Gazelle (oz92)

About this Plan

Gazelle. Keil Kraft kit plan for a 28 in wingspan control line stunt and combat model for 1.5cc engines.

Update 08/06/2013: Printwood scans added for this one, thanks to vintage1.

Update 18/01/2020: Replaced the instructions file with a clearer copy, thanks to JedBond.

Quote: "The GAZELLE has been designed as a quick-to-build, strong and powerful control line model. It is suitable as a beginner's first power model and for more experienced modellers, it provides a small and cheap version of combat flying,yet it is equal in excitement to the SMAE class (24 cc motors). The design has been through several prototypes to its final version presented here and you are well advised not to modify the layout or construction at all.

PRELIMINARY INSTRUCTIONS. Study the plan and the contents of the kit, together with these instructions and be certain that you are familiar with the model before attempting any construction. No snags should be found when making this model PROVIDING YOU KEEP TO THE NUMBERED BUILDING SEQUENCE. When ready to start, press the diecut parts from the panels and keep in a safe place until required.

BUILDING SEQUENCE.

1. Lay one of the 24 x 1 in pieces of 1/16 sheet trailing edge on the plan and pin firmly in place. Cement all of the wing ribs W1-W7 to it, supporting them temporarily with the stripwood supplied for the leading edge. Take care that all ribs are parallel to each other and vertical to the trailing edge. Use pins to hold them in place while the cement sets.

2. Cut the engine bearers to size and cement to the fuselage nose together with the fuselage front block. (See sketch on plan). Stick a 1/16 ply nose doubler on each side using plenty of cement and clamp in a vise or under some heavy books for at least an hour. While this is drying, progress with the next stage.

3. Stick one of the 3/16 x 1/8 wing spars into the upper notches in the ribs, then cement the other trailing edge strip in place.

4. Round off the edges of the elevator and tailplane, then hinge together with the tape provided. It is most important for the hinge to be perfectly free in movement.

5. Unpin the wing structure from the plan and pin back in place upside down. Glue the other spar in place, followed by ply pieces Z and the leading edge.

6. Remove wing from the plan again. Cement in place pieces W8, followed by W9, W10, W11 and one of the X pieces.

7. Make a small rectangular block of lead or plasticise weighing about 1 oz and install between the wing spars next to the X piece, then complete the box with the other X piece.

8. Install the bellcrank, with a 6 BA bolt as the pivot, in between the ply Z parts. Bend the 16G pushrod to shape and attach to the bellcrank by soldering a washer to the end. Bend the inner ends of the leadouts and attach to the bellcrank as shown on plan. Check controls for easy movement.

9. Sheet in the centre panel of the wing with 1/16 sheet, top and bottom. Slide 1 in lengths of tubing over the outer ends of the leadouts and cement and sew to the under-surface of the wing tip. Bend the outer leadout clips to shape shown on plan. Carve and sand LE to section.

10. The fuselage should be dry by now; so remove from the clamps and round off the top and bottom edges, drill the bearers for the motor, then bolt the motor in position.

11. Glue tailplane firmly to the fuselage and add the fin. Slide the wing through the fuselage from the inner tip. When in position, cement very liberally and use plenty of pins to hold the assembly secure while it dries.

12. Slide the elevator horn on to the end of the pushrod, and bolt the horn to the elevator with a 6 BA bolt. Trim the bolt down to minimum length. VERY IMPORTANT The elevator must move freely with no binding and the range of travel should be at least 25° up and down. It probably will be more. Make sure of a good control system before progressing any further with the model.

13. Cement wing trailing edge extensions Y to the wing and fuselage.

14. Using the metal strip provided, bolt the tank in place behind the motor. (See plan). This completes the construction of the airframe of the model.

COVERING. When you are satisfied that all parts have had ade-quate time to set firmly, unbolt the engine and tank from the fuselage, remove any remaining pins and spend a few minutes with fine sandpaper making sure that all the wood parts are smooth with no small lumps of cement to spoil the job.

Covering is usually the most difficult part of making a model for a beginner, but if you use the following method you should have no trouble in producing a beautifully tight, strong covering.

Cut a piece of heavyweight modelspan supplied to the approximate shape and size of one of the wing panels from the fuselage out. Allow about 1" all round for trimming.

Now, using Keilkraft tissue paste, spread a very thin layer of paste over the entire trailing edge sheeting and the Y piece, along the leading edge of the wing, around the edge of the wingtip and a strip alongside the fuselage on the centre panel sheeting.

Hold the tissue under a tap until thoroughly soaked with water, and squeeze the paper hard until it is only damp. Do not screw or wring the paper out, or it will tear.

Lay the inner edge of the paper on the wing against the fuselage, then, working very slowly, pull the paper in all directions gently until it is smooth, fairly taut, and there are no small wrinkles.

Trim the excess paper off the edges and leave aside until dry. Repeat for the other three panels and when all are dry, give the entire wing covering a liberal coat of clear dope. When dry, give another coat of dope and then a third.

The rest of the model does not require paper covering, merely dope the parts with three or four coats and then sand the wood parts before applying any colour dope. There is no need to save weight by restricting the colour dope, so use all you wish to get a colourful, well finished model. The completed model should balance at the point shown on the plan, or slightly forward of it.

FLYING: Having spent a few hours carefully constructing the model, it is well worth waiting until a good opportunity presents itself for initial test flights. By this we mean a fairly calm day, and not raining! (water binds lines together, causing loss of control and a wrecked model).

The lines should be around 40 to 45 feet long, single strand steel wire.

This model uses no undercarriage as this would give pointless extra weight and drag, so the model is hand launched. For the launch, it is only necessary to hold the outer wing and let go when the pilot is ready. There is no need to push the model, as the motor will have enough power for what is called the 'snap launch'.

On take-off, the elevator should be at neutral or very lightly up. After becoming accustomed to flying the model, many of the aerobatic manoeuvres can be flown. The model is capable of loops inside and outside; horizontal, vertical and overhead 8's, inverted flying, wingovers, and if the pilot is experienced enough, the square patterns as well.

Probably the best fun is had if your friend also has a Gazelle - or a Skystreak (oz1376) - and you can fly combat. Use a streamer 5 ft long on 5 ft of thread attached to the fin of the model. The object is to clip his streamer with your propeller, at the same time flying evasively to protect your own streamer from his model!

Naturally this is much easier to describe than to carry out, and it takes considerable skill and practice to be a consistent winner in combat, to say nothing of a large slice of luck!"

Supplementary file notes

Formers.
Instructions.

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