sig somethin extra
 

great kit! I loved building it and right now just about ready to fly mine.

2nd plane
 

Build you a Spad Das Plas Stick, the plans are at http://www.spadtothebone.com
A little ugly, but a fantastic flyer for very little money, and without any EDF (emotional debt factor) you can fly the wings off it without fear and get real good...then move on to something really nice for your 3rd plane...and have more than enough confidance to fly it!

Ugly Stik
 

Any of the Ugly Stik clones make excellent second planes. I have a Thunder Tiger Stick that has been put through the mill and it is still going strong. Needless to say, the stick-on covering leaves a lot to be desired but it held up well for three (3) years before needing to be replaced. When I stripped the old covering off, I was pleased with the workmanship that I found on the airframe. I found one place that the leading edge sheeting was not adequately glued to a rib. Other than that, it was structurally sound.

2nd plane
 

The Somethin' Extra is usually a bit sensitive for use as a second plane... Very large control surfaces, and close coupled (short fuselage) designs are great for Fun Fly maneuvers... but poor for people that haven't had more experience than just flying a classic trainer type.

The 4* series is a much better choice. The control surface size and the fuselage length are closer to the trainer design. Build with the full wing, and when that's not maneuverable enough to pleasy you... clip off the outer wing bays, and move the tips. roll rate increases. :) For even more aerobatic ability, incrase rudder and aileron area. (up to double the rudder and 1.5 times the aileron) Move the CG as far back as 1/2 inch behind the spar... (better be good at flying first...) It then is capable of competing in most Fun Flys... (if using a .46 and a long low pitch prop) The 4*'s are planes that can grow in capability as your skill improves.

On another track... try the Sig Kobra (you'll need a .25 FX or equiv) For a light, FAST aircraft, with good slow flight characteristrics and trainerlike landings. The progression here is to slowly make the plane heavier, to practice for flying scale warbirds. When you've got it carrying about 1 lb of lead it is about the same as a Top Flite Gold Edition P-39, except the Kobra will stall in a straight line due to built-in wash-out.

2nd plane
 

Knowing which trainer you have... doesn't tell us where you want to go in the hobby....

There will be different recommendations (as parially illustrated by my earlier post here...) for different goals.

The "SPAD" aircraft are fine as second planes. (one of them's OK as a trainer too...) especially if you want to get into R/C combat.

What's YOUR goal?