[smuzz]

Date: 3 Sep 11
Conditions: Light westerly breeze
Aircraft: No-name Ryan ST-A
Pilot: Yours Truly

I got this as an ARF kit from an eBay seller last year some time, thought it might make a placid "Sunday afternoon" flyer.
It turned out to be a rotten kit to build, but I expected that for $69. It's of a balsa and ply built-up construction, covered with solarfilm and none of the parts would fit without major mucking about with the scalpel and Dremel. I went to install the elevator and rudder servos in the rear of the fuselage as instructed, but the flimsy wooden structure fell apart - so it was time to make a tray and mount them with longer push-rods up near the wing as usual. The stock motor mount was completely the wrong shape and wouldn't even permit the cowl to be fitted. The instructions said 2deg right thrust and no down thrust, but there was none built into the mount or firewall at all. The wings wouldn't fit into the saddle, the wing retaining bolt didn't want to fit the blind-nut and the undercarriage was completely useless - I ended up fitting some old Trojan legs inside the wheel pants. The construction also recommended gluing small plywood stoppers onto the ends of the push-rods to stop them falling out of the horns and servo arms - totally lame, so I replaced all of that with Z-bends and proper clevises.
To the flying - the CoG was the only thing that correctly matched the instructions, once I'd put a 3S 2200mAh battery in place. Of course, it continually nosed over on the cross-strip even though I had more than the recommended forward rake on the legs, so I got Junior to hand-launch it for me. It flew, but it wasn't as much fun as I was hoping it was going to be - I need to upsize the prop from the current 8x6 to perhaps a 10x5 for more thrust, don't really care about the top speed. I had the aileron and elevator throws at minimum and it would barely roll and loop. It was stable enough but I need to make a few changes - reduce the amount of right thrust, upsize the prop (which means replace the ESC as well in this case) and do something to make the undercarriage a bit more rugged. Then, I'll have another go ...

Overall impressions: The HK version made of EPO would probably be better, but the Parkzone F4F is still the pick of our crop.

   

Update: Just got back from an afternoon re-test flight. I fitted an APC 10x5E and removed the wheel pants so that I could bend the undercarriage legs even further forward. This time it flew better with the prop lifting the power consumption from about 135W to about 160W and it climbed more rapidly and rolled properly, but it would still sink alarmingly in turns and just wasn't all that eager to please. On the second landing, it decided to leave the starboard undercarriage behind. When I got to look closely at it, it was a really weak fixing point made with two tiny pieces of lite-ply CA'ed to the main wing spar. The factory-installed oracover/solarfilm covering was expertly applied, but it covered the proverbial multitude of sins in a weak and brittle structure.

I'm not sure what to do with it now - perhaps it would benefit from a bigger motor, but at 760g the whole thing is already 110g over the 650g maximum quoted flying weight. A better option might be to follow ~KevJ~'s lead and remove the undercarriage completely, since that little blue and white machine of his (from JohnC) is the kind of thing I'm after. If that doesn't work, then the thing will be getting gutted, and kicked into touch. Cheap no-name models are always likely to require a bit of work to get them performing, but with the time I've already squandered on this one I could have built a better model off plans out of depron.
Live and learn ...