Checked out a few things last weekend.

• Elastic had gone on stinger, bit of a fiddle to replace but easy in the end.
• Checked the battens, all OK which shows that the original shape (bent) was very unlikely the first 20hours of flying (30 on it since then...). So it was delivered with rather dodgy battens shapes.
• The VG rope (bottom part) was indeed twisted once around the lower cable retainer - hence the extra friction. Easy to sort out when you know what to do - easiest to pull off the bottom of the upright. At least with the normal uprights and FAST bar re-threading the rope is easy.

The glider now flies good and straight with no feeling of skewness... seems I've got completely through that phase now.

1:56:29 PM    

Put on the standard A-frame today, finally arrived and went down to Parma to collect it from Franco. Looks nice, actually quite clean. Uprights much safer. I have also a new FAST speedbar, since the old one has the holes drilled slightly differently and cannot be used. Looks like I'll need to try and sell the whole ZOOM frame to someone.

Even though it's been of a bit of pricey exchange, it's the right thing to do. What I should have done all along - just gone for the FAST speedbar upgrade, which was quoted at 100 euros. This way round has cost me a lot more, even if I manage to sell the ZOOM frame to someone, I'll be more than 500 euros out of pocket. At least I have more chance of keeping my arms if I crash.

Took the opportunity to weigh the glider - just under 32kg, exactly like the manual says. In the bag it's 35kg (I'm amazed that the non-flying stuff weighs so much). I also completed the manufacturer's sticker, which was mostly blank (for example, date of manufacture of glider, date of test flight, etc...

8:42:46 PM    

 30 September 2003

I'm 99% sure it came cross tuned, that is a setup fault (outer wands differentially rotated) was tuned by setting it up wrongly (one sprog raised about a cm compared to the other). I had to learn to tune the glider to get rid of it. Thank Dennis Pagen for his articles in HG mag for the explanation. The manual wasn't much use. Tuning this glider is possible, but not for the faint hearted. It takes hours of fiddling.

9:46:46 PM    

 04 June 2003

And the result is - DHV 3. Take off and landing set at 2, but the rest of the in-flight stuff at 3.

Personally, I'm quite surprised, since the handling is very nice especially VG off. I guess that VG you could get into trouble if you are not aware of how the handling is transformed. But that's pretty obvious.

Double surface given as 87%, not 70% as I remember from somewhere (Dennis Pagen's review?). 

2:26:55 PM    

I seem to have finally sorted it. The glider was clearly not symmetric and I had what Dennis P. calls a "cross-tune", i.e. flies straight but isn't set up straight.

I got the tape measure out and measured all the wires, also to the trailing edge. All OK, but the tips still clearly differential by 2 to 4 cm. Decided the only way to sort out the trailing edge was set the left sprog higher, it was also visibily screwed in by a thread or two. Unscrewed it half a turn: better, not perfect. Unscrewed it another half turn: nearly spot on. Flies nicely, a bit more high siding required on the left turn, but that's where the inboard concentric gives a bit more anhedral.

Adjustments so far: right tip set to neutral from 10mm downward (more lift). Right sprog net movement maybe 1/4 or 1/2 turn down. Left sprog a whole turn up. Trailing edge is now near perfect, but I haven't checked the sprog height against the keel yet.

Probable next adjustment: set both inner concentrics up (more anhedral) and then the tips up (rotate concentric down), which should give fast response and a bit of high siding.

9:52:08 PM    

I figured that it still wasn't right. I had the feeling that the glider was cruising with the nose about 10 degs right of the true heading. Maybe more drag on the right wing. Who knows. And maybe it was me, but I couldn't thermal to the right on the 24th April.

Set the whole thing up in the garden. The Moyes manual is sensible, tells you what to check first, but doesn't tell you how to correct things if your glider is not symmetric.

Battens: nr 6 green over 1cm too flat in the middle. most of the outer battens too flat, but that's at least symmetric. Outer concentrics: set to zero, inner concentrics, +/- 10mm down (backward).

From the front: everything looks OK. But looking from the back, no sprogs in, clearly the right wing trailing edge too high. It was the batten symmetry check that was the worst - from the 3rd, the right wing sat higher.

So I set the right concentric to neutral, and lowered the right sprog half a turn. Seemed to have reduced the differential twist.

Result: flies even better - no apparent bias left or right, no nose pointing off-glide. But it's still not symmetric - I can see when It's parked that the left tip sits nearly on the ground, and the right one is up in the air. So the frame is not balanced. Yet. We'll get there.

Why was it delivered like this?

 08 April 2003

Bit difficult to tell from last Saturday's flight, but my reseting of the tip wand socket and the sprog seemed to have pretty much cleared things up. It'll take a flight in good conditions to really tell, but certainly I had no major turns. So maybe the tip wand socket was strangely set up rotated by someone who perceived a turn.

The trailing edge is also now pretty symmetric, still maybe a slight rise on the right: the screw is six threads out compared to four on the other side, but I guess this is of no relevance since the engineering tolerance on the tensioning cable cannot be much better than a mm, and that is the aproximate difference. I need to do several long glides, however, to be really sure. I just didn't detect any turns in the last flight.

 31 March 2003

I had thought I had tuned out a slight left turn with the VG on. After fiddling a few times with the right outer sprog, it seemd more or less OK - maybe a touch too much, seemed to turn right slightly now. Rigging in the garden after replacing my bent upright, I pulled the VG on and sighted the trailing edge. Wow, that right sprog was lifting the edge over a cm. It was a disturbingly asymetric sight.

Next rigging, I check the tip wand socket. Left side, centred on the mid point mark. Right side, rotated backward (down) 1cm... so just the opposite of the sprog adjustment. Hmmm.

Email Moyes to ask if all of this makes sense. Few days later I get an email that "looks like I feel the need to tune my glider". Sure. I guess it's probably not realistic to expect much sense over the internet from halfway round the world (or 100km for that matter). So I've adjusted the tip wand socket back and rewound the sprog back in (lowered it) half a turn (it was 5/4ths). We'll see. I bet after I've finished with this the sprog will be back where I started and the tip wand socket balanced with the one on the left.

If so, why was it rotated back? Someone's perception of a spiralling right turn? No hint of that so far.