Close Call

[sean]

We had a quiet day at Bald Knob and Brandenburg yesterday. A few of us got to Brandenburg about 1pm and it was literally dead-calm. We all drove up to Bald Knob to try our luck but not much better. I got out my bungee and used it to launch the Erwin- lots of fun! It was getting some really good height from a catapult style launch.

But.. the Erwin used up yet another of it's 9 lives. Following a bungee launch I had it up nice and high hunting for thermals, flying a long way out to the North of Bald Knob, must have been getting close to Brandenburg. Then it rolled sharply, and stopped responding to control inputs. I held the tx high above my head and it came back online after which I flew it straight back toward Bald knob, then it rolled sharply again and locked out a second time. Fortunately it came back under control and I flew it back as quick as i could for a hurried landing with no further control problems. It felt an awful lot like interference and i was very spooked after losing the Pike to loss of radio a few weeks back.

We then drove down to Brandenburg and the wind had picked up, there were a number of people flying there including a fellow I hadn't met. He wasn't sure what frequency he was on because the sticker had come off the crystal. We quickly figured out he was using the same frequency as me!! Scary... I'd often thought this could happen, seems like a one in a million that it actually did though! The Erwin has a PCM receiver, meaning if it gets a signal it doesn't like it simply holds the controls steady rather than glitch or move. This meant I couldn't tell that someone else was on my frequency by switching it on with my TX off.

I guess the moral of the story is be very carful flying at a site that is close to another flying site. In future I'll be much more careful flying at Bald knob in a north-easter. It's getting more and more tempting to try 2.4 in the Erwin...

Sean.

[airtime]

Not a good feeling that. When you have got no control of ur plane. I've just bought a glass v tail passer-x with a balsa ribbed wing. It flew great for about a week. Until on Sunday, the first flight it was sloping with no problem, wind was lite though "she's a good thermaler"brought her back in for rest. Eric turned up with the scorpion"love that plane" he launched, nige launched his. So I switched mine on ...no problem ... gave it throw went straight then it started going haywire I had no control. She flew straight into the ground. CRACK is what we heard.
When I went to retrieve the plane it was still glitching away. Surprisingly
the wing was intact and the fuse only had a few cracks, all fixable. I'll have her back inthe air in a week.

O yes I'm gonna throw in a decent receiver this time. multiplex rx-7-synth ds ipd
If it works good I might put one in my Erwin that's on the way

[thevon]

Man that's scary. But having said that it's a perfectly expectable situation - it has to happen sometimes - we're all operating on good luck most of the time unless you're on 2.4. Freaky.

[airtime]

But I've heard that some blokes have had trouble with 2.4 in fully carbon models. I'm thinking of going that way but how do you install
the receiver so the antenna's will transmit through the carbon.

[sean]

Yeah 2.4 would be nice but installing it in an all-carbon plane is tricky. You have to extend the short antennas by a precise amount and have them sticking outside the airframe at right angles so that there's at least one visible from any angle. This could potentially create quite a bit of drag at high speed.

I'm going to try to buy "2.4 friendly" carbon planes whenever I can in the future. They usually have a glass or kevlar nose that doesn't block the 2.4 signal, no need to extend the antennas.

Aside from this incident the JR RS77S PCM receiver in the Erwin has been absolutely rock soild, very impressed. No glitches at all at Bald Knob (touch wood). I've had good luck with the JR PPM RS70 in my Bird but it does glitch occassionally at Bald Knob, but not enough to be a concern.

[skyboyken]

Sean,

what you're saying about 2.4 installs is out of date.

Please have a look on rcgroups. Basically the guys in the US have done all the hard work and it is now a straightforward proposition for anyone who can use a soldering iron.

You can easily add any length to the antennas with the right grade of coax, so as to get them out of the fuse. You can turn a pair of whiskers into 1 longer antenna and have it stick out the back of the fuse - it's only 62mm long.

All this is tested and working reliably in carbon planes.

Of course it's a good idea to buy 2.4-friendly fuses whenever possible, but don't be limited in your options if that isn't available. 2.4 can be installed reliably in any plane.

Ken.

[sean]

Hey Ken,

Sounds good, do you have any links? I've honestly searched RCGroups top to bottom and haven't found anything except tales of woe. I'd be happy to ditch 36MHz in favour of 2.4 in my Erwin.

Sean.

[thevon]

Ken I'm interested too. Sounds good. How is your new 2.4 module for the Coc*kpit going?

[skyboyken]

Sean,

I looked at all this stuff a while back while trying to decide which way to go, so I don't have it handy any more.

There are several good threads in the High Performance forum, including this one:

www.rcgroups.com/forums/showthread.php?t=929170

From memory there's also good info in the radio forum.

I would try searches on 2.4 and carbon, and also 2.4 and coax .

I'm lucky in that all my planes are 2.4 friendly, but the info is there and so are the real-world results, including the fact that a lot of guys flew 2.4 at the F5B worlds which are just completed, and they had zero problems. If it works reliably in an insanely-high-powered electric with carbon fuse it'll work anywhere.

Andrew,

I have put it together (dead easy) but not tried it yet - pressures of work as I'm sure you'll understand.

Ken.