Carl Goldberg Extra

[Mr Ficky]

Hi folks,

I'm thinking of building a Carl Goldberg Extra, downloaded from outer zone, and converting it to electric. Looking at the plans, I see that most of the build is plywood. Has anyone got any experience building this from a plan, and perhaps not using ply but traditional balsa grades?

Thanks in advance!

[Andy Stephenson]

I built one some time ago, the advantage of the ply construction is that it's self gigging. If you assemble the fuselage and hold it together with rubber bands, once complete, you go round all the joints with cyno and it's done.

[Diamond Geezer]

I have not built one but I have one and yes the majority of it is ply, I bought one from a guy who had never finished it am just about to fit the engine but I have no plans for it maybe you could help me to get the motor shaft central to the cowl the engine mount is 2p0 mm off centre is that right.

[Adrian Smith 1]

I have the CG Extra 300 plan in front of me and yes there 2 degrees of right thrust , no down thrust. Also the main wings and tail plane are at 0 degrees to the datum line. Hope that helps.

[Diamond Geezer]

Hi

Thanks for the reply but what I mean is would that put the engine mount 20mm off centre

[Andy Stephenson]

The way to work out the offset of the engine mount is to measure the distance from the mounting surface to the back of the spinner. Using simple trig you can work out what 2 degrees amounts to in terms of offset. 20mm sounds like too much to me.

[Diamond Geezer]

Hi Andy 

how do you do that then

[Andy Stephenson]

DG

Let's say the distance from the firewall to the back of the spinner is 150mm for example and you need 2° side thrust.

tan 2° = offset/150

Therefore tan2° x 150 = offset

tan2° = .035

offset = 0.035 x 150 = 5.2mm