Sopwith 1-1/2 Strutter (oz14867)


Sopwith 1-1/2 Strutter (oz14867) by Phil Smith 1972 - plan thumbnail

About this Plan

Sopwith 1-1/2 Strutter. Radio control scale model WWI biplane.

Quote: "Sopwith 1-1/2 Strutter. Building Instructions.

Though originally built to an Admiralty specification in 1916, and destined to be called the SOPWITH 2-SEATER, the 'W' formation of its centre section wing strutting gave rise to its colloquial and immortal name of '1-1/2 Strutter'. It served in the Navy as a single seat bomber and the RFC as a two-seat fighter.

Of all the Sopwith designs, this machine has all the best attributes for representation as a Radio Control model for two channel proportional control on Rudder and Elevator only. Only the tail surfaces have been slightly enlarged so the model conforms to Class 2 (Stand-off) Scale. For powering with 2.5 to 3.5 cc (.15 to .21 cu in), an optional third control may be fitted for engine speed control with compact servos. The Veron prototype model flew well with a Webra Glo-Star 19 (with silencer) and two channel single stick control with Digital Proportional, the all up weight being 3 lb 10 oz (1.644 kg) with a 500 Deac pack.

The Profile Publication 'The Sopwith 1-1/2 Strutter' No.121, is available from Profile Publication, Coburg House, Sheet Street, Windsor, Berks. and will give full information on decor, rigging and detail etc.

Strutting and rigging on the model has been reduced to a minimum, but the 'W' braced wing centre section structure is amazingly rigid for securing the top wing with rubber bands to reduce any impact damage. A unique feature of the angled engine mount is that it imparts automatic side and down thrust and enables the silencer to be fitted in a trough underneath the cowl. It also locates the engine in a position where an expansion chamber type silencer would project inconspiciously on the underside of the model.

Simple modelling tools are needed. Bead headed modelling pins; White PVA adhesive such as HUMBROL 55, also Epoxy glue such as HUMBROL 38. Balsa knife with spare blades; HUMBROL Banana Oil, HUMBROL Clear dope and Matt Hot-fuel proofer. Use only sprayed HUMBROL colour dopes or HUMBROL Enamels brushed on for colour schemes. Modelling pliers; 1/16 (1.5 mm), 3/32 (2.5 mm) and 3/16 (4.8 mm) drills with wheel-brace; Grease-proof paper to protect the plan; Tissue-paste and garnet paper (med and fine) 5 and 15 amp fuse-wire for binding with use of a soldering iron. Also thread for binding. PTFE Control cable and links may be preferred to the 1/4 sq (6.4 mm) balsa actuating rods with 18 swg ends provided.

Recommended tank is a 2 oz (56.70 grms) Polythene Clunk Tank single or double vented (-not supplied). Alternatively, drawings are given for a rectangular metal tank for 2.5 cc motors. Extra fuel leads of 3/32 (2.5 mm) PVC or Silicone tubing will be required.

A good building board is essential. The general sequence of assembly is laid out in the following instructions and these, coupled with the numbered diagrams on the main plan will facilitate construction.

Study the plan and these instructions carefully before commencing, and so familiarize yourself with the complete sequence of assembly. Note that numbers in brackets after all inch dimensions are decimal millimetres. Identify (and mark) all semi-circular formers on 3/32 (2.5) die-cut balsa sheet from layout on plan sheet 3.

1. FUSELAGE SIDES Select even grade balsa for upper and lower longerons. Locate and secure with pins whilst setting. Cut, trim and fit vertical laminations front of k x 3 (6.4 x 76.2) balsa sheet supplied with lower lengthwise piece le x ik x 14 (6.4 x 31.7 x 356) - see sketch upper left hand corner of plan. Add verticals and diagonals indicated. Make a pair of sides - the only difference being the rear tail-bay vertical of 11 x 1/2 (3.2 x 12.7) which is placed accordingly. NOTE ALSO CHAMFERED TOPS TO TAILBAY TO GIVE 112° POSITIVE INCIDENCE TO TAILPLANE.

2. DIE-CUT PLY LAMINATES PHOTO 1. Addition of the die-cut 1/16 (1.5) ply doublers with P.V.A. glue (ensuring you make left and right hand sides), will themselves act as a template for cutting out slots for cross pieces and trimming lower k (6.4) lamination for wing cut out. Note that photo shows lightened doublers used on prototype - not deemed necessary in the kit. Mark and drill out 3/16 (4.8) holes for wing pegs. Mark in pencil location of jury struts - see photo 3.

3. SLOTTED HARDWOOD CROSSPIECES PHOTO 2. Cut out slots ensuring they will be A VERY TIGHT FIT on slotted hardwood cross-beams. Trim ends of beams to exactly match width of fuselage (top view) from 33/4 (92) supplied.

4. BASIC FUSELAGE STRUCTURE PHOTO 3. Add the second side to the 3 basic cross-beams, ensuring fuselage squareness. Then add all cross-pieces at front parallel section of fuselage. Chamfer rear inner faces of tail-bay and draw together, gluing and securing with clothes peg at rear. Steam longerons at area immediately behind doublers. Add remaining top and bottom cross-pieces cut to length as plan. Check for alignment and squareness of fuselage. Fill in nose bay with solid balsa bulkhead cut from 1/4 x 31/4 x 3 (6.4 x 82.5 x 76.2).

Lay circular die-cut ply bulkhead reverse side down over bulkhead diagram No.2. Draw projected lines in pencil onto face of bulkhead to aid its' exact location to fuselage. Double coat with P.V.A. and pin in place whilst setting. Cut through slots for 1/2 x 1/2 (12.7) beams. Install beams, chamfered edges to top, projecting correct distance 1.11/16 (42.9) in front of ply. Beams are stabilised within fuselage with triangular balsa supports as shown in Diagrams 2 and 3..."

Direct submission to Outerzone.

Update 20/10/2023: Added kit review from Radio Modeller, June 1973, thanks to RFJ.

Supplementary file notes



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Sopwith 1-1/2 Strutter (oz14867) by Phil Smith 1972 - model pic

  • (oz14867)
    Sopwith 1-1/2 Strutter
    by Phil Smith
    from Veron
    48in span
    Scale IC R/C Biplane Fighter Kit
    clean :)
    formers unchecked
  • Submitted: 01/10/2023
    Filesize: 1321KB
    Format: • PDFbitmap
    Credit*: Edubarca
    Downloads: 813

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  • Plan File Filesize: 1321KB Filename: Sopwith_Strutter_oz14867.pdf
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  • Supplement Filesize: 2695KB Filename: Sopwith_Strutter_oz14867_review.pdf
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