RE: Bob Cat Copy Falcon 120 Jet
Just to clarify, with my old kit and the newer one, the kit is suppilied with an Ally front spar and Ally rear spar.
Inside the wing, there is a lightweight paper/fiber guide tube, that guides the spars into the wing only, it has virtally no strength. It is a guide
The newer kit, has the same two spars but has an additional bolt, towards the front of the wing, which clamps the front of the wing to the fuse. The Older kit, only has the one bolt, which you access through the bottom of the fuselarge.
The newer wing is built lighter, and the wing ribs are spaced slightly further out. This means that the front and rear spares, are approx 1 inch too short to reach the outer most wing ribs, they were supposed to meet up with. This is what i found on mine and as I was abroad at the time, with no access to model equipment, I extended both my spars by 1 inch, by using a piece of fiberglass fishing rod inserted inside the ally tube and joined a 1 inch extension at one end. This is extreamly strong.
I have always used a replacement carbon rear spar, I think its around 20 or 22 mm diameter.
With the addition front bolt on the newer wing acting as an anti rotation device, I am sure the manufacturer, would have left the front spar out of the kit, to save money, if they didnt think it was neccessary.
As I said before, if the spars do not reach their end ribs in the wing, there is a serious lack of of strength and also I would never fly without both spars fitted. cheers Tim