KA8b (oz15551)

About this Plan

Schleicher KA8b. Radio control scale model glider. Wingspan 1.5 m. Scale is 1/10.

Quote: "Classic glider for the slope, flat filed or aerotowing, witha added transportability. KA8b, by Dave Ridgeway.

With well over a thousand built between 1958 and 1976, the Alexander Schleicher Ka8 became one of the all-time classic post-war gliders. Developed from the earlier and more complex Ka6, the Ka8 was simpler and less expensive to produce; other aerodynamic modifications were carried out to make the Ka8 an ideal training machine. With such a high production, the Ka8 is still a familiar sight throughout Europe, many trainee pilots taking their first solo flight in one. The Ka8 employed an easier to produce fabric-covered steel-tube fuselage, replacing the complex wooden monocoque of the Ka6. Flying surfaces are conventional fabric covered wooden construction.

Specification: span: 15m; length: in; Wing Area: 1415sq.m; Wing Section: Go 533 17% (root), Go 532 (tip); weight: 310Kg, Designer: Rudolf Kaiser.

Traditional model for the modern era: With the ready availability of mini and micro RC gear, the smaller scale 'mini glider' becomes an attractive proposition, being easy to transport - even on foot or cycle - and offer the possibility of aerotowing with even quite small electric tugs. However, the temptation is always to go too small - OK on the slope, but not for aerotow - unless you use a gas turbine tug!

A scale of 1/10 was chosen as an ideal compromise between performance and portability, the latter further enhanced in this design with knock-off wings and detachable tailplane and fin - enabling the model to be stored in quite a small 'hangar' for safe transport.

To me, the Ka8 is the epitome of the classic post-war sailplane, especially with the later type (larger) moulded canopy and cute snub nose, The fabric-covered fuselage proved very easy to reproduce with a sheet balsa covered structure; the wing however was the focus of a great deal of attention. Typical of the period the full-size machine uses the then universally popular Gottingen GO 533 (root) and 532 (tip), which becomes problematical at a 4 in average chord. After literally weeks of study and deliberation, a thinner more penetrative modern section was decided on which works well, both on the slope and at low wing loadings for towing applications, despite being considerably more difficult to construct accurately with high strength and low weight. Result? Traditional modelling and great satisfaction!

Construction: Important, take care with wood sizes. Please note the plan is drawn in metric sizes - if using imperial or mix of imperial and metric, please adjust dimensions accordingly.

This model is a really satisfying build for the traditional builder, albeit not for the novice, but suitable for those with a few projects under their belt. It cannot be stressed too highly that wood selection is of great importance - do follow advice given on the plan.

I always start with the tail surfaces, it gets me in to building mode and means when the project is gaining momentum these small irritating, but vital parts are done and dusted. In this case, the tail surfaces are simple frames built over the plan and sanded to section. It is important to keep both tailplane and fin as light as possible. The tailplane is retained by a single 3-4mm nylon wing bolt, allowing easy adjustment of incidence and ease of transport..."

KA8B from R/C Model Flyer, June 2005.

Direct submission to Outerzone.

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