Need advice about RC options for ultralight paper airframe project

Discussion in 'RC Aircraft & Watercraft' started by liftline, Sep 29, 2010.

  1. liftline

    liftline Member

    Thanks for that vital safety tip. Thought 2Amp sounded really high - I know lipos don't like to trickle charge but the default setting is a fire hose!

    Found the receiver screws you mentioned (easy to miss, even easier to lose), found a tiny Phillips screw driver. Just the top to the case weighs a gram! Removing the entire case looks to cut weight by roughly 4 g. That's about 10% of expected take-off weight. Definitely worth doing!

    I haven't taken the board out of the bottom half of the case...would you recommend cutting through the small hole in the case to remove the antenna wire. Or maybe just cut through the wire and reattach later? What about the shrink tubing on the end of the antenna? Can it be removed too? Something else is in the shrink wrap- perhaps it's just something to keep the antenna wire straight? Might that be removed to save a bit more weight? I don't think the receiver has a satellite antenna.

    Once the antenna wire is free it appears the board just pries out. Or is it possibly trickier than it appears?

    I sent an Email to Hobby Partz tech support about whether the receiver will work reliably at 5V. No reply yet. Also checking about on the RC boards. The Turnigy boosted board seems like a potentially simple and light weight solution.
  2. schorhr

    schorhr Member

    As I said somewhere way back in this discussion, Lipo usualy charge with 1C.
    So a 100mAh pack charges with 100mA, a 2000mAh with 2A.
    Newer, better cells may handle 2 or even 5C, and some small ones will do too- but their lifespan is longer if you charge them slower.

    Yep, the casing is defenatly something not neccesary as long as you dont use it as landing break ;-)
    Before cutting the antenna I'dd just break the case- but that's only my oppinion.
    The second one has the shrink tubing arround the antenna top too.
    I took it off to look what's inside...Does not look like the "copper can"(?) it can be removed. I think its something to fine adjust the antena before boxing the product?

    Use a sharp exacto knife/cutter, saw, nail clip or anything really and just make a gap into the casing so you can take out the antenna. This way you can take it out, and put it in again without breaking the case to the point it is unusable.
    Better then resoldering the antenna and risking crappy reception....

    Go to RCGroups or Hobbyking and post there, most likely someone at rcg has the hobbypartz rx and can tell you...

  3. liftline

    liftline Member

    Good idea, placing messages in various hobby blogs.
  4. liftline

    liftline Member

    Checking around the RC boards was interesting. In general, the 2.4 GHz receivers are reported to work well on 1S power .... that is they work reliably at 3.7 V. In fact, reviewers report they work well at even lower voltages! :killer:

    So, my next step is to order a non-defective, non boosted ESC and do some experimentation in "the lab." Reports on the HK 1.7 g micro servos are generally good, but it's been suggested that you buy more than you need and select the best. So I'll throw in a few more when I order the ESC. Another 5-10 d delay :curse: But now I know the tracking system.

    Reviews on the little 2g motor suggest it runs pretty hot. So, I guess I'll make those louvers on the front of the model functional! The tiny motor just rattles around in the nose of the model, so there is a lot of air to circulate nearby. In flight engine fires may be historically appropriate, but would alarm the neighbors. Reviews also suggest to expect thrust a "bit" less than the advertised 30 g. More like 20. So, weight reduction is taking on urgency. Who knows, at some point I may take a hole punch to some of the paper - cool way to make Zeppelin girders
  5. schorhr

    schorhr Member

    Well you could make a sailplane for now perhaps, untill the esc arrives?

    motor & temp: Don't worry. If you do not run full speed all the time (rather unlikely) it will be fine. Heck, even the brushless on my cb100 gets hot as hell, but those brushless motors are more rigid then the ones with brushes.

    Making a functional cooling seems to be even more scale, hehe.

    "Do not worry dear neighbots, it is a scale model, the fire is just authentic"...

    I forgott most my stuff at home so I can't finish my quadrocopter wall1
    But I am now going to order a 3d printer, so even people like me can do scale models :p :mrgreen:
  6. liftline

    liftline Member

    The forum has been very helpful on my issue. RCers are a very friendly bunch in general and put up with my general ignorance and resulting dumb questions with good humor. :inw:

    Back when I had my first Mac (with laser B&W printer) I actually built a paper sailplane. Not very successful - but an early effort! I'll put it on my to do list - could probably knock off a basic design in a day or two.

    If the receiver works on the bench, at low voltage and a decent range I'll start to work on installing servos and push rods. That ought to take up a few days. At least I've found charger connectors for the mini 1S. Incremental progress.

    Wow, a home 3D printer. :thumb: ow much do those set you back? A local high school got one, or maybe just access to one, and it was in the newspaper! Local engineering students get to print only 1 object per semester. Can your 3D do thin sections? You'll certainly be able to make molds for your own casting projects.
  7. schorhr

    schorhr Member

    Yeah, rcgroups is a nice place.

    Good luck with your builds, keep me posted ;-)

    3D printers... The basic makerbot cupcake or reprap kits start at +/- $600 bucks unless you source the parts cheaply somewhere else... The pp3dp cost's a whooping $3,000 but there's a promotion going on so it's only $1,500/$1,680 for the plus version... Nothing I can easily afford, but I got lucky with a few extra dollars recently ;-)
    $1,500 still sounds much better then the usual "entry level" machines at 15,000 :eek:

    As for precision, the pp3dp seems pretty good compared to the basic versions of the cheaper kits. Even though the thing is not open source, the printed supports break off easily, are generated automaticly and the warping seems to be worked on.

    Fast-forward this to get an impression
    and one of the user made videos

    Thin enough for me :)
  8. liftline

    liftline Member

    Impressive little 3-D printer

    Screw cap sez it all! Pretty close to a Star Trek replicator. Sirius Cybernetics! I wager we'll see entry level 3-D printers in the Big Box Electronic stores within a few years. There is no smilie for envy exactly, but :mrgreen:. I'm still looking for an affordable high res color laser printer.

    Taking off the plastic case to my receiver saved an honest 3g! :thumb: Left the shrink tube on my antenna for now, just to keep things durable while I bench test.

    What type of female 3 hole plug fits over those seven sets of 3 pins on the receiver? Is it perhaps called a JTS connector? I've been looking at the online catalogs and can't really tell. If I get a chance I'll stop by my local hobby shop and see if they can help - seems like the pins are pretty conventional. I would like to refit the micro plugs on my servo with some kind of quick disconnect - at least during the bench test phase.

    I'll keep you posted on the build. If you ever want to try a paper quad copter framework, just send some specs!
  9. schorhr

    schorhr Member


    HP also wants to enter the 3D market. While they aim for small businesses now, this might get the whole thing going, resulting in price drops and small home devices from other manufactors.

    Look at the cupcake makerbot 3d printer kit... $649 for all parts... I know laser printers that cost more ;-)
    Botmill sells kits from $500 as well (though the huxley kit is not complete out of the box and "beta")...
    While these kits require assembly, the botmill pre-assembled kits ($1545), the bfb3000 and the pp3dp show it can be done, quality is getting better and better too.

    The only advantage I see for lasers is the UV resistant printing, resolution, cost and printing cost is - at least with devices not sold for $40 - very good, some aspects even better.

    Rx Plugs

    "female header" :)
    Before buying some locally (at least here) I could buy a inexpensive servo and cut the cable/plug off of it.

    A paper quad, now that would be fun ^_^ I think the problem would be torsion, but as "canopy"... a "iron vulture" body would be nice :D
  10. liftline

    liftline Member

    Would that be the Disney Iron Vulture?

    I'm getting some basic flight systems up and running now. The transmitter driver and software are properly installed on my PC and I've verified stick, rudder, throttle and assorted knobs & switches are all working properly. Not the easiest set of instructions to follow and there are a few terms I still can't deciper: for example what in the world is "yarage"? There is also an angel, maybe they mean patron saint, of better control. The printed instructions don't match the video, not all the recommended instructional links work, neither did the first set of drivers. Situation normal in the world of hobby engineering I guess.:cry:

    I found a nice $20 charger at the local battery that can charge 8 AA transmitter batteries at time. That should do.

    The connectors on servo extension wires are just what I needed to attach my micro stuff to the conventional receiver pins. Simply clip off the female connectors and solder 'em on to the leads of my micro servos. Problem solved!

    Hooked up my Hobby King $17 battery charger and tried it out with my salvaged 12V power supply. Had to buy some Park Zone nano-battery connectors (local hobby store again) but everything worked perfectly. The charger recognized the number of cells, gave me real time voltage data, beeped and stopped at 4.2 volts. I verified the battery charge was spot on with my volt meter. I'm under amping the batteries just a bit (0.1A) but apparently nothing compared to what the fly-out-of-the-box chargers do (0.03 A or so according to the hobby shop guys. Charging took about 17 min & the battery stayed nice & cool. My cats enjoyed the blinking blue lights.

    So the next step is to bench test the receiver and see if it can drive those servos of mine at 1S voltage levels....and at what range. If all goes well, and I'm cautiously optimistic, I'll start figuring out how to mount the servos in the fuselage. What can possibly go wrong?

    Not a bad evening's work :wave:

  11. schorhr

    schorhr Member

    Yep, that one :)

    "yarage" - never heard of it. Translator failing me as well.
    According to google it's ship related;
    Yarage [See Yare] (Naut.)
       The power of moving, or being managed, at sea; 
    said with refer. to a ship
    Which links do you need?

    Charger - or charge the AA with the lipo charger as it should have a nimh and nicd programm as well.

    Wires- just make sure the connection is the right way arround and that the boosing esc does not fry the servos if you ever get that, even if you just hook up data :)
    I think the servos are made for 1S?

    The slower you charge the betterm but 1C works fine.
    They ship almost full and will cycle in over the first few charges, developing more power.

    ->What can possibly go wrong?

    ->Not a bad evening's work :wave:

    Hehe, that's the spirit. Sound's like you're doing great and will be flying in no time ;-)
  12. liftline

    liftline Member

    Re yarage, I owe the tech writers at FlySky an apology. It's a perfectly cromulent :wink: word in the context. The internet certainly embiggens :rolleyes: one's vocabulary!

    There is supposed to be an improved manual, but every time I try and load it just seems to stall. It would be nice to know what the various profile settings do, things like that.

    Could do so, but I'd have to build myself a battery box and that would take time and probably be pretty funky. Besides, my $17 charger is going to be very busy charging Lipos :twisted:

    I think this is the deity in charge of servos.

  13. schorhr

    schorhr Member


    Got the link? I'll try to see if I can find the file.

    hehe, I like the idea of rc hobby gods. Though my planes usualy seem to have been jinxed by the underworld.

    Charger: Well, okey then :) Either will work :thumb:
  14. liftline

    liftline Member

    It's the expanded manual by Shaw et al. As luck would have it, I got the link to work today - looks like the server was a bit overworked with all those new T6 users. Copied it for future ref. Turns out it's mostly oriented towards copters. I'll probably tackle copters shortly after I master space flight. Space flight looks easier!

    Projected all up model weight is now around 38 g...not counting minor things like plugs and rods which will add "just a bit" more. I can probably lighten my wheels.
  15. schorhr

    schorhr Member

    As I said for planes the basic 4ch setup is fine, the mixers and all that are more usefull for helicopter pilots - and some easy to fly models arround these days :)

    Good luck with your plane's diet :D
  16. liftline

    liftline Member


    7:50 EDT Bench Test

    It's alive! It's alive! Feeding happily on just 1S! Initial voltage 4.16, it dropped a little overnight.

    All 6 channels are working, albeit verified by moving just one test servo from channel to channel. No smoke, no drama. Servo doesn't jitter, moves pretty fast. Can't verify range just yet - it's pitch dark and pouring down rain. The hook up is not beautiful...shrink tube over the solder joints. Could unquestionably be lightened if I found the right connectors and used thinner wires-but hey, things are moving on a good trajectory!

    aussie A beer has been opened.

    I'll verify range tomorrow. I'll also see how well things go as voltage dips towards 3.7, but I'm pretty the system will work well enough to proceed to the next phase: putting components into the AC.

    I'm going to place an order for a new (and lighter) ESC. Plus an additional 3 servos (they are so inexpensive), might as well take the pick of the litter and have some spares. I'm a bit concerned the radius of the prop may be a bit small given the width of the model - a full inch at the nose.

    Many thanks. Couldn't have come this far without you Schorhr :inw: !!!!!!!!! Still much left to work out, but this is a conceptual milestone. You are right - this model will ultimately fly!
  17. schorhr

    schorhr Member

    Great, congratulations! :)
    Seems like it's all ready for the next phase :D

    Range won't be critical for most flight systems, especialy indoor or slow flyers.
    I'm certain it'll be just fine!

    If all works on 1s, I'dd say go with one of these <1g ESC without voltage booster... Saves the worries about frying the servos.
    Sure, spares are nice, and the prices are incredibly low (even if there's some quality issues once in a while and manuals are not shipped, but the advantage of the bigger stores compared to chineese ebay sellers is the online community and the documentation online).

    No problem, hope it all works out well :D
  18. liftline

    liftline Member

    The TX/RX responds out to at least a few hundred meters. Time to place an order for a new ESC - looks like a perfect application for the HobbyKing 0.7 g gets good reviews and should be able to handle the current load with no problem.

    The weight of the electrics (less plugs) is estimated at 17.8. That leaves just under 5g for "weight creep" to stay below 40 g take-of-weight.

    I'm seriously thinking of just gluing the servos to mounting boards of paper backed foam in order to save weight. Will order extra servos in case that doesn't work out!
  19. schorhr

    schorhr Member

    Well that range sounds just fine- the silverlit/airhogs toy planes get 100m-150m ratings, and thats enough for park flying...

    Gluegun? There'S nothing you can't do with one. :cool:
  20. liftline

    liftline Member

    Rats! Orders in, but the ultralite ESC are both on back order & can't find an alternative vendor...guess I'll have plenty of time to optimize servo placement. There is nothing you can't do with a glue gun, but plenty of things you shouldn't :twisted:.

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