Greyhead

Sorry for the delay Giles but here it is!

The Se5a had its first “real” flight 2 weeks ago now but I’ve been on holiday so the write up has had to wait; the flight wasn’t without its problems, but it flew well and looked good.

There’s nothing major that needs doing but as always seems to happen with my models the first flights highlight a few things that need some work.

The 14Ba bolts used to secure the landing wires just aren’t strong enough, at least one has sheared off at every landing so I’m in the process of replacing them with solid pins. I don’t want to make them too strong, as I’d prefer them to shear off on a heavy landing rather than over-stress the airframe.

My previous SE5a had very poor aileron response, and a Flair “scout” flown by another club member is the same; therefore I had set this model up with quite a large amount of aileron deflection. I don’t know if it’s because I’ve used the scale aerofoil section this time or that the gap between the wing and aileron is shrouded but this model certainly doesn’t suffer from poor aileron response. The flight was very “exciting” until I switched to ½ rates!

It is also quite sensitive on elevator despite the CG being at the forward limit. I had controlled the elevators using separate servos on separate channels slaved together, the elevator and spoiler channels. Unfortunately this made the elevator trim only move one elevator, meaning that the spoiler knob had to be used as the trim control, this proved to be too coarse and I couldn’t trim for level flight. Before I left for my holiday I ordered a “Y” lead with servo reverse and have now fitted that so the elevator trim works as normal now.

The ground handling was pretty good so I decided against fitting a gyro but I have bent the axle to impart a few degrees of toe-in as suggested by Glider Guider, a lot cheaper!! I’ll let you know how well or other wise it works if we every get some decent flying weather.

Here’s some information that may help Linney with the calculations for his SE5a.

Wing span 58 in.
Wing area 1220 in²
Weight 9¼ lb.
Prop 16 in. dia x 4 in. pitch
Static revs. 6800 r.p.m.

Of course I don’t know the all-important figures for lift, airspeed and drag, which you really need to do any meaningful calculations. All I can say is that there is sufficient lift at what appeared to be a ”scale” airspeed and the large diameter low pitch prop turning at fairly low revs overcame the drag much better than the 13 x 6 prop at higher revs.