Long John (oz7297)

About this Plan

Long John. Radio control sport model, for .40 power.

Quote: "The Long John is a sport aircraft and intermediate trainer that is easy to fly and yet combines excellent performance with aesthetically pleasing lines, a combination often hard to find in trainers and sport aircraft. Long John, by Ian Mitchell.

The Long John is a ship that was originally designed to bridge a gap that same slot that is used to bury a load of low wings! After cutting my teeth on the RCM Southern Gentleman (oz9081), I looked to the RCM New Era II (oz9439) to become the flagship of the fleet. After many hours of waxing and polishing, a nagging little doubt began to emerge - Wouldn't it be a pity if...? The flagship was shelved for a while.

Something was needed to cut the anticipated low wing mortality rate. The range of ships in this intermediate area was found to be surprisingly limited and, in fact, very few suited the general requirements which seemed to be applicable. These characteristics were:

(1) A wide power range (.35 through .60) to provide scope for improvement in the pilot's ability.
(2) A maneuverable ship, yet one which, if necessary, will fly hands off.
(3) Rugged enough for cow pasture flying and 'beginner's bumps'.
(4) Straightforward and quick con-struction.
(5) A relatively low wing loading with-out loss of penetration.
(6) Trike and taildragger options.
(7) Able to show a fair turn of speed.
(8) And, finally, not look like an intermediate ship.

The prototype is a 60-1/2 inch, 4 lb 12 oz shoulder winger which is powered by the fabulous OS H4OP engine which, with a 10/6 prop, develops a useful output comparable to many .45-.50 engines. Flying the Long John is a snap. Beautifully realistic take-offs may be achieved on 3/4 throttle and up trim; the pilot has only to keep the wings level. In fact, it was found that the ship displayed absolutely no tendencies to fall off on a wingtip on take-off, idle flying, or landings. Interested? Well, more on this after construction details.

Before diving for the glue tube, cut all components to make a 'kit' - this will speed building later.

Fuselage:
(1) Glue 1/16 ply doublers (front and rear) to 1/8 sheet sides.
(2) Install 1/4 square longerons, 1/16 ply wing /brace triplers and 1/4 square diagonal braces.
(3) Jig up the fuselage sides and epoxy pre-drilled formers F2, F3, and F4. Fit the 1/16 ply wing dowel triplers and the 1/2 triangular firewall reinforcement.
(4) Join the fuselage sides at the rear and install the 1/4 square cross braces.
(5) Epoxy the stab and fin in place.
(6) Fit the 1/4 square turtledeck spar and uprights. Position the 3/32 sheet turtledeck half from the fuselage side up to the spar; mark and trim the turtledeck half to the centerline of the spar and to the fairing line marked on the fin. Repeat for the other half and glue in position. The result will be an attractive oval section from F4 to the fin.
(7) Install the pre-tapped motor mount and trial fit the motor to locate F1. Draw the fuselage sides together and epoxy Fl and the lower cowl block in place.
(8) Block in the nose section and install the hatch. Remove the motor and sand the cowl to shape.
(9) Trial fit the servos to fix the link-ages in position. Remove the servos and epoxy the 1/8 ply cabin floor and 1/8 sheet cross grain flooring.

Wing:
(1) Jig up the ribs (or use building tabs) and fit 1/4 square upper and trailing edge spars. When dry, turn over the wing half and complete the spar placement and epoxy the 3/8 leading edge and 1/4 square hinge reinforcement strips in place.
(2) Repeat (1) for the other wing half.
(3) Epoxy the four 1/8 ply dihedral braces to the wing halves being sure that you have 3 dihedral with one panel flat.
(4) Position the ailerons and hinges (do not install as yet) to locate the 1/8 ply servo mount and make the neces-sary cut-outs. Install the control fittings if a bellcrank system is used.
(5) Remove the servo; ailerons, and hinges and sheet the leading edge, center section and trailing edges with 1/16 x 3 sheet (bottom first to locate the servo access hatch).
(6) Complete the 1/16 sheeting and install the 1/2 sheet tip plates and 1/16 x 1/4 capstrips.
(7) Sand the leading and trailing edges to shape.
(8) Reinstall the ailerons and pin the hinges. Fiberglass the center section with 4 tape, if desired.
(9) Trial fit the wing to the fuselage to trim and epoxy F4A as well as to secure the cut-down canopy in place.

Finishing: The Long John has no compound curves, etc, and should prove quite a simple model to finish with any of the iron-on coverings. The original was completed the old-fashioned way with plenty of silk and dope. A light and glass-like finish may be achieved by rubbing back successive coats of dope and talcum powder - but I am told that this, too, is old fashioned.

Install your radio and juggle the battery pack to achieve the correct Center of Gravity position. With my Futaba gear, the battery is immediately in front of F3.

Flying: The Long John has flown in quite strong winds, so picking a day for that first flight is no real problem. The prototype is a taildragger and has exhibited virtually no torque drift on take-off. As mentioned earlier, the Long John will depart gracefully on up trim only. The use of ailerons close to the ground is not critical so don't be afraid to steer the ship into the air.

The actual flying of the Long John is a little difficult to describe. It can be stooged around in circles as a trainer as docile as you like, or be sent barrelling through a top hat. In fact this is the virtue of the ship - it has a great pilot range and would probably make a good club project.

Final approaches may be made quite slowly for such a fast ship. Remember that, with the inherent stability of a comparatively large wing area, ailerons again may be used all the way in and those spot landings should not be so elusive. So, if your personal state of the art lies somewhere between the beginner and the expert, try the Long John, and find out what relaxed flying is all about."

Attached is Ian Mitchell's Long John from RCM magazine issue 07-77.

Direct submission to Outerzone.

Supplementary file notes

Article pages, text and pics.

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