwood tailwheel block. Bend the tailwheel wire to shape and epoxy together with the block into the rear fuselage.
The plan shows a built up balsa engine cowl however, a preformed fibreglass cowl is available from Airborne. Being a prototype, I built the balsa type which ended up looking as if it was formed from metal.
Cut out the plywood cowl rings and glue the square balsa stringers between them, checking carefully for alignment.
The planking is rather thick 6.5mm balsa, however this size is necessary for the fairly rounded shaping towards the front. Glue the planking strips to the cowl frame extending 40mm beyond C2. When set, sand the ends flush and also begin to sand the front curvature.
Glue the laminations required for the cowl front C, then glue onto the planked cowl section - when the glue is dry, complete sanding the front section to shape. Add the cowl flaps to the rear section of the cowl from the line near the bottom as indicated on the plan and up over the top. Sand to shape to allow a gap for flow through cooling of the engine.
Bolt the engine onto the radial mount and fit together onto the firewall. Glue hardwood blocks onto F1 for mounting the cowl. Check that the cowl fits over the engine and muffler. There should be plenty of room to have the muffler enclosed within the engine cowl. Make any cut outs required to suit the muffler, needle valve etc. Make an additional cut under the cowl for better cooling if desired.
The wing was built up in the traditional method but is fully skinned with 1.5mm balsa sheet. Note the swept forward spar to allow adequate room for retract wheels near the root chord.
Decide whether you will have a fixed or retractable undercarriage as it will have a bearing on rib cut outs. Also decide on the type controls for aileron and flaps. The plan shows bellcrank control for ailerons and torsion rods for flaps with respective servos in the middle. Some modellers may prefer to have separate servos inside the wing for each control. Cut out all ribs to suit. Cut the main sppars, leading edges, aileron and flap spars to length and also the dihedral brace. Build one side of the wing at a time. Pin tars, leading edges, aileron and flap spars to length and also the dihedral brace. Build one side of the wing at a time. Pin the lower spar over the plan and onto the building board. Glue the dihedral brace into position then glue all the ribs W1 - W9 into place over the brace and out to the tips. Glue the ply bellcrank plate between W6 and W7. Pre-join the aileron and flap spar and insert SJ into W6. Glue the aileron/flap spar onto the end of the ribs, then prop up the structure to incorporate 2 degree washout. Glue the leading edge including the brace DB2 and then glue the top spar.
Add the vertical grain shear webbing to the rear of the spars, followed by the gussets in the corners. I chose to sheet the top surface of the wing at this point. Some builders may prefer to sheet the bottom first then set up the 2 degree washout into the wing and holding it in with the top sheeting.
When the wing half is set, repeat the above with the other side. The completed side will need to be propped up with the wing tip at W9, 150mm above the building board to give the correct dihedral. Fit the control rods to the aileron bellcrank.
Insert the hardwood undercarriage blocks for the fixed undercarriage OR the mounting plate for the retracts. Cut out sections of the inner ribs to accommodate retracts. I then sheeted the underside of the wing.
Add the wingtip blocks and sand to shape. Install the aileron torsion rods then glue in the centre section trailing edge. Sand the leading edge to shape and lightly sand the wing overall. Install the aileron and flap servos making cut outs and mounting plates to suit.
Make up the ailerons and flaps as triangular units. Insert blocks for control rods in flaps and control horns in ailerons before fully sheeting these parts. Shape the leading edges of ailerons and flaps then hinge onto the wing. Insert the wing locating dowels. Fit the wing into position onto the fuselage. Drill holes and tap holes for wing bolts. Add the underside fuselage section onto the bottom wing centre section ensuring a flush fit to the fuselage.
COVERING AND FINISHING
Being a fully sheeted model, I first smoothed the surface with dope and talcum, then covered the model with tissue and dope. An extra couple of coats of dope and talcum and rubbing down with 220 grade sandpaper prepares the model for painting.
I sprayed a light coat of automotive primer overall then rubbed the surface smooth using 400 wet and dry paper. Silver is a difficult paint to use as far as fuel proofing is concerned, so after painting and decorating the model in automotive acrylics, I sprayed the model 2 part clear matt polyurethane to seal everything. Prior to adding the clear coat finish, I drew the panel lines with black felt marker pen.
The colour scheme I chose was that of a P-47D-40-RA of Mexico's 21st Escudon that served alongside US forces in the Phillipines in 1945.
Install the radio gear and balance the model to the Centre of Gravity marked on the plan. All up the prototype model weighed 7lb 12oz.
The Thunderbolt flew straight off the board with no major vices. I aimed for lightness and it paid off with this type of model. It handles well with crisp control handling at any speed. It is capable of the types of aerobatic manoeuvres typical of fighter aircraft - slow rolls and fast fly-by passes are most impressive. Onlookers will comment on how realistic it looks.
Flaps are quite effective for landings. Use plenty of flap to slow the model down, partial flap will still see the model floating with ground effect on round out to land.
In summary, the Thunderbolt is an impressive model that flies beautifully and will certainly attract plenty of attention at the flying field.
SPECIFICATIONS P-47D Thunderbolt
Type: R/C Model Scale 1/8
Plan No. 665 (2 sheets)
Moulded canopy: AU$27.50 plus AU$6.00
This page was last modified on the 21-May-02