Seagull Spacewalker II 1.20

Seagull Spacewalker II 1.20 (Late December 2011)

The Spacewalker was purchased from Horizon Hobbies from mad money from a steering conversion sale. I was happy with the build of the Seagull AT-6 and the Spacewalker caught my interest because of its good looks and reported good flying characteristics. With poor rainy weather and the need for something to build, it was taken off the shelf and put on the work bench.

The build went well but like the Yak 54, it had an issue with variation of trim between power off/on flight. Power on flight required 1/4" up elevator trim but when landing, it wanted to be trimmed back to neutral elevator to establish a proper glide slope. A check of incidences showed a 0-0 and 0 engine thrust. I suspected the cause of the pitch down during powered flight to be the drag of the long and thick low wing. There were three possible fixes. A trim mix where at low throttle the elevator is trimmed back neutral, up thrust of the motor but with a spinner set in position on the cowl doing that would be problematic, or a decalage adjustment to counter the needed up trim in the elevator under power. The mix worked OK, but I decided to mess with the wing incidence so that the plane wasn't flying tail down under power.

The fix was simple, it required a sliver of 1/64" ply under the leading wing peg and over the aft wing peg, thus giving the wing a nat's hair of positive incidence trim. The result was that both power on/off were happy with a neutral elevator.

A better picture to come later. Power is a Zenoah G-26ei swinging a Vess 18x6 prop.

Typical to many arfs, it appeared (at least to me) that some additional structure support was needed and the typical additions were made to the firewall as well as additional support to the gear mount, documented below.