Tuesday, 16 June 2015

Kwik Fli IV (2)

This is going together very quickly - the mix of insomnia, spare workshop time and nothing broken has given me a  rare window of Summer build activity.

The full build blog is here on the Model Flying Forum

 A few photos and a bit of description

 The fuselage went together very quickly. Basically, its a box with corner reinforcement. I have made a couple of minor changes to simplify it further - hopefully keeping the weight down and the fuselage straight

It looks like this after the formers and sides have been added.

The top deck is light 3/8 sheet balsa that sits on the 1/2" square longerons. This is carved and sanded down to a nice curved cross section profile

The tailplane is hollow - hinges are made from Kevlar sailcloth which I find to be very tough.

When complete, its sheeted top and bottom in 1/16" balsa. Light and strong

For the first time, I used a bubble app on a smartphone to align the tailplane. The upper deck is parallel to the fuselage datum so it was quite simple to set the fuselage level then move the phone onto the tailplane and make the minor tweaks to get the tailplane level and horizontal. I still use the three point method to check that the tail wasn't twisted. Basically, this involves using a length of string, measuring from the tip of the tail to the centre of the deck at the front and adjusting so that the distance to both tips is the same. Easier to write than do - quite a fiddly exercise

The fin was aligned using a laser alignment tool. You need to make sure that the laser is dead centre on the fuselage or you will build in a twist trying to get the alignment right

SLEC snake pushrods have been fitted and the lower sheeting added - the grain running crosswise for stiffness