Mostiko (oz15699)

About this Plan

Mostiko. Hand lanch glider model. Wingspan 1400 mm.

Quote: "Mathieu Scherer describes his French hand launch glider. Mostiko.

If there is a current fashion in the world of French r/c gliders, then it has to be the hand launch variety. The one I am offering to you here is a synthesis of all the classic and most efficient points of the best of earlier designs I have flown, hopefully combined to provide a pretty model, both cheap to build and of high performance.

After using and abusing my earlier model, a Slider which resembled more a plastic bag full of cyano, by the time I had finished last season, I decided to design a new one, with a number of key features which I consider very important. It had to be lighter in weight, if possible below 300g, a little smaller to allow higher launches, but of enough wing area to keep wing loading down. A battery of 270mAh must fit easily, with two Hs101 servos bought specially for it, and my existing two function radio of course. Finally it had to be stable in the sort of low level turbulence in which we fly in my home region.

I think I have been successful in meeting these objectives. The fuselage is a front pod with tubular boom and the wing is of 1.40m span and built in classic construction. The wing section is Selig S-4083, which was developed especially for hand launched r/c gliders. I am happy that if properly built, you will have a neat aircraft which will perform with the best, so lets get the tools out and start construction.

Timber and Adhesive Choices: Before starting to build, it might be a good idea to offer some advice about this as the final model needs to be kept light. I advise the use of cyano glue for all joints, except where otherwise specified as I find this keeps the weight down and gives a high quality bond. Secondly the choice of balsa is very important. Go for light weight but medium density sheet and strip, as with a bit of care you can get top grade material but still at the cheapest prices! Finally I have to say that building this model structurally sound and also down to weight is not that easy and perhaps not a project for a beginner, especially the wing and tail covering.

Fuselage: This is effectively a balsa box rounded at the edges, extended by a carbon tube to the tail. The sides of the pod are cut from light grade 2mm sheet, and joined by four plywood formers. The corners are reinforced by triangulated balsa strip. The wing is supported by a balsa plate of 5mm thickness, sanded to the wing underside profile. The top and bottom of the fuselage
and catch!

are also in 2mm balsa, apart from between formers 1 and 2, which is planked in 8mm sheet so it can be rounded by carving and sanding. The nose is formed from laminations of balsa sheet with harder denstiy in the middle and set cross grain between thicknesses.

The carbon tube on my model was produced for a kite, my other interest in thing, and it is a very high quality carbon tube rolled in spiral fashion to give great stiffness at 8mm o.d., as against the normal 10mm tube. It is however, rather expensive and you may well decide to use 10mm standard tube and accept the weight penalty. On the other hand, if vou can afford it, then go for the best you can get.

The tube is located in openings in the rear formers, and you must adjust carefully the holes, to give a straight fuselage with the right incidence for the tail. On this accuracy depends the flight characteristics of your model. When you are happy, rough up the carbon tube to give a good bond, and fix in place with two part fast setting epoxy used sparingly, to keep the weight down. Once fixed you can trim the tube to length. The fuselage once sanded to shape, looks a bit like the body of a prehistoric bird!

The final work on the fuselage consists of installing the radio tray, cut from 2mm plywood, which gives the forward part of the fuselage a great deal of stiffness, especailly if you run a fillet of thickened cyano down each longitudinal joint..."

From R/C Model World November 1998.

Direct submission to Outerzone.

Supplementary file notes

Article pages, thanks to RFJ.

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