This is a 100S contest glider, the class rules dictate that Rudder Elevator and Spoilers are the only flight controls permitted, i.e. no ailerons and wing span restricted to 100". This class of model is also eligible for the 'OPEN' class events as well - F3J and F5J if electric powered.
There are very few 'modern' designs around that are suitable for home scratch building, so this is my own design with a great deal of help from Jef Ott on the BARCS forum.
The full build blog is available here on BARCS:
To add a little extra, this model will be an 'E' version with an electric motor, height limiter etc. so that it will qualify for the Bartlett's league - if I ever manage to get down there.
Our local field isn't particularly brilliant for tow or bungee launching so I need to have an alternative method of launching models.
There have been several iterations of the design, starting from a simple 'Vee' dihedral aircraft in imperial units and ending up as 6 panel wing in metric units... Wing section is Mark Drela's AG35 at the root tapering to AG37 at the tip.
I used a spreadsheet to calculate the various stability values, that in itself was a very interesting exercise..
These are the 3 key stability values, I need a model that can fly by itself if I ever need to rest my eyes momentarily.
The latest iteration looks a little like this:
The wing went together in a similar manner to the Bubble Dancer, the spars are actually thick soft balsa webs capped with carbon fibre caps that go down the length of the panel. Thinner caps are used in the tip sections to reduce moments of inertia (weight!)
The spoilers were a bit tricky. I originally wanted to use wing mounted direct drive servos but I couldn't get them to fit so resorted to a bell-crank and fuselage mounted servo driving snakes through the holes originally intended for the servo lead.
Next job was to get the fuselage pod made.
The Front end - a 40mm Aluminium spinner and a reasonable fit, 5 degrees of downthrust, no side thrust
Servo's are mounted at 45 degrees so that the arms don't interfere with each other (the spindles are on the fuselage centre line. The 3mm Carbon wing alignment rod passes through the fuselage as you can see
A bit of work finishing the fuselage, making some nice curved hatches and covering the wing
And it weighs this much with batteries.
And a shot of the Cheshire Cat modelled by my beautiful No. 2 daughter :)
Just a maiden to come..