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RE: Abused LiPos
I agree, generally that's true but not all of them are whimpy. Just looking at what HobbyKing has to offer, they have a few 100-200W per port multi chargers available for around $100. I'll do some shopping around & see what's what.
Posted on: 9/18/2012 9:35 AM by Author "Nodd"
in the forum "Batteries & Chargers"
http://www.rcuniverse.com/forum/fb.asp?m=11232437
RE: Abused LiPos
Yeah I'm going to build a couple of regenerative dischargers, looks like a great way to place batteries in storage mode. As for the "OMG it isn't raining" scenarios I'm still undecided. I think I'm leaning more towards using a quad-charger Vs parallel charging but we'll see.
Posted on: 9/18/2012 7:46 AM by Author "Nodd"
in the forum "Batteries & Chargers"
http://www.rcuniverse.com/forum/fb.asp?m=11232319
RE: Abused LiPos
Thanks for the feedback, much appreciated. 3.7v is more or less storage voltage although 3.8v is more common but close enough. So yeah that's how I aim to store mine from now on. No more letting my LiPos sit around for days on end busting at the seams with energy. I also posted this over at RC groups & it was suggested that I look into parallel charging instead of using a cheap low powered quad-charger. I may need to invest in a more powerful charger to pull off a parallel fast charge though, not sure my current "four button" charger is up to the task. There was also talk of regenerative charging/discharging where a fully charged pack is hooked up to a discharged pack via a resister. The idea being, once you're done flying you dump the power in your unused packs into the spent packs until both arrive at around storage voltage. I think that's friggin brilliant! Info on that can be found here... http://www.rcgroups.com/forums/showthread.php?t=1255751
Posted on: 9/17/2012 5:35 PM by Author "Nodd"
in the forum "Batteries & Chargers"
http://www.rcuniverse.com/forum/fb.asp?m=11231697
Abused LiPos
I'm likely dragging up an old topic here so my apologies if so. I'm looking for current advice on current tech (most relevant threads I found were several years old). I'm trying to get a feel for how most folks maintain their LiPo batteries. We all know its bad to keep them fully charged between flying sessions. We're supposed to maintain them at "storage voltage" (approximately 3.8v per cell) while they're not in use. I have a couple of problems with this though... I fly several times a week. That's a lot of work to charge/discharge all my batteries between flying sessions. Time consuming & labor intensive. Keeping the batteries at storage voltage means I can't go fly at the drop of a hat. I have to plan ahead if I want to fly. So like many, I've been abusing my LiPos by keeping them fully charged, all the time. Most have started to puff & now fail to balance properly. As a result I'm also seeing greatly reduced flight times, not good. So what to do?.. First off, I've invested in some new batteries. I'm considering buying a "quad charger" that can deal with as many as four batteries at once. There's several fairly cheap four-in-one chargers I'm looking at (I'm between jobs so need to do things on the cheap). My current plan is to do one of the following... Pre-Charge The night before I fly I'll bring all my batteries up from storage voltage to full. That way when I get to the field the next morning I'm ready to roll. Charge-on-demand The problem with pre-charging is I don't necessarily use all my batteries when I fly. So some inevitably end up being unnecessarily cycled. So maybe I should charge my packs at the field, only as required? My new nano-tech LiPos can be charged at a high C rating, so theoretically once I get to the field, I can decide what I want to fly then fast-charge up a pack or two & start flying. So I think for either of these methods to work efficiently, I'm going to need the ability to charge multiple packs at once. My question is, what do you folks do?
Posted on: 9/17/2012 11:45 AM by Author "Nodd"
in the forum "Batteries & Chargers"
http://www.rcuniverse.com/forum/fb.asp?m=11231314
RE: Tip-stall prone Cub
As I posted earlier it was not a clipped wing Cub (measured & confirmed). As I also stated, the airframe was already tossed out, so no I'll not be fixing her up. At some point I'd like to get another Cub, its just one of those must have planes. How's the Great Planes Cub, flies nice?
Posted on: 9/12/2012 7:04 AM by Author "Nodd"
in the forum "Crash & Rebuild"
http://www.rcuniverse.com/forum/fb.asp?m=11225686
RE: Tip-stall prone Cub
I have plenty of old beat up planes already *smile*. I know what you mean about carefree "old beater" flying. Yeah IMO the Cub was too far gone, the foam would have been an easy fix but the plastic cabin / wing support area was completely shattered, not an easy fix. If she'd been a better flying plane maybe I'd have taken the time to fix her. Better to move on & fly something nicer. I did keep the wings, might reuse those in some Frankenstein project down the road.
Posted on: 9/12/2012 7:03 AM by Author "Nodd"
in the forum "Crash & Rebuild"
http://www.rcuniverse.com/forum/fb.asp?m=11226036
RE: Scratch Designed/Built Sailplane Fuselage
Construction begins! Enough design work, time to start building this thing. I printed a set of templates from my CAD software... Used the templates to cutout the various parts then started putting things together... She's starting to look like something... Filled in the rear of the pod with scrap balsa... A little pre-shaping of the hardwood nose blocks. Once installed I'll finish carving these until the motor fits... I'm using 1/4" plywood for the pod support (the piece that connects the pod to the wing)... Test fitting the support. I won't glue this in until the pod has been shaped & sanded as it'll just get in the way... That'll do for today. I'm headed to the NEAT Fair so will get back to this when I return next week. Cya there.
Posted on: 9/11/2012 7:54 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11225673
RE: Scratch Designed/Built Sailplane Fuselage
Bounce Bounce Bounce A guy over at RC Groups pointed out that my pod fuselage may cause ground handling issues. Specifically he felt the design would be prone to skipping during landing. Once the pod contacts the ground the tail will hit next raising the nose alarmingly & back up she goes, hop hop hop. So to fix the issue I'm thinking a small tail-skid should keep the AOA from getting out of hand during landing. It looks kinda cool too...
Posted on: 9/10/2012 6:01 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11224376
RE: Itchy LiPo
That'd work but then you have an itchy glove to deal with *grin* I was actually considering salad tongs...
Posted on: 9/10/2012 3:03 PM by Author "Nodd"
in the forum "Batteries & Chargers"
http://www.rcuniverse.com/forum/fb.asp?m=11224169
RE: Itchy LiPo
Someone suggested using a vacuum cleaner to remove any lose fiberglass particles from the bag. Much less itchy supposedly. It was also pointed out that its probably not a great idea to allow a LiPo to go THUD on a hard surface like my work-bench. I also cringed when I played back that footage. I'm still not going to stick my hand in there though.
Posted on: 9/10/2012 1:46 PM by Author "Nodd"
in the forum "Batteries & Chargers"
http://www.rcuniverse.com/forum/fb.asp?m=11224077
Itchy LiPo
Although this seems obvious now that I've figured it out, this itchy issue was driving me nutz for a while. Check out my video to learn more... Itchy LiPo YouTube Video [youtube]http://www.youtube.com/watch?v=pQRBf6K01Qc[/youtube]
Posted on: 9/9/2012 8:09 PM by Author "Nodd"
in the forum "Batteries & Chargers"
http://www.rcuniverse.com/forum/fb.asp?m=11223292
RE: Tip-stall prone Cub
From what I can tell, mine was not a clipped wing Cub. Its wing was 155% of its fuselage length. After taking measurements from various clipped wing Cubs they seem to have wings ranging from 125-147% fuselage length. Mine cirtainly wasn't very aerobatic either. That's good advice about using the rudder to stop a spin, I'll have to practice that. Truth be told, I doubt there was much of anything I could have done to save her though... just too low. I would have loved to twist in some washout but not sure if that's possible with a foam wing. I assume applying heat, much the way you do with a built up covered wing, might work? Sounds a bit iffy for foam though. I really like the throttle to aileron mixing idea (ailerons move up a little at low throttle), that's brilliant! I'll have to give that a try on my Spacewalker & see how she handles. Anyway I have no plans to rebuild her, already tossed the airframe in the bin (although I did keep the electronics & the wing). I think my next Cub will be a nice built-up from Sig or Great Planes or if I'm going to do another foamie, the Fun Cub flies nice. Interestingly it looks like Nitroplanes may have discontinued the model I had. Not a big surprise there.
Posted on: 9/8/2012 7:11 PM by Author "Nodd"
in the forum "Crash & Rebuild"
http://www.rcuniverse.com/forum/fb.asp?m=11221795
RE: Scratch Designed/Built Sailplane Fuselage
Fleshed out I did a little more work in CAD, here's how the pod looks fleshed out in 3D...
Posted on: 9/7/2012 6:55 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11221297
RE: Scratch Designed/Built Sailplane Fuselage
Yeah I know what you mean... "Balsawood? Do we look like a lumber yard? We do have over priced lumps of foam shaped kinda like airplanes though". Well I'm back from the hobby store & bah (big surprise) they don't have the sizes I need. I'll have to hit the other store tomorrow, either that or order some online. Thankfully I do have internet *grin*
Posted on: 9/7/2012 4:02 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11221124
RE: Scratch Designed/Built Sailplane Fuselage
I may have to make a chicken plane some day but not this day *grin* Enough doodling I could go on for weeks playing around with exotic pod shapes but I'd like to move on. Taking into account everyone's input (thank you) I've settled on this design that's a mixture of E3 & F3... Artistic babble While I like some of my more excentric designs, I think this one with its modern canopy merged with a retro pod works well. It has a few curves to keep things interesting without coming across as over-the-top. Well I'm off to the LHS to pick up some wood. Time to start the build.
Posted on: 9/7/2012 12:37 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11220925
RE: Scratch Designed/Built Sailplane Fuselage
That's an interesting idea soarrich. Here's how that might look... Under-slung pod I'm leaning more towards an under-slung pod design, pretty sure that's where this is sailplane is headed. Its fun, different & I can't see any major reasons why it shouldn't workout. So here's a new set of doodles...
Posted on: 9/6/2012 5:32 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11220081
RE: Scratch Designed/Built Sailplane Fuselage
Great feedback, thank you all. I've pooled the opinions from this & my mirror threads on other forums & as expected, the more modern sailplane profiles (A, B, F) were the most popular. I could certainly go with one of those & end up with a very nice sailplane. However after thinking about it some, I've realized I'm not necessarily looking for the most efficient, most sleek design. I'm now leaning towards doing something a little out of the ordinary. Something that'll stand out in the crowd. The gull wing achieves that goal to a point but I'd like a "quasi-vintage" fuselage to go with it. So here's another batch of doodles... A2 Modern sailplane profile, while sleek, lacks uniqueness. B2, C2 Has a subtle avian feel (looks a little like a bird's head). I think these tie in wonderfully with the gull wing. Flying a giant bird might be fun. D2, E2 An under-slung pod design. Inspired from some vintage sailplane designs I've seen. Again these work with the gull wing & would be a little different. Once again I welcome comments & thoughts.
Posted on: 9/5/2012 2:54 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11218651
RE: Sailplane Wing Design Round II
Thanks for the openfoam link. I'll check that out. And that's a wrap At this point I'm going to call this project a done deal. The wing is, for the most part, complete. I'm really happy with the way it turned out, she totally exceeded my expectations. I couldn't have done it without the help of the community here. You folks rock. So what's next? I've come to the realization that this wing has surpassed the quality level of my original fuselage. It'd be a crime to fly her on that flimsy pod-n-boom. Not to mention it was involved in a pretty harsh crash & who knows what unseen damage it sustained. So the plan is... drum roll please... design & build a new fuselage. I'll be starting a fresh thread to document the fuselage's progress. You can find that here... http://www.rcuniverse.com/forum/fb.asp?m=11217436&key= And to properly wrap up this thread here's a moody, over processed picture of the completed wing...
Posted on: 9/4/2012 5:06 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11217451
RE: Scratch Designed/Built Sailplane Fuselage
A new look While I liked the profile of my old pod-n-boom design, seeing as I'm rebuilding this from scratch I have the opportunity to change the design if I wish. Here's a few "out there" ideas for the new pod. I'd love to hear your thoughts on which if any you like... Let me know which you like & why.
Posted on: 9/4/2012 2:49 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11217438
Scratch Designed/Built Sailplane Fuselage
This is a continuation of a couple of build threads I've been working on... Scratch Designed/Built Sailplane Sailplane Wing Design Round II My original design flew beautifully but suffered from a design flaw in the wing (consequently it folded in half mid-flight). Since that fun learning experience I've redesigned & rebuilt a better wing. In fact the new wing turned out so nice that I'm reluctant to fly her with the original fuselage. So I'm going to redesign/build that also. This thread will document that process. Subscribe if you're interested.
Posted on: 9/4/2012 2:47 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11217436
RE: Ugly Duckling
Here's video of me trying to fly her... Flight Video
Posted on: 9/4/2012 12:12 AM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11216576
RE: Ugly Duckling
[quote]ORIGINAL: A10FLYR ...Hmmm...I did post good luck earlier but don't see it?.. [/quote] Yeah that was over on RC Groups. I'll take all the luck I can get, regardless of where its coming from *grin* thanks.
Posted on: 9/1/2012 8:19 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11214054
RE: Ugly Duckling
Thanks for the link to the SKSS photos. No I hadn't seen those, looks like there's a shot of me in photo #15 taking my own pictures. That was a great aerotow although I only got two flights out of my bird before she got all banged up. For tomorrow's aerotow I'm bringing four planes including this one *grin* Now to get this bag of parts installed... Installed the radio tray deck complete with an assortment of appropriate holes... And the gear is in... F-UGLY is ready to fly... I'm heading to a big aerotow tomorrow. Once again wish me luck.
Posted on: 9/1/2012 5:02 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11213848
RE: Ugly Duckling
Good advice, thanks. Yeah I slapped glass all around the important bits, especially the wing rod. F-UGLY Okies we have epoxy! Today I set about reinforcing the heck out of her. I added two layers of heavy glass cloth to the interior... Then I started work on the new radio tray... That's looking pretty solid... I also glassed some of the scarier looking external cracks... Structurally I'm pretty happy... Here's that worrying crack in the tail... After beefing her up I stood back & admired my work. It was at that point I realized how utterly ugly she was looking & you know what, I kinda like it. So instead of spending hours messing around making her look pretty, I slapped this on the side... That takes care of the cosmetics... Tomorrow I hope to get the electronics installed then Sunday its off to the aerotow.
Posted on: 8/31/2012 9:05 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11213214
RE: Ugly Duckling
Time to start over again I should have done this from the get-go, gut her & start fresh. Here she is before I removed all the gear... Electronics removed... Radio tray removed... First layer of fiber-glass tacked down with 3M contact cement... I noticed I don't have anywhere near enough epoxy for this job so this'll have to wait until I get some more tomorrow.
Posted on: 8/30/2012 8:20 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11212198
Tip-stall prone Cub
I'd been flying this Piper Cub (from Nitroplanes) for eight months now. She entered a spin around 60 feet up, this was the result... She was a nice looking plane, lots of scale detail, fair quality parts. She always felt a little on the heavy side though, flew like she had a moderate wing-loading, not very Cub like IMO. She also had a real nasty tendency to tip stall. I played around with the CG, that didn't help. Looking at the wings, there appeared to be zero washout built into the wingtips. That combined with the weight & a short coupled tail meant she was a real handful if stalled. Probably didn't help that I botched a stall turn (hammer head) at around 60', sent her into a nasty spin. As expected at that altitude there wasn't enough room to recover. Also didn't help that I nailed the throttle in hopes of powering out... CRUNCH... right into the dirt. Oh well. I probably could repair her but I think I'm going to lay her to rest. If she was a nicer flying plane maybe I'd break out the glue but I think I'll salvage the parts & use them in another project. ...and another one bites the dust
Posted on: 8/29/2012 4:12 PM by Author "Nodd"
in the forum "Crash & Rebuild"
http://www.rcuniverse.com/forum/fb.asp?m=11210773
RE: Sailplane Wing Design Round II
Wingtip Ornaments Although I've done a load of research into the science behind winglets, I've come to the conclusion, for a sailplane of this size, winglets are little more than eye candy & I'm fine with that. So today I put away my research notes & got down to building these puppies... I stumbled upon some wood in my workshop that's perfect for the job, a lowly roofing shingle... The shingle, made of pine I think, is both light & fairly strong. Best of all it has a nice ready made taper... The other parts are balsa & light plywood... After carving an airfoil into the shingle winglets I epoxied them to the balsa & then began the sculpting... Checking symmetry between the two wing-tips. This would make one wicked pinewood derby car :-) For ease of transportation & so I have the flexibility to experiment with different wingtips I made these detachable... I don't know about you but they look pretty sweet to me... Pretty happy with these. They look cool yet are small enough that they shouldn't screw with the aerodynamics too much & if they do, I can always take em off...
Posted on: 8/28/2012 7:14 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11209749
RE: Sailplane Wing Design Round II
Yeah as much as I appreciate a good debate & I do find this subject interesting, for the sake of folks reading this thread, I'd like to keep it at least somewhat on topic if we could. Besides this stuff could be deemed a little too technical for this, & I quote, "numb nut brained person".
Posted on: 8/21/2012 3:40 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11201318
RE: Ugly Duckling
Unfortunately the tail servo access hatch doesn't offer much access. There's a hardwood post that runs along the LE of the v-stab that blocks the area with the crack. I think an external fix will be okay, besides I've been meaning to learn how to finish fiber-glass smoothly, so this'll be an opportunity to give that a try. Funny you should suggest relocating the elevator servo. The previous owner had it setup with a flexible push-rod with the servo located in the nose. When I showed this to my club mates they all told me to rip that nonsense out of there & "do it properly" with a servo in the tail. Their reasoning was, because this has a full flying h-stab it was essential that I have a rock solid linkage with zero binding, zero slop & no double neutral. A short metal push-rod hooked up to a high torque digital servo was what they suggested. I hear what you're saying about the weight savings but with a bird this big (she weighs 10lbs (160 Oz), a couple of Oz here & there don't amount to much. I'm pretty sure she'd fly happily with a small child strapped to the wing *grin*. I appreciate the advice. I'll look into maybe dripping some epoxy down inside the access hatch & possibly getting some in the vicinity of the crack.
Posted on: 8/21/2012 3:16 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11201304
RE: Ugly Duckling
Back to Square One Well the good news is she flies, flies quite nicely actually. The bad news is she suffered a hard landing & now looks pretty much the way she did when I got her, all banged up. So I'm back to square one. The Good News Lets start with the good news. Here's a video I took at an aerotow event (the first part features my Discus in action)... View the Maiden Flight Video The Bad News One of the two spoilers failed to deploy during landing. I'd noticed it was glitchy the day before but made the fatal mistake of figuring it'd be okay. So when only one spoiler poped up she started to yaw badly. I retracted the spoiler & came in hot, very hot. Rapidly running out of runway I pushed forward on the stick & planted her down... thud. It did the trick & got her stopped before the tree-line but at a cost... So what to do now? My plan is to strip out everything in the nose & fiber glass the heck out of the interior. Basically do what everyone suggested when I first started this thread. Although I'd done some glass work, most of my previous repairs were purely cosmetic. This time I'm thinking structural. Glassing the inside of the nose shouldn't be a problem. My biggest concern is the crack where the tail-boom ends & the tail begins. I'll have to glass on the outside to fix that, hopefully without making her look even more ugly than she already does. Anyway given the way she flew, I think she's worth repairing. She's a good ship but has some structural issues. Something tells me this'll not be the last round of repairs.
Posted on: 8/21/2012 1:28 PM by Author "Nodd"
in the forum "RC Gliders, Sailplanes and Slope Soaring"
http://www.rcuniverse.com/forum/fb.asp?m=11201184
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