|
Post by felix on Dec 3, 2008 22:20:56 GMT 10
Hey good to see you back playing with monkeys mate! After seeing mikeys fly on a regular basis they seem like a top little model. Good to see your using FG rod instead of CF tube but at $7.99 mtr?! Sh*t lucky it’s a small model lol. Look forward to hearing the flight report
|
|
|
Post by Pij on Dec 4, 2008 6:38:29 GMT 10
Yes, I absolutely love flying the Monkey. Problem is, they belong to my sons. DV prefers to fly my Duck, as it's more sedate. I love the sheer zippiness of the Monkeys, but remember I intended them to be an all-purpose tough but lightweight and light-wind glider for the boys to practise on. In terms of beginner-friendliness and toughness, the Monkeys have failed. BUT they are a success for using with a simple 4ch radio. Mechanically reduced throws and mechanical differential (less than specified) makes them behave well.
If only I'd been able to get Bees for the 3 boys. But programmable Txs for 3 was the budget killer.
My plan at this stage with the FG rod, is to have a 25cm piece on the underside, and maybe a 15cm piece topside. I can't put in the FG full-length, as well as the CF already in, as this little wing shouldn't have to carry that much weight. So I want to just stiffen the break-zone, without having a new sudden end-of-stiffness section for the CF ribbon to break at next time. I'm hoping that keeping the top and bottom stiffeneners unequal will help smooth-out the transition from stiff to unstiff.
I'm also considering the value of thinning the FG towards the ends, like a fishing rod tip, to further blend towards unstiffness. What do you think, Felix?
|
|
|
Post by Pij on Dec 4, 2008 21:12:44 GMT 10
To fix DV's Monkey, I went with a CF ribbon splint about 8cm long, a 35cm slightly curved FG spar near the CF spar, and a shorter FG spar behind, all on the underside. This time I hot-melt glued the wing back on, though I did buy some M4 gauge nylon bolts and nuts that I might use for a removable wing on #2 and #3 Monkeys. I covered the spar incisions with light-weight bi-di fibre tape, mainly because I couldn't find where I'd put the heavy bi-di tape. The wing feels good, but only a crash-test can prove for sure.
|
|
|
Post by Pij on Dec 5, 2008 19:34:06 GMT 10
Monkey #1 is all back together, awaiting re-testing, and I made good progress on Monkey #2 (dihedral version) today.
Ailerons and tail surfaces cut, bevelled and shaped. Then all balsa parts coated in thinned dope, then dope coloured with cheap red spray paint. Next time I think I'd be better to add the colour to the thinned coat. Ended up thinning the coloured dope, and got better coverage. Lovely and smooth, hard surface, and fairly even colouring. In all those respects, better than Monkey #1 with coloured Goop painted onto the balsa surfaces.
Made up the pushrods and cleared the foam for the arm movements. Set the mechanical differential, and glued the servos in. Then noticed the differential wasn't the same on both (damn, I was careful making sure they were the same, don't know what went wrong - something to do with the kids coming home from school at that time?) so had to cut slot in the foam to re-do one servo arm.
Sorted out the receiver, battery, crystal, y-harness, and tested the cheap transmitter. (The other cheap transmitter failed - I think a bad Tx crystal).
Next stages will be inserting the components into the fuselage, making charging jack, routing wiring, Gooping the fuse, and attaching the tail gear.
I'm pretty pleased for today.
|
|
|
Post by Pij on Dec 6, 2008 18:59:03 GMT 10
Great progress today. It might not sound like it, but I spent the whole day working on the Monkey: Cut spaces and inserted elevator servo, pushrod, and receiver. From the Eneloop pack from Laanguy, cut the long battery lead and made charging jack into the middle. Cut spaces and inserted battery, charging jack/switch, and wiring. Tested all the electrics, then made balsa component covers, glued them in, 3M sprayed and bi-di taped the fuse. My eyes won't focus any more. Used the last of today's eyesight quota watching team Vodafone polish off the V8's and typing this update. There's a few differences today with this #2 Monkey, from the #1 and from the specifications: Charging jack is built into the battery lead, rather than as a separate component, and this time is mounted forward. Receiver is mounted edge-in, with wiring space behind, to allow future changes to crystal or leads. Aerial is zig-zagged along the fuse, so less hanging out the back. Resulting from the above changes, wiring tunnels are simplified. Mounted elevator servo a/c to the specs, below the fuse surface, allowing servo and connection to pushrod to be completely buried. Note: The instructions say to CA the pushrod housing in. But CA doesn't stick to Teflon. Hot-melt is needed. No Gyprock tape this time. Using more standard bi-di tape, to be followed with coloured Goop. Will probably be gluing the wing on, after all. The idea of screw-mounting it still appeals to me, but the wiring and receiver cavities weaken the middle of the Monkey, and the gluing of the wing is the only thing in the plan that re-strengthens that section. Otherwise, I'd have needed to re-engineer the stiffening of the mid section to allow for a removable wing. Still, as I'm using more hot-melt and less Goop this time around, I feel the wing is reasonably removable anyway.
|
|
|
Post by Pij on Dec 7, 2008 7:25:45 GMT 10
This morning by 7am, 2.5 coats of Marine Goop, thinned with Glue Rid, coloured by 20 squirts of black paint and 4 of silver. I'm not happy with the bumps at the nose - the tape puckers didn't stay stuck. These will have to be surgically removed before some more Gooping.
|
|
|
Post by Pij on Dec 7, 2008 10:36:47 GMT 10
Trimmed the bumps off the fuse, did touch-ups and final coat of Goop, then masked and Gooped the crosses onto the top of the wing.
|
|
|
Post by Pij on Dec 7, 2008 18:31:37 GMT 10
Here's the setup I had to use to work with a dihedral wing when flat working surfaces were required. This is ready to do the laminating film covering on the wing. The covering went well, a few touch-ups on the fuse, and here's the mock-up before final assembly. We have storms tonight. Lucky I got the covering done, as the power's on and off a bit now. #2 son loves the look of #2 Monkey.
|
|
|
Post by Pij on Dec 8, 2008 15:45:58 GMT 10
All finished, ready for testing. (Well, after I set the CG.) The hot-melt was still warm when the kids got home from school, but I was packed up. Does the new Monkey owner look pleased? I used the lightweight bi-di fibre tape along the elevator hinge, and it's almost invisible. For appearance, I might consider using that for aileron hinges in the future. But, that gives me a leading edge of tape that might lift up. The hinging I did on the ailerons on this Monkey gives me no leading edge of tape, though it is ugly.
|
|
|
Post by felix on Dec 8, 2008 17:10:44 GMT 10
Nice job pij, look forward to hearing the flight report.
|
|
|
Post by Pij on Dec 8, 2008 18:39:41 GMT 10
Thanks Felix. We just got back from chuck testing at the park. Grinning. Very happy.
I had added one fishing sinker, slightly flattened, into the nose, to balance at 47mm from LE. A small bit of lead, 1.5mm x 5mm x 8mm, flattened out, slipped under the tape near one wingtip balanced it left-right.
At the park, aimed it at a bunch of galahs (the feathered kind) and expected to be wrestling the elevator for the first flight: Nope. It launched from a medium chuck, flew straight, and just needed elevator tweeked for the landing. It had failed to gain height, though, so I added one click of Up.
All other tosses were good too. Bigger chucks gave long glides, around 100m the best - way better than Monkey #1, and way more manageable too. After straight glides, I did some gentle turns, and it handled these well too.
I can't give a correct weight, as my digital scales tell porkies, but I think it is lighter than #1, and slicker on the fuse too. I set this up with some slight "flaps", or undercamber, on the ailerons (mechanically, remember, no digital effects here!), and I think this is part of the reason for its added floatiness, and perhaps the manageability at low speed. I'm not suggesting that's the best way to set it up for slope performance: that's just my idea of making it suit a beginner. But we might be tempted to adjust #1 a bit this way.
As I said to DV, I am feeling a bit sorry that #2 has turned out to be so much better looking than #1, and better performing in the park - BUT - when we flew #1 at the slope, we felt it was great, only lacking in loop-ability (CG might be a bit far back). So DV says, he doesn't care if #2 is prettier - he only cares about how his glider flies, and he's very happy with it at the slope.
So, now it remains to be seen whether better flying at the park will equate to better slope gliding. Need the rain to stop to test that.
|
|
|
Post by felix on Dec 8, 2008 18:47:59 GMT 10
Wow 100mtrs from a handlaunch! Think the only problem you’ll have at the slope is getting it back down haha. A quick tip on having the ailerons set to give a slight flap effect (just in case) –really test out the ailerons at low speed/high AOA and check for any tip stalling, if you find that it will tip stall taper the ailerons a bit at the tip. Lowers the AOA at the tips so you can get away with a bit more throw btw- good to year your young son more concerned with performance over cosmetics future engineer right there lol.
|
|
|
Post by thevon on Dec 8, 2008 18:59:01 GMT 10
strewth, that's ridiculous! I think the Kite magic stuff is only about $1.50 a metre for 2.4mm!
|
|
|
Post by Pij on Dec 8, 2008 21:17:27 GMT 10
Yeah, www.kitesite.com.au has 2mm for $1.85. Felix, yes, I think there were the beginnings of tip-stalls during testing. Of course, hand-throws guarantee low airspeed, so breed stalls. I did GENTLE turn testing, as I had to back off any attempt at a tighter turn - it had a tendency to tuck into the turn, as in almost tip-stalling. That's a big part of the reason I didn't give the 9.9 year-old a chance at the sticks (the Monkey has shown it likes to break wing spars, so prefer not to hit wingtips on ground). So, I was thinking, he can learn to avoid tip-stalling while buddy-cord training. Your idea - engineer the glider to avoid tip-stalls. Gotta admit, I never thought of that. The ailerons are already tapered, but I suppose I could taper them some more. Or undercamber less. Or just go with plan A - teach him to avoid tip-stalling. I dunno.
|
|
|
Post by Pij on Dec 9, 2008 14:08:37 GMT 10
I'd like some advice, please, if anyone can help.
I went to the coast today for a little slope testing. The Duck wouldn't stay up in the light lift, but the Monkey could sustain flight, just, if I was able to fly in the best zone, close in. I wasn't always able to.
The behaviour in turns is a bit strange. A lot of this applies to Monkey #1 too.
Firstly, the Monkeys are very sensitive to aileron input. The cheap Tx also adds to this. A tiny bit of left or right stick, and it banks - but does not turn, well, hardly at all. Add some elevator, and it completes the turn quickly, and in a very tight space. Big slow lazy turns are difficult to achieve, but on-the-spot 180's are easy. Of course, these wipe off a lot of energy, though less than you'd expect - usually the Monkey loses a bit of height but comes out of the turn with fair airspeed.
So, there's a few things I could wish for. 1) More delicacy of control in turns. 2) Less imperative to use elevator to complete the turn (remember, beginner owner for this plane) 3) Turn without losing height 4) Able to do big turns more easily, and less tendency to turn on the spot.
I was thinking that I should decrease the amount of differential, perhaps to zero. My thinking is that I need more lift under the wing during turns, not more down-force, so a) less elevator (nose-up) would be needed and b) may be able to maintain height during a turn. I know this will mean I lose speed during the turn, but I'm willing to make that trade.
But perhaps somebody with more trimming experience may be able to tell, from the symptoms, that a simple trim alteration (eg CofG, or undercamber etc) might improve the behaviour.
I'm happy to hear different suggestions and sort through them. Anybody, please?
|
|