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Post by ezza on May 7, 2007 9:59:20 GMT 10
Andrew, have you manage to DS yet? That field where you left me seemed to be a great spot. You will have to hook up with that old guy we met there to give you some tips as his little foamy was going off DSing there. I expect you to be a DS expert by my next Oz trip so you can teach me Is this a new DS spot?
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Post by thevon on May 8, 2007 9:16:15 GMT 10
Ezza it's a private property, so I have to line it up with someone. But yes.
Update on Drongo: Yesterday flying at Mt Mee , (Labour Day holiday) it was a top day, with quite a crowd. My main aim was to get as much time as possible flying the Drongo and it was really excellent - I feel like I've "tamed the beast" and it was really on song. I've been taking the weight off the nose to move the CG back, bit by bit. It was generally great lift - mostly not enough to put the Drongo "in its element" but it was really firing. But before the rain band came thru, there was about 20 mins of building up wind, and man, the Drongo was awesome. That's when you can really start to play with it.
In short, when others are starting to think it's getting too windy to fly, that's when the Drongo is at its best.
I set dual rates for 55% elevator control at speed, which helped. Without it, when you dive (and man, the speed it builds up is really just scary) it gets hard to control the up/down; particularly the down - when it's heading downhill at warp speed, it only takes touch of down and it tucks under steeply. So the D/R really helps with that.
The only problem I have is that when I do big dipping dives down over the face of the hill, I have to pull the stick back quite hard to pull it up (even with normal rates). So when I did it with D/R on, I probably forgot that it was even less responsive so I didn't pull enough up and unfortunately it belly crashed hard into the long grass again at high speed, spun and snapped the tail off, broke all 3 rods. But being desperate I did a bodge job; glued them up with 5-minute, and taped it, and flew it again just fine later - couldn't even tell any difference.
It seems like it's a lot more sensitive to down than to up, so I'm asking Glenn the guru whether I should fiddle with anything or just get used to it. Andrew
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zipper
> 50
Off The Edge Sailplanes
Posts: 88
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Post by zipper on May 8, 2007 21:19:17 GMT 10
I got to fly my drongo on the weekend for the first time after programing it into my new JR 9x radio (fantastic radio) and got it to fly even better than before the rolls are now straight and can really pump the turns. I have measured the setup and it is as follows: up elevator 6mm down elevator 4mm up aileron 13mm down aileron 11mm One thing I found while I was measuring the throws is that my servos are not centering back to zero, when I push the elevon up it centers to zero and when I push it down it centers to 2mm up . I will have to see if it dose it on the old radio.
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Post by ding on May 9, 2007 7:28:15 GMT 10
I will have to see if it dose it on the old radio. It won't be the radio ...it will be the servos. It will be a combinatiion of servo precision, and linkage binding and precision. Also look at the mechanical setup. Ie if you have a lot of leverage this will exaggerate the problem. I used to spend over $150 a servo, and then around another $50 on linkages on every surface of the f3a models to avoid these problems If there is one positive airflow is a bit of a leveler ... so to speak.
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Post by thevon on May 9, 2007 14:25:49 GMT 10
It is not easy trying to get the rates right for both aileron and elevator, up and down! The Optic 6 gives end point adjustment for each servo for both up/down. But when you get the aileron throws set equally, you find that the elevator throw is different for each side. The Optic 6 elevon programming gives you control of the rates for elevator vs servo, but not up + down for each. So I ended up with up elevator 6mm down elevator 4mm up aileron 13mm down aileron 10mm. I can't get more up aileron as my hinges are too tight.
But as always, looking forward to the next try-out! Tail is being rebuilt with some fibreglass rods; can't be bothered going to a hobby shop for carbon ones.
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Post by thevon on May 12, 2007 12:08:15 GMT 10
Since I started this thread to chronicle my attempt to "get into" DS, and the procurement of the Drongo for that purpose, I'd better report on the latest progress.
Big day at Mt Mee yesterday - winds of 25+ knots, and lift everywhere. First of all I went to a spot up on the main Mt Mee road, about a km north of the lookout. I used to fly there before I found Pedwell rd site - it's a gnarly spot, but the ground dishes back and drops down into a gully behind the road so it sounded like some of the spots that Ezza describes in his DS spots. Not the best frontside spot, but I wondered if it might be good for DS. I kept doing circuits with the Duck but it never really started to rip into it and like Sean, I kept dead-airing it over the back and having to scramble down the scrub, past snakes (!) to retrieve it.
I even got the Minij out and had a go with that (better speed retention) but it just didn't seem to work. There seemed to be stronger lift a bit further up the road but there were trees everywhere so I gave up.
At Pedwell Rd I got back into it again. There's such a small backside area there, rimmed with big trees, that 1) it only suits small flattish circuits and 2) there's no room for error! So I got the Duck and began to work it, diving and coming clockwise around the back of the clearing. It's quite do-able. When you are on the way back out you can see the effect of a very definite shear layer - the plane shakes and you can hear it "whoosh" a bit. But the big risk at this point, as you rip fast back up into the moving air, is that the plane can pitch up steeply and at Mt Mee this can mean that you end up very high in the trees. I've done this twice, the first time it took 2 weeks before I got it down!
But armed with Ezzas advice that you need to keep the plane on its side, I got the thing really hiking around the circuit, going into the area where that side road goes down, circling back and down, and coming so the plane flies over the gate. It definitely cranked the speed up but then it would just fly "normally" out over the slope ... ie I could do it again and again, but it wasn't anything like the faster-and-faster loops of DS.
I should add that during this process I also went into a tree during the approach dive (ie very hard), crashed into the fence, and bellied onto the road.
I got braver and made the circuits steeper, so the plane was coming up higher on exit, and ... bingo! that was it. Straight away, I could feel that it was doing what it was supposed to. The only problem with it was that my brain couldn't really keep up with the action and I'd lose the pattern before I could keep it going. The trick was to come up and out with the plane on its side, and let it roll upside down at the top and curve back to enter the same circuit on its side. As it went down to the bottom turn (talking about 1 - 2sec here!) it helped to push a bit of down to open the circuit up a bit. Arc around the bottom, keep on the side coming up and out, roll upside down, pull up a bit to enter the circuit ... hey, this is working ... whack! - bugger, I didn't think that road was so close ...
I had a direct nose-in on the road and the Duck died! Must have broken a battery contact I think - no power to the switch. (later - yep it was - fixed now)
Anyway, it was progress! So far, I am experiencing everything people have said about it ... it's fast, it takes lots of coordination, it takes sloping to a new level, and it's very destructive! And I haven't really done it properly yet.
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Post by thevon on May 12, 2007 12:50:04 GMT 10
As well as killing the valiant Duck in its glorious DS attempt, I was dead keen to fly give the Drongo a workout in the perfect conditions, after making the aforementioned changes to aileron/ elevator throws.
I had rebuilt the tail using some fibreglass rods and trimmed a bit of size off the bottom of it. I also increased the aileron up throws and reduced the down throws a lot, effectively changing it from negative to positive differential. I set the dual rates at 60%, up from 50%. I buried the taped-on nose weight into the nose.
The wind was 20 - 30 knots up the valley, just excellent. Straight away, the Drongo flew brilliantly. The new throws gave more positive "up" response coming out of dives. When I banked, the nose came up, not down. Absolutely fantastic. If you haven't flown such a fast heavy thing I can say ... it's definitely an experience! I've really learnt a lot from having this plane.
The only fault I picked was that it corkscrewed in rolls. I watched and worked out that the inside wing was pulling back, ie it was the opposite of "adverse yaw" - the up aileron was dragging more than the down one. So I landed it and increased the down throws by 15% each and straight away, the rolls were more axial. Not perfect, but there's a conflict here - the Drongo is extremely down-sensitive. Whereas it takes quite a bit of "up stick" to pull up at the bottom of a dive; it only takes a whisker of down to initiate a dive ... and it doesn't pull out of dives - they're totally neutral! A bit more down throw would give perfect axial rolls but I didn't want to get any less up control or any more down control. So I've left it as is.
I could rave on about the way the thing carves up the sky but I guess you have to fly one to get the idea. It covers so much ground so fast that when you're doing big diving fly-pasts, you're really at the limits of concentration keeping it in the right place. I went way out to the left and climbed way, way up in the huge tower of lift. But the Drongo often flies thru the lift and you have to circle back to find it again. Gained huge height, then dived down into the valley, pulled up and shot back up to follow the slope towards me. This all happens incredibly fast ... one second it's so far away it's hard to see, and in a few seconds it's coming at you like a Cruise missile. My radar didn't scan the small tree just down the slope and suddenly there was an explosion of leaves and Profilm and the Drongo hit the deck. The only major damage was a rip into the foam at the leading edge, near the V where the nose and main sections join. Determined to keep making the best of such a day, I realigned it and taped it all up, and kept flying. No difference. Man, that thing is really tough, no kidding. It must have hit that tree at 140kph or so - I can't tell, but it is insanely fast.
Later I tried my remaining objective ... to install all 550gm of ballast! I'd been flying it with 2 slugs installed, now I put the other 6 in. I've checked, and with full ballast it coincidentally weighs exactly 2.0 kg.
When I threw it out ... well ... nothing! There's no difference! I expected it to plummet a bit when thrown, but no, it jumped up and away. To me, there's no detectable change, and if anything, it goes better in every respect. I just couldn't stop flying it. Poor Greg really wanted me to have a go of his Starling Pro, but I was having too much fun with the Drongo. But when it's diving fast with all that ballast you need to give it a bit more room to pull up. So once again, I did a big belly-in on the grass at full tilt ... so hard it ploughed thru the grass & scraped the ground ... but again, no damage and I kept flying.
My next "objective" with the Drongo is to get to a good big air DS site, like the backside of the Bald Knob ridge in an easterly, and try it out. Woo- hoo!
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Post by callun on May 12, 2007 13:40:08 GMT 10
Sounds fun Andrew Wouldn't mind having a go at some stage if you wouldn't mind. I had a bit of a go at Steve's Skua at Shornecliff a few weeks ago, and it was pretty scarey. My warrior is so docile I can virtually do whatever I like to it. When I flew the Skua, I really had to change my brain-phase, cos I really couldn't fly it like a combat machine. Wasn't the most enjoyable experience at first, because I really wasn't prepared for it. But in the right frame of mind, I'd quite enjoy it I'm sure.
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Post by thevon on May 12, 2007 16:10:23 GMT 10
Callun, no worries - love you to have a go. But it will have to wait until if/when you come to Mt Mee again. Can't fly it at Shorncliffe - it needs lots more room. (well, I wouldn't try it I reckon)
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Post by callun on May 12, 2007 18:51:06 GMT 10
I can understand that Andrew I really like the opportunity to fly other people's planes.
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zipper
> 50
Off The Edge Sailplanes
Posts: 88
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Post by zipper on May 13, 2007 23:06:50 GMT 10
I will be up at Qld race way (Ipswich) at the end of the month, If I have time I will have to come for a fly.
Glenn
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Post by thevon on Jun 9, 2007 10:34:37 GMT 10
Well, I think I can say I am no longer a DS virgin, but it's still a bit of a mystery to me and I don't think I've really gone all the way. My first experiences were tentative and I was too overcome with anxiety to really let myself go and let the whole thing really happen. We went to Bald Knob in a turbulent due westerly and I found that by flying just below the gate, circling clockwise and shallow dipping down the backside the plane really started to rip as you pulled back up the ridge, emerging knife edge just in front of yourself. The Drongo kept speed up well but if you went too far back, or too far out front it would lose speed. Then Sean arrived and he reckoned to go more over the back of the main hilltop. The best success I had was to stand about 50m up from the gate, just over the back of the hill and dive down to about 50m to the N of the gate, circling around the back of the hill and coming back up in front of myself. It worked best if the plane was on its side as it arced out of the bottom. It was nice to hear it start to whine as it came back up over the top, and it really shook as it went thru the turbulent shear layer. So much so that once it twisted the tail fin around in mid flight!
Sean then had a go and showing his amazing control and coordination, he immediately went well over the backside and started doing much steeper loops. It didn't really get the true DS acceleration going, but as he said "it must be working because I'm on the wrong side of the hill and it's staying up there!". It really did look very impressive.
I need to get the committment factor going, ie to keep the plane hooking over as it comes out of the bottom turn. I start to chicken out as it goes inverted and that's where you need to keep the speed up.
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Post by ezza on Jun 9, 2007 16:53:16 GMT 10
Hey great to hear you guys were ds'ing. ;D I have often wondered what it would be like up at Bald knob on a Westerly Ds'ing really is a game nerves and concentration. I find I am constantly learning. Today my son and I went to a ds spot that we fly sometimes on a e or se wind, out past Casino. I have wanted to try this spot with a westerly. After flying at several spots we found the sweetspot. It was quite windy but I could only manage 85mph, as I was getting chucked around, all over the backside. I landed and filled her up with lead. The frontside has minimal lift and you have to launch out over trees/lantana. However the backside is about 150m down! Usually we fly on the big side and ds on the small backside slope. It took only three laps to get from 50 mph to 106mph then on the fourth lap managed 115mph! My new foamie PB. That last lap was only about 1 metre above the ground the whole time. So fun!! The plane seemed to get most of it's acceleration on the bottom turn. I have not experienced this before. So I started going 'way' down and she would come up quicker everytime. I didn't have to go so close to the ground and the circles were footy oval sized! I was consistantly over 100mph and quite a few laps over 110. Unfortunately my laps got so big that I found a dead tree at 113mph! The plane flailed like a dead bird for over 100m down the back. No sooner had it hit the gound, than the two very large resident Wedgetails dove down for inspection of the wreckage. I wish I had the video camera!!!! The fuse and wing seperated nicely. A little shoe goo and some work with the iron and she'll be dsing again! I have to say I am soo happy with the Reaper it is amazing for a piece of foam! Sean, did you have yours going today?
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Post by sean on Jun 10, 2007 9:44:06 GMT 10
It was a fun day up at Bald Knob, but as Andrew said we couldn't quite get the DS thing happening as well as we were hoping. You'd think that the best spot would be down near the gate like Andrew describes (the hill is quite pointy there) but I had the most success a bit further up, about 50 metres up from the gate. My best result was 4 or 5 circles on the backside that were reasonably fast, but only about as fast as you'd get on the frontside. The lift became very patchy in the afternoon and was blowing about 45 degrees to the slope so our DS attempts after that were pretty unsuccessful, overall we didn't get a lot of time to improve on our earlier attempts. It is hard for us to know exactly how to fly the circles without seeing someone who knows do it! And I personally found it quite difficult to find the shear layer (story of my DSing life so far )! Anyway, it was rather exciting, and enough of a taste for the addiction to set in The Reaper is still in the workshop, but work has been delayed because I'm in the process of moving house right now, we're moving up to Montville actually! Pretty exciting! I have about two more weeks in this house, so if I can find the time I'll get stuck in and finish it. Ezza, your DSing at Casino sounds awesome, as does your spectacular crash! It sounds like your fuse separated nicely in the crash, did you goop the fuse to the covering on the wings?
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Post by ezza on Jun 10, 2007 10:34:17 GMT 10
Hey Sean,
Yeah I did goop it to the covering, but I also cut a couple squares, about 25mm x 25mm, right through to the foam. The break is pretty ugly(lumpy) but it does key back together nicely.
I have never ds'ed on a westerly up there. I would have guessed walking eastwards from the gate, once the plane was up high and diving in, nice and deep there would have been the spot? Maybe the wind just does not seperate enough there? It would be a little scary diving down really deep there, as it drops off pretty steep to the road.
Site and conditions are 90% of ds'ing. Yesterday we tried to ds at 6 different places along this ridge (which is pretty long) until we found the sweet spot, where the air on the backside was dead. By dead I mean still enough not to wipe too much, if any speed off. Yesterday was the first time I had ds'ed where the plane seemed to accelerate off the bottom turn. ;D ;DThe other places we tried, you could manage a couple or few laps and then all of the sudden get thrown around by wind on the backside, which usually results in loss of speed and then a landout or crash. When this happens try something different. Different lap direction, diving deeper, diving lower, different angle, higher dive in, etc,. Yesterday I was trying little circles and couldn't get it happening, then I tried a huge dive, way down the back and it came screaming back up! Some places like small laps, others huge.
I know it works quite well on a E or ESE, just back from the gate behind those trees. Hope you guys get some good conditions soon! ;D
Montville should be good hey. I believe there are a few flying spots around there!!
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