My first balsa build in 30 years
- Thread starter kkelly
- Start date
speedbirdted
Legendary member
I've suffered crashes caused by this exact thing in the past, so I wouldn't risk it. Often a range test won't show anything is amiss, until you're flying along and suddenly you have no control, and a few seconds later no plane either. If you can get a new antenna identical to the one on it right now, you can disassemble the receiver and solder the new antenna in the place of the broken one, and this will fix it.
kkelly
Member
In that case I'm not going to chance it on a plane I've put so much work into. I can't find any replacement antennas of that type for sale, so I emailed Spektrum about repair options. That receiver is probably overkill for this plane anyway. It just happened to be what I had available. While I'm getting it repaired I may order a smaller one.
kkelly
Member
The model is built!
All I have left to do is set the control throws and install a receiver (currently down a rabbit hole about whether antennaless receivers are safe). The windscreen ended up a little far back and makes removing the hatch slightly wonky, so I may move it forward later.
According to the plans 17 ounces is the average flying weight. With the bigger 3S battery I'm at about 21.5oz. With an 8x4.7 prop it maxes out at 95W, going up to 102W on 9x4.7. That puts it at the top end of the park flyer category. That seems reasonable for how and where I fly.
All I have left to do is set the control throws and install a receiver (currently down a rabbit hole about whether antennaless receivers are safe). The windscreen ended up a little far back and makes removing the hatch slightly wonky, so I may move it forward later.
According to the plans 17 ounces is the average flying weight. With the bigger 3S battery I'm at about 21.5oz. With an 8x4.7 prop it maxes out at 95W, going up to 102W on 9x4.7. That puts it at the top end of the park flyer category. That seems reasonable for how and where I fly.
TooJung2Die
Master member
The antenna wire is coaxial cable, the same as TV cable but much, much smaller in diameter. The antenna part of the cable is the piece that broke off. It is the center core of the cable with insulation. It looks like there is just enough broken cable left to make a new antenna tip on the cable. Carefully strip off the outside insulation and the braided shielding just underneath to leave a length of the core exactly as long as the piece that broke off. Be very careful not to cut into the center core wire or the clear insulation around the core. You made a new antenna. Much closer to the receiver but just as functional. Try it, you have nothing to loose and a functioning receiver to gain.
kkelly
Member
Indeed there is enough to do this while still leaving a few millimeters to spare. It's been about 30 years since I stripped a coaxial cable, and I've never done one anywhere near this thin, but I may give it a try depending on the options I get from Spektrum regarding a repair or them sending me a new antenna. I'm confident in my ability to solder on a replacement, but less so in my ability to strip a wire this fine without damaging it.
Piotrsko
Master member
Just think of: you're just cutting the outer insulation. Once you get to the strands or aluminized film ground, you can finesse it with your fingers then waste a knife blade cutting them off. Not sure if these are matched or not but it's better than what you have now and wee longer is better than shorter
FlyingTyger
Elite member
It turned out great! Nice work. It will fly very nicely at 21.5 ounces.
TooJung2Die
Master member
That is a very sharp looking airplane. If it flies as good as it looks it'll be awesome. 😎👍
kkelly
Member
Thank you. I'm quite happy with how it turned out. It's not perfect, not by far, but it looks better and is better-built than any of my previous balsa planes. I just need to sort out a receiver and she'll be good to fly.
I appreciate all the guidance everyone gave in this thread. I certainly avoided some big mistakes as a result.
kkelly
Member
Spektrum wants me to send the receiver in for repair. By the time I pay for shipping each way, the new antenna, and the labor it would be around $50 to fix an $80 receiver. I'm going to try to fix the antenna myself. Before I trust my shiny new plane to it I'll put it in a beat-up foamie and fly it to within an inch of its life to be sure it's reliable.
$80 for a receiver?! Thank god I don’t fly spektrum
kkelly
Member
Well that was easy:
I expected a long arduous process as I delicately cut through the outer layers one molecule at a time, but it took about 10 minutes including the time to precisely measure the location of the cut. I don't see any signs that I damaged the insulation around the core of the wire, so I think I'm good to go.
I expected a long arduous process as I delicately cut through the outer layers one molecule at a time, but it took about 10 minutes including the time to precisely measure the location of the cut. I don't see any signs that I damaged the insulation around the core of the wire, so I think I'm good to go.
TooJung2Die
Master member
See?! That'll work as good as new. 😎👍 Easier than soldering on another antenna, you'd have to strip the soldered end to separate the core and shield anyway. The antenna has two soldered pads on the receiver; one for the antenna core and the other for the shield.
speedbirdted
Legendary member
I fly Spektrum, but the only genuine Spektrum products I own are the transmitters and a handful of recievers, mostly out of E-flite BnF planes that I beat to hell and salvaged the electronics from. Most of my fleet is either equipped with Lemon or the counterfeit Spektrum gear sold on Ebay. I have a few of the Redcon brand sold on banggood and they seem to work just fine, most of the time. I say that because I bought a couple of CM421s a while ago and one of them I never got to bind properly. All the others I've gotten have worked fine. The receiver in my pylon plane is Redcon and that plane has had hundreds of flights with no glitches.
The counterfiet Spektrum receivers have also worked fine for me. I've actually heard it said by some that the fake Spektrum equipment is actually totally genuine, equipment wise, because the manufacturer in China that they contract out to sells some out the back door to other companies to sell themselves with their own branding. Indeed, a while ago I disassembled a genuine Spektrum AR6210 and a clone of it I bought from Ebay, also confusingly marketed as an AR6210 (though it's worth mentioning even though the case of the clone did say Spektrum on it, it never said Spektrum anywhere in the ebay listing) and the components used and quality of manufacture looked extremely similar. I know these things get changed around a bit between production runs, so even two genuine receivers may look a little different internally, but this is close enough that something has got to be up...
The main point is there are ways to get quality receivers that don't break the bank. The fake AR6210s are selling for $17 at the moment. Lemons are a little more, $30 I think for the 7ch one, but they come loaded with so many goodies it's very worth it.
Good job. Just make sure it passes the range test.
The counterfiet Spektrum receivers have also worked fine for me. I've actually heard it said by some that the fake Spektrum equipment is actually totally genuine, equipment wise, because the manufacturer in China that they contract out to sells some out the back door to other companies to sell themselves with their own branding. Indeed, a while ago I disassembled a genuine Spektrum AR6210 and a clone of it I bought from Ebay, also confusingly marketed as an AR6210 (though it's worth mentioning even though the case of the clone did say Spektrum on it, it never said Spektrum anywhere in the ebay listing) and the components used and quality of manufacture looked extremely similar. I know these things get changed around a bit between production runs, so even two genuine receivers may look a little different internally, but this is close enough that something has got to be up...
The main point is there are ways to get quality receivers that don't break the bank. The fake AR6210s are selling for $17 at the moment. Lemons are a little more, $30 I think for the 7ch one, but they come loaded with so many goodies it's very worth it.
Good job. Just make sure it passes the range test.
kkelly
Member
I'll be putting it through a plethora of tests before I trust it with anything of value.
I only have this receiver because it was bundled with the DX8. I've never used more than 5 channels on it. I haven't even hooked up the telemetry sensor for the battery voltage on the last few models it's been in (which would have saved a battery from over-discharge after I got it confused with a full one). I've looked at some of the non-Spektrum stuff but haven't tried it out so far. I've heard good things and bad things about Lemon receivers. Orange also seems to be popular. I'm planning another build for the near future. I'll look again at other receiver brands for that one.
kkelly
Member
Such is the life of a perfectionist who remembers every mistake he ever made.
Yeah, I'm still figuring that one out. The plane is on the tail-heavy side. I'm trying to keep the receiver as far forward as possible to help counter that, but then I have to worry about an antenna being right next to wires from the battery or ESC.
TooJung2Die
Master member
It doesn't matter where the antenna tips are located distance-wise from each other as long as they are optimally at a 90 degree angle to each other on a geometric plane. You are only concerned with the tip section of the antenna cable.
You can leave the short antenna tip pointing towards the tail. Attach the tip of the long antenna at a right angle to the fuselage closer to the tail (along a fuselage former would work).
Or, angle the short antenna 45 degrees to the right and angle the tip of the long antenna 45 degrees to the left. (or, 45 down and 45 up). 2.4 GHz receivers rarely have interference issues, especially with diversity antennas. The old FM radios were notorious.
Piotrsko
Master member
Similar threads
