Back to Basics

I have to be careful with the spending Simon, I've got to save up for a TV licence, whatever that is.

Working on the SIG Kadet has been delayed a bit by refurbishing the old Panic, and fitting an even older Lazy Bee with floats. I did a little work on the Kadet yesterday, I coated the edges of its wing with thinned PVA glue ready for covering with Polyspan. This should be a lot of fun as I haven't used that type of covering for almost twenty years. All I can remember is that the fabric has a smooth side and a hairy side. Unfortunately its very difficult to see the difference, which only shows up when the surface is doped. Trouble is, when the pieces are cut from the roll, its all too easy to get one the wrong side up.
I'll have to see if there's any archived info somewhere.

Brian Jackson wrote: I have to be careful with the spending Simon, I've got to save up for a TV licence, whatever that is.

:lol: :whistle:

Now that the Panic has been patched up and has had a few flights, its high time I got back on to the SIG Kadet. The sewn hinges were fixed to the ailerons first, then trimmed to length. The method I use is to attach the top part of the aileron hinge to the top of the wing first. The aileron is then rotated so that it lies on the top surface of the wing, then the final part of the hinge can be attached to the aileron spar. To get a successful bond using the "iron on" method, the temperature of the sealing iron needs to be adjusted to a temperature high enough to completely melt the film of PVA. If the temperature is too low, its all too easy to think the covering has bonded, where in fact is is only lightly "tacked". The Polyspan covering is OK at high temperatures, and the method of applying it is pretty much the same as heat-shrink film, apart from the higher temperature, and the need to move the iron quite slowly to achieve a good bond.

Nice days will be getting fewer now so it seemed like a good idea to get the wing covered. The fuselage and the rest of the bits can be done in the relative comfort of the shed. The Polyspan went on with no dramas at all, and the wing is now in the shed and oozing the heady smell of cellulose dope. I think the resident spiders will be a bit miffed by the smell, with a bit of luck they'll go find somewhere else to make a mess with their webs.

There was a slight delay in finishing the Kadet's aileron covering. I was distracted by a calm morning and the need to go and try to fly my old Lazy Bee from the lake at Longham. The LB is a three channel model and I'd completely forgotten to set it up with the rudder and elevator on the RH stick. The model taxied around nicely, I lined it up into the very gentle breeze and it lifted into the air very quickly. Unfortunately, before I could get it high enough to trim out, the Bee started to roll to the right, I eased in a little aileron and began to close the throttle. Unfortunately the more aileron I applied, the worse the roll to the right became. The crash was a non event, the floats parted company with the fuselage, as designed, and floats and model were left drifting peacefully on the calm water. Fortunately a fellow flyer had a Graupner SeaBee, he used this to push the floats and finally the LB to shore. The final recovery was made by another brave chap who waded into the edge of the lake and retrieved the, by now, waterlogged LB. I flushed all the electrics with alcohol, and left things to dry out for a couple of days. I was surprised to find that everything worked perfectly. With the Rx re-bound, RH stick configured for rudder and elevator, three sets of rates and 20% expo dialled in, I think it might fly a little better next time. The LB has had a couple of extra coats of clear dope, and something I completely forgot was the air outlet in the bottom of the fuselage. This is now covered with a doped on patch of LiteSpan.
Now I'll get back to the Kadet, until another calm morning arrives.