Thursday, January 15, 2009

3D Foam flying

I ordered some new lipo's from Hobby City in Hong Kong. This is my third order from them, and they seem to have pretty good stuff. The chargers, lipos and motors are all much cheaper and seem to be ok quality. I've been wanting to try to get into the 3D foamie flying. SloFly.com is a great site and resource for free plans and doing 3mm EPP foam home built. There are also a lot of people that even do plan cuts for you, routinely. The foam seems very inexpensive, once you get use to how to build and work with the carbon fiber rods and all the best components. I gather it takes a little experience to get it all just right and the weight down to a reasonable level (sub-7oz planes are routine fully flight capable with battery and everything).



These planes are also mostly indoor fliers, and use the 5g or 9g servos and 300-500mA 2S lipos. There are some great examples of very good indoor 3D flight all over. These planes are light. Super light. They go so far as to measure out the CA glue they use to make the bonds and don't run with the servo screws in the arms to shave weight. Drill out the servo bodies to cut weight, strip the insulation off the wires from the battery/ESC and put thin tape on it. Anyway, I'm not going to get quite that extreme (yet!), but I think I can get a good ~8oz plane with a 400mAh 2S battery, and even probably have a good 9oz 3S 700mAh outdoor flier.

I was going to order one of the pre-cut slofly models, for $30, shipped, but you still have to put CF tubes and motor and hinges and stuff on it. Found the Turnigy Piaget on Hobby City and figured I'd start there. Can always build another one from scratch once I figure it out a little more. It has motor and all the hinges and CF rods already for $39. Have to add some 5g or 9g servos (so ordered some of the cheap HXT's). Put in a 9g 10A Turnigy BESC. Add a cheap light weight GWS 4ch SC Rx, and a couple 300-500mAh lipos at around 40-50g. I also got a HexTronic 24g 1300Kv outrunner to replace the one on the plane if it doesn't work too well. I am really excited to get this order in and start playing with it all.

Youtube Video

Update: finished photos





11 comments:

  1. Got my shipment, and I'm also really thinking about building my own EPPYak55 from 9mm foam, but I'll see how this goes. The 2S lipos and even the 610mA 3S ones are super small. Got all the new micro deans connectors soldered on last night. The motor that came with the piaget is super small and light. Still no idea what it is, though it is billed as an 1100kv motor. Everyone says the GWS 0950 prop is WAAAAY to much for this motor, and an 0837 is better, so I'll try something like that. I have the replacement 24g blue wonder to put on if I have to...but it is a lot heavier and bigger. We'll see. Bought enough HTX 9g and 5g servos to try both. Will probably go with the 5g's for all of this to begin with (since the aileron is dual servo on this).

    The packing was VERY good on the piaget (almost TOO much tape and stuff, but it is all good). The instructions aren't the best, but I think it should be pretty straight forward with some hints and build hints from other plane threads. I really should have ordered the Corona 4ch synthesized 72MHz Rx rather than the GWS, cause now I am still scrambling trying to find a SC ch 30 xtal. Sigh. Need to try to see if I can get it all built this weekend.

    ReplyDelete
  2. Got the Piaget all built today. Took about 6 hours all total, and that seems like a pretty good time, given how slow I went and how much I probably overkilled on glue and fretting about stuff. I feel a lot better about how I would build the EPPYak55 now (if I ever do).

    Got the last little gluing done, and put all the radios on and got the lipo figured out on positioning and stuff, and sort of all of the sudden, I figured I was done...and it was still light outside. Then I realized I hadn't been charging my new little lipos!! Doh! But they were at 50%, so I took a couple across the street to the little 200'x100' park area and gave it a little toss. OMFG! This plane flipping rocks! Straight as an arrow, and I never knew you could do knife edges like that (at least I never could). Hovers like even I know what I'm doing. Water falls (I just learned what that even was last week while doing some 3D training in Realflight..grin), loops, I simply love this plane. It was just a touch breezy (~5 mph winds), so it really floated coming into the wind back to me. It calmed down and was getting really dark on my 3rd 460mAh 2S lipo (they were only charged to about 4.0v, so only about 5 minutes on each). I noticed that even on a semi-fresh one, it wasn't pulling any more. Swapped in a 3S and still wouldn't. Hum...hope I didn't fry my ESC. Turned out I had a loose prop shaft and I had to replace the POS 1.5mm allen screw, because it was all dinged and deformed (luckily one from my blue wonder base mount fit). Took it back out and tried some 3S lipos. Wow, those make this thing really rocket. Almost lost it a couple times in the dark, so I brought it in and stopped.

    I'm not real happy with the throws I'm getting on the Ailerons, so I may have to see if I can find a longer control horn. I also have sort of a nasty differential on the up/down portion of the aileron, and I think it is binding or something. Have to play with that a little. I didn't have the spoilers on the trailing edge of the ailerons, so I'll try those tomorrow if it is calm out.

    I'm going to LOVE this plane, I can tell. Seems pretty durable and tough, even after a soft nose in (no power). The 8x3.8 EP prop seems pretty good, but I'll have to check amperage when I get my new "whatsup" meter next week. I'm also pretty sure I'm going to have to put the blue wonder motor on it rather than this smaller one. I think it will really help it.

    ReplyDelete
  3. I LOVE THIS PLANE! Grin. Except I really built it too heavy at 230g AUW (sans battery), and 2S lipos are not quite enough umph for it. More importantly, 400mAh is only good for about 3 minutes on 2S (at least out doors). I really think 600-800mAh 3S are ideal for this plane/weight. I'll have to check currents with different prop setups and maybe consider swapping over to the 24g Blue Wonder. For not much more weight, I think it will be a better motor turning a GWS 0950.

    I spun my prop saver and prop off and lost it this morning, but the plane was fine. Had a blast doing some bathtub stall turns, just back and forth. This thing does some very tight 90's and really responds (had a little problem with tip stalling into some hovers with the 2S, just not spinning enough to pull out and get air moving across surfaces).

    ReplyDelete
  4. Flew the plane a couple days ago at lunch out at the local soccer field, and went through 2x 3S-610mAh, 2x 2S-470mAh, 1x 2S-800mAh, 1x 2S-700mAh lipos. There was a little wind (5mph gusts), but the plane handled beautifully. I got to the point where I could hover the plane and tail scrape the plane on the ground (scary...cause it gets really dicy right after that...grin). Need more work on flying inverted, but I spent about 30 minutes of good flight time playing with just coming in close to myself and doing some harriers and hovers and some stall turns, as well as got a lot more respect for how well this plane does a nice about face rudder turn into the wind or whatever without much roll factor. Knife edges forever on this plane are easy. Probably could play with the CG a little more, and all these different lipos really change things up, since the batter is forward of the CG to help bring it forward...so that is variable.

    ReplyDelete
  5. Flew the piaget again today. Wasn't quite as good as the other day, but I think part of that was because I nosed in just a little on the first flight, and popped one of the carbon fiber support rod connections to the bottom of the wing. It was really wanting to roll bad in a tight loop. Plus there was about a 7mph wind, but overall, it was fun. Kept losing the aileron spoilers, so I just took them off (I haven't CA'd them so I could decide if I liked them or not). Ultimately, the plane is a lot more unstable in low flight hovers (tip waggle/stall) without them, and I'm just going to permanantly CA them on.

    I have been surprised how well the stock motor has held up. I had planned to replace it with the 24g blue wonder and get a bit more thrust, which would probably help this plane at 7.9oz AUW (sans batteries), since I got a little glue happy on this first time build. But so far, the motor is lasting really well. And it works pretty well, with plenty of punch with the 8x3.8 prop and a 3S lipo. 2S is a little sluggish, especially after about 50% capacity (and I only get like 50sec/100mAh on a 2S). I think the 3S 610mAh Rhino's are just about a perfect balance on power, time and they put the CG pretty well where I like it.

    I plan to buy another kit next time I order from Hobby City. I just think I can build it so much lighter the second time. Either that, or I need to just buy some 1.3# 9mm EPP foam and cut my own EPPYak54. But, I'm a little worried about doing that, given how much I didn't like the Piaget without the spoilers. If I did do the EPPYak54, I'd have to fashion some of those and some of the SFG's too, since it really seems to make a difference on the knife edges and how the plane flies.

    I really think I should try to build a lighter version, though, I'm not sure why. This one flies so stinking well, and since I mostly fly out doors, it probably doesn't hurt. I need some more 3S 600-800mAh lipo's though...grin.

    ReplyDelete
  6. Hi Jeff :)
    thanks for your review, i'm currently look for this plane, but as there are a lot of different opinions with motor/lipo/servo...

    So, can you tell me your "best" setup for nice indoor stuff ?

    I'll continu looking at your new post :)

    ReplyDelete
  7. The one that comes with the plane from Hobby City (1100kv outrunner of some sort, though I sure haven't been able to identify it) is great pushing a 0837 prop and 10A ESC is plenty. Seriously, I had planned to swap it out to the 24g HXT blue wonder, but so far, this little motor has just been great. Plenty of power on 3S lipo's (use 610mAh 3S for outdoors...and maybe you can get by with some finesse and some 400mAh 2S indoors).

    ReplyDelete
  8. Just to comment on the motor size above. The Hobby City site says it is 1100kv. But several folks have confirmed it is more like a 2050kv or so motor, and the current draw and tach also confirms this. I'm also getting about 10A peak on 2S with 8x3.8 prop and 15A peak on 3S. Flight times for typical outdoor 3D (about 2/3rds to 3/4ths average throttle) is about 50-55sec/100mAh on a 3S and about 35-40sec/100mAh on 2S.

    It is worth mentioning that you really need a pretty long aileron arm for this to work really well. The angle on the control horns doesn't quite intercept in toward the plane enough, and I bent the wire control just as it exits the carbon fiber part of the rod so it would line up better, but that makes it want to flex out rather than push straight (knew that wasn't going to work real well). So, I just went back with solid metal push rods on this last itteration. The throws are still skewed due to how the angle intercepts a straight servo arm (a LOT more down aileron than up in the final extreme throws), but it is much more solid. It ultimately would be better to have an aileron arm that was about a 120' V, rather than a simple 180' straight arm. Seems like that would be a common issue on these 3D foamies with a single aileron servo? Maybe there is something that this is GOOD for (like providing more up lift than down force)? Seems bad to me for such a symetric plane. You could reduce the effect a lot moving the aileron forward more to reduce the angle of incidence too, I suppose. Please, someone comment on this?

    If you are using the HXT 900 for an aileron servo, then you will want to get a Dubro 932 control arm kit, which should fit. Also, if you are risking using HXT 500 servo for aileron, you want Dubro 930, or you can probably use the really long control arm from a Hitec HS-55 kit (I'm pretty sure that fits).

    I just ordered another one of these planes from Hobby City. Not sure why, but I just love it too much, and I really want to do another build just to work on the weight and not put nearly as much glue on.

    The frame tends to want to flex/crack/split the horizontal part of the fuse right behind the wing with any hit (tail wips around). I think I'll plan to put a short length of CF strip into both sides for about a 10-12" run similar to what is in the main wing. Another thing, don't bother putting the foam wheel pants on.

    ReplyDelete
  9. did you build it w/o the air brakes on the aerloins?

    ReplyDelete
  10. No, I put the airbrakes/spoilers on the ailerons. They were just slip on at first to test it out, and they weren't on in the pictures above, but I have since put them on (glued) permanantly.

    ReplyDelete
  11. Hi Jeff, found your build log and pics very helpful. Looks like the Piaget is a winner. I have a friend who also built it and has the same problem with aeleron dihedral as you have. The solution to overcome this is pretty simple: cut your own aeleron servo arm extension from a 1 mm (or 0.8mm) plywood, cut holes and tie it to the plastic arm (which you can cut/file if needed) with some threds and then add 2 drops of glue. The angle between your new arms must be such that the lines you trace from the center screw through each arm's hole are perpendicular with aeleron pushords in neutral position. Given aeleron horns that have holes above the hindge line as they should, you will get symmetrically-deflecting aelerons. Hope this helps.

    -Dmitry

    ReplyDelete

Note: Only a member of this blog may post a comment.