Kirby Cadet Mk 2 (oz14205)

About this Plan

Kirby Cadet Mk 2. Radio control scale model sailplane.Wingspan 72 in.

Quote: "Kirby Cadet MK 2. Build Keith Humber's pretty 72 in span mini-scale soarer from our full-size drawings.

The Kirby Cadet Mk 2 was a tapered wing improved performance version of the original parallel chord Mk 1. The concept was to change wings as the trainee pilot improved his or her skills. In practice most clubs and ATC wings left the Mk 2 wing on as it proved to be just as easy to fly with not too many vices.

So herewith a mini Slingsby. Those of you who built the Kirby Cadet Mk 1 (oz12218) need only build the wing - it should bolt straight on for an improved looking, slightly better performance mini-scaler. Constructionally the points to watch for are (as the Mk 1) the servo tray which is mounted in slides and retained with a 16 swg wire pin. This gives an open cockpit for a full-length pilot - it goes without saying that if you use only a head and shoulders figure, then put the servos in under the pilot.

The servo for the ailerons is also in the top of the fuselage with a longish 16 swg pin engaging same for the wing aileron pushrod; this is a bit fiddly so. if you have a mini or micro servo, put it in the wing conventionally.

The wing is reasonably straightforward but do not forget the washout - approx 1/8 in or so under the TE at the tip - it's vitally important. Also if you wart a slightly more relaxed model to fly and are not that fussy about scale accuracy then a 1/2in or so dihedral under each wing tip will work wonders, The aileron horns are raked backwards to obtain differential movement. This is also very important otherwise the model with the non-dihedral wing will yaw about a bit when control is applied, even with the rudder coupled to the ailerons (CAR). The wing struts are bent from I 6swg bound with thread and glued to 1/4 x 1/4 in spacers which are mounted across the fuselage, ie left in situ when the model is deriggecl, which is rarely! She will fit into most hatchback cars fully rigged.

You will have to be careful with adjusting the length of the struts; it is critical and I have only shown an approximate length on the drawing. You will appreciate that every builder's model will vary slightly in small details, hence bend the wire struts to suit your own model. Get them slightly wrong and you can twist the wings with dire results.

I set my model up by bolting the uncovered wing to the fuselage, Loosly position the front strut in the fuselage, awn the model upside down on the bench and bend one side clip into the wing. Adjust for wing squareness check length of the opposite side with a spare piece of wire and mark the strut length, Bend and hopefully it is about right, Repeat for the rear struts.

The struts are faired with 1/16 x 1/4 in spruce epoxied to the wire and sanded to a streamline section. The strut/wing junction is retained with a brass collet, The control surfaces are hinged with mylar tape retained with cut household pins and superglue.

Tail bits: The tail group is 1/4 in soft sheet but could be built up to save weight; rib spacings are simulated with rape. I carried a couple of ounces of lead in the nose so rear end weight is worth considering on this rather short-nosed model.

My model is covered with Solartex and sprayed with car aerosol cellulose - I used Toyota No.2 silver which is a fair representation of the original silver doped fabric.

Up and away! Flyingwise she is a bit skittish but, with a wind of about force 3-4 and the CG well forward (do couple the ailerons and rudder together) she is fun to fly and certainly looks good in the air. Finally I must thank my wife Margaret for the flying photo; I have finally trained her to use my old camera (no telephoto lenses) so we have to fly pretty close. Didn't come out at all bad Margaret! Happy landings."

Direct submission to Outerzone.

Quote: "Hi Mary & Steve, Please find attached plan and article for the Kirby Cadet Mk2, designed by Keith Humber. This fills the gap in your files between his Cadet Mk1 (oz12218) and Cadet Mk3 (oz11577). Note that this plan is referenced in the article text for the Mk3 so you may wish to add a link there. Details as follows:

Name: Kirby Cadet Mk2
Span: 72" (1829mm)
Designer: Keith Humber
Publisher: Silent Flight (No. 16)
Date: Jun/Jul 1994
Description: 3 Channel Scale Sailplane

Kind regards,
Ian Salmon."

Supplementary file notes

Article.

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