[a.k.a. MADSLIDE 2300]

This is my new model

So, it's now the end of January 2021 and the Chinese Wuflu, or more correctly the SARS-CoV-2 B. variant, plagues us all with more virulence than ever in this pandemic. It's back to the building board for me again to bide my time until slope soaring becomes a possibility once again. This will be Lockdown model number four.

The image on the right is my new model. I haven't made it yet, of course, but it exists in my mind's eye. Here are wood, metal and foam, carbon, resins, and servos that I will transform by skill, thought and Dark Energy into an aerobatic slope model for Graham, it's maker, to fly.

I have the huge plan, downloaded from Jivaro* and a pair of foam cores cut by Cloud models. I have been collecting all these bits and piece over weeks and months; pretty soon I'll start the build. I shall be covering the wing with 0,4mm ply under vacuum, something I did many years ago before carbon fibre cloth was readily available. The beauty of the ply is that one saves on using polyester film or paint and primer and the model can be simply finished with a thin coat of epoxy, Aerokote or clear lacquer from Rustoleum or Halfords.


My second image on the left shows the basic things I shall need for the vacuum process. The rope is simply to create an air-escape pathway inside the Nylon vacuum bagging material which can seal itself when it touches itself and 'seals' before all the air is extracted.

The pressure gauge does what you would expect, in my case here I shall only need a partial vacuum to get the 0,4mm ply to go over the curve of the foam core (<0.4bar). The snap joiner is a reusable connector for the stiff 'un-crushable' vacuum line and the pressure is adjusted by allowing air leakage into the bag.

The bag connector has two silicone washers which go either side of the nylon of the vacuum bag. The vacuum sealing tape (1cm) is a reusable mastic, bit like Blue-Tack, that sticks to everything for sealing serious leaks and sealing the bag.

I have a very heavy Edwards High Vacuum Pump that gives almost a complete vacuum, given to me by Doc Hammond decades ago. The only thing I have not yet made is a simple trap to catch any excess resin that escapes the bag which can find it's way along the tubing into the vacuum rotor vane assembly (I know, it happened to me).

First, I need to prepare the cores by trimming them to match each other, then cutting the ply to size and preparing its surface for epoxy by wiping with solvents (Lighter fluid and Acetone) to remove any release agent of wax on the ply skins before a light sanding for keying the epoxy. I shall not do any other prep on the foam or ply as I want the top surface of the ply covered wings to look as perfect and blemish free as possible. All the other stuff, the cabling, spars, joiner tubes will be done from the underside before the underside layer of ply is vacuumed in place.